demonspeed

Say you have a 91/92 non G92 305/5 speed LB9. Still 3.08's, but could you get rear disc brakes. The reason is, say you had a G92 305 and a non G92 305, the ONLY difference is the cam and exhaust? So say you wanted t-tops real bad with a 91/92 and you wanted to have the same G92 performance with the 305/5 speed, all you needed was to swap 3.42's, dual cats, and the cam???? Following this? So you have a t-top, 305 5speed 91/92 with J65 brakes, you only need to get a G92 cam, dual cat and 3.42s? ok... enough for now, Ineed some replies hehe

Benny

I don't believe G92 has anything to do with a cam, the engine has the same output and cam if you have a G92 or not. G92 is the performance axle ratio option which is 3.23 on Auto and 3.42 on a 5 speed, also G92 has nothing to do with dual cats that is RPO N10. 4 wheel disc brakes is J65 which you mentioned. You could have ordered all of these and it would have flagged other stuff like engine oil cooler ETC, but G92 is only gears.

demonspeed

I've always thought the non-G92 had the "peanut cam"... hmm... I mean, the dual cats were only supposed to be 10hp, so 205 plus 10 is only 215 whereas the G92 had 230...

demonspeed

Here's what I found...

Lift Duration Lobe
Int. Exh. Int. Exh. Separation
305 5spd/305 AT .350 .384 179 194 109.0
305 G925spd/350 .413 .428 202 207 114.5

edit... well, that doesn't look to well here... just look in the tech and you'll see it down at the bottom...

Benny

I'm really not that sure, but i have heard of that "peanut cam" thing. The RPO decoder says that G92 is "performance axle ratio" I have the L98 so I am not up to snuff on the 305, however G92 on a 305 could have flagged other stuff, I believe someone out there knows. Interesting.

Benny

Just read the tech article and you are correct, the G92 equipped 305 received a different cam to boost HP to 230. I never knew that.

demonspeed

that's cool... everyone learns it sometime...

TPIterror

Actually, the G92 performance axle was part of a larger package called the R6P Performance Ehnacement Group. This package was available from 89-92(although it was not named this in 89-90) and included the KC4 oil cooler, the J65 disc brakes, the N10 dual converters, and the G92 performance axle(G80 limited slip+GU5 3.23 or GU6 3.42 gears).

I do not believe the G92 axle was available without getting the entire package. The package was standard on 5.0 TPI 5spd and 5.7 Formulas and GTAs(and 5.7 TAs). I beleive it was also an option for 5.0 TPI 5spd Trans Ams but I've never seen one with it.

Also the 89's had a different rear ratios of 3.27 and 3.45. Whew! I think that covers it.

f-crazy

iTrader: (-1)

damn u beat me to it lol..

yea what he said...RPO R6P...hey i got one of those!!

BORLAZ06

interesting my car never showed R6P and I have 'ALL' the above options. info in my sig.

TPIterror

Oh..well thats how Pontiac referred to it. Maybe its different for Chevy.

demonspeed

Yeah, I know about the cooler and stuff, I was just refering to the things that made it perform better. Not all 305 5 speed TPI's were G92 either.

TPIterror

Well..pretty much what was mentioned earlier...the exhaust and the cam.

ALL 89-92 Formulas and GTAs with a 5spd and TPI have G92.

TransamGTA350

iTrader: (2)

The part about the cam is correct through 89', but not for 90-92. There was no "peanut" cam in any TPI motor from 90-92, only in the LO3 305 TBI. The only cam available was the same as the 350TPI. In order to reduce the horsepower from 235 to 205, they changed the exhaust to the single cat 2.25" diameter setup from the LO3. If you do a search on this board you will find plenty of confirmation of this theory.

avro206

yes--what he said. Cam is the same--although for some curious reason redline is still 5000rpm for the auto cars and 5500rpm for the standards

Drakar

1990-1992
305 5spd / 305 AT 10088155* .350 .384 179 194 109.0


305 G92 5spd / 350 AT 10111773* .413 .428 202 207 114.5 (116/-116)


There was a peanut cam, as well as an exhaust revision for the 90-92 non G92 models.

Also the R6P I believe is only Pontiac.



PS, I think the peanut cam is the same cam they use in the L03 and LG4.

TransamGTA350

iTrader: (2)

Drakar,
Although the tech boards do state that there was a peanut cam in the 305TPI for 90-92, it is incorrect. It was proven through actual engine teardowns and performance gain comparisons of exhaust upgrades earlier in other posts. For example, a speed density 305TPI, non-G92 auto car can achieve 1/4 mile times in the mid to high 14's with only upgrading to a full 3" exhaust and mid to low 14's with headers. In comparision, stock 86-89 305TPI/auto combos with the peanut cam did come with the 3" exhaust and ran in the mid 15's. If you do a search on this topic you will see enough proof to change your mind.

Drakar

Thanks for clarifying.

Seems some stuff needs a bit of an update on the site.

TPIterror

I'm not saying you're wrong because I'm a little unclear on the cam thing too, but the only thing with that theory that doesn't add up is the dual cat exhaust alone being worth 25hp. Most literature I've seen(including my 90 brochure) says its worth 10-15 hp(it varies). And I think you meant 230 vs 205 hp.

