If/When you go to siamesed Intakes?

[alnukem]

In a conversation on Sunday, One of the evil influences, which shall nameless("ZZZZZR1") started talking about siamesed intake ports for a 385 cube engine. It got me wondering, when & what parameters to use this method. I do comprehend the concept of drawing from 2 ports. I am sure RPM & Engine Size dictates use, just curious when. And, if cylinder porting would be different. I doubt I would ever do, just curious how it is used. Thanks, Tim

[LGAFF]

I have one on my 350 w/cams.....have not been to the dyno but trust me no loss in torque.....pete drove it as well and came to the same conclusion. In fact, someone put it on a lift and checked the revolutions because they thought it has a 4.10 gear.

[Daniel_Mc]

..........("ZZZZZR1") stared talking about siamesed intake ports for a 385 cube engine...........

Now why would he go and do that?? ;)

Lee,

The set up on the 90 you did is pretty much where I want to go eventually. Good gains for the amount of work IMHO.

-Daniel

[Kevin]

Siamesed and dropped plenum on a 385 is sexy. We need to meet up soon

[LGAFF]

Pic after rough porting was done:

http://i134.photobucket.com/albums/q115/lgaff/156.jpg (http://s134.photobucket.com/user/lgaff/media/156.jpg.html)

Stock:

http://i134.photobucket.com/albums/q115/lgaff/152-2.jpg (http://s134.photobucket.com/user/lgaff/media/152-2.jpg.html)

[Kevin]

WANT!

[Schrade]

Anyone done a bench flow test on this?

[RHanselman]

Siamesed and dropped plenum on a 385 is sexy. We need to meet up soon

You are correct sir! Beware of the pretenders, unless it looks like this it's not a true siamesed plenum... This is my 93'

http://i1132.photobucket.com/albums/m578/rhanselman/SiaPlen.jpg

[Kevin]

you aint kiddin ron

http://i1181.photobucket.com/albums/x438/lt5zr180/DSC_0014_zpse4fd688c.jpg (http://s1181.photobucket.com/user/lt5zr180/media/DSC_0014_zpse4fd688c.jpg.html)

[LGAFF]

Ron, I would say this is more of a monorunner than siamesed.......they actually cut the runner out and reweld.....


You are correct sir! Beware of the pretenders, unless it looks like this it's not a true siamesed plenum... This is my 93'

http://i1132.photobucket.com/albums/m578/rhanselman/SiaPlen.jpg

[RHanselman]

Ron, I would say this is more of a monorunner than siamesed.......they actually cut the runner out and reweld.....

Ya Lee, that's a common mistake. No such thing as a mono-runner. The plenums pictured are referred to as Siamese’d. The plenums that have been joined internally only are referred to as a fully ported. Lot's of differance in flow and price...

Cheers,

[RHanselman]

TQ is still good on my 368

http://i1132.photobucket.com/albums/m578/rhanselman/DynoSheetlg.jpg

[alnukem]

Ron, You wouldn't have port pics, would you? Wow, lots more to know!

[Locobob]

I like to think of them as full siamesed or partial (figure 8) siamesed.... and then there is my B-port siamese :D

http://i418.photobucket.com/albums/pp270/locobob68/Head%20porting/P7120021.jpg (http://s418.photobucket.com/user/locobob68/media/Head%20porting/P7120021.jpg.html)

http://i418.photobucket.com/albums/pp270/locobob68/Head%20porting/P7120036.jpg (http://s418.photobucket.com/user/locobob68/media/Head%20porting/P7120036.jpg.html)

[LGAFF]

The Siamese port actually started with Gulstrand and then TPIS who both made a siamesed TPI runner....TPIS version was more like the one Locobob and I did.....

[LGAFF]

I will call it an infiniti port.........

[Schrade]

If it's mine, I'll call it what I want.

If it's yours, I'll call it what I want.

...................http://www.xnormal.net/Images/bananaDanceInverted.gif...


...

[LGAFF]

http://www.hark.com/clips/ggxynsnpxs-thick-as-peanut-butter

[batchman]

I would think the separation between runners would become important with respect to cam timing of the two valves - do they open in unison (stock cam) or is there a difference in cam timing?

