Dyno Day

[XfireZ51]

Finally got opportunity to put car on dyno yesterday at Speed Inc.
It was somewhat disappointing for a couple of reasons. In its previous configuration on the same dyno, the motor pulled ~399rwhp with a peak of 6800rpm. With several successive pulls, we didn't get more than 414rwhp this time. The previous config. was ported top end, headers, full exhaust, and my tuning. Now the motor sports GVD heads, Pete's Intake regrinds, again full exhaust and previous top end porting.
As a caveat, don't take these numbers as etched in stone at this point. It took 9 pulls and 2 hours to get the AFR numbers near where they should be. Quite a bit of additional fuel was needed for this configuration. Myself and the dyno opertor had agreed that if we saw an AFR > 13.2, he would shut it down. So we did this and got to 7000rpm+ in stages. The AFR curve I now have is much better than what I came in with. In some cases, AFR was climbing towards 14:1. One GOOD reason not to run the car last Sunday before getting it on th dyno. The curve still needs a bit of tweaking but it needs to be right before I would play with timing. I did do some datalogging just to check for Spark Counts. With the timing tables I have there now, I only had 1 Spark Count near 6K and then very briefly. Timing was retarded by 1d for 1-2 frames. Not enough to be concerned.
Consulting w Pete, our thoughts are that:

1. The air bridge is likely collapsing. It continues to squirm off the air cleaner assembly regardless of how much I tighten the worm screw. Pete says that is a sign of the snorkel being pulled away by the suction of the motor. Although I have one of Marc H's "hoops" inside, the air bridge may be collapsing particularly at the housing end.

2. I may have discovered the limits of the MagnaFlow resonator. Up to this point, it didn't appear to be a bottleneck, but with the increased flow (the addtional fuel needed really suggests that) it may not be able to move the exhaust efficiently at this level of power.

Bottom line is I will try to get back to the dyno before the snow flies but first addressing the airbridge collapse and resonator restriction issue.
In the meantime, here's a vid of the car on the dyno yesterday.

http://vid187.photobucket.com/albums/x198/Z51Xfire/th_PICT0003.jpg (http://s187.photobucket.com/albums/x198/Z51Xfire/?action=view&current=PICT0003.mp4)

I'll post dyno sheet one I get data file of it from Speed Inc.

BTW any suggestions on the exhaust issue are welcome. Right now I am trending towards removing the resonator and Xpipe combo and replacing with SW Xpipe and 2-3" straight pipes in its place. I'll worry about the drone later I guess.

[GOLDCYLON]

Dom maybe a solid Coplan insert for the accordian? Vice the Haibeck hoops or install 2 more hoops toal of 4. 2 Each opening and 2 in the middle ?

I can loan you a Corsa spare resonator I have in the attic to test out.


BTW always love that sound

[Paul Workman]

At different times I've run across discussions regarding the intake to the plenum as another consideration. To that end, the surface of that "accordion" pipe between the air horn and the filter housing...always troubled me. Everywhere else, runners sweep this way and that, turns follow careful radii, and attention is paid to keep the surfaces relatively smooth. And, then there is that convoluted, accordion-like snorkel...:icon_scra

I wish I had "before and after" data; "before" being the stock tube (or maybe allowing wire hoops in the convolutions to prevent the tube from collapsing) and after with a sleeve inserted in the tube, not only to keep it from collapsing (what they are usually used for), but to see if straightening out the flow has some tangible value.

In talking with Pete, he removed his snorkel for racing one time, and is convinced it slowed him down. Reinstalling the tubing picked the performance back up (he says-and he races a lot). Just wondering what the rest of the Brotherhood's experiences/comments might be..

P.

[John Boothby]

I run a Samco intake duct. Smooth and won't collapse.

[GOLDCYLON]

At different times I've run across discussions regarding the intake to the plenum as another consideration. To that end, the surface of that "accordion" pipe between the air horn and the filter housing...always troubled me. Everywhere else, runners sweep this way and that, turns follow careful radii, and attention is paid to keep the surfaces relatively smooth. And, then there is that convoluted, accordion-like snorkel...:icon_scra

I wish I had "before and after" data; "before" being the stock tube (or maybe allowing wire hoops in the convolutions to prevent the tube from collapsing) and after with a sleeve inserted in the tube, not only to keep it from collapsing (what they are usually used for), but to see if straightening out the flow has some tangible value.

In talking with Pete, he removed his snorkel for racing one time, and is convinced it slowed him down. Reinstalling the tubing picked the performance back up (he says-and he races a lot). Just wondering what the rest of the Brotherhood's experiences/comments might be..

P.

Why I use the Coplan insert... Smoother no collapsable airflow is key

[FU]

Smooth Samco here. If anyone would like to borrow it for a back to back runs on the dyno or at the strip ? Just lemme know.

[XfireZ51]

I had some aluminum sheet so I built an insert today. Quite a bit stiffer!

[GOLDCYLON]

I had some aluminum sheet so I built an insert today. Quite a bit stiffer!

Cool do you want to borrow my Corsa resonator? Daryll

[XfireZ51]

GC,

Think I'm going w a SW X and some straight pipes. Another alternative could be using LT4 resonator.

