Frankenplenum

[LGAFF]

Several years ago I bought a plenum from phrogs that was missing the MAP sensor ears. I Siamesed that the Inj housings and the heads....with small intake cams(222 .415 primary/236.425 secondary) I made 441RWHP/7100RPM; that's untuned.

Since then I ported the inside of the plenum removing all of the water passages and guts(There are significant blockages to the #1 and # 2 intake ports, etc. Added a 63MM TB.....

I decided that now I am going to add volume to the plenum; I will be cutting off the roof unshrouding the runners adding an inch, and cutting the bottom off and doing the same.

I am also going to do some air intake testing.....I know people say there is nothing there, but I want to try a few ideas.

Here is where I started with the Siamese
http://i134.photobucket.com/albums/q115/lgaff/DSCN3804.jpg

[Bearly Flying]

Sounds like an interesting project, Lee.

Have fun and Good Luck.

[LGAFF]

The LT-5 Plenum is know to be too small.....on a manual trans car you really want at least 1X the CI of the motor, some say 1.5X. I also know that in testing larger plenums did better during engine development....approximately 55-80 additional cubic inches are needed.

A lot of people told me the plenum roof would not clear the hood, however I have 1.14inches in the front and 2" in the back. I think the issue is raising the entire plenum and not just the plenum body....the runners might hit the outside of the raised section of the hood; but the plenum box has room...I also have no AC.

I would like to have unshrouded the #7/#8 runners but the fuel rail is a challenge

[Blue Flame Restorations]

I like it when someone tries to do what others say they shouldn't.

[efnfast]

Lee, keep in mind the engine twists when you accelerate, it will lift one corner. Sounds like you'll be real tight. I like where you're headed with this. MORE POWER wuh-wuh-wuh.

[Bearly Flying]

A High Rise Hood would solve some of the height issues.

Be interesting to see what could be done.

Keep Us posted, and We like pictures.....

[Paul Workman]

Interesting project. I've been pondering something similar; thinking about using a split air box, vis a vis the Coyote's "Y" approach and straightening the runners; reducing that (90º) bend into the IH. (I believe it was Grahm (?) that said they were able to increase the 90 LT5 output to something well north of 430 chp by straightening out those runners some, IIRC. But, anyway, let's face it: GM isn't going to be coming up with anything for the LT5s. It's up to us ZR-1 loyalists to do it. And, so learning from what others are doing with the DOHC motors is a good place to take notes, I recon!:cheers:)

[phrogs]

Put some silly putty under the hood and see if it touches anywhere.

It might hang on long enough haha

I remember that plenum.
Pretty sure it came out of tommy morrisons stash

[LGAFF]

Way ahead of you phrogs, nabbed my daughters playdo and checked it...put the enture can shape on the plenum and dropped the hood. lots room

[tccrab]

Lee:

What about those people who put on the phenolic plenum spacers some years ago complaining about rubbing holes in the hood?
If I recall correctly, those spacers were only 1/2 inch or so, surely what you've got planned will need more room than that.

'Crabs

[Hog]

I wonder if eliminating the common plenum entirely would be of benefit? This would require 8 t-bodies. and 8 velocity stacks. I always wondered how those systems on teh older hot rods really worked. Individual runner length is easily individualized.

Complex as all heck, but would look cool poking through the hood!

[Paul Workman]

Yup! A sheet metal box(s) with shortish curved (funnel) runners... I haven't crunched the numbers yet for the runner/air box dimensions yet, but a Toledo hood (or the like) is prolly going to be part of the answer.

[LGAFF]

Lee:

What about those people who put on the phenolic plenum spacers some years ago complaining about rubbing holes in the hood?
If I recall correctly, those spacers were only 1/2 inch or so, surely what you've got planned will need more room than that.

'Crabs


I wonder if the runners are hitting, I am only raising the box...

As far as run a velocity stack setup, shorter runners make it more difficult to keep the car at idle.

[Dime]

It makes me happy to think that an aftermarket plenum may one day be made available by a savvy member of the brotherhood that will give our cars even more umph. :happy1:

[Bob Eyres]

Lee:

What about those people who put on the phenolic plenum spacers some years ago complaining about rubbing holes in the hood?
If I recall correctly, those spacers were only 1/2 inch or so, surely what you've got planned will need more room than that.

'Crabs

I'm one of those people. They're still on there. The spacers are only 1/4", and it does rub enough to take the under hood paint off at the front.

This sounds like a job for one of those 3D printers...a big one that can use some heat resistant plastic.

[LGAFF]

What part of the plenum is rubbing?

[XfireZ51]

Yup! A sheet metal box(s) with shortish curved (funnel) runners... I haven't crunched the numbers yet for the runner/air box dimensions yet, but a Toledo hood (or the like) is prolly going to be part of the answer.

Pete used a Hogan sheetmetal plenum on Kevin's 441 several years ago. I believe it really didn't offer much improvement.

[LGAFF]

Pete used a Hogan sheetmetal plenum on Kevin's 441 several years ago. I believe it really didn't offer much improvement.


I wonder if the volume was sufficient...also velocity stacks might have helped flow....intake runners that share a wall with the plenum generally have flow opportunities....

[-=Jeff=-]

Pete used a Hogan sheetmetal plenum on Kevin's 441 several years ago. I believe it really didn't offer much improvement.

I wonder if the volume was sufficient...also velocity stacks might have helped flow....intake runners that share a wall with the plenum generally have flow opportunities....


But that Hogans was a short runner intake.. Lee is looking to keep the runners as they are and expand the 'box' if I understand it correctly

[LGAFF]

But that Hogans was a short runner intake.. Lee is looking to keep the runners as they are and expand the 'box' if I understand it correctly

Correct, in terms of the plenum volume I had 2 Engineers from the program tell me thats were the most potential was; and in looking at intake development on Porsche, Audi, and the Coyote motor I saw comments on flow improvements on "unshrouding" runners from an intake ceiling/wall.

I will also add that there was a ZR-1 race car with a raised roof plenum in another country with a documented 15hp increase due unshrouding of the roof side of the runner.

[-=Jeff=-]

Is this for the black car? if so.. wanna sell your hood?

[LGAFF]

My hood has chipping paint in the center, someone dropped the hood on something at some point, but I am keeping the stock hood

[Bob Eyres]

What part of the plenum is rubbing?

