Heynow

This is a great thread, I didn't think TPI's were capable of making those types of gains with just bolt ons. You said no to headers though, right? Keep it up great thread.

89RsPower!

vette throttle bodies say Tuned Port Injection on them. The only difference in the runner is the rough casting on the outside.

cmk-2

iTrader: (1)

OK everyone last pull of this testing was made today. Temp 71 Hum about 68% corrected numbers went down by 2Hp to 242Hp TQ went down by 2 points as well. NOT a good day at the dyno. Plugs and no A.I.R. pump didn't do a thing. I would say 2 points is in reason with different days. So there you have it. A good amountof $$$ was spent in mods and testing but the info was worth it, I think. I know that before the first bolt was turned, from a standing start the rears would break lose pretty good but before 2nd gear they would be "hooked up" now I'm all over the road and 2nd gets a good chirp. This has been fun and I hope it has answered some questions for you as well. How many of us has read in some advertisement about 15-20 easy HP and thought I wondered if it's true...Well now we know what works and what doesn't.... Robin

cmk-2

iTrader: (1)

Well here is an update on my 1987 5.7. It now has 66,500 miles and just had 1.6 roller rockers and a new fuel pump installed by the same company that did all the work a few years ago. After the work we dynoed again 3 runs and all were pretty consistance. SAE rwhp 248 @ 4500rpm and 350 Tq. Still no headers however i'm starting to think that they would really help out. The old fuel pump was maxing out at only 35psi and the dynomax exhaust has become louder so I'm sure it's more flow through now then when new.

godreject

iTrader: (1)

headers would be a great addition to the mods. any port work on the intake, runners.

Tony89GTA

iTrader: (7)

Great thread! Can't believe I missed it years ago

The best bolt on mod I did when my car was stock was some SLP 1 3/4 headers, to bad they don't make them anymore but dyno don has some nice ones for sale to fill the void if your interested. I also had my SLP headers jet hot coated at the time and the underwood heat difference was noticeable.

cmk-2

iTrader: (1)

Okay you guys talked me into it. I have purchased a set of 13/4 inch SLP shorty headers and Y pipe I'll have them put on and dynoed this week. Anyone want to guess what the HP gain will be? I'm keeping my fingers crossed for a 10-12 HP gain.

Genopsyde

iTrader: (2)

i had starter heat soak problems with my long tube headers, but that went away when I installed a starter blanket.

Ingram78

I'm betting more hp than that and it will also peak at higher rpm!

NagleMac

iTrader: (1)

Should be more than a 10-12 gain. This is an awesome thread.

Keoman

iTrader: (3)

Great Thread!!

Just read through it all, Thank you so much for posting this information!
It is more of a help to everyone than you could imagine.



EDIT*

To add to Reid's records:


Stock: 215 WHP
!cat & 2.5" Dynomax: 228 HP and 308 TQ*
TPIS LTR, Big Mouth, plug wires: 238 HP and 302 TQ**
TPIS chip (stage 1), Mac's Y-pipe: 244 HP and 333 TQ***
Powerpluse Spark Plugs, Removed AIR pump belt: 242 HP and 331 TQ
1.6 roller rockers, new fuel pump: 248 HP and 350 TQ****

Overall gain = 35 WHP

* HP peak @ 4400 RPM
** HP peak @ 4800 RPM
*** HP peak @ 4800 RPM
**** HP peak @ 4500 RPM

Gregdonna

iTrader: (4)

This is a great tread you have help me out in such a big way and I'm sure I'm not alone.

cmk-2

iTrader: (1)

Well raw numbers are in. A bit disapointed with the results. Peak HP went to 253.4 BUT peak TQ went to 365. This is with stock timming and he is going to try to move it up a point or two to see if it helps. Where the motor fell off before the headers at 4800 it now pulls very well past 5000RPM. It did gain HP and TQ all through the band and is much better in the higer RPMs and is not as effected by heat as it was before the headers. Before I would loose 8 to 9 HP with heat soak and does not seem to care about the heat and gives 253 with each pull. He is going to adjust the timming Monday and see if it gives some more. Stay tuned.

