89IrocZ350TPI

I may be racing a 1995 Corvette LT1 with a 6-speed soon. How do you guys think this race will go 1/4 wise. Not sure about this one.


BTW I have an 89 Iroc 350TPI with a Cat-back w/high flow cat, Headers, Edelbrock Intake manifold and high flow runners [both ported by the guys at tpis], Ported plenum, Air foil, TB bypass, AFPR, K&N's, Gutted air box, Hypertech stage one, 160 thermo, MSD ign, cut out fins on the maf, re-maped the injectors, all the little bolt ons.

Heres an engine pic

92droptopws6

iTrader: (10)

nice and clean.
do you have a stall converter?
drag radials?
you should be running 13.70-13.90 at this point that lt1 vette should be doing the same or better so i would say if the vette has a driver you may not be in the winner circle.

ShiftyCapone

iTrader: (7)

As stated above the vette should be a mid 13 second car and you shouldn;t be too far behind. Do you have any chip work? If not I would say he gets the win. Racing from a dig would give you the best chance though.

89IrocZ350TPI

I did forget a few things. With the stock 2.77 gears I was running 13.8 at 97. Then I got 3.42's and drag radials then I ran 13.5 at 99. Had the car dynoed and got 245rwh and 325rwt.

80smetalfan

I thought I'd remembered you saying you'd hit a 13.5 with your car. That's all you needed to say!

I think it will make for a very close race if he's stock. If he can launch his 6 speed well and has sticky tires, you may be in trouble, as that eliminates your advantage off the line.

Orr89RocZ

iTrader: (20)

he'll pull you if he can drive. they are mid 13's stock easy.. but trap 100-102. from a dig, it will be somewhat close. from a roll, i think he'll edge u out

89IrocZ350TPI

My car has 51K on it his 100K if that matters at all. I actually got to drive this car a year ago. At the time I was driving a 15 second lg4 so the Vette amazed me. I remember it felt extremely quick in third and forth gear.

And yes he is 100% stock. Good for me right.

80smetalfan

I don't consider mileage to be a big factor. I've got a buddy with a built MKIII Turbo Supra with over 200k that would probably murder most of the under 100k cars on here, lol.

Now, if his car smokes blue like a frieght train and yours compression tests like new, that's different .


But the fact that he is stock does help you. And DEFINITELY go from a dig.

89IrocZ350TPI

All I know is that it ran near perfect last summer. Are the LT1 Corvettes underated like the LT1 Camaros were? I looked it up and it said it has 300 hp and 340 lb ft.

80smetalfan

Nah, I'd say that's the proper rating. With the LT1 F-bodies, it was more a matter of them having an almost identical motor and being rated 25 ponies less. I'm pretty certain the only difference between them is that the f-body LT1s have an iron block with aluminum heads like L98s, instead of being aluminum block as well, like Vette LT1s and LS1s.

However, I did just get an idea. If you guys aren't having anyone flag the race with their arms and are using the horn system, have him honk the 3 honks. It should make it more difficult for him to launch it.

89IrocZ350TPI

lol, If i win I want to beat him in fair game. Its not for money so its not a big deal. I found this on one of those sites that gives 0-60 and 1/4 times for factory stock vechiles.


1995 Chevrolet Corvette LT1 5.2 13.7

80smetalfan

Not surprisingly, that's a wee bit slower than they are.

https://www.thirdgen.org/newdesign/a...arofyear.shtml

Those sites usually rate L98s in the 15s for the 1/4.

89IrocZ350TPI

That one is rated at 13.4. The 95 has 10 more lb ft of torque. This is going to be a tough one. I hope my car has more in it than a 13.5 at 99 lol

nick418

My opinion the Corvette is still the winner. If that guy can shift and launch properly he will win. The LT1 vette is an awesome car. Ive driven them plenty times. You still have a good chance though. I love a L98 beating a later LTx or LSx.

nick418

I know that site is lame...