- Jeff the curious, who will wind up with exactly one chance to get it right and still meet class rules....

[LGAFF]

I believe the stockers have some offset timing and lift, my regrinds have different lift and cam duration for primaries and secondaries...there is also a dog leg to one port that acts as a swirl generator

[tpepmeie]

It got me wondering, when & what parameters to use this method. I do comprehend the concept of drawing from 2 ports. I am sure RPM & Engine Size dictates use, just curious when. And, if cylinder porting would be different. I doubt I would ever do, just curious how it is used. Thanks, Tim

650 rwhp and the inj housings are still divided on mine, and only 35mm ports. The plenum runners are the figure eight style like Bob posted. Definitely not the welded mono style.

Different ways to skin the cat, bigger isn't always necessary. LPE got good power for the times with the mono plenum runners. However, if you've seen pics of their inj housings they were not siamesed either. Either "D" port on the secondary, or "double D" ports, from what I've seen.

Todd

[Schrade]

I would think the separation between runners would become important with respect to cam timing of the two valves - do they open in unison (stock cam) or is there a difference in cam timing?

- Jeff the curious, who will wind up with exactly one chance to get it right and still meet class rules....

This is a good question - the reason I asked if anyone has done flow test on the bench OR IN A LAB.

Airflow through the tubes - just like water flow - has dynamics - AEROdynamics. The column of air has LAMINAR flow - momentum, going through the tubes.

Introduction of turbulence can create eddies. But, DEPENDING on where it is in the intake mechanics, it can be good (think of GM's VORTEC induction), OR, it can be 'not beneficial'.

And I say 'not beneficial', as opposed to BAD, conditionally; with some reservation here.

Making a bigger hole WILL allow more air, which without question, will benefit an engine with the hammer on the floor.

But what about mid-range? And low end?

Best example that I can think of, is L98's intake manifold. Flow characteristics of L98 intake are 'templated' on flow characteristics of an LB9. L98 loses out top end, NOT because of the VOLUME THAT THE INTAKE ALLOWS, BUT BECAUSE OF FLOW DYNAMICS.

Another example came from another forum board - discussion of the 'Foil', on the throttle body. After thinking on it - how it would stop air from 'bouncing' (turbulence), off of the OEM TB divider (of the 2 TB openings), made me think further on it's benefits. Throw a rock in a pond, and watch the waves 'bounce', AND COME BACKWARD EVEN, WHEN THE WAVES HIT THE "No Fishing" sign. Then I posted that in a forced air induction system, it should REALLY be beneficial, to reduce the 'bounce'. User 'Joe', whom some of you probably know, after lurking about, posted up 'Bingo', on the forced air induction/ benefits.

A true MONOrunner plenum has dynamics already considered.

So I'm asking again here; has anyone done flow dynamics tests, of any sort, on OEM vs 'siamese-d' tubes? Or even, Before and After TQ/HP numbers???

[Kevin]

i'd like to see down into the IH of Mark H's 385. with that dropped plenum I'd like to see what LPE did there

[LGAFF]

Really what I would like to do it

Divide the plenum in two to create a helmholtz resonator
Create a air horn/veolicty stack entry into each set of runners

[RHanselman]

The Siamese port actually started with Gulstrand and then TPIS who both made a siamesed TPI runner....TPIS version was more like the one Locobob and I did.....

Lee, I have to recover some brain cells lost at BG this past year however I ran into a guy that told me about the first true Siamese and it wasn't for Gulstrand. I believe it was for LPE or Jeal. I'll do some research and get back with you. You know, it might have been Graham telling me?? Guess I'll have to give him a call... Billy K comes to mind but again, those brain cells are dead...

Cheers,

[Kevin]

i remember the sheet metal intake that billy k made for his car.

[LGAFF]

I am talking about the TPI stiff Ron, TPIS/Gulstrand did siamese with TPI runners...which is were I think the term was first used......you are correct on the LT-5....I was just speaking to the way it was done on those...some combined with no center ridge, some did not

[RHanselman]

I am talking about the TPI stiff Ron, TPIS/Gulstrand did siamese with TPI runners...which is were I think the term was first used......you are correct on the LT-5....I was just speaking to the way it was done on those...some combined with no center ridge, some did not

Copy, your talking L98 then. I wasn't sure because of the 1990's having TPI on the side ;)

[RHanselman]

i remember the sheet metal intake that billy k made for his car.