The parts that scrape are, the ribs on the plastic intake duct, and I'm not sure what you call it but it's the sheet metal shroud around the throttle mechanism. The actual plenum does not hit.
The intake duct ribs could be swelled up a bit from stock because I have one of Mark Colplon's stainless liners inside it.

Both of these areas aren't real bad. Just enough to take the paint off, not enough to scratch the fiberglass.

[LGAFF]

Good feedback, thanks Bob!

[tpepmeie]

Pete used a Hogan sheetmetal plenum on Kevin's 441 several years ago. I believe it really didn't offer much improvement.

I can offer an opinion on that sheetmetal intake. I did have it flow tested, and it was 2 to 6 cfm better than my (highly) modified plenum and housings. That was with the TB and Airhorn attached, and the other ports taped.

From what I remember, Pete and Kevin said it lost a ton of torque almost all the way through the rev range, only crossing over >7000 rpm. I could be wrong on that--its been awhile.

Why? My belief is two factors. 1) the runner cross section area was pretty big. I didn't measure it, but visually, most of the runner was oval with no divider. Only like maybe an inch at the head was two separate holes. 2) the runners were exceptionally short, as they have to be for hood clearance in that style of manifold. We need runner length to catch the stronger harmonic waves for best cylinder filling. That's why I didn't go to a sheetmetal manifold on the 427. The stock runner length is pretty good for the rev range we need. Downside is that the runners have to contort to get that length without too much height, if that makes sense.

Anybody got $10k to develop a cross-over style IR manifold?

:cheers:

Seriously, Lee is on the right path by enlarging the plenum. We need more volume for the big motors. Especially because the TB is undersize when you get to that level. I saw over 1" of manifold vacuum @ 7000 rpm. A large plenum box would crutch that a little. Of course, a big billet oval throttle body will help too :-D

[LGAFF]

[QUOTE=tpepmeie; a big billet oval throttle body will help too :-D[/QUOTE]


Cobrajet is running a single blade 1640cfm TB

Also remember the LT-5 Dogbone TB; not only was it bigger, but it pushed air down the center of the plenum to better balance airflow to the rear runners.

http://i134.photobucket.com/albums/q115/lgaff/DCP_1509.jpg (http://s134.photobucket.com/user/lgaff/media/DCP_1509.jpg.html)

[LGAFF]

Raised/Dropped plenum should compliment my straight through air horn

http://i134.photobucket.com/albums/q115/lgaff/DSCN5715.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN5715.jpg.html)
http://i134.photobucket.com/albums/q115/lgaff/DSCN5717.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN5717.jpg.html)

[Pete]

With the Hogan's we did loose some low end torque about 20 when you make 450 @ 3500 and you loose 15-20 you barely feel it,anyway the more low end you make the harder it is to stick it to the ground.:)
The low end has nothing to do with high speed runs (1/2 or 1 mile) or even 1/4 after your 60ft.

This was in an automatic and drove just fine could not notice a difference.

It did raise the power to 7k rpm from 6800 it gained 12-14RWHP.

Lingenfelter has sown that we need more plenum volume.
The work that goes into it,is not cost effective,among other issues.

It's like we went from Tune Port Intake to LT1 intake.

Pete

[SAM/CH ZR-1]

I don't think to increase the plenum volume will bring a significant benefit. The intake has to many corners and angels. That restrict the airflow. The size limited trottle body and airhorn are additional air restrictors.

With our racing team we removed on a 350 cui LT5 the plenum and installed single runners and put our eye on the correct runner volume, lenght and shape. With stock compression ratio and stock cams but fully ported heads we got around 580 crank HP at 7'500 rpms. It was our first build LT5 for the 2014 racing season. We did first steps and are satisfied with the results.

For the coming season we design new runners and cam profiles and continue our researches.

I hope to see some of you guys this May in BG.

[LGAFF]

I anticipate 15hp or so...its actually already been proven when they were developing the LT-5

[tpepmeie]

I anticipate 15hp or so...its actually already been proven when they were developing the LT-5

On a 350 cu in. engine? Call me skeptical. I think this really benefits the bigger c.i. engines when the TB becomes a restriction. Not sure you'll see that much on a smaller engine. Interested in what you get, nonetheless.

[LGAFF]

How big was the plenum on that Aurora V8 indy motor.....opinions vary but some say you need a minimum of 1ci of plenum to 1ci of motor....some say 1.5. Really what you are trying to do is come as close to atmosphere as you can...we will see.

[LGAFF]

http://www.can-amcarsltd.com/photo/engine_aurora.jpg

[LGAFF]

http://rejsa.nu/im/_annat/12288-new_2008-07-22-bild_006.jpg

[LGAFF]

From Enginelabs....just so one thinks I am full of ****; Todd Berry Custom intake manifold designer

Berry mentions that with custom intakes, the volume of an intake plenum generally matches the displacement of an engine. This means if an engine displaces 500 cubic inches, then the volume inside the plenum is typically going to also have a volume of around 500 cubic inches. Under this type of design, ideally no cylinder is starved for air because the volume inside the plenum is enough to fill all the cylinders simultaneously.
If the volume of the intake plenum is not properly matched and is too small for the application, an engine could develop a stall or sluggish response from an engine at the starting line or after each shift, as combustion events literally draw all the available air from the manifold faster than it can be filled by incoming air. Engines with too small of a plenum may perform well at lower RPM but suffer as RPM increases

[LGAFF]

As I stated, I spoke to two lotus developers on the LT-5, they said best results came with a plenum 1 liter larger than stock. Minimum to start with is 350cu...

[Bearly Flying]

That's quite the set of exhaust headers on the Aurora.

You might have trouble fitting them into your ZR-1.... lol....

Keep up the Good Work Lee,

[LGAFF]

Convertible LT-5

http://i134.photobucket.com/albums/q115/lgaff/DSCN6197.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6197.jpg.html)

You can see the roof sat right on top of the runner

http://i134.photobucket.com/albums/q115/lgaff/DSCN6199.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6199.jpg.html)

[XfireZ51]

How big was the plenum on that Aurora V8 indy motor.....opinions vary but some say you need a minimum of 1ci of plenum to 1ci of motor....some say 1.5. Really what you are trying to do is come as close to atmosphere as you can...we will see.