[GOLDCYLON]

Ok offer still holds. Haibeck used the Corsa system in his slides. Just saying

[-=Jeff=-]

I have a LT4 resonator in my garage.. :)

[Kevin]

i wish the coplin duct was still made, but i do have one of the last ones he made on my car :)

[GOLDCYLON]

i wish the coplin duct was still made, but i do have one of the last ones he made on my car :)


http://www.ebay.com/itm/ZR1-ZR-1-LT5-LT-5-Intake-Connector-Duct-Stiffener-/310059954936?pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr&hash=item48310372f8

Closest thing to it sans metal

[Kevin]

that it is, didn't know that existed

[GOLDCYLON]

that it is, didn't know that existed


Yep when anybody asks thats where I send em lol ;)

[Pete]

GC,
Think I'm going w a SW X and some straight pipes. Another alternative could be using LT4 resonator.


Dom,WTF LT4 resonator, might as well put bananas in your tailpipe.

Go with SW X-pipe and fatten her up a bit before you do first pull.

Pete

[GOLDCYLON]

Dom,WTF LT4 resonator, might as well put bananas in your tailpipe.

Go with SW X-pipe and fatten her up a bit before you do first pull.

Pete


http://www.youtube.com/watch?v=HktV2yGtLv8

[sammy]

dominic ,i went with 2 balance tubes in my exhaust one up front and one behind the rear end just before the pipes turn away from each other . i dont have any drone and actually picked up .5mph over the x pipe at the strip

[Paul Workman]

GC,

Think I'm going w a SW X and some straight pipes. Another alternative could be using LT4 resonator.

Naw...I'm w/ Pete. You spent a lot of $$ to get the Nero Rosa together; heads and cams, etc, etc. See what power she'll make first, and then fuss with the droaning, later. That way too, you'll have a base case to compare whatever changes to the system that you make later.

P.

[Pete]

My suggestion.
Buy the SW X-pipe and 2 Dynomax Ultra Flo mufflers 3"inlet/ dual 2 1/2" outlets.
Cost around $450
Before you order mufflers call Al he will give you the right part # don't want you to order some grandma mufflers.LOL

Optional:
Find C6ZO6 mufflers cut off & use vacuum actuators on your Dynomax mufflers.

Pete

[XfireZ51]

Pete,

As usual you were, of course, right about the air bridge. I built a sleeve yesterday from some aluminum sheet stock I had laying around. Pretty much along the lines that Paul has outlined in another post. Took the car out to thrash it a bit. When I got back, I popped the hood, and lo and behold the air bridge was where I had tightened it. Previously, one corner of it would have been sliding off the air cleaner housing leaving a gap. I could always tell because the idle would get erratic. I think tho I will use the one GC has pointed out on ebay. Its smooth, doesn't have ragged metal edges and for the money, looks like a nice piece coming from up the street in Milwaukee.

[GOLDCYLON]

Pete,

As usual you were, of course, right about the air bridge. I built a sleeve yesterday from some aluminum sheet stock I had laying around. Pretty much along the lines that Paul has outlined in another post. Took the car out to thrash it a bit. When I got back, I popped the hood, and lo and behold the air bridge was where I had tightened it. Previously, one corner of it would have been sliding off the air cleaner housing leaving a gap. I could always tell because the idle would get erratic. I think tho I will use the one GC has pointed out on ebay. Its smooth, doesn't have ragged metal edges and for the money, looks like a nice piece coming from up the street in Milwaukee.


LMK how it works out for you Dom!!!!

[XfireZ51]

GC,

Just bought it.

[GOLDCYLON]

GC,

Just bought it.

I predict.... Improvement !!!!!

[XfireZ51]

So here's the dilemma. Do I get an Xpipe like the 3" SS Magnaflow for about $60 and install w 3" pipes in place MF resonator OR get the SW xpipe for $350
+ 3" pipe and install? Do I go for just eliminating the restriction and dyno to test the hypothesis OR put in the SW xpipe which would stay there?

[-=Jeff=-]

well you know the SW X pipe works.. if installed there is no change you will not be questioning that pipe then

[XfireZ51]

well you know the SW X pipe works.. if installed there is no change you will not be questioning that pipe then

Do you really think that if I remove resonator and sub a decent Xpipe I won't see a change? I can get xpipe, straight pipes and install done for price of just the SW x. However, if I am going to end up with SW, what about cost of removing the brand x xpipe and installing SW later?

[-=Jeff=-]

Do you really think that if I remove resonator and sub a decent Xpipe I won't see a change? I can get xpipe, straight pipes and install done for price of just the SW x. However, if I am going to end up with SW, what about cost of removing the brand x xpipe and installing SW later?

No, I think you WILL see a change, BUT if you use a different X pipe and the numbers don't move as much as you think/ Pete thinks, then the exhaust still is a question.

[XfireZ51]

I think the reason I should do the SW x is economic not for the horsepower. Frankly I could skip the x and just go straight
to the mufflers. According to what Paul described as the shortcomings of the MF system, a standalone X would be an improvement. Not sure that SW X is worth that much more. At least I haven't seen any indication of how much more it's worth.

[FU]

Optional:
Find C6ZO6 mufflers cut off & use vacuum actuators on your Dynomax mufflers.