IROCThe5.7L

Go from a stop. You're going to lose from a roll. I raced one from a stop, and did ok until about 60ish. But I lucked out and grabbed hard off the line (Horray for 2.77's!).

89IrocZ350TPI

So are these cars pretty much even with a stock 00-02 LS1?

nick418

A stock LT1 vette will run mid to low 13s. There even with a LS1 fbody and lil behind a LS1 vette. Not by much tho. A LT4 vette can beat or stick with a LS1 vette tho. Are you sure his vette is 100 percent stock?

89IrocZ350TPI

Up I checked it out 100% stock. I ran a 13.5 at 99 BUT I am not that good of a driver. Maybe if I get more experience first I can get better times.

urbanhunter44

iTrader: (3)

imo you're only going to beat him if you can NAIL that launch like a ****. And you will have to race 1/4, because he's going to trap higher than you. I've seen those things routinely trap 103 bone stock.

The only difference between the Corvette and the F-body in the LT1 era is a difference in exhaust routing. nothing to cause 25 hp. Both had an iron block and aluminum heads. Same cam specs. They just underrated the Fbody. The reason the vette is faster is because it weighs several hundred pounds less. My '94 T/A weighed 3500 curb weight.

nick418

are u sure about that urban? Just the exhaust setup was diffrent? I know the vette had true duals all the way. Fbodies in 94 has a single cat.. I think in 95 is when they came with dual cats agian for a option? Also the Lt1 fbody had alum heads? Your right the LT1 vette traps higher then your l98. Thats what going to kill you. You ever think about switching it for an aftermarket intake 89Iroc?

89IrocZ350TPI

Ya, but I got alot of money into the TPI setup, had it all ported out and so.

nick418

True. You did spend decent money on it.. I thought you bought it like that? With the runners and ported and everything? Isnt it like 600 bucks for a HSR? Also where in Mass you guys gonna race! Serioulsy did you hit snow at all in your area!

89IrocZ350TPI

Ya I bought it like that. Still alot of money into it. I HATE snow and hope it clears soon. Doesnt look like it will but I like to think positive.

fly89gta

iTrader: (1)

I agree.

urbanhunter44

iTrader: (3)

I've actually researched this very topic. The only thing that's different is the dual exhaust on the vettes.

And yeah Fbodys have aluminum heads.. I used to own one

89IrocZ350TPI

I am also looking into a 2800 stall, along with a Comp cam. By the time all this damn snow melts I will proably have enough cash for a few new mods.

Dan8289gta

Spray it with 100 shot

89IrocZ350TPI

I saw a video of a White 91 Camaro racing a LS1 car. The 91 had a nos kit and dusted the LS1 off the line. Pretty cool video its in a thread on this site somewhere.

ShiftyCapone

iTrader: (7)

In '95 the dual cat cars were for California. Every other state had single cat cars. If you have a '95 with dual cats then it was sold in CA. In '96 they switched to OBDII with dual cats.

The vette had a better exhaust and air intake. That was the only difference.

Yup.

Nitrous Al

With no money on the line, just race him! Please post the results. Any chance I could attend the race (MA here, PM the location)?

89IrocZ350TPI

Damn I havent lost a race yet with the new car, and I have a feeling this time is going to be different.


btw I sent you the location....

hot92z

I raced an auto LT1 vette one day stoplight to stoplight....he put a couple lengths on me

By the looks of the list of stuff on your car and the fact you got an L98 I think you got a fighting chance at the very least you can get him in the 1/8 mile

89IrocZ350TPI

The one thing that I have going for me is that my car is very well tuned. I do have him beat in the torque department, and we are about even in horsepower. I am at least going to put up a fight

ShiftyCapone

iTrader: (7)

No offense, and I think your car is awesome, but a hypertech chip does not constitute as well tuned. It could actually be making you slower and have your car terribly out of tune. With the amount of mods you have a serious weekend of chip burning could add serious power. The mods you have have no doubt increased the VE of your motor by 10% or more. The hypertech just adds some fuel and timing to WOT where it may or may not be needed. It does not touch part throttle tune. Just FYI.