When doing dyno runs, one thing to look at is the MAP value. This can indicate if there is restriction somewhere ahead of the intake. In the runs I have recorded on my 5.7L, kPa at WOT ~ 97-98 and it doesn't drop hardly at all after peak.
That's pretty close. I also check my KEY ON MAP signal because unless u are at sea level, your MAP won't be at 100kPa anyway.
I'm a bit skeptical like Todd but it's good to have someone like you Lee who'll test it out.

[LGAFF]

Quotes from LT-5 Engineers

"Lee,
As you rightly say splitting the plenum would lend itself more favorably to even cylinder firing events. The net result of doing this on the LT5 plenum would be more torque up to around 2-3k rpm and less everywhere else. As an aside the LT5 is inherently compromised on plenum volume for high rpm operation in its stock form."


"Hello Lee, we found the best results were from adding a liter of volume to the plenum"

[LGAFF]

I don't know what will happen, but its a 90 Z with 144K miles on it, and a bunch of parts that I got hacked up....so nothing to lose. Possible my cams might be a restriction...and the fact that the heads narrow to 32.5 on the primary ports as they enter the head.

We will see....good times :)

[LGAFF]

I think the plan will be to weld 1/2 solid square stock to the intake opening, then build a lid to make it modular as new Holley Hi Ram LS intake is....

this will allow for volume variance, as well as testing divided plenums, etc....

Will also ensure when its welded up I can check the runners and clean them up

[-=Jeff=-]

If you need to cut the hood on the black car.. I will trade you hoods before cutting

[Bearly Flying]

Would there be any advantage to extending the individual runners into the plenum, ala the LS series of intakes?

[batchman]

Or in adding the volume in the valley, after having removed A/C, relocated coils, removed secondary actuators, re-done PCV?

A lot of room under there, too bad you can't readily relocate the starter or alternator...

Hmmm,
- Jeff

[LGAFF]

Tacked a few 3/8 steel plates together, getting reading for the welder

Yes they are ugly welds:)

http://i134.photobucket.com/albums/q115/lgaff/DSCN6228.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6228.jpg.html)

[LGAFF]

Plan will be to weld 1/2 X 1 inch flat stock or 1/2 X 1/2 square stock to the edge....then build a top with 1/2 inch stock, will need to check for clearance on the outer edge first

http://i134.photobucket.com/albums/q115/lgaff/DSCN6234.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6234.jpg.html)

[cvette98pacecar]

Lee, You are going to have to create a way to cool the Aluminum faster as you TIG or you will warp the flanges. The 3/8" Steel that you are bolting to the plenum will not move heat fast enough to keep the flange from warping.

[LGAFF]

Its actually two 3/8 plates welded together.....I will let the welder address the cooling, he did my Airhorn and no issues.

[FU]

Volume !!

[LGAFF]

I actually thought about doing this completely with high temp panel bonding epoxy...still might

[LGAFF]

Mocked up some 1/2X1/2 and checked hood clearance, good so far

http://i134.photobucket.com/albums/q115/lgaff/IMG-20150207-00224.jpg (http://s134.photobucket.com/user/lgaff/media/IMG-20150207-00224.jpg.html)

http://i134.photobucket.com/albums/q115/lgaff/IMG-20150207-00222.jpg (http://s134.photobucket.com/user/lgaff/media/IMG-20150207-00222.jpg.html)

http://i134.photobucket.com/albums/q115/lgaff/IMG-20150207-00223.jpg (http://s134.photobucket.com/user/lgaff/media/IMG-20150207-00223.jpg.html)

[rkreigh]

I remember some of the early 415 had the drop plenum mod that was supposed to be worth 10-15 hp on the big 415. I believe raising the runners and adding more volume will help and is a better way to go, but not enough to be worth much more than 15-20 hp

kirchoffer spent a ton on a box ram on his big 421 and it didn't seem to work nearly as well as I would have thought. it had a pretty big "plenum box"

with the "s turn" in the LT5 intake, I prefer the the ITB option. now that OBX has a 1300 setup for the LS1, use that as a starting point and cast up or fab some new base plates for the LT5

I spoke to graham about this and much like the lotus "caliope" stacks they used on the race car this a 4500 up mod, and low rpm thottle response can be a bit abrupt and hard to control the big "stacks" can really kill low end torq so you need some gears to get it rolling

my LPE has the crazy "bifurcation" manifold where they saw in half to do a better job of porting

they did a nice job of dressing the welds and keeping it straight

so, if we "scrap" the manifold and go ITB why not go the extra mile and raise the port? I saw an old ford where they filled the bottom of the port with epoxy and ground away the port roof and used thick billet "plates" recessed into the head

this provides a very high velocity straight shot with a low profile crab style ITB

tuning would be a challenge to be sure as you get LOTS of airflow with little throttle movement and the car will really jump!!

I thought about putting an ITB on the old LS1 in a C3 for sex appeal

the OBX stuff is beyond cheap and looks to be of good quality

nothing like the inglese but still very nice! borla does this stuff too

as small as it is, you could 3d print" the adapter manifold to make the ITB work with the LT5 head and it would likely be strong enough to work just fine

sounds like fun!!

[cvette98pacecar]

I remember some of the early 415 had the drop plenum mod that was supposed to be worth 10-15 hp on the big 415. I believe raising the runners and adding more volume will help and is a better way to go, but not enough to be worth much more than 15-20 hp

kirchoffer spent a ton on a box ram on his big 421 and it didn't seem to work nearly as well as I would have thought. it had a pretty big "plenum box"

with the "s turn" in the LT5 intake, I prefer the the ITB option. now that OBX has a 1300 setup for the LS1, use that as a starting point and cast up or fab some new base plates for the LT5

I spoke to graham about this and much like the lotus "caliope" stacks they used on the race car this a 4500 up mod, and low rpm thottle response can be a bit abrupt and hard to control the big "stacks" can really kill low end torq so you need some gears to get it rolling

my LPE has the crazy "bifurcation" manifold where they saw in half to do a better job of porting

they did a nice job of dressing the welds and keeping it straight

so, if we "scrap" the manifold and go ITB why not go the extra mile and raise the port? I saw an old ford where they filled the bottom of the port with epoxy and ground away the port roof and used thick billet "plates" recessed into the head

this provides a very high velocity straight shot with a low profile crab style ITB

tuning would be a challenge to be sure as you get LOTS of airflow with little throttle movement and the car will really jump!!