Pete

That sounds like the ticket !

[sammy]

if i were to go with an x pipe i would go to dr gas the people that created it .stainless works xpipe is way over priced .jmho

[Bob Eyres]

I have the Dr. Gas unit with 3" B&B's. It's the cheapest, and they have done quite a bit of development work on it, (with Mustangs).
Painted mild steel, not the prettiest, but works good. I clocked 117mph. in the qtr. with a stock motor, Coplon duct, Watsons, Dr. Gas X pipe and 3" dumps, no mufflers.

One "problem". It is loud enough to WAKE THE DEAD !! :eek:

[XfireZ51]

I have the Dr. Gas unit with 3" B&B's. It's the cheapest, and they have done quite a bit of development work on it, (with Mustangs).
Painted mild steel, not the prettiest, but works good. I clocked 117mph. in the qtr. with a stock motor, Coplon duct, Watsons, Dr. Gas X pipe and 3" dumps, no mufflers.

One "problem". It is loud enough to WAKE THE DEAD !! :eek:

Bob,

Prior to this last configuration, my motor was similar to yours with the exception that I had ported the top end. My best trap speed was 118.5.
That's w the same complete (read resonator/xpipe) MF cat-back system I have on there now.

[XfireZ51]

I have the Dr. Gas unit with 3" B&B's. It's the cheapest, and they have done quite a bit of development work on it, (with Mustangs).
Painted mild steel, not the prettiest, but works good. I clocked 117mph. in the qtr. with a stock motor, Coplon duct, Watsons, Dr. Gas X pipe and 3" dumps, no mufflers.

One "problem". It is loud enough to WAKE THE DEAD !! :eek:

Bob,

Which Dr.Gas X did you use? The X-over Junction or the X Scream tandem?

[sammy]

the x over is your best bet. they can make it to your exact dimensions. works nicely if you want to cruize quietly with your resonator on some times . they made a complete exhaust for my black car. i use the spin tech mufflers when at the strip and can put on the factory mufflers in about 15 minutes if i want to go quiet

[Bob Eyres]

Bob,

Which Dr.Gas X did you use? The X-over Junction or the X Scream tandem?

This was a few years ago and they only offered one model. It looks like the X Scream Tandem pictured. I told them the exact length of the resonator that I was replacing, pipe size (3"), and the distance between the pipes. They fabbed one to match those dimensions. It fit nicely.

[XfireZ51]

I visited Al's Brakes Plus shop on Thursday. We took some measurements to replace the Mflow resonator. Looking at the alternatives, Al spent my money :dancing and I ordered a SW X pipe. Should be here this week.

[Pete]

I visited Al's Brakes Plus shop on Thursday. We took some measurements to replace the Mflow resonator. Looking at the alternatives, Al spent my money :dancing and I ordered a SW X pipe. Should be here this week.


Now that's using the old noggin,even though it had to be beat into you.

Your halfway there,now have Al order 2 mufflers for you,don't half a$$ it,let her breath.
It's like having a marathon runner breath thru a coffee stir.

Pete

[XfireZ51]

Pete,

I know I'm a stubborn WOP, but Paul is making 432 at the rear using the MFLOW muffs. For the purposes of getting the dyno run done, I'm leaving them on. I'll see if the drone is something I can tune/tolerate. If not I'll go w the Dynomax muff/flapper combo. Let's see what happens with the airbridge duct and resonator removal first.

[Pete]

Then you'll be happy with 432
Yeah your right your an old stuburn WOP

Pete(

[XfireZ51]

Then you'll be happy with 432
Yeah your right your an old stuburn WOP

Pete(

Well at least not as old as Frank.

[Paul Workman]

Well, it will be interesting to see what you get with the same system that I have. I guess it will come down to a test of the heads and your cams.

But, one of my "winter projects" will be to change the muffs to the 3" Dynas, and coupled with the new radius in my IHs, maybe I'll see 440 ish...not to put the screws to an old WOP friend of mine...at least not toooooo bad!
:sign10:

P.

[XfireZ51]

Paul,

You'll need to do that on the same dyno in order to compare apples to apples.

[FU]

Well at least not as old as Frank.

Sure........leave us white hair's out of this !

[XfireZ51]

Got the SW Xpipe. I thought this was interesting and not expecting to see this:

http://i187.photobucket.com/albums/x198/Z51Xfire/SWXpipe001.jpg

http://i187.photobucket.com/albums/x198/Z51Xfire/SWXpipe002.jpg

Is this a newer version? Trying to deal w resonance?? How does it affect flow?

This "baffling" is in the aft part of the Xpipe. Its in the section behind the X where they are merged.

[Pete]

Got the SW Xpipe. I thought this was interesting and not expecting to see this:

http://i187.photobucket.com/albums/x198/Z51Xfire/SWXpipe001.jpg

http://i187.photobucket.com/albums/x198/Z51Xfire/SWXpipe002.jpg

Is this a newer version? Trying to deal w resonance?? How does it affect flow?

This "baffling" is in the aft part of the Xpipe. Its in the section behind the X where they are merged.

WTF is that?
Send it back,looks like sh!t.
All the ones i've seen are straight 3"

Can you post a picture of the outside body.