I thought this thing was cool looking. You could see the top flex when he revved her up... Probably needed a little more volume and some stiffeners.

[LGAFF]

Actaully Ron, the first Siamese was the snakeskinner car......from sports car illustrated:

"The secondary throttles have been removed, so the engine is always drawing air through both runners. The intake runners have been siamesed along part of their length by cutting out the wall separating them. The cams are stock......."

This car ran 11.83@123 .....launching at 1600 RPM

This is from May 1992 mag...the 1989 Snakeskinner 1

[RHanselman]

Actaully Ron, the first Siamese was the snakeskinner car......from sports car illustrated:

"The secondary throttles have been removed, so the engine is always drawing air through both runners. The intake runners have been siamesed along part of their length by cutting out the wall separating them. The cams are stock......."

This car ran 11.83@123 .....launching at 1600 RPM

This is from May 1992 mag...the 1989 Snakeskinner 1

Yep but who did the work? I cannot remember... I guess JVD would know unless you do...

[Kevin]

Yep but who did the work? I cannot remember... I guess JVD would know unless you do...

since that was a gm project i'd have thought mercruiser did it

[LGAFF]

Yep but who did the work? I cannot remember... I guess JVD would know unless you do...

Ron this is the GM test car.......I am guessing either Mercury or Scott Leon at GM

[Polo-1]

If you go down this road to Siamese , make sure you have someone who know what they are doing........ this thing cost me major $$$ for the plenum, work done, then GVD to fix it...

http://i7.photobucket.com/albums/y292/kpie/DSC07909.jpg (http://s7.photobucket.com/user/kpie/media/DSC07909.jpg.html)

Hey Todd

Sure would like to see those double DD's ;)

I have only seen the single D

http://i7.photobucket.com/albums/y292/kpie/lt-5006.jpg (http://s7.photobucket.com/user/kpie/media/lt-5006.jpg.html)

[RHanselman]

You know, GVD was probably the guy...

[ALZR1]

If you go down this road to Siamese , make sure you have someone who know what they are doing........ this thing cost me major $$$ for the plenum, work done, then GVD to fix it...

http://i7.photobucket.com/albums/y292/kpie/DSC07909.jpg (http://s7.photobucket.com/user/kpie/media/DSC07909.jpg.html)

Hey Todd

Sure would like to see those double DD's ;)

I have only seen the single D

http://i7.photobucket.com/albums/y292/kpie/lt-5006.jpg (http://s7.photobucket.com/user/kpie/media/lt-5006.jpg.html)

what's warped the plenum or I/H ?

AL.

[Locobob]

You know, GVD was probably the guy...

GVD was certainly involved in some interesting testing but I don't recall him ever mentioning working on the SS motor...... hmmm

[Polo-1]

Hey Al

It was both that Greg had mill flat.
I bought all new plenum, and housings, sent out for siamese runners got back a wrapped used mess from Kirchhofer. I sat on it for a few years then had Greg Van Deventer port it and mill it all flat. So I bought new parts, got used parts back that would not seal, then Had the right Guy fix it.... This is why I say " go to the right guy first ".

http://i7.photobucket.com/albums/y292/kpie/DSC08640.jpg (http://s7.photobucket.com/user/kpie/media/DSC08640.jpg.html)

[scottfab]

...snip...
So I'm asking again here; has anyone done flow dynamics tests, of any sort, on OEM vs 'siamese-d' tubes? Or even, Before and After TQ/HP numbers???

I've never heard or read of anyone doing a flow dynamics study on
the LT5 intake. I'd like to hear more about how this would be done.
(specifics)
As for before and after TQ & HP numbers, yes I've seen them years
back on a HI car called the Pineapple Express. They were posted on the list server (mail list). I can't promise to find them, but I'll look. As for the stock numbers. They're out there in spades.