I thought about putting an ITB on the old LS1 in a C3 for sex appeal

the OBX stuff is beyond cheap and looks to be of good quality

nothing like the inglese but still very nice! borla does this stuff too

as small as it is, you could 3d print" the adapter manifold to make the ITB work with the LT5 head and it would likely be strong enough to work just fine

sounds like fun!!


Ron, I could not agree with you more. The OBX ITB is one of the sexiest pieces of equipment that I have seen to date. With the fuel lines on top of the ITB it opens up a lot of room to reconfigure the current IH and build a new plenum.
One of these years I am going to be done with all my LT5 and I am going to install one of these on my 98PC

http://i1199.photobucket.com/albums/aa468/rdemarco06/Open/KGrHqZHJE0FF11PzSwvBRhUbc8760_57_zpscd155fc4.jpg (http://s1199.photobucket.com/user/rdemarco06/media/Open/KGrHqZHJE0FF11PzSwvBRhUbc8760_57_zpscd155fc4.jpg.h tml)

[FU]

Just an idea.......

https://www.youtube.com/watch?v=t7ils9Ir7EM

[XfireZ51]

Something like this.

http://i173.photobucket.com/albums/w80/shermannelson/DSCF7017.jpg

[Tony Davila]

Has anybody ever thought of putting a bifurcation into the runner up into the plenum open area? Making the length of the runner individually longer just like a Tune Port intake. I wonder if it would give more bottom end.

Just wondering.

[cvette98pacecar]

Something like this.

http://i173.photobucket.com/albums/w80/shermannelson/DSCF7017.jpg

Dom, Do you still have the Cross fire plenum?

[XfireZ51]

Dom, Do you still have the Cross fire plenum?

Robert,

No I don't. Haven't had it since I bought the ZR. Should be fairly easy to come by if you want one.

[batchman]

I've wondered what goes on inside the plenum, is post #52 stock inside?

I would think there could be some merit in taking an approach found on SHOs and late four-valve 4.6s: differing runner lengths for the 2 valves.

Adding something like a french cut exhaust tip on 1st, 4th, 5th and 8th runner one side, maybe 3-4", with the opposing one offset to the other valve. Hope I'm describing this reasonably.

Just a thought,
- Jeff

[Mr Blue]

Something similar to the Ford / Yamaha SHO plenum might be interesting. Long runners on the primaries and short direct runners for the secondaries. Hood clearance would be a nightmare, but that engine ran extremely well for 3.0 L.
David

[Z06scentair]

Something similar to the Ford / Yamaha SHO plenum might be interesting. but that engine ran extremely well for 3.0 L.
David

Yes it did!

[LGAFF]

The nice thing about the removable top is I can try several different things...divided plenum, reduced runner length, air horns/stacks...maybe even a clear top just for shits and giggles

[rkreigh]

at BG when kirchoffer fired up the cammy 421 we could see the top which looked like it was made out of a 1/4 plate of nice alum (about 2 ft by 20 inches or so) would flex and pop like a beer can

it was pretty amazing, but it didn't deliver the big hp hoped for and it was a solid looking design with nice taper built into the runners, injectors on the outside, and a big plenum box

I'm more enamoured with the look and audaciousness of the cross ram individual throttle body

those big caliope stacks bring back memories of screaming big blocks at the drags in little altered cars and some door slammers only the blower cars were cooler!

the injector housing creates a rather torturous path with the s bend

cutting up and rewelding the OBX would be a major chore, but it's cost effective would look like the corvette racers (which have beautiful carbon fiber cross rams)

with the 3d printing technology, we could print up and individual base and then cast it. with the right media, like a heavy nylon plastic, it would probably work right off the printer with a heat insulating gasket

anyone want to give this a go? tuning will be tough, me thinks the megasquirt piggy backed into the factory ecm to run the spark and injectors would do nicely there

I may yet try one of these on my c3 to see how well it works out on a little screamin 4.8 iron block

the short stroke revs up nicely and the car is light enough to make this work

cheers!

[LGAFF]

http://i134.photobucket.com/albums/q115/lgaff/Frak.jpg (http://s134.photobucket.com/user/lgaff/media/Frak.jpg.html)

[cvette98pacecar]

http://i134.photobucket.com/albums/q115/lgaff/Frak.jpg (http://s134.photobucket.com/user/lgaff/media/Frak.jpg.html)

Lee, how about a photo from the front and side Horizontally to show the height.

[LGAFF]

I will get one, have not picked it up yet...put it should have added 1/2 inch or so...will get some this weekend

[Tony Davila]

http://i134.photobucket.com/albums/q115/lgaff/Frak.jpg (http://s134.photobucket.com/user/lgaff/media/Frak.jpg.html)

It looks like you are building or modifying the intake just like this ZR-1 that is in Japan. Keep it up, I'm watching how it turns out.
http://i69.photobucket.com/albums/i66/Zrace1/wmzevetwlei5niyer5fr_zpsvb9rhpir.jpg
http://i69.photobucket.com/albums/i66/Zrace1/d7telktwyweexrhhsh70_zpsnhrmwnbf.jpg

[LGAFF]

We will address cosmetics with epoxy at some point to make it "prettier"

http://i134.photobucket.com/albums/q115/lgaff/DSCN6290.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6290.jpg.html)

I matched the curve on the back with alittle finesse and a vise

http://i134.photobucket.com/albums/q115/lgaff/DSCN6288.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6288.jpg.html)

[LGAFF]

The runner no longer is part of the wall at the top which will help flow also

http://i134.photobucket.com/albums/q115/lgaff/DSCN6293.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6293.jpg.html)

[cvette98pacecar]

Lee, check to see how much clearance you have from the front of the throttle body to the hood. If you have room and you are doing this many mods you may want to raise and center the TB with the center of the plenum.