Pete

[sammy]

wow thats different . looks like the noise reduction cones that they put in header collectors to quiet open headers at the track . also kinda looks like someone welded a cheese grater in your pipes jk:-D . sure could mess with your exhaust flow

[Paul Workman]

Looks like an X pipe with a bad case of hemeroids!!:jawdrop:

I don't like it - at least not until there is some "with and without" data to at least show it is benign (which I doubt!). I guess we'd like to hear what SW has to say about it, as I'm sure you're going to give 'em a call.

P.

[XfireZ51]

Looks like an X pipe with a bad case of hemeroids!!:jawdrop:

I don't like it - at least not until there is some "with and without" data to at least show it is benign (which I doubt!). I guess we'd like to hear what SW has to say about it, as I'm sure you're going to give 'em a call.

P.

Paul,

Yeah I'll be calling them later today. I'll keep you posted on what they say. This is definitely not what they have pictured on their website. This isn't cheese grater stuff. It's bumps in a spiral pattern located in about a 10-12" section of the Xpipe behind the merge point and prior to the exit opening.

[LGAFF]

Bumps reduce velocity loss against the wall of the pipe?

[Bob Eyres]

I'd like to see a CFM flow test before I used that piece.

[jrtoffroad]

Now that's using the old noggin,even though it had to be beat into you.

Your halfway there,now have Al order 2 mufflers for you,don't half a$$ it,let her breath.
It's like having a marathon runner breath thru a coffee stir.

Pete

Pete,

You really think the magnaflow mufflers would be a restriction? Have you seen them in person? They are nothing more than short 3" smooth perforated tubes. No baffles and no reduction in diameter.

I'm running a 3" system with a magnaflow x & mufs. It's loud and has some resonance with the top on, but sounds awesome with the top off.

[LGAFF]

Says on the SW website its ribbed for pleasure!

[XfireZ51]

All,

I just got off the phone with SW. The piece I got is their "resonated Xpipe". I was told by Paul at SW they don't build them any other way but they would for an extra $100. Needless to say, I'm confused. Paul W. I believe has a pic of his SW Xpipe and it was clear thru. The "baffling" is there to hold down the resonance. I agree w Lee that they are there to break up any standing waves which would actually impede flow. Maybe our resident Fluid Dynamics guy PW would care to chime in. The spiralling is similar to a rifle barrel leading me to believe it straightens out the gas flow. The twisting probably helps to "compact" the stream.
Discuss amongst yourselves.

JRT,

I agree. Don't see the impedence on the MFlow muffs. At the least, its negligible.

[Pete]

Pete,

You really think the magnaflow mufflers would be a restriction? Have you seen them in person? They are nothing more than short 3" smooth perforated tubes. No baffles and no reduction in diameter.

I'm running a 3" system with a magnaflow x & mufs. It's loud and has some resonance with the top on, but sounds awesome with the top off.


Not sure but i know Dom's MF mufflers go from 3" to 2 1/2 inlets.

Dom, you went from banana to grapes in the tailpipe.
I gather you like fruits.

Pete

[Kevin]

would be interesting to see back to back dyno runs and see which dynos higher, even flow rates would be great to see. I wonder if the little bumps hurt anything, they way their designed looks like it may help suck the gases out a little better.

[jrtoffroad]

Not sure but i know Dom's MF mufflers go from 3" to 2 1/2 inlets.

Dom, you went from banana to grapes in the tailpipe.
I gather you like fruits.

Pete


hmm, well I may not be running the exact mufflers that come in the magnaflow kit, since my system was built ala carte :)

[Pete]

All,

I just got off the phone with SW. The piece I got is their "resonated Xpipe". I was told by Paul at SW they don't build them any other way but they would for an extra $100. Needless to say, I'm confused. Paul W. I believe has a pic of his SW Xpipe and it was clear thru. The "baffling" is there to hold down the resonance. I agree w Lee that they are there to break up any standing waves which would actually impede flow. Maybe our resident Fluid Dynamics guy PW would care to chime in. The spiralling is similar to a rifle barrel leading me to believe it straightens out the gas flow. The twisting probably helps to "compact" the stream.
Discuss amongst yourselves.

JRT,

I agree. Don't see the impedence on the MFlow muffs. At the least, its negligible.

Seems to me SW is getting too big for their own good.
I remember the days when they were begging for business.
Now the @sshole wants another $100 tell him to go f@ck himself just get a refund and for that price make your own or send it to China have them copy it,it would cost $50 then SW will go back to the days they were begging for business.

Dom, get a refund i have found another source/way,cheaper.


Pete

[Pete]

Now how is this possible $200 you get all this with cutouts,covers,flanges etc,

http://www.summitracing.com/parts/PYE-XVX13/

SW you pay almost double and get less.

At these prices i would go with mild steel X-pipe and ceramic coat.

Guess who SW got the measurements to start making X-pipes for our Z's.
Our very own FBI member Al

Pete

[LGAFF]

Get a Magna flow Tru-x 3 inch, have it on the 92.....for less than the SW you can get the dmn thing installed at Twisted Pipes

[sammy]

if you look in the summit cat. they have a 3 in x pipe thats a narrow one with the exact spacing you need all for 80 bucks

[-=Jeff=-]

There are some on eBay.. right center to center for less too

[XfireZ51]

Jeff,

The correct c to c is 4 1/8"

[Pete]

Jeff,

The correct c to c is 4 1/8"



Dom,you have a tolerance of i would say at least 1"

Since you'll be cutting the front and rear of the resanator you can move the pipes and insert them into the x-pipe,so you have some tolerance.