You may be even/higher in peak HP/tq (but I doubt you are at 300hp yet) but he wins the average power curve trophey. That makes a car faster.

89IrocZ350TPI

I also have a reprogramable chip from TPIS. When I had the car dynoed the Hypertech had 5hp more and 10 lb ft of torque over the TPIS. The car made 245rwh and 325wrt. When I posted my dyno graphs on here awhile back alot of people agreed that I am making around 300-306hp at the flywheel. I hear its a 20-25 percent loss for the auto but I am not sure, its just what they tell me.

ShiftyCapone

iTrader: (7)

Can you post those graphs now? I can help you determine crank power as well as gains through additional chip work.

89IrocZ350TPI

Here is the thread.......




https://www.thirdgen.org/techbb2/sho...i+dyno+numbers

Mod edit: I fixed your link.

Orr89RocZ

iTrader: (20)

your numbers dont seem all that bad. stock manifolds and exhaust really chokes the car, cuz bone stock my car seemed somewhat quick, but once i added the headers, it really rode out!. i'm trappin 100mph so thats gotta be close to 230-240ish rwhp. near 280ish crank? L98's really wake up with exhaust mods

ShiftyCapone

iTrader: (7)

Your graphs are decent but still expose the weaknesses of a TPI system. None the less your car hauls. Do you have the full graph that shows AF ratios. In that thread they are cut off from the dyno printout.

89IrocZ350TPI

No but i'll get some new ones up if you want. I hate math but 245rwh considering a 25 percent loss is 306 at the engine I believe. Also a car that runs mid 13's usually has 300+ hp. I dont really know I guess it all depends on what you use for percent loss.

btw I was told it had a better fuel ratio w/tpis chip.

ShiftyCapone

iTrader: (7)

Your math is correct but the 700R4 does not have a 25% parasitic loss. It is closer to 20. None the less you are close to a peak of 300hp at the crank.


Mid 13's in a 3rd/4th gen equates anywhere from 320 to 400 horsepower. You are not there yet. Less power goes farther in a car that weighs less. Mid 13's in a 3400 to 3600 lb F-bod take roughly a flat 400hp. I would say that you are in the high (13.8/13.9) range.

Based on various back to back chassis vs engine dyno tests it is normal for chevy owners to assume 18% for manuals and 20% for auto's.

89IrocZ350TPI

Oh ok I didnt know that it matter that it was the 700R4. There are so many factors its crazy. Dynos also vary alot so there isnt really an exact figure I guess. Is it the same concept in figuring the torque made at the engine as well? Which would be a 20 percent loss.

ShiftyCapone

iTrader: (7)

Dynos can very up to 8% percent. That is why you never take a dyno readout as an end all performance messure. It is a tool to look at power curves and AF ratios. A day at the track tells all.

As for parasitic loss. Automatics use planetary gear systems encased in fluid plus a fluid converter. Manuals use a helical gear system encased in fluid. Yadda yadda yadd, automatics suck up more power (greater coulumb and viscous losses) compaired to manuals.

89IrocZ350TPI

So I guess im in the ballpark of 290-300 give or take. I also have 325wrt is that equal to 390 at the engine. Or is that wishful thinking lol....

ShiftyCapone

iTrader: (7)

Correct on all accounts. It is pretty normal for a motor like yours to make near 400ft lb.

89IrocZ350TPI

Cool...Thanks alot for the information its been very helpful.

80smetalfan

But he's already hit a 13.5, as stated in his second post....

89IrocZ350TPI

That was beacuse of gears and better tires......had nothing to do with power being added.

80smetalfan

Yeah, I know. I was simply pointing out that you have already hit a 13.5 with less than 400 hp.