Bandit400

anyone have figures for what hp/tq the stock L98 cars put down? I am particularly interested in the '90-'92.
If anyone has figures for the 305 cars, I'd like to hear those, too.

3.8TransAM

I put down 225 hp and 315ft lbs on a dynojet

Mods:
SLP catback
24 # svo inj
my own chip tuning

later
Jeremy

D Stroy H8

Typical L98 Dyno BONE STOCK

190-215 RWHP
290-315 RWTQ

White91GTA

On my old L98, with 159,xxx miles:

169.7 RWHP
239.0 RWTQ

That was the first of 3 runs and each of the other 2 was lower due to car not cooling and ended up spinning a bearing.

92BLKL98

Before any mods with 205,000 miles mine was:
214.4 RWHP
338 RWTQ

White91GTA

your car must have been well taken care of in order to still put those numbers down with 205K on the clock

D Stroy H8

I am always surprised at how much RWTQ these babies put down. AVG is 290-315, and this guys L98 puts down 338RWTQ at 205,000 miles!!


Even if you hate the TPI cliffhanger at 5,000RPM, you gotta love the 300+ RWTQ stock

c4boom

yup yup love being able to nail it at 25-30 and smoke em

Bandit400

pretty impressive #s - especially the torque. thanks for the responses.

Yield

arnt the horse power and torque numbers on this site acurate? just curious because according to this site a 90 to 92 305 can get 205 horses? is that number wrong?

Shaun 90 Iroc

90 Lb9 (305) bone stock... TPI A4, converter issues.. 179rwhp and 243rwtq at 135,000 miles.

Figureing in the 22% drivetrain loss for the 700R4


218hp and 296 tq at the flywheel.

I think the only real mod at this point was 80 series flowmaster exhaust and high flow cat. 3" cat back system. Airfoil. Hypertech Performance Chip. not reall much.

So i would hope the l98 would be around 200+ to the wheels. since they were rated 35 more hp than the lb9.

D Stroy H8

The tech data provides GMs flywheel numbers. We are talking about actual wheel numbers.

Flywheel numbers will always be higher than wheel numbers because after the flywheel, power must be transferred thru the transmission, driveshaft, and rearend.

For an appropriate example, a 1990 Firebird Formula 5.7 TPI is rated at 245hp & 345tq. These are flywheel numbers. Put that 1990 Firebird Formula on a dyno and actual output (power reaching the actual ground after drivetrain travel) is about 200hp and 300tq.

RWHP = rear wheel horsepower & RWTQ =rear wheel torque

JerseyIrocZ

The other day i got the 89 l98 put on the dyno and it put out 227 to the wheels and 317lbs of torque. Thats with full exhaust including headers, 48 lbs of fuel, air foil, 3.45 rear, K&N filters, and 67k on the clock. I ran on the first run 187 to the wheels. We let the car get to 230 deg. F. and ran it and it ran 223 to the wheels then took out the air filters and it did 227 rwhp. So if anyone gets their L98 done let it warm up to open the loop and you will probably get better hp. I gained 40 rwhp by doing this and thats with #3 wire arching on the header. and with no tuning.

Shaun 90 Iroc

yea, i said 179rwhp and 243rwtq

White91GTA

With the exception of mine Shaun...you know the reason behind that.

Shaun 90 Iroc

c4boom

ok whats the inside joke

White91GTA

there is no inside joke...what happened was while i was dynoing, the car would not cool and ended up spinning a crank bearing.

c4boom

well it is sort of an inside joke its inside your motor and it was a very very bad un funny joke man that sucks sorry to hear that

White91GTA

its all good...now i have a fresh motor

PsychoGTA

On my 92 GTA 350 tpi. I got 208 rwhp and 300 rwtq stock. With the exhaust done I got 232 rwhp and 325 rwtq. Then w/ cut-out open I got 242 rwhp and 338 rwtq.
Peace Out,
PsychoGTA:lala:

D Stroy H8

These cars are definitely choked up w/ exhaust. I'll bet with !cats or even new cats you'd see 250rwhp and 345rwtq. Man so much torque for almost no work.

dj haf

when i took out my cats, i gained .3 in the 1/4 mile. before that, with just flowmaster 80 series exhaust and free ram air i put down a 14.8... my tranny sucks

aaron7

iTrader: (7)

Totally off topic... but for some reason I couldn't send a PM. Why is the Iroc on your door towards the front like the 85-87 ones?


Yah I wish I knew what my car dynoed, but it's so dang expensive!

Shaun 90 Iroc

The person who owned it before me heard the horror stories of the factory paint and put on a few more coats and put new decals on it. He put them in the wrong spot though. I have gotten the hood, roof all the way down past the gas tank cap to the stripes on the rear panels and the spoiler and deck lid painted, but i am waiting on doing the doors and front bumper and everything else until its not a daily driver. I will move them to the correct location when i do. My dad bought the car in 94 and gave it to me when i turned 16 in 99.

formul8!!