Pete

[-=Jeff=-]

Jeff,

The correct c to c is 4 1/8"

As Pete Said you are removing the current 'tied' pieces so the 1/8 would not be an issue

when I did the custom Resonator for my 89 is was 4" c-c, as is Pete's X pipe

[XfireZ51]

And speaking of Xpipes, I dropped ROZA NERO off at Al's to have the
MFlow resonator/Xpipe combo removed and the SW Xpipe installed. While there we looked at the SW unit. The pics I have posted here are taken from the direction of looking towards the motor. When we flipped the Xpipe around, we could see that the insert w the bumps was actually a
"cheese grater" style. IOW, the bumps are little cups when looking towards the diff and are there to slow the flow or disrupt it to a point. There still is a clear path for the gases to get out but certainly the turbulence caused by the cheese grater would affect that path. The backside of the Xpipe is much smoother and less disrupting, so Al has decided he'll install the Xpipe backwards with the smooth backside of the "cups" facing the flow. We're hoping this way the interference will be minimal but that we'll still get some benefit from breaking up standing waves in the pipe and therefore lower drone. In comparison to the MFlow
resonator and Xpipe combo which merge into one pipe in the resonator and then splits back out, the SW provides a pretty consistent 3" ID flow path for both banks. Cheese grater or not, it should significantly reduce backpressure. I am still a fan of the MFlow system. I like the low bass note it produces and the mellow exhaust note at cruise. And I think you get good value for the money. IMO, it clearly was capable of supporting a 400rwhp motor as my dyno runs and track runs showed last year. So for the LT-4 it was designed for, its a pretty good system. Beyond that seems to be its limits but I am only specualting until we see the results on the dyno. Hopefully that'll be soon before the snow flies.

[XfireZ51]

Picked up ROZA NERO today from Al's Exhaust Emporium and got a happy ending. He ended up removing the baffle inserts from the SW Xpipe. Its definitely louder and SOTP tells me definitely more power. Al says 20rw. I think I believe him driving this thing home. More responsive,better idle and it just flat out feels faster. I made sure I kept the ASR on getting it home. Overall interior noise isn't too bad. May need to go w Z06 flappers next.
Here's pics of baffle inserts:

http://i187.photobucket.com/albums/x198/Z51Xfire/SWXpipeInsert004.jpg

http://i187.photobucket.com/albums/x198/Z51Xfire/SWXpipeInsert003.jpg


http://i187.photobucket.com/albums/x198/Z51Xfire/SWXpipeInsert002.jpg


http://i187.photobucket.com/albums/x198/Z51Xfire/SWXpipeInsert001.jpg


http://i187.photobucket.com/albums/x198/Z51Xfire/SWXpipeInsert005.jpg

[GOLDCYLON]

Great news all around. And.... The wife has a new chesse grater :dancing

[Pete]

Now that's doing it the right way.:cheers:

Next,mufflers have to go.

Pete

[XfireZ51]

Now that's doing it the right way.:cheers:

Next,mufflers have to go.

Pete

Pete,

I'll try and get over by you thus week and see if you can tell SOTP
if there's a difference

[GOLDCYLON]

Dom start looking for those ZO6 flappers

http://www.ebay.com/itm/Corvette-C6-Z06-Dual-Mode-Remote-Exhaust-Control-Kit-/320783816585?pt=LH_DefaultDomain_0&hash=item4ab0349789

heres the wireless controller

[XfireZ51]

I thought you guys would be interested in whether or not I could verify my SOTP on idle quality w the SW Xpipe in place of the MFlow Xpipe/resonator combo.
I did some datalogging this morning to tweak the tune a bit. There are some spots needing additional fuel, but overall nothing major.
I had felt that idle quality was better now than before and I am posting a before and after datalog of the idle. You'll see that the motor is now idling at about 3-4kPa lower than previous. That translates to about an increase of 1" Hg vacuum. That will make the difference between using the 50kPa-800rpm cell or 55kPa-800. Can idle a bit leaner since velocity will be better.

[XfireZ51]

Returned to Speed Inc. after removing the perceived restriction of the MFlow resonator and replaced it w SW Xpipe (sans baffles, thank you Al).
The first jpg attached is from the final run of he previous tuning session.
The second jpg is of one of last three runs and I was still adding timing here with change showing up in torque. Nothing else was done to the tune in the interim. I also added the airbridge insert to keep it from collapsing. I didn't need to retighten any band clamps with the insert in place. You can see there was no significant difference between the two runs. Now whether the SW Xpipe allowed me to improve on that performance would be speculation at this point. I'd need to reinstall the MFlow resonator and run with the tune I now have. The last jpg shows the change in performance from adding some more fuel and reducing timing at WOT. Paul W and I were on the dyno for about 2.5hrs. I probably can coax it to about 430rwhp with a bit more tweaking but I decided I'll leave that for a spring run. The torque is the real improvement so far.
Remember this setup is using GVD ported heads. Our sense around the pizza table last night was that there was more to be had by re-doing the heads ala "the Greek spec". It would be interesting to get Dave Johnson's AB turtle on the dyno and see what difference there is if any. I'll post some other graphs with layovers of runs once I can get the files from Speed Inc. These graphs really don't tell the full story The layovers will show the change in the "area under the curve". The torque is increased and never less than 10rwtq difference from 4500rpm through 7000 with a peak differential of nearly 25rwtq around 5300rpm. Let me just say you can feel that.