[LGAFF]

They picked up 15hp with this slight change in the plenum roof

http://i69.photobucket.com/albums/i66/Zrace1/wmzevetwlei5niyer5fr_zpsvb9rhpir.jpg (http://s69.photobucket.com/user/Zrace1/media/wmzevetwlei5niyer5fr_zpsvb9rhpir.jpg.html)

[cvette98pacecar]

It looks like you are building or modifying the intake just like this ZR-1 that is in Japan. Keep it up, I'm watching how it turns out.
http://i69.photobucket.com/albums/i66/Zrace1/wmzevetwlei5niyer5fr_zpsvb9rhpir.jpg
http://i69.photobucket.com/albums/i66/Zrace1/d7telktwyweexrhhsh70_zpsnhrmwnbf.jpg

I just noticed that car has Gen 2 Dymags

[Locobob]

They picked up 15hp with this slight change in the plenum roof

http://i69.photobucket.com/albums/i66/Zrace1/wmzevetwlei5niyer5fr_zpsvb9rhpir.jpg (http://s69.photobucket.com/user/Zrace1/media/wmzevetwlei5niyer5fr_zpsvb9rhpir.jpg.html)

Interesting.... what all do you know about this motor?

[LGAFF]

I want to say its a 380-385 ci car, no mention of cams if I recall.

[LGAFF]

Looks like is 402-408ci

[Pete]

Lee, the 15 HP gains does not necessarily mean it's the height of the plenum.
Lingenfelter was also getting 15HP but he went the other way (under) on big inch motors.

What this tells us is plenum volume is not enough no matter which way you go up or down.

Test this at the track (same day) do some runs with a nicely ported plenum then change out to this plenum,better yet i'd like to try it on my Z.

Then if it gains performance i'll just drive away with it. :-D

Pete

[LGAFF]

It is a crap shoot....plus lets consider who is building it(me) ...so another factor. its also not so pretty....but I am not spending a fortune on it either($125 in it as it stands). Will be interesting to test.

[LGAFF]

For those who are quick to dismiss the increase in plenum size due to it being only a 350

http://www.hotrod.com/how-to/engine/ctrp-1202-intake-manifold-secrets-when-bigger-really-is-better/

"We tried it on a 303ci motor, a 358, and a 370, and the results were all about the same. The three motors didn't have the same peak power numbers but they all improved by about the same percentage.

[mgbrv8]

Good old West racing. Ledgend has it they have played with flat plane cranks in LT5s ;-)

https://www.facebook.com/video.php?v=10201883569317756&l=1458715605822403339

Dave Hetrick



It looks like you are building or modifying the intake just like this ZR-1 that is in Japan. Keep it up, I'm watching how it turns out.
http://i69.photobucket.com/albums/i66/Zrace1/wmzevetwlei5niyer5fr_zpsvb9rhpir.jpg
http://i69.photobucket.com/albums/i66/Zrace1/d7telktwyweexrhhsh70_zpsnhrmwnbf.jpg

[LGAFF]

Pete if you read up on the car, they actually state the intake change gained 15RWHP over the prior test

**if you are saying its doesn't prove adding to the top vs bottom adds HP; I would agree you cannot tie the gain back to where the volume was added

[NVMYRC51]

So I see that somebody mentioned a 3D printer. I don't know that much about them but is that, or maybe in the near future, a possibility? I was thinking more for a weight savings and possibly straightening out lines etc? Any thoughts?

[rkreigh]

So I see that somebody mentioned a 3D printer. I don't know that much about them but is that, or maybe in the near future, a possibility? I was thinking more for a weight savings and possibly straightening out lines etc? Any thoughts?


the 3d printing with the right materials is what makes a cross ram style manifold even more appealing.

or fab up some short oval "adaptors" and buy the obx

it would be much better to "print" the adaptor as you could get exactly the shape and port contour you want to transition from the round throttle body to the lt5 head shape what would really be cool is to retain that shape like the "mono runner" modified manifolds and use an oval throttle body for EACH of the runners

for now the obx with a custom fabbed "base" would work if you are willing to go with a Toledo pro hood for clearance

I believe the throttle response would be glorious but hard to control

with the little tiny primary on the LT5 I've always felt like the engine would benefit from having that hole ported too and I really like the "goggle valve" secondary as it seems it would reduce a lot of turbulence and promote better intake filling

anyone handy with a 3d printer? I might mock it up with balsa blocks to get the shape

as soon as I saw that OBX cross ram pictured in the early thread the gears started turning.

don't know if I'll make it to BG or not, just got a new job, but I hope to.

let me know if there are any last minute rooms!

[rptech]

So I found this post very appealing. I own several commercial 3D printers, and ironically just finished 3 different intakes for a race teams big block chevy. What I usually do on something like this is scan the existing manifold (Reverse engineer). This gives me CAD data of the of all the factory geometry. For those of you that are not familiar with the design engineering world, this basically means I now have the factory manifold digitally recreated on my computer screen in 3D. I can then manipulate the design, building off the existing port geometry to create the new plenum and runners.
From my new CAD model, I can then do a CFD analysis to see how well it flows in the virtual world. This eliminates the cost of just blindly making parts until you find a design that works. We find all those gains/deficiencies on the computer before we build a physical part. From here I now send this data to my rapid prototype machine, or 3D printer as they are called by most people now, and print my new manifold out in plastic (FDM). These can then be mounted, and ran on a dyno. The ABS plastic usually does not last long though due to deformation from the heat. They do however last long enough for the testing required to validate our virtual data results.
Once the design is optimized, the plastic prototype can be used to create an aluminum casting for a permanent part. OR, hold onto your shorts, we can now actually print out these permanent parts in all kinds of different metals (DMLS) that are as strong as what would be manufactured using the traditional casting methods that created what came on your car. It is amazing what we can do these days. The technology is mind blowing.
Sorry to bore everybody this early in the morning- was anybody able to stay awake for that long boring dissertation? LOL

[LGAFF]

So when are you printing the lid for my plenum:cheers:LOL

[rptech]

I replied via private message.

[FU]

I (we) need to look into this plenum idea , 441 inches needs more intake than it's getting now :-D:-D

[XfireZ51]

Not boring at all! This is exciting stuff that opens up some new avenues.

[batchman]

hold onto your shorts, we can now actually print out these permanent parts in all kinds of different metals (DMLS) that are as strong as what would be manufactured using the traditional casting methods

Whoa. Rapid Prototyping directly in Metal. The world just changed.