Keoman

iTrader: (3)

I dont think that's anything worth being disappointed about.
As i understand it, until now, you are still with your stock L98 heads and cam?
Those will be your limiting factors as you start to move up from the power your making right now.

cmk-2

iTrader: (1)

Yea just bolt ons. No engine work.

KMdoza7

iTrader: (1)

sorry if it has been stated before but just to clarify is this HP to the crank or to the wheels?

cmk-2

iTrader: (1)

To the wheels

blackgloves

One of the more entertaining threads Ive read in some time here. in more ways than one

thanks

Ingram78

In my experience with chassis dynos, less timing usually makes bigger numbers,unless the timing is ridiculously low to begin with.

That thing is making some steam for a bolt on TPI car! It's a ringer from the factory too!
Probly can hurt some LT1 feelings!

cmk-2

iTrader: (1)

Thanks! Yea the tech said I was making close to stock LT1 numbers. I also have an 1992 Corvette with LT1 and auto, I bought brand new and now has 144,000 miles. It has some of the same mods( 1.6RR,Shorty headers,Kand N with a flipped over air cleaner and chip) it still has the cats but a Corsa exhaust. It dyno at 284.8HP and 345TQ so the IROC beats it with TQ (of course). I still have a way to go on my IROC (to catch up with the Corvette) but To tell you the truth I'm gone as far as I want to go with both as far as the HP wars.

Imadude_134

iTrader: (9)

any chance you could post up the dyno graphs from the various rus? I would be curious to see how the curves have changed over the mods, rather than just peak vs peak measurements... peak may only go up a little, but area under the curve could increase greatly, meaning more lots more "usable" power with only a slight bump in peak...

and keep up the good work!!

cmk-2

iTrader: (1)

I'm not tech savy but i'll try. The car is still at the shop hope to pick it up tomorrow afternoon.

cmk-2

iTrader: (1)

Okay picked the IROC up yesterday and can tell you the good and bad. Good the car while only picking up 7 PEAK Hp and 15 Peak TQ it has gained power under the curve,WOW! I was at 45mph and floored it to get around a SUV and the power difference was more then just noticeable it was a real kick in the seat. It also revs MUCH quicker once past 4000rpms then before the headers. Also from about 4800 rpm before the headers the power band would drop like a rock and now with the headers while it still drops it's not nearly the lost of before. The bad is, it's louder and some harshness that makes me feel that the y-pipe might be touching something. I'll put it on my rack at home and see what I can see. I'll try to scan the dyno graphs in a bit. I would say that the headers have made the most noticable difference in power and harshness of anything I have done to the engine.

cmk-2

iTrader: (1)

Okay this is before headers and after. We did many diferent runs and this is the one I could put my hands on at work.

Kennerz

You need to check and make sure it's not banging on anything, the computer could be seeing knock from the exhaust taping. Hence pulling timing & HP. I have SLP's and they don't bang, or sound too raspy at all. I guess sound is really all about preference, but just saying there shoud be no exhaust contact with any other part of the car.

cmk-2

iTrader: (1)

I'll post this in a day or so in the for sale thread. I have for sale the MAC 21/2 Y-pipe that I had installed a few year back. Now that I went with an SLP header and y-pipe set up i'm selling this. If you have read this thread you will see that with a chip the MAC Y-pipe the increase in HP was about 6 rwhp BUT31 Foot pounds of TQ.The MAC Y-pipe fit perfect to the stock manifolds and my "Test" pipe to the rest of the exhaust. It lists for $180.00 plus shipping. It in great shape (no dents) I would like to get $100.00 plus shipping.email me at rbailer@embarqmail.com

Keoman

iTrader: (3)

Just curious, have you done any data logging at all?

cmk-2

iTrader: (1)

none