[Pete]

So with intake cams and heads you gained 25 RWHP from your previous no heads and cams.
Differance in the heads might be 10 hp not worth the expense.

I know your looking at Paul's #'s but i would've loved to seen Paul's Z on the same Dyno yesterday,that would've been real comparison.

Lean does not make power feul does,you ever wonder why the factory ran them at 12.6-12.8 AFR
Pete

[XfireZ51]

So with intake cams and heads you gained 25 RWHP from your previous no heads and cams.

I know your looking at Paul's #'s but i would've loved to seen Paul's Z on the same Dyno yesterday,that would've been real comparison.

Lean does not make power feul does,you ever wonder why the factory ran them at 12.6-12.8 AFR
Pete

I agree Pete. That would be the real compare and would also agree that with some added tweaking in the direction your talking about, I'm pretty sure it'd be about 430rwhp. Too bad because Paul did have his car there. I don't recall tho what Paul's rwtq was and where peaks occurred. I asked Marc if he thought there would be any diff between the D&M dyno and Speed Inc.
I'm posting the final run of the motor from last year. The numbers are using a smoothing of 5 which lops off about 4-5 peak hp from the graph but compares apples to apples.

[XfireZ51]

So what we can state with certainty is that with GVD ported heads annd Pete's intake cams we got 30rwhp/35chp, and 26rwtq/31ctq using a 15% driveline loss factor. Same motor, same dyno. That's the only way we can really compare. By using 0 smoothing, the graph would show 430rwhp. Actually not too shabby for a 350. From there I think some additional tweaking mostly of fuel would give another 5-7rwhp and that would really put us at about where we think it should be. And that's really the only thing we can judge unless we get other cars on the same dyno same day. ;):cheers:

P.S. Personally I think LT-5 owners are spoiled rotten on hp numbers. We poo poo numbers under 400rwhp. I would have killed for 300rwhp in my Xfire!!!:jawdrop::mrgreen:

[sammy]

i think your numbers are great and the best bang for the buck .430 rwhp will allow you to have alot of fun with the car without frying your tires in the first 3 gears .jmho

[XfireZ51]

i think your numbers are great and the best bang for the buck .430 rwhp will allow you to have alot of fun with the car without frying your tires in the first 3 gears .jmho

Brad,

Thanks. It certainly gets up and goes. With street tires I'm keeping the ASR on.
In reviewing the results w Pete yesterday there was another thing to note. the car made the same hp on the first run as it had made on the last run of the previous day at Speed Inc. However, it ran leaner in this first run due to the
SW Xpipe. Where I had gotten AFR down to 13.1 in the previous set of runs,
that same calibration was showing up at a 13.4+ this time. So some of the lack of change in the hp could have been leaning of the mixture due to the Xpipe better scavenging and less restriction. When I started richening it up,
it started to pick up power.

[Paul Workman]

Disclaimer: Keeping in mind it is different (DynoJet) dynos on different (tho similar) days (conditions), its always interesting to compare general characteristics, even if absolute value comparisons have a % of ambiguity.

If I'm not mistaken Dom's specs are (Dom, correct me where I'm wrong and I'll edit this..)

Stock bottom 350
Pete's spec regrind "stage one" intake cam w/ Pete's timing
Stock exhaust cam
Watson 1-7/8" headers
plenum and IH ported by Dom
secondary throttle plates and rods removed
heads ported to Greg V's spec
3" exhaust with SW X pipe
Magnaflow (2.5" in, dual exits) muffs

Dom's final run...

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/DominicLT511-11-11.jpg

Equipment comparison (my car):

Stock bottom
Stock cams
secondaries removed
SW 2" headers, X=pipe, MF muffs (same as Dom's)
Plenum ported to 37mm, septum (knife edged) and length reduced by 13%
'90 IHs ported to ~36.5mm
Heads ported and relieved by me, incorporating taper along with nuance of designs by Marc Haibeck and Pete P, aka the "FBI" patterns.
cam timing by Pete,
final tuning by Marc

My sheet from a year ago...

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/DynoLT510-19-10.jpg

Of special interest is the torque curve comparisons, which leads me to believe Dom's car is leaving some hp on the table - more even than A/F/timing might buy. I have my hypothesis, y'll can develop your own.

Interesting stuff. Too bad dyno time is so pricy for us mortals (except apparently those mortals owning pizza joints!:p) But, kidding aside, it would be interesting to take Pete up on his offer to slap his heads on Dom's motor to ferret out the head variance. There is expense involved with pulling Dom's motor and swapping heads and dyno time. I wonder if the Registry would be interested in sponsoring such an experiment, if the porting specs were revealed. That would be between the Registry, Dom, and Pete. (I'm just playing devil's advocate:p)

P.

