I cant find the original post anymore, but it was from four years ago. Here are the pics of what we did:

http://para.noid.org/~thresher/images/albums/082901/

SLP runners were modified by JerryWho on this board.

Unfortunately, I have changed a few things since my car was first dynoed.

I ported the L98 heads some more, went from 1.6 roller-tip rockers to 1.6 full roller rockers, went from 3" exhaust with flowmaster muffler, to 3.5" exhaust with a bullet muffler in the middle and a magnaflow muffler at the end, and changed my T5 to a T56. Camshaft is still the LT4 HOT cam and I still have SLP 1 3/4" headers. Also, this was not the same dyno I used before.

Unfortunately the dyno graphs didnt get copied to my flash drive when I got everyone else's graph. I will call the dyno guy on Monday and see if he still has them on his computer.

Previous Results: 318 RWHP at 4700 RPMs, and 419 RWTQ at 3600 RPMs.
New Results: 321.5 RWHP at 5200 RPMs, and 390 RWTQ at 3600 RPMs. The HP peak was still flat at 5400 rpms and started falling off after that. I dont remember the torque without the graph, but it was fairly flat too.

There are a lot of things that changed which makes this test almost worthless, but those runners did move the HP peak up 500 rpms while only giving up a little bit of torque.

Now, on my father's 1990 Trans Am (Dyno Don), he has a 350 L98 with Edelbrock ETec 200 heads with a Scoggin Dickey vortec base, similar ported SLP semi-siamesed runners, a ZZ9 camshaft, 1.5 roller tip rockers, SLP 1 3/4" headers, and a 3" Magnaflow cat-back.

His car made 317 RWHP at 4600 RPMs, and 394 RWTQ at 3400 RPMs. The only explanation I have for his car making max power at 4600 is his camshaft is smaller and not taking advantage of the better heads. His HP peak was still above 310 at 5000 and started falling off after that.

 

It will be good to see the curves. Losing almost 30 ft/lb of torque in the usable range may not be considered a "gain" by some people. Your dyno graphs may show what's the curve actually does, and may prove that wrong.

 

I am in the process of trying to scan them now, as soon as I get it I will try to post them.

Don>>>

 

Kevin's car has more in it. With every chip mod he was gaining horsepower. Time ran out with the amount of cars that showed up. If he had had more time he would have wrung out more HP.

With my siamese SLP runners it flattend the torque curve just like on an LS1. Mine made peak torque at 4800rpm. We will have to see what Kevin's graph looks like.

It was an interesting day with Julie putting down 253RWHP with her 91GTA and with stock heads and cam. Vincent put down 370RWHP with his 355, trickflow heads, super ram and California street legal as he just past smog. Ron put down 413RWHP with his highly modified carb'd 350.

 

that lower torque could also be partialy due to the bigger exhaust.

but seems like some good numbers.

 

HOLLLY CRAP BOYZ !


Guess I could have run a little more cam in my setup. I only went in 4"deep on mine .I topped out at 4900 rpm ...but am runnnig the ZZ4 cam. Nice to see that Hotcam work in a LTR setup. I only got 251 rwhp ( stock 305 AYPS bin. ) but I suppose there is room for improvement before


How "ported" are these heads ? I know someone who was debateing the potential of these 083's .... this kinda straightens me out on them .

 

My heads are not iron 1083 f-body heads, they are aluminum L98 Corvette 113 heads with upgraded springs and 7/16" studs.

 

Here is the dyno graph of my dad's car. Mine is similar but the HP peak is at 5200.

 

You lost quite a lot of torque. I don't understand what everyone's obsession is with trying to make TPI's make hp up high where they can not, by design. If you really need high rpm HP every intake other than TPI is a good idea. Otherwise the TPI has its own advantages, not up top though.

 

One of the obsessions is it is a cool looking design. Another is a lot of us like to tinker. Another is that some say TPI can not make good horsepower above 4500rpm. We like to prove them wrong and what can be done. Here is my graph with an automatic transmission at the same dyno day. By the way figuring a 20% drivetrain loss I would be at 403HP at the crank. More to come.

 

A CRossfire was a "cool looking" design, just like the old Chrysler Cross Ram from the '50s. Tri-Powers were a "cool looking" design as well. We just all learned that there were better ways to get fuel charge to the chambers. Even GM figured that one out for themselves. Apparently, the "coolest working" intakes are plastic.

