Stock L98 with only exhaust and 1.6rr dyno numbers ...

Just put my IROC on the dyno for the first time today. I never thought I'd do it because it's just my beater car and I've never really had any intentions of doing anything with it (motor wise) so dynoing a pretty much stock 3rd gen just felt kinda silly. :lol:

But since one of the car clubs I'm in was having a get-together and we a $50/2 dyno pulls deal, I figured why not. I'd dyno the car just for sh*ts and giggles. :lol:


Here are the details of the motor.

- 1988 L98 with 180,000km on the odometer

- SLP headers
- Dynomax cat-back
- Crane 1.6 RR
- A pair of factory replacment K&N filters


That's it and that's all.

All else is 100% stock. The runner's, plenum and intake base are all 100% stock. Heads and cam, all stock.

Basically, just an exhaust and rockers and the car made 212hp and 290 lb of torque at the wheels.

I'm happy considering how little I've done to the car. I've got AS&M runners on the way and I'll be upgrading to a full 3" exhaust pretty soon (my current Dynomax is some strange size like 2 7/8 or something weird- not even a full 3" )

. I'm absolutely positive I'll put out in the area of 230-235hp and 310-315lb of torque at the wheels with those two extra mods alone. Can't wait. With an aftermarket intake base, and ported plenum, this car will really wake up. I'm guessing well over 250 at the wheels and in the area of 340 torque.

Assuming a loss of 20% through the drivetrain, I'd say those numbers come out to roughly 265hp and 360 lbs of torque at the flywheel.
Since these cars came with 220 off the assembly line, that means I gained nearly 50hp with just an exhaust and rockers. I'm sure it would have made even more if it didn't already have 190k on the odometer... :)

So what do you guy's think? 212/290 for 3 mods. Sounds good? I'd really like to hear what others have dyno'd with similar mods or what you guy's would reccomend I do next....

Here are a few pic's I snapped of my car. (excuse all the dirt, it rained all night long and I didn't have time to wash the car this morning :lol: )

http://memimage.cardomain.net/member_images/12/web/2376000-2376999/2376432_27_full.jpg
http://memimage.cardomain.net/member_images/12/web/2376000-2376999/2376432_28_full.jpg
http://memimage.cardomain.net/member_images/12/web/2376000-2376999/2376432_26_full.jpg

Sounds about right for a high mile (or KM :) ) 88 L98 with those mods - maybe even a little low. Have you tried cleaning the injectors or playing with the fuel pressure at all? That would certainly yield a little more power.

BTW - Why did they strap the car down so far forward on the rollers? Changing dyno variables like strap down location can greatly affect numbers. Not only that but if that car had a loose converter with some decent power you're asking for trouble being so close to the floor.

A little low? Thanks alot. Now you've gone and depressed the hell out of me. :( .....:D

The injectors are still stock yes, never been cleaned. I don't have an adjustable FPR 'cause like I said, with just exhaust and rocker's, I didn't really think playing with the fuel pressure would bennefit much at this point.
We'll see what happens after I install my AS&M runners and March under-drive pully's. Maybe an adjustable FPR will benefit me more than.

As far as the placement of the rear tires on the roller, yeah, I though it was strange too they put the car so far forward. I was actually worried the car might fly off the dyno and into the wall. I mean, the rear tire was only about 1" away from contacting the floor.

The guy doing the dyno said that's the position they always put their cars in :confused: Oh well. Nothing bad happened so it's okay I guess.

You haven't purchased the runners yet have you? For just a little more $ converting over to Holley's StealthRam will make tons more power. Enough to make bolt-on LT1s worry :)

21 of us got together and did a group purchase on the AS&M "big tube" runners. Our discount brought the price down to $340 compared to the usual $415+.

AS&M began production as soon as they received the orders and we should see them in about 2-3 more weeks.

We're also trying to get a group purchase going on either the Lingenfelter "Super-Ram" base or the TPIS "Big Mouth" base as well.

I'll be porting my plenum at the same time.

I know that when all is said and done and I have the base/runners, even with the money I saved on the group purchase deals, I still would have spent a lot more than if I had just gone with an HSR.. a LOT more, but I'm kinda parshal to TPI. :lol:

I'm not really interested in thr HSR for my application. I enjoy the low and mid-range torque TPI puts out and don't want to give it up by going with an HSR just to pick up HP at an RPM I'm never in anyways (5800+). In my opinion, torque is what makes these cars so much fun to drive. I realise that at best, this TPI set-up will flow to about 5500 and that's just fine with me. How often am I spinning the motor past that anyways? This is my daily driver and will also see some autox on the weekends. Another reason to keep TPI. Low and mid-range torque when you're coming out of turns is a huge advantage.

Top end HP is only good on long-enough straight away's where you actually have enough roadway to spin the motor that high in the RPM range.

Who knows, maybe one day I'll change my mind but right now, I'm dead set on keeping TPI. My IROC is my current "beater" car which, like I said, will see some autox on weekends.

My 4th Gen 396 stroker Formula Firebird is my "race car".