[LGAFF]

Might come down to the valve relief being the difference or the coolant injection on Pauls:cheers:

[Paul Workman]

Might come down to the valve relief being the difference or the coolant injection on Pauls:cheers:

Well, valve relief, maybe. But, the coolant injection experiment was definitely a bust!

Last year I ran a 12.6 at 117, but my 7200 rev limit cut me off well before the trap. The oil pressure switch ended that day's further experimenting.

This year I ran 13.0 at 115 on 7 cylinders, while laying down a thick vapor trail behind me. Naaa. The coolant injection experiment was not a good idea.

P.

[LGAFF]

It was reported after your run that mosquito counts were down

[XfireZ51]

It was reported after your run that mosquito counts were down

Lee,

That's why Bob G was able to run as fast as he did. Fewer insects hitting windshield and slowing car down.

BTW, in terms of overlaying Paul's dyno on mine, Marc H will be getting the data file from Paul's session so we can get an accurate compare of the curves and area under the curve. Looking at Paul's sheet, the increments on the two graphs are different.

[sammy]

Disclaimer: Keeping in mind it is different (DynoJet) dynos on different (tho similar) days (conditions), its always interesting to compare general characteristics, even if absolute value comparisons have a % of ambiguity.

If I'm not mistaken Dom's specs are (Dom, correct me where I'm wrong and I'll edit this..)

Stock bottom 350
Pete's spec regrind "stage one" intake cam w/ Pete's timing
Stock exhaust cam
Watson 1-7/8" headers
plenum and IH ported by Dom
secondary throttle plates and rods removed
heads ported to Greg V's spec
3" exhaust with SW X pipe
Magnaflow (2.5" in, dual exits) muffs

Dom's final run...

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/DominicLT511-11-11.jpg

Equipment comparison (my car):

Stock bottom
Stock cams
secondaries removed
SW 2" headers, X=pipe, MF muffs (same as Dom's)
Plenum ported to 37mm, septum (knife edged) and length reduced by 13%
'90 IHs ported to ~36.5mm
Heads ported and relieved by me, incorporating taper along with nuance of designs by Marc Haibeck and Pete P, aka the "FBI" patterns.
cam timing by Pete,
final tuning by Marc

My sheet from a year ago...

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/DynoLT510-19-10.jpg

Of special interest is the torque curve comparisons, which leads me to believe Dom's car is leaving some hp on the table - more even than A/F/timing might buy. I have my hypothesis, y'll can develop your own.

Interesting stuff. Too bad dyno time is so pricy for us mortals (except apparently those mortals owning pizza joints!:p) But, kidding aside, it would be interesting to take Pete up on his offer to slap his heads on Dom's motor to ferret out the head variance. There is expense involved with pulling Dom's motor and swapping heads and dyno time. I wonder if the Registry would be interested in sponsoring such an experiment, if the porting specs were revealed. That would be between the Registry, Dom, and Pete. (I'm just playing devil's advocate:p)

P.i would invest a cnote towards the expense. hopefully this year will be better and i can get the heads on the black car done and some intake cams

[XfireZ51]

Some more info to take a look at. Speed Inc. was good enough to send me the data files of Friday's runs. There's a compare of the first run on Friday with no additional tuning and the swap in of the SW Xpipe and last run of previous set with MFlow resonator in place. Numbers are very close but look at the AFR. Significant difference. Xpipe appears to have leaned the AFR by almost .5:1 requiring richening of the fueling. There's also a compare of the first run with the final run on Friday and then one of just the final run. If you play with the WinPep7 reader software, you'll find that torque increased in some spots by ~20lbft rw between the first and last run. There's almost a consistent 15rwtq/rwhp between these runs and removing the smoothing shows a Max HP of nearly 430rwhp which I expected.

[sammy]

nice detailed write up of the differences . will show alot of people that they need to retune the car when going to an x pipe from a resonator shows the importance of retuning the car when you make a change before bitching that it doesnt run any faster . how many times have we done/heard that .lol

[Paul Workman]

Some more info to take a look at. Speed Inc. was good enough to send me the data files of Friday's runs. There's a compare of the first run on Friday with no additional tuning and the swap in of the SW Xpipe and last run of previous set with MFlow resonator in place. Numbers are very close but look at the AFR. Significant difference. Xpipe appears to have leaned the AFR by almost .5:1 requiring richening of the fueling. There's also a compare of the first run with the final run on Friday and then one of just the final run. If you play with the WinPep7 reader software, you'll find that torque increased in some spots by ~20lbft rw between the first and last run. There's almost a consistent 15rwtq/rwhp between these runs and removing the smoothing shows a Max HP of nearly 430rwhp which I expected.

Looking good, Dom. Welcome to the "500" club!

Now a nice 4.30 gear for the rear, and you can bench race with the best of 'em!:p


(U know I'm juss pullin yer tail, buddy! LOL!)

P.