Not boring!
- Jeff

[cvette98pacecar]

So I found this post very appealing. I own several commercial 3D printers, and ironically just finished 3 different intakes for a race teams big block chevy. What I usually do on something like this is scan the existing manifold (Reverse engineer). This gives me CAD data of the of all the factory geometry. For those of you that are not familiar with the design engineering world, this basically means I now have the factory manifold digitally recreated on my computer screen in 3D. I can then manipulate the design, building off the existing port geometry to create the new plenum and runners.
From my new CAD model, I can then do a CFD analysis to see how well it flows in the virtual world. This eliminates the cost of just blindly making parts until you find a design that works. We find all those gains/deficiencies on the computer before we build a physical part. From here I now send this data to my rapid prototype machine, or 3D printer as they are called by most people now, and print my new manifold out in plastic (FDM). These can then be mounted, and ran on a dyno. The ABS plastic usually does not last long though due to deformation from the heat. They do however last long enough for the testing required to validate our virtual data results.
Once the design is optimized, the plastic prototype can be used to create an aluminum casting for a permanent part. OR, hold onto your shorts, we can now actually print out these permanent parts in all kinds of different metals (DMLS) that are as strong as what would be manufactured using the traditional casting methods that created what came on your car. It is amazing what we can do these days. The technology is mind blowing.
Sorry to bore everybody this early in the morning- was anybody able to stay awake for that long boring dissertation? LOL

I have a Simese plenum and IH if you need to use it for scanning.

[rkreigh]

we could likely mock up something in fiberglass and light plywood that could be scanned for the base for an obx cross ram

I was looking into a "transition runner from a mono style port over the the 2.25 or whatever size the obx throttle body is

this would allow positioning of the throttle body at exactly the right angle and might even allow a shorty cross ram to clear the hood which would be desirable

I also have a fabricator that can do it in sheet alum, but the 3d print would be SOOOOO much more precise and better

can you do a high temp plastic that would hold up to the temps???

that would be even better as it would isolate the throtte bodies from the heat

my LPE manifold may soon be up for sale! like to try this with a MS just running the fueling and coil on plug ignition and leave the factory stuff intact with the ecm

I think it would work pretty slick and you would only need 1 injector of the correct size I'm going to try a 50 lb as it would still idle good and provide plenty of fuel

robert, you in??

[NVMYRC51]

Man I gotta tell you this is interesting and not boring at all. I can just imagine a 3D printed plenum that is at the max specs and/or customized as you guys are all taking about. The ability to flow test in the virtual is amazing. So I see some messages have been exchanged, mock ups are being discussed, avenues of approach to improve on the existing plenum but here is my question: what kind of cost are we talking about? If we had a viable model that we wanted to attempt to print in whatever metal would suffice would it be prohibitively expensive to do?

Craig,

PS: Guys we have to keep this on the front burner. The leaps and bounds that are going on with 3D printers is super exciting for any of us that have cars that need or may need in the future specialty parts that can't per se be fabbed. Our "savior" may be at hand.

[cvette98pacecar]

we could likely mock up something in fiberglass and light plywood that could be scanned for the base for an obx cross ram

I was looking into a "transition runner from a mono style port over the the 2.25 or whatever size the obx throttle body is

this would allow positioning of the throttle body at exactly the right angle and might even allow a shorty cross ram to clear the hood which would be desirable

I also have a fabricator that can do it in sheet alum, but the 3d print would be SOOOOO much more precise and better

can you do a high temp plastic that would hold up to the temps???

that would be even better as it would isolate the throtte bodies from the heat

my LPE manifold may soon be up for sale! like to try this with a MS just running the fueling and coil on plug ignition and leave the factory stuff intact with the ecm

I think it would work pretty slick and you would only need 1 injector of the correct size I'm going to try a 50 lb as it would still idle good and provide plenty of fuel

robert, you in??

Ron, I am in. I think if we can get 10 people involved the cost would be minimalized.

[LGAFF]

I think my thread got highjacked!

[cvette98pacecar]

I think my thread got highjacked!

We are not hijacking it, We are giving you alternatives. OBX builds a cross ram single TB per cylinder for just over $125.00 per cylinder. If we could get at Cross ram single TB for even $200.00 per cylinder that would be sweet.

[LGAFF]

http://i134.photobucket.com/albums/q115/lgaff/11106414_820540268038215_1260395809_n.jpg (http://s134.photobucket.com/user/lgaff/media/11106414_820540268038215_1260395809_n.jpg.html)

[cvette98pacecar]

http://i134.photobucket.com/albums/q115/lgaff/11106414_820540268038215_1260395809_n.jpg (http://s134.photobucket.com/user/lgaff/media/11106414_820540268038215_1260395809_n.jpg.html)

This is what I am talking about.

[Bearly Flying]

Actually Lee, You are the inspiration for this thread.

You gotta admit with 3D printing, it opens up a whole bunch of possibilities.

[rkreigh]

This is what I am talking about.
a

ohhhh yaaaazzzzzz the tuning will be a big cost factor as the obx style runner will need lots more tip in fuel

lee, sorry to hi jack we really should start another thread

thanks for the pics, that setup just needs to "lay down" just a bit so we can get it under the hood

I'm noit wanting to go to the toledo but that for sure would be an option

the obx is only like 1400 or so On the bay, a good fabricator should be able to update the base with sheet alum for about 20-30 hours roughly

if I build it out of plywood (no I'm not joking) I can mock it up and we can scan it not sure what a "print in the cloud" will cost but there are many companies that offer the service and having a mocked up part that they know will fit should be fine

Honestly I think a fabbed up thick sheet alum base will end up being the best approach but it will be more expensive to fab up

I'm hoping a high temp plastic media comes out for 3d printers as that would be ideal. a phenolic resin is very strong and head resistant and would keep the inlet air nice and cool

phase II of course is the boxing of the end of the runners for a pair of hair dryers then I think I'll be done :dancing

now I just need the $$$

I'm selling a 68 vette which should get me there!

[batchman]

I think if we can get 10 people involved the cost would be minimalized.

I'd be all over anything that:

- saves weight (this is high and forward, best bang for reductions)
- improves mid-range power too (not just above 4k)

These factors have kept me from jumping on the normal updates, I don't often hit above 5.5k and if so it's only once/twice per run, as opposed to pulling from 2500-3500 a dozen times. I really need to start logging data somehow...

Extra points for reducing complexity, not sure ITB's really does that but man they are pure sex.