Still, you've got some good numbers for a TPI-based intake.

 

We're limited in CA to two intakes: TPI and SuperRam. The SuperRam is nice but expensive, and its a pain to install. So we have set about to modify our TPI to make more power. When my dad first put these siamesed runners on his car, he went two tenths faster. Unfortunately, I am still learning how to drive my car with this combo, so I havent gone any faster.
Plus, its nice to put those LT1 and LS1 boys in their place when they say TPI cant make any power above 4500.

 

Oh, I keep trying to forget about C.A.R.B., but you have to continually remind me. That throws a wrench into the works, I'm sure. No approval numbers for the StealthRam, eh? I suppose retrofitting the LT1 intake is out of the question as well.

 

Here's a page that shows a bunch of dynos I've made over the years. With an automatic tranny instead of a manual, my rear-wheel numbers are lower, but a power peak at 5300 rpm and the power staying above 280 rwhp until almost 6300 rpm.

http://users.erols.com/gcwestph/Dynoruns.html

1989GTATransAm, I'd like to see your dyno graph with engine RPM instead of wheel speed. Looks like you left quite a bit of power on the table since you were running quite rich...

 

why not look into the "FIRST" intake. its' very similiar to a TPI, has a better power band(more HP) and has EGR. even Cali legal I believe...

 

StealthRam has no EGR, so its not smog-legal. LT1 intake technically isnt smog legal, since they want to you convert to the whole engine, not just the intake. But when you put the distributor on it you block off the port for the EGR valve.

Where am I supposed to find a FIRST intake, and why would I want to convert to that when I already have this?

 

Where
http://www.firstinjections.com/

Why
https://www.thirdgen.org/techbb2/sho...irst+Injection

https://www.thirdgen.org/techbb2/sho...irst+Injection

 

Those are some impressive dyno graphs. The ported runners and base certainly flattened the torque curve, and thus brought the HP numbers up all through the range. There seems to be no significant loss of torque at lower RPM either.

 

Here I just figured I;d toss mine up ... just to show the difference . I have the edlebrock hi flo TPI ... went in only 4" with the siamese ....but maybe the cam is whats hindering the topend .


Thats with the stock 305 AYPS .bin ... on the new 353ci.

 

Here's my graph.

I had Dyno Don to post it for me.

 

Ours are close in shape ....but you got alot more power WTG man .

 

Vincent

What blows my mind is that we make peak power at the identical spot of 5250 RPM. Yet you have 12 degrees more cam on the intake side. One would think that your peak power would be at least in the 5600+rpm range. Maybe you need the Mufflex 3.5" exhaust.

 

Little retro....cool is the three duces on a 66 GTO at wide open throttle....I may have just dated myself.

 

I done excactly the same thing when i had the motor out of my grand national putting on some ported heads and staying with the stock cam. I was told it wouldn't make no power over 5k with the stock cam.

well i dynoed the car @ 20 psi of boost and it churned out 350 RWhp with 440 RWTQ on pump gas 93 octane and the the neat thing was it made it all the way to 5500.

My nest mod is going to be 1.65 roller rockers to make up the diffrence of the stock cam being on the small side for the big valved ported heads.

 

Finally got the dyno graph for Kevin's car:

Max torque was actually 386, and max power was at 5000.

 

Here is the dyno graph from before, with AS&M large tube runners, showing 317 RWHP at 4700, and 421 RWTQ at 3200:

http://para.noid.org/~thresher/dyno.jpg

Rumor has it Jerrywho still has those runners on his shelf. Perhaps I can convince him to let me borrow them for our next dyno day in January and we can get a better comparison.

 

You have definitely moved the torque and power up the rpm band. Quite abit actually. Also there is more power in your current combination with more time on the dyno.

Also you need to finish up your 3.5" exhaust system. You are half way there already.

 

I have a stupid question......

Why do cars dyno lower when you change to a bigger gear?

Example, nothing has changed on my buddies 4thgen, except he went from 3.23's to 3.73's, now it dyno's slightly lower (LS-1 / T-56). It's faster in the 1/4 now though.

 

i want 400crank hp