Does anyone know why GM put the "peanut cam" in the 86 tpi? did they reduce the cam in other camaros or other car lines? Just wondering.

Rich

 

To Make you Slow.

 

LOL

 

I think it was because the 85 tpi had problems with emissions and to fix that they changed the ecm and cam also the mass air flow from what I have heard??

 

At least a peanut is solid, like the Cam. Hey Hey Hey, Don't diss the 305 TPI.. If you dont think it can be fast then thats a buncha

 

Rumor had it that in '85 the IROC's performance was way too close to that of the corvette, as in almost exactly the same. And we all know that none of the cars made by GM were allowed to crowd the performance of the flagship.

 

which 85 engine are we talking about? Even the lb9 tpi has a 55ftlbs dis advantage compared to the vettes l98, and a carbed car would be left behind pretty quick.

lb9
0-60 7.0 1/4 15.2

vette l98
0-60 5.7 1/4 14.1

I think it had more to do with emissions than a threat to the vette. Its clear there isnt one.

 

Not much performance difference between the '85 IROC and '86 Vette. 215 HP IROC, 230 HP Vette 15 HP? not enough difference to really seperate them in performance. And those times are what GM quoted, the IROC came out quite a bit better than what they told you.

 

ok we are talking about the lb9 yeah its only 15 hp, but how much weight? 2-300lbs? im not sure, my 84 weights 3100 dry with no driver, the 85 will be the same. Whats the camaros weight?

The vette is more aerodynamic, and those times are from different magazines, i listed the most common ones i found.

The lb9's time matches similar to what my car ran stock with 205hp and the l98s times are comparible to what my car runs now, with about 230hp, the same as the 85 l98.

So it does stand to reason that its not as simple as a 15hp difference.

I do know my stock 205hp 84 vette is faster than the 215hp 87 t/a i used to own. And there both a lot slower that the 91 vette i had a year ago. Even modified with about 230hp my 84 is still a good deal slower that the 250hp 91. Its not the 20hp that makes the difference its the 50ftlbs difference.

Also gearing could play a role? Whats gears where on the 85 iroc? An 85 vette would come with 3.07's or 3.43's

 

3:73 or 3:42 were the only options for gears in '85

 

well if you lined up an auto c4 with a 3.07 rear and a stick iroc with a 3.73, it would definitley close the gap..

 

Some L98 corvettes got manual trannies too.....

 

I believe the new cam was for fuel milage and emissions reasons. The 85 IROC was nowhere close to the Vette in terms of performance. Most of the times in my pile of 85 magazines shows the TPI IROC running mid 15 second 1/4s, which is a good second slower than an 85 Vette. Being within 15 rated hp of the vette was not likely to be the reason. Look at the 1991 model year: 245 hp for the L98 f-body, 250hp for the Vette. Vette was still substantially faster.

 

I READ THE ARTICLE ON THE 85 TPI IROC AND TA WHERE THEY RACED EACH OTHER THE IROC RAN 14.93 WHILE THE TA WAS CLOSE BEHIND AT 15.10 THIS WAS THE FACTORY RACING THESE TO CARS I WISH I COULD FIND THAT ARTICLE FOR YOU GUYS THEY SAY THAT BOTH THE TA AND IROC HAD AUTO'S WITH 3.42 GEARS

 

I NO I RACED A 85 350 VETTE WITH MY 86 TA WITH TPI HE BEAT ME AT LEAST BY 5 CAR LENGTHS

 

Did you skip school often?

 

that damn caps lock key is busted again

 

3.42 or 3.73?
Pretty sure you couldnt get a 3.73 with the TPI in 85. I know my 85TA TPI had a 2.77 rear in it, 3.27 was optional.

 

You couldn't get 3.73 with TPI, and if somebody was running 14.7 with an 85 IROC, it definately wasn't stock. That's about what the 87 L98s ran. The 85 IROC was a mid 15 second car on a good day.

 

Huh there Jim?

My 1986 WS6 with peanut cam and 2.77 gears runs 15.6 all day long, BONE STOCK! add 25 hp and better 3.27 optional gear, 14's would be fairly easy with a good driver.

 

In 1985 you had 2 gears to choose from in the IROC, 3:42 or 3:73, I would imagine the T/A would have had the same gears avialable.

 

Incorrect, there were ONLY 2 gears offered in the '85 IROC and 3:73 was one of them, I chose the 3:42's for mine.

 

I've never heard of a TPI with a 3.73 rear. Iroc or not. I know you could get the 3.73 with a L69, but not LB9.

 

By the tech data you could get the 3:23 or the 3:42

 

Well, when I ordered my IROC in '85(ordering was the ONLY way to get one in my area), I was offered either 3:73 or 3:42 gearing. I opted for the 3:42 in hopes of better gas mileage.