[ALZR1]

[QUOTE=Polo-1;182755]Hey Al

It was both that Greg had mill flat.
I bought all new plenum, and housings, sent out for siamese runners got back a wrapped used mess from Kirchhofer. I sat on it for a few years then had Greg Van Deventer port it and mill it all flat. So I bought new parts, got used parts back that would not seal, then Had the right Guy fix it.... This is why I say " go to the right guy first ".

http://i7.photobucket.com/albums/y292/kpie/DSC08640.jpg (http://s7.photobucket.com/user/kpie/media/DSC08640.jpg.html)[/QUOTE.

Typical of him to pull shiit like that,I know exactly how you feel.



AL.

[rkreigh]

Hey Al

It was both that Greg had mill flat.
I bought all new plenum, and housings, sent out for siamese runners got back a wrapped used mess from Kirchhofer. I sat on it for a few years then had Greg Van Deventer port it and mill it all flat. So I bought new parts, got used parts back that would not seal, then Had the right Guy fix it.... This is why I say " go to the right guy first ".

http://i7.photobucket.com/albums/y292/kpie/DSC08640.jpg (http://s7.photobucket.com/user/kpie/media/DSC08640.jpg.html)


all hail the almighty ported IH. I'm having a 2010 space odyssey flash back the way the light is reflecting off those beautiful ports

who is doing the "mono runner/siamese" work now and how much would it cost? I'm thinking of putting my current plenum "up on the wall" to save the sigs and getting the engine repainted. Like to try and see if these injector housings and a mono runner would pick up some top end

I am however worried about low end torq. with the big cams and light flywheel the LSV feels a little soggy until you kick it just a bit and then all hell breaks loose. even though the light flywheel is great for power and revs, it's not so great for launching the car. the heavier flywheel "dumps the intertia" and gets the car moving

I find I need to rev the car a bit more than with a stock zr1 for sure and even with the 4.10 gears it's not quite as "punchy" as I'd like on the hit until I get to 2k revs and then all is forgiven

good news is that it's got enough torq to let the clutch out at idle and not stall the car!

like to hear more about this intake mod. for sure it looks very sexy and has good potential up top. that's where the lsv lives anyway 6k and up!!

[FU]

with the big cams and light flywheel the LSV feels a little soggy

Yep that will do it.

[A26B]

Originally Posted by rkreigh http://www.zr1.net/forum/images/buttons/viewpost.gif (http://www.zr1.net/forum/showthread.php?p=182769#post182769)
with the big cams and light flywheel the LSV feels a little soggy


Not a problem. just a few minutes work

1. raise the idle to about 2 grand (for better idle roll-out)
2. throw on a set of 10" slicks
3. launch at about 5K

Presto change!! no more "soggy" feeling.;)

I think what you REALLY want, is the angelic TT feeling...... smooth & docile grocery getter with the devil himself hiding below the loud pedal where all you have to do is step on his tail.

[RHanselman]

all hail the almighty ported IH. I'm having a 2010 space odyssey flash back the way the light is reflecting off those beautiful ports

who is doing the "mono runner/siamese" work now and how much would it cost? I'm thinking of putting my current plenum "up on the wall" to save the sigs and getting the engine repainted. Like to try and see if these injector housings and a mono runner would pick up some top end

I am however worried about low end torq. with the big cams and light flywheel the LSV feels a little soggy until you kick it just a bit and then all hell breaks loose. even though the light flywheel is great for power and revs, it's not so great for launching the car. the heavier flywheel "dumps the intertia" and gets the car moving

I find I need to rev the car a bit more than with a stock zr1 for sure and even with the 4.10 gears it's not quite as "punchy" as I'd like on the hit until I get to 2k revs and then all is forgiven

good news is that it's got enough torq to let the clutch out at idle and not stall the car!

like to hear more about this intake mod. for sure it looks very sexy and has good potential up top. that's where the lsv lives anyway 6k and up!!


Boost is the key to your ills...