[XfireZ51]

nice detailed write up of the differences . will show alot of people that they need to retune the car when going to an x pipe from a resonator shows the importance of retuning the car when you make a change before bitching that it doesnt run any faster . how many times have we done/heard that .lol

Brad,

Absolutely. And its not the kind of thing where you buy a tune "off the shelf" either. I spent 2 1/2 hrs on the dyno Friday and so far almost 5 hrs total. And that's just WOT. I've probably burned about 50 cals for this motor so far. Some of the changes are minimal or tweaks. Some more substantial and involving quite a few parameters for driveability, idle quality, and PThrottle. :coffee::eek:

[XfireZ51]

Very nice day in Chicagoland for mid-November. Had to take car out for a brief playtime. The power is intoxicating. 2nd and 3rd gears pull. You can feel the power on reserve. Just tip the throttle and there's MORE, period.
Torque? Yep!
Banging 3nd gear, the car jumps as tires grab. Still keeping ASR ON with street tires but the Nitto Invos feel pretty good. I find myself looking for unsuspecting GTs, Sti's or M3s. Damn this is fun!!!!!
What's fun is having a ZR-1 with 100k+ on the ODO and not giving a shi* about driving it to keep the miles down.

[4-cam]

Nice job Dom, sounds like all the effort paid off. I'm salivating, reading these threads. It's great having you guys doing all the beta testing, paving the way for us ZR-1 rookies. I need to start ordering parts!

[Paul Workman]

Very nice day in Chicagoland for mid-November. Had to take car out for a brief playtime. The power is intoxicating. 2nd and 3rd gears pull. You can feel the power on reserve. Just tip the throttle and there's MORE, period.
Torque? Yep!
Banging 3nd gear, the car jumps as tires grab. Still keeping ASR ON with street tires but the Nitto Invos feel pretty good. I find myself looking for unsuspecting GTs, Sti's or M3s. Damn this is fun!!!!!
What's fun is having a ZR-1 with 100k+ on the ODO and not giving a shi* about driving it to keep the miles down.

You've come a long way "since then", Dom!:thumbsup:

As for the "unsuspecting", you can add all C5s and base C6s to the "road kill".:mrgreen: Now, Pete, Kevin, Bob G, and Al...doan hafta tip their hat to nuttin!:jawdrop:

P.

[XfireZ51]

Looking good, Dom. Welcome to the "500" club!

Now a nice 4.30 gear for the rear, and you can bench race with the best of 'em!:p


(U know I'm juss pullin yer tail, buddy! LOL!)

P.

Paul,

With my 19" Z06 wheels the 4.30's would reduce down to 4.10's or so. I'd at least like to raise the current gearing which is 3.45 but runs as if it's about a 3.0 gear. A 3.90 gear should get me very close to the stock setup.

[tomtom72]

From the peanut gallery.......A tip 'o the hat ( a ZR-1 hat ofcourse! ) to you Dom. :thumbsup:

That looks like it will be another FBI-land Killer Z!


:cheers:
Tom

[XfireZ51]

From the peanut gallery.......A tip 'o the hat ( a ZR-1 hat ofcourse! ) to you Dom. :thumbsup:

That looks like it will be another FBI-land Killer Z!


:cheers:
Tom

Tom,

Actually tip of the hat goes to FBI guyz! Pete, Kevin, Al, Bob G., Marc are all very helpful and real enthusiasts when it comes to the ZR and LT-5. They're the pioneers who have spent the time to investigate, the trial and error and money it costs relentlessly pursuing the power and performance. Paul and =Jeff= just are always ready to lend a hand or tool.
:cheers: =D>

[FU]

Actually tip of the hat goes to FBI guyz! Pete, Kevin, Al, Bob G., Marc, Paul and =Jeff=

And too you also Dom. Congrat's to all :cheers:

[XfireZ51]

Here's a Before and After when looking at Ported Heads + Intake Cams v.
stock heads and ported top end. At the end of the day, its significant. :dancing

[XfireZ51]

At our last pizza night, I asked Marc if he could access the final run from his tuning session for Paul W's motor. He was kind enough to send it to me last week and so I have attached a .jpg with each of our final runs superimposed. Paul's run is in BLUE, mine in RED.
As you look at this, recall the variables still in place when doing a apples to apples, but regardless its an interesting comarison. The differences are:

1. Different dynos although both are DynoJet
2. Paul has used the Pete the Greek porting template
3. Paul has stock cams
4. My heads were done by VanDeventer
5. My cams are Pete's Stage 1 intakes at 236/.425" single pattern profile
6. Paul has SW 2" primary headers/ I am using 1 7/8" Watsons. We're both using SW Xpipe and MFlow mufflers.

Also if you look at top of Dyno run, you'll see that Gear Ratios are different. Not sure what that means or why because Paul and I both have 3.45's. AFR is only available for my run since Marc uses his own WB during his tuning.

The question that occurs to me is whether porting or cams is the bigger bang for the buck. It would be interesting to get Dave Johnson's car on the dyno since he has the same cams I do, BUT with the cylinder head porting by Pete.

[mike100]

Too close to tell if they weren't dyno'ed the same day. A drag race might be the best way to find out who has the most area under the curve. ;)

[XfireZ51]

Too close to tell if they weren't dyno'ed the same day. A drag race might be the best way to find out who has the most area under the curve. ;)


The curves are both SAE corrected. However, not on the same dyno. Same dyno, different day would be closer.