TransamGTA350

iTrader: (2)

I meant 235hp for the 92' 305TPI/5-speed combo with dual cats. The dual cats were worth 10-15hp, so that brings you down to 220-225hp. Then there is the next reduction due to the 2.25" diameter pipe instead of the 3" which is another 15-20hp. The 205hp rating was probably a little conservative since GM wanted it's customers to pay the extra $1000 for the 350 which is almost 100% profit since a 350 costs just about the same to build as a 305.

demonspeed

yeah, that's what i've been thinking... but reading this stuff is making sense...

TPIterror

First of all, NO 3rd gen 305 TPI had more horsepower than 230. Second of all, why wouldn't they figure in the gain from the 3 inch pipe when they were quoting the extra horsepower from the dual cat exhaust? I believe the 10-15 hp from the N10 already figures this in.

TransamGTA350

iTrader: (2)

Ok, whether it's 230 or 235, it really doesn't matter. As was stated earlier in this post, the tech board is not 100% accurate and I have seen ratings from a 1992 edition of Car and Driver of 235hp for a G92 305TPI/5-speed. The 10hp gain for the dual converters claimed by GM was also in their 1989 product literature where the single 3" cat and dual 2.25" cats were offered simultaneously. You will also see the 10hp difference in the Tech boards for 89' TPI motors, and that part of the tech board I do believe is correct. So lets just say that the G92 305TPI was 230hp. Now, you need to lose 25hp to get to 205hp for the non-G92 version of the same motor. 10hp loss by changing to a single 3" converter, then another 15hp by changing the entire exhaust system including the manifolds to the LO3's single 2.25" system. Now, look back to 85' when the 305TPI in the Firebird has 205hp and lost 15hp in 86' due to the "peanut" cam. You will see that you will lose much more than 25hp by changing from dual 2.25"converters to a single 2.25" and a cam change.

TPIterror

I realize the Tech board is full of errors(including the 89 info). Thats why I dont even consider it a valid source. I base my information on articles and brochures that were available at the time(I'd like to se that Car and Driver you're mentioning). So based on what I've seen, logically, it should break down like this:
87 305 TPI 5spd 205 hp
88 305 TPI 5spd 215 hp(slightly better cam and better air inlet)
89 305 TPI 5spd 225 hp(dual cat exhaust)
90 305 TPI 5spd 225/230 hp(I've seen both.. no mass air)
91-92 305 TPI 5spd 230 hp(lighter pistons)
(this is all based on Firebirds)

The exact horsepower IS important , if you're going to be subtracting 5 here and 10 here to get to a new figure. All I'm saying is that I believe Pontiac was figuring in the gain from the ENTIRE exhaust system when they were quoting the 10-15 hp increase. The cam(which has different part numbers from auto to manual) should account for the difference.

My car for example; 225 hp and 200 hp with automatic. Lets say thay DO use the LO3 manifolds on the auto and they didnt figure them in with the gain from the N10. Are they really worth another 10-15 hp? Both the TPI and LO3 manifolds are pretty restricitive. I'd say a gain of no more than 5 hp, if that. The rest should be attributed to a cam.

Check this site for cam info:
http://www.3rdgenformula.com/

TransamGTA350

iTrader: (2)

So you do agree that a 10hp gain was solely due to the dual converters. The 88 305 TPI 5-speed had a single 3" exhaust system including the high flow manifolds. The only change in 89' being the N10 dual cat exhaust which resulted in the gain of 10hp. I do not believe that changing from a single 3" with the better manifolds to the a single 2.25" with low output manifold will only gain 5hp, it's more like 15 and that where the 25hp comes from.

The fact is, from 87'-88' the difference between G92 and non-G92 package was 25hp and due to the smaller cam only, since both had the single 3" exhaust. 89' was a 35hp difference because of the smaller cam and the dual cat exhaust(there's the 10hp). But then, in 90' they introduced the single 2.25" exhaust on the 305TPI/auto which had never been there before and yet the hp difference between the G92 and non-G92 was 25hp. So, they had to give up something to maintain that 25hp difference since the smaller exhaust was now on there, so all TPI's got the same cam. If they put the peanut cam in there, there would be a 50hp difference basically turning it into the LO3.

Also, your 230hp figure is based on Firebirds, and I'll agree to that. I'm sure that you're aware that from 85-87, the Camaro TPI engines were rated 10hp better, and from 88-92 they were 5hp better. That would make the 92' 305TPI/G92 235hp in the Camaro.

TPIterror

Nobody is saying they used the peanut cam in the autos, just a DIFFERENT cam with less lift. Did you see the cam charts on the link I gave you?

The 230 hp figure applies to both the Firebird and Camaro. The hp differences in the air intakes was negated once Pontiac went with the better intake after 87.

I respect your opinions, but I'll reserve my judgement until I see more valid proof.

TransamGTA350

iTrader: (2)

Yes, I looked at it and the cam has the same specs as the peanut cam.

TPIterror

Oops my mistake, I just noticed that. The bottom line though, is that the cams are different and account for horsepower variances.

Drew

iTrader: (58)

This thread is chalk full of misinformation, speculation, guesses, and ignorance.

Do a search, read a couple sales brochures and GM paperwork, and then post your findings.

Everything from the Firebird DOES NOT CROSSOVER to the Camaro.

If you don't know, don't act like you know. I'm locking this thread because its crap and it shouldn't be read by anyone except those who are into conspiracy theories and debate. Take this kinda crap in the chatroom.