Compared to some of the above numbers and lack of mods, I must be doing something wrong...



My mods to this car are here: www.cardomain.com/id/formul8

D Stroy H8

Running a bit rich no?

c4boom

no he is running a tiny bit lean he would probaly get a few mor HP it he got it to about 12.5- 13/1 good job man that thing is doing awsome for stock

D Stroy H8

It is not stock. And I failed to look at the WHOLE fuel curve... definitely a bit lean

1bdbrd

iTrader: (1)

i think mine is a freak or somethin. had 151k miles on it at the time of dynoing:

229rwhp and 359rwtq. i can list every mod ive done to it at the time of dyno:

vette stall, vette servo, ghetto wai, 3 inch catback 3 inch cutout, and an msd stock replacement coil. no other mods.

DSM

iTrader: (1)

I just dyno'd mine yesterday -

-stock 89 350 shortblock, stock 89 Vette aluminum heads
-ported plenum. stock throttle body, runners and base
-Edelbrock TES and test pipe, STOCK cat back!
-paper air filters, stock pulleys, no air-foil, MAF screens in place
-very close to stock roller cam 202/207@.050, .476 lift
-custom calibration

With a 5 speed and 3.42 gears, it put down 248 hp and 345 ft/lbs.

cronsformula350

my 89 formula 350, ran 14.70's while slipping at the track with 125K on the odometer.

What kind of times were you guys running in your cars, before or after you dynoed them?

I might take my 87 iroc-z to the track this tuesday, I chirped third the other night(no shift kit/orig. trans), the porting work I did to the base, runners and plenum has definitely made a difference, even though the car has 138K on it, it runs good.

check my beasts out.

http://www.cardomain.com/id/cronsformula

swisscheese

I dynoed 204rwhp and 308lb. ft.

engine 305 TPI
(official numbers were 230hp, 300lb.ft. for dual cats)


mods at this time: cat back, afpr, airfoil, k&n with cold air

aaron7

iTrader: (7)

Sounds like a nice setup... why the stock exhaust?

DSM

iTrader: (1)

Thats the way I bought it from a coworker earlier this year. A cat back is at the top of my list....

cronsformula350

have any of you guys, put a cam in that works great with the tpi, and then used a HSR or Mini ram, with the same cam.

dj haf

comp cams 08-503-08 is the cam you'd want if you're going to go with LTR's or the HSR. you might want to think about going with 1.6 rr's too if you go with that cam, for the extra power you get from increasing the lift.

cronsformula350

thats the cam I'm already going to run with 1.6 rrs on my formula, I might put it in my iroc too, but you see I have two f bodies, 89 formula 350, and 87 iroc-z.

check them out: http://www.cardomain.com/id/cronsformula

87-5.7iroc-z

I had the guys at school run mine on the dyno. 175000 stock. 165 hp on the first run, but it would down shift and spin the tires. So we unhook the kick down lever and ran it again. 195 hp and 255 ftlbs.

aaron7

iTrader: (7)

Wait, do you have a dyno at your school?? I was lucky to have woodshop class!

whiteshadow87

iTrader: (1)

Got mine dynoed yesterday and put down 206 RWHP and 300 RWTQ. This was with a really bad miss that has been mistaken for a cam on many occasions and is clearly seen on the dyno sheet.

cronsformula350

after I put my edelbrock shorties and y and custom 3" dump on my iroc and a fuel pressure regulator, I'm going to put my car on the dyno and see what she'll do.

White91GTA

i am going to dyno mine again after i get the tranny rebuilt. don't want to take a chance of it crapping out on me.

87-5.7iroc-z

I am taking Autobody courses at the community college. The Automotive shop next door has a Dyno.

Yield

anybody have any dynos specs for 305s?

Black 91 Z28

This was after the Headers, Catco Cat, and hooker exhaust.

swisscheese

There you go:

Link to Dynorun

Theres a pics of the sheet. couldnt post it as a pic here

Firebreather

I saw a guy's 87 (L98) with shorties,3" exhaust, UD crank pulley,K&N, and 1.6:1 roller rockers. It dynoed at 225rwhp and 337rwtq. His said his car ran 13.9 . I never had a change to take mine to the dyno. What do you guys think it would have put down?

White91GTA

firebreather...ditch the flowmaster dude, they sound like ***. you would be better off with the dynomax bullet race mufflers. they are a straight through muffler that flows upwards of 2200cfm and sounds sweet.

cronsformula350

flowmasters sound tight on stock cammed motors, in my opinion. Bullets kick more ***, I have some on my dads 68 gto off the headers, sounds mean as hell with the cam intake combo on it, but a mid twelve second car putting out over 450 flywheel horses will. I'm going to be running edelbrock shorties through the cat, then a bullet dumping before the right rear wheel, it should be loud and sound sweet as ****.