Panting,
- Jeff

[XfireZ51]

I like the idea of a twin plenum, dual TB Xram ala C6R.

[SAM/CH ZR-1]

I like the idea of a twin plenum, dual TB Xram ala C6R.

I would be interested too.

[NVMYRC51]

Hey Lee sorry it has been highjacked per se but your work has definitely been the inspiration and in my estimation is looking at a project from two different angles but ultimately chasing the same thing. I am very interested on how the frankenplenum will perform.

[RICKYRJ1]

Instead of plywood wouldn't it be better to mock it up out of foam? easier to work/sculpt with. I have no idea just putting it out there, I watch Velocity channel lol

[rkreigh]

yes, foam would work great for shaping the transition sections and the plywood would be for the base amd throttle body flanges

the marine ply is amazing stuff the thin stuff I use for model airplanes you can bend into a tube.

it would be strong enough to support the throttle bodies for fitting

[RICKYRJ1]

yes, foam would work great for shaping the transition sections and the plywood would be for the base amd throttle body flanges

the marine ply is amazing stuff the thin stuff I use for model airplanes you can bend into a tube.

it would be strong enough to support the throttle bodies for fitting

Cool, looking forward to how this works out. Good Luck to all involved in creating this piece. :cheers:

[-=Jeff=-]

Lee, don't hack up that hood.. if you are going to, I will trade you

[LGAFF]

Well Plenum is decked and now they are CNCing a lid for the top with recessed bolt provisions.

[NVMYRC51]

Hey Lee how close are you to any testing? Are you going to flowbench it or put it on and dyno?

[LGAFF]

I need to get the lid back, then off to Powdercoater....then to the dyno.

[Blue Flame Restorations]

http://i134.photobucket.com/albums/q115/lgaff/11106414_820540268038215_1260395809_n.jpg (http://s134.photobucket.com/user/lgaff/media/11106414_820540268038215_1260395809_n.jpg.html)

Holy schnikees!!!!!!!!!!!!!!!

[LGAFF]

Thats not mine by the way...

[Blue Flame Restorations]

Thats not mine by the way...

I sure do love that thing though. Maybe I should pit an LT5 in my GTP?

[XfireZ51]

I notice he has a crank trigger on the nose. I'd be interested in seeing the layout for the Crank Sensor and the mounting of it on front of block.

[LGAFF]

Pretty, uh....no..but....1" added to top of plenum..

http://i134.photobucket.com/albums/q115/lgaff/DSCN6301.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6301.jpg.html)

http://i134.photobucket.com/albums/q115/lgaff/DSCN6302.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6302.jpg.html)

http://i134.photobucket.com/albums/q115/lgaff/DSCN6303.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6303.jpg.html)
http://i134.photobucket.com/albums/q115/lgaff/DSCN6304.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6304.jpg.html)

[LGAFF]

http://i134.photobucket.com/albums/q115/lgaff/DSCN6300.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6300.jpg.html)

[XfireZ51]

So you think the TB has enough capacity to fill the additional plenum volume?
Or does that now become your choke point?

[LGAFF]

I think the TB will be fine at 63.5. Monoblade would be better, but I wonder if cams might be restrictive I have the split duration intake on these

[LGAFF]

Going to leave the lid as is....what color for the plenum base and IHs?

Silver or gloss black?

[LGAFF]

The lids roof is 1/2" thick

[SAM/CH ZR-1]

I think the TB will be fine at 63.5. Monoblade would be better, but I wonder if cams might be restrictive I have the split duration intake on these

A interesting Job. What are the cam specs if it's not a secret?

[LGAFF]

These are 222 .415 primary and 236 .425 secondary. The other cams I have are all 236 .425

[LGAFF]

Some Epoxy helps clean up the looks

http://i134.photobucket.com/albums/q115/lgaff/DSCN6305.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6305.jpg.html)

http://i134.photobucket.com/albums/q115/lgaff/DSCN6300.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6300.jpg.html)

[-=Jeff=-]

will it fit under the hood or will you need to cut the hood? remember I have one to swap if you are going to cut....

[LGAFF]

Here is a runner inside the plenum; its was mildly ported before; I am opening up the runners completely(This is a work in progress)

before
http://i134.photobucket.com/albums/q115/lgaff/DSCN6306.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6306.jpg.html)

After
http://i134.photobucket.com/albums/q115/lgaff/DSCN6307.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6307.jpg.html)

[-=Jeff=-]

Will this fit under the hood?????????

[LGAFF]

Going to be close, the lid is thicker than my original plan by 1/4 inch

[Bearly Flying]

Be interesting to see a dyno run after you get this manifold in service....

Good Luck Lee.

[XfireZ51]

Be interesting to see a dyno run after you get this manifold in service....

Good Luck Lee.

I would like to see an A/B comparison.

[LGAFF]

Going to leave the lid bare...what color should I make the rest of the plenum....I know its lipstick on a pig, but...

[-=Jeff=-]

Why not test it first, then worry about color..

[LGAFF]

Obviously test fit is in the plan.....going on one way or another

[-=Jeff=-]

Obviously test fit is in the plan.....going on one way or another

Well, that is not what I meant..

not Test Fit.. Test it, meaning.. why make it pretty if you put on and it makes the motor run worse..

I suggest test it out for a while first before making it pretty

[LGAFF]

She is about 1/4 too tall.......will shim the hood

http://i134.photobucket.com/albums/q115/lgaff/LT5tf_1.jpg (http://s134.photobucket.com/user/lgaff/media/LT5tf_1.jpg.html)

[-=Jeff=-]

just DON'T CUT IT!!!

I am telling you I will swap you if you are going to cut the hood

[LGAFF]

Runner no longer shrouded....roof of runner raised to reduce curve and 36mm all the way through

http://i134.photobucket.com/albums/q115/lgaff/DSCN6326_1.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6326_1.jpg.html)

Lipstick on the pig
http://i134.photobucket.com/albums/q115/lgaff/DSCN6317_1.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6317_1.jpg.html)

[LGAFF]

Inside Stock plenum
http://i134.photobucket.com/albums/q115/lgaff/DSCN6327.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6327.jpg.html)


http://i134.photobucket.com/albums/q115/lgaff/DSCN6326_1.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6326_1.jpg.html)

[-=Jeff=-]

those runners look as if they were sanded smooth prior to the black PC or is the PC really thick to make it smooth?