[rkreigh]

Boost is the key to your ills...

yes indeed, you guys know me too well. I'm a boost junkie and the TT ZR-1 is the holy grail.

sooooo........ how is that megasquirt project coming anyway? like to hear more about corey's progress on the raptor builds

a nice 800 at the tire is about all I need. smooth idle, endless torque that pulls to 7500 will work just fine

and shucks, I'll go back to a dual mass to kill the rattle.

the megsquirt is the key. I was surfing the DIYTune site the other day and noticed the nice 8 channel EGT box so we can tune each cyl

nice!! wondering if I can adapt that to my haltech ecm on the TT Z06 as it's quite a bit cheaper than the two 4 channel egt boxes and probes (1500!!!) from haltech. my bet is that it would work just fine and plug and play!!

here's my wish list for santa. some stretched liners, grooves in the heads, 93 cams (don't need my big stg II thumpers, let someone else have them) 16 60 lb injectors, a pair of walbro 340 pumps, the megasquirt, raptor TT, some fresh pistons, carillo rods (someone can have my TI rods), and yes, maybe a mono runner (looks cool)

stir in a good corey tune, and VI OOOOLA !!! TT ZR-1

stir in a roll bar (DRM), bikini top (have that already it folds up so you can put it in back), R&D Brace for top out crooze (have it)

and a ram 9" dual disk for grins. probably go back to a 3.45 gear at that point as well, someone can swap me for my 4.10 rear.

this is all doable, just need the PILE O CASH that will be needed to freshen up the old gal.

meanwhile, I'll keep trying to wear out the soggy ol LSV :salute:

[Schrade]

I am however worried about low end torq. with the big cams and light flywheel the LSV feels a little soggy until you kick it just a bit and then all hell breaks loose.

Could this be because there's still a bottleneck in the intake flow, with even with siamse-ed tubes?

WHich might be creating impedance in intake flow at mid throttle? And which is 'overcome' at WOT?

:confused:

[Pete]

Hmmmm
Siamese vs Nicely Ported

Here are some thoughts.

Today we have big inch Z's with smaller cams no siamese intakes that run good 1/4 ET's/MPH.

Technology/performance has gone beyond Siamese intake, today we go just as fast with less.
Siamese/droped plenum does not hurt performance it does give you reserve air.

Tested Hogan's Intake (for sale) gained power raised peak RPM.
Hogan's comes with all lines,pressure regulator/gauge plug n play.

I would consider cost to gain.
Pete

[rkreigh]

Hmmmm
Siamese vs Nicely Ported

Here are some thoughts.

Today we have big inch Z's with smaller cams no siamese intakes that run good 1/4 ET's/MPH.

Technology/performance has gone beyond Siamese intake, today we go just as fast with less.
Siamese/droped plenum does not hurt performance it does give you reserve air.

Tested Hogan's Intake (for sale) gained power raised peak RPM.
Hogan's comes with all lines,pressure regulator/gauge plug n play.

I would consider cost to gain.
Pete

flow velocity is a very important factor. really big ports can hurt that and while they work ok upstairs, not so great getting rolling and hampering the overall area under the torq curve is not a good approach for a street car. you want that torque curve to be wide and meaty rather than "peaky" like a race car.

the LSV has the "state of the art" bifurcation ported plenum that was heavily ported and the "best at the time" but clearly the heads aren't ported that well, and no fancy drop plenum ect... it's and old school build and not that impressive relative to Pete's work with top end porting and cams relative to displacement.

as pete is saying "today we can do more, we have the technology"

and pete proves it every day by pulling 129 with a stock block which is as good as I can do with a 390 and the "full boogie LPE" package

key is in the endless hours of experimentation, tuning and optimizing the overall combination. Pete you are the man!

like to see that hogans intake!

kirchoffer spent a TON on his fancy fabbed intake on wild jeal cams and 421 build only to discover the design didn't seem to help much. I remember seeing it in BG and like Ron H said the "top plate" would flex up and down as he would rev it

he only got to run the car a few times and eventually blew a freeze plug out of the back of the motor

but overall there didn't seem to be a huge gain.

I've always wondered what the LT5 would do with an individual runner crab style harrop slide throttle intake. it would clearly be soggy down low, but flow like gang busters up top. ahhh.... it's good to dream and experiment, now I just need that 14th mortgage ;)

[Pete]

Ron,this is the only picture I can find.
This top plate does not flex.

Pete

[Polo-1]

Hmmmm
Siamese vs Nicely Ported

Pete

Who asked you.;)

Back when this was done, it was the question of the day. Go BIG or High Tech porting.
Both mine and Todd's were at GVD at the same time. Same bench flow machine.