[LGAFF]

No black gloss really covers well...no sanding

[LGAFF]

Definitely going to need to shim the hood....and even take 1/4 inch out of the center of the plenum cover(its 1/2 thick)
http://i134.photobucket.com/albums/q115/lgaff/DSCN6329.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6329.jpg.html)

[-=Jeff=-]

Just dont cut that hood

[RICKYRJ1]

What are you looking to gain with this set-up? Looks very cool :flag:

[LGAFF]

Hoping to see an HP increase, would take 10-15hp...I think opening the inside runners and moving the roof away from the runner will help with flow....but I have been wrong before:)

[LGAFF]

"Frank" is up an running, need some new tires and will then do some testing

[Blue Flame Restorations]

:dancing

[XfireZ51]

Hoping to see an HP increase, would take 10-15hp...I think opening the inside runners and moving the roof away from the runner will help with flow....but I have been wrong before:)

Will you be posting Before and After dyno runs?

[LGAFF]

Yes

[XfireZ51]

Yes

SUPER!

[LGAFF]

By chance I opened up the oil fill cap and my upper chain guide faceplate has come off and is floating....:censored:

[SAM/CH ZR-1]

When will you go on a dyno? The german racing Team did a 2nd dyno run with impressive numbers.

[LGAFF]

Had Frank out last week.....running good....getting new Toyo Proxes TQs put on this week. Still one small oil leak(,ight be the oil sensor), but its about time to get to the dyno.

[LGAFF]

Dyno Test 9AM Monday:cheers:

@

http://www.dynotunemp.com/contact.html

[XfireZ51]

Dyno Test 9AM Monday:cheers:

@

http://www.dynotunemp.com/contact.html

Good luck. Waiting to hear results.

[LGAFF]

Seeing 99/100 KPA readings on my Tech one.....can't wait til tomorrow

When doing dyno runs, one thing to look at is the MAP value. This can indicate if there is restriction somewhere ahead of the intake. In the runs I have recorded on my 5.7L, kPa at WOT ~ 97-98 and it doesn't drop hardly at all after peak.
That's pretty close. I also check my KEY ON MAP signal because unless u are at sea level, your MAP won't be at 100kPa anyway.
I'm a bit skeptical like Todd but it's good to have someone like you Lee who'll test it out.

[LGAFF]

http://i134.photobucket.com/albums/q115/lgaff/DSCN6363.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6363.jpg.html)

http://i134.photobucket.com/albums/q115/lgaff/DSCN6367.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6367.jpg.html)

http://i134.photobucket.com/albums/q115/lgaff/DSCN6364.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6364.jpg.html)

http://i134.photobucket.com/albums/q115/lgaff/DSCN6371.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN6371.jpg.html)

[XfireZ51]

Lee,

Came out looking great. Excited to see the dyno results.

[LGAFF]

I will be curious to see myself....could be anything from a loss in power to significant gains. Crap shoot....fingers crossed for tomorrow.

I left the Corsa system on for apples to apples test.

Next dyno test will be a 3" ....and finally a tune

[-=Jeff=-]

What was the previous result? Prior to the plenum change?

[LGAFF]

Win some lose some; car lost power....only interesting piece was at 7400rpm the car was only down 8hp from peak.

Frank Set Up
426hp@7100
361 ftlbs


Siamase
441hp@7100
373 ftlbs

[LGAFF]

Car was running pretty fat

11.8 to 12.46 most of the run...

11.8-12.1 from 5100RPM to 6900

[LGAFF]

By the way....Jerrys intake bridge did not collapse...held up well

[XfireZ51]

Car was running pretty fat

11.8 to 12.46 most of the run...

11.8-12.1 from 5100RPM to 6900

So I don't think u arrive at any final conclusions just yet. But let's say w tuning u pick up 20. ROI looks thin.
I'm assuming peak was 7100 which says u moved that up ~ 200rpm.
Is this stock cams?

[LGAFF]

No these are the 222 .415 236 425 intake and 222 .415 exhaust cams

Peak was 7050 or 7100 on the run with 441rwhp

Here is the dyno sheet(This is from the 2nd run)

http://i134.photobucket.com/albums/q115/lgaff/1c9be747-6b2e-4749-9179-98079793be9d.jpg (http://s134.photobucket.com/user/lgaff/media/1c9be747-6b2e-4749-9179-98079793be9d.jpg.html)

[A26B]

By the way....Jerrys intake bridge did not collapse...held up well

I noticed you put the logo on top! =D>

Nice work on you concept and testing the results. Does look like you may have extended the power under the curve at the upper RPM range. That's useful!

[XfireZ51]

No these are the 222 .415 236 425 intake and 222 .415 exhaust cams

Peak was 7050 or 7100 on the run with 441rwhp

Here is the dyno sheet(This is from the 2nd run)

http://i134.photobucket.com/albums/q115/lgaff/1c9be747-6b2e-4749-9179-98079793be9d.jpg (http://s134.photobucket.com/user/lgaff/media/1c9be747-6b2e-4749-9179-98079793be9d.jpg.html)

OK, so peak didn't change from Siamese ports. I was also comparing peak HP w mine since cams are similar. My peak is ~ 6900rpms w 36.5mm plenum port and head runners that neck down from 36.5mm at the top, down to about 34mm by the bowl.

[XfireZ51]

Went back to look at the last time I tuned my setup specifically, what happened at 7100rpm. HP was pretty flat losing 4hp between peak of 6850 and 7100rpm.
That seems to suggest little contribution from added plenum volume BUT
the tune needs to be cleaned up before drawing any conclusions.

[LGAFF]

Hmmmm; divided plenum test?

http://i134.photobucket.com/albums/q115/lgaff/IMG_0428.jpg (http://s134.photobucket.com/user/lgaff/media/IMG_0428.jpg.html)

[Bearly Flying]

Might as well, Lee.

Hellofa project you have taken on.

Don't know that I would use cardboard tho..... Good Luck.

[LGAFF]

Thats called a template my friend:cheers::cheers:

[LGAFF]

Hmmmm.....what can I do with this thing? Any ideas?

[LGAFF]

Doorstop....Christmas tree stand?

[USAFPILOT]

Morph it into a supercharger?

[Billy Mild]

Morph it into a supercharger?

Roots type would be neat.