Todd's twin holes out flowed the mono ( Siamese ) bottom line. It was very close together at my SGC II cams lift, but on higher lift where Todd was going..... I got my azz handed to me. If I had to do over, find the guy who is making the power you want and go with their package. The Siamese looks cool ( my taste ) but was VERY pricey $$$

[Hog]

Do we really even require siamesed ports anymore? Just going by tpepmeie's high output427, 638 rwhp(on chassis dyno) and 702hp at the crank 700hp from 6500-7000rpm & 588lb/ft torque(engine dyno) while running short of injector.

[alnukem]

Do we really even require siamesed ports anymore? Just going by tpepmeie's high output427, 638 rwhp(on chassis dyno) and 702hp at the crank 700hp from 6500-7000rpm & 588lb/ft torque(engine dyno) while running short of injector.

Thank God!!!!! I knew this siamesing was $$$$$. I'll just get it dynoed, figure out any bugs & if it's not up to snuff, I'll go see my buddy Pete!

[rkreigh]

Ron,this is the only picture I can find.
This top plate does not flex.

Pete

like to try that with a 1300 cfm oval mono blade throttle body

I think the stroker "starves" for air running off the tiny little primary port and then all hell brakes lose as the secondaries crack open

for what you pay to modify a stock intake, a hogans would be cheap

I think LPE charged about 4k to do the bifurcation job

welding up a sheet metal intake isn't cheap, but it's not rocket since either

I'm seeing more "billet tubes" that are CNC machined and then welded to the base.

cool stuff. like to do a 3D carbon fiber printed intake someday. it would take a bit to do the CAD, and the 3D printers aren't cheap, but they are getting more affordable all the time.

you could design a much better shaped port with the right taper and plenum volume sized to the displacement for 7500 rpms and my bet is that it would work quite well.

even the "crab style" cross ram would look very cool and as long as the tubes are small enough it should build great port velocity

the LT5 intake has WAY too many turns and pinch points to really flow well up top due to the compromises for the packaging and injector housings

it looks cool, but me thinks we can do better with the modern high tech equipment

the nylon stuff on the LS motors is light, rejects the heat, and flows pretty decent without all the hassle. but the casting process is expensive to tool up and it would be tricky to make

the more I learn about the carbon fiber and 3d printing, the more I get excited about it. it's gone from "prototyping" to "small volume manufacturing" which is exactly what us LT5 guys need for a bunch of the parts no longer made

can you say "group buy" they we digitize and make up whatever we need. the technology is getting cheaper and easier to use every day.

it's the bomb:cheers::dancing:dancing:fahne:

[LGAFF]

I have seen a few of the "siamese" intakes, seems that they forgot to port them first....my whatever the hell you want to call it has more volume

[Pete]

I have seen a few of the "siamese" intakes, seems that they forgot to port them first....my whatever the hell you want to call it has more volume

Yeah, your right Lee some of those siamesed plenums were not ported any bigger then stock size ports I think they were relying on the volume of the Siamese.
Some like the Siamese look.

POLO 1 :p

Pete

[Polo-1]

for sure on port size. this is a 36 ball and before it went to Greg for repairs.

http://i7.photobucket.com/albums/y292/kpie/P1010209.jpg (http://s7.photobucket.com/user/kpie/media/P1010209.jpg.html)

Dont do the siamese intake. It's money lost in todays porting out there. buy Pete's cam's instead, you will do better then siamese.

[tpepmeie]

Both mine and Todd's were at GVD at the same time. Same bench flow machine.

Here is the data I have for mine and Kevin's induction system. These are loss percentages. Higher loss = lower flow. This is a loss compared to each of our cylinder heads with just a clay radius, nothing else.

http://i1036.photobucket.com/albums/a441/tpepmeie/400lift.jpg (http://s1036.photobucket.com/user/tpepmeie/media/400lift.jpg.html)

http://i1036.photobucket.com/albums/a441/tpepmeie/450lift.jpg (http://s1036.photobucket.com/user/tpepmeie/media/450lift.jpg.html)

http://i1036.photobucket.com/albums/a441/tpepmeie/500lift.png (http://s1036.photobucket.com/user/tpepmeie/media/500lift.png.html)