I can't seem to find on TGO why the 1990 305 TPI has 5 horses more than the 91-92? They had the same camshafts as the 91-92. Well the one I'm putting in my RS is from a 1990 T/A, and it did have the 350 cam in it. I checked. I've read that most to all 305 SD TPI's had the 350 cam.

Does anyone have some insight as to way the 5 extra horses. I'm not complaining, just wondering.

 

The TA has 5 less than the Z28 because of the air intake or snokel.The motors are all the same from 90-92.I hope this was helpful.

 

I understand the T/A's have a more restricted air intake, but the HP ratings on TGO are for Camaro's. So mystery still unsolved, thanks for your input.

 

Not to be the devil's advocate or anything here, but since when were the the Speed Density LB9's not 220hp or 230hp??? Maybe a FAQ someplace around has them listed as varying amounts from previous A4 years (205/210?), but IIRC all 305's became the 220/230HP mill after 90 or so, when they all (A4/M5 alike) got the L98 cam. I know their fueling maps are about identical to the L98's, suggesting that the cam is the same in profile, further suggesting that they are all 220/230HP. The 10 Pony difference there is whether it was a dual cat car or not.

If you were to ask a question, ask why you even have the figures 205 and 210 HP for SD LB9's to begin with, because those are wrong.

Previous A4/single cat LB9's made that power, but that changed once the L98 Profile cam became standard on all LB9's, and especially with the dual cat option.

 

When did the L98 cam become standard in 305's. Is that whats in my 87?

 

It was either 89 or 90, that it came in LB9's across the board.

The L98 profile cam came in M5 cars 87+, so if you have a 5 speed, you likely have the L98 cam. If you have an A4, you have the peanut cam.

 

I was only going by what's listed in TGO's tech data page. Thanks GodOverYou for being insightful. I haven't started messing around with chip burning, but what you described makes sense. Thanks again!

 

The 205 hp versions had single 2 1/4 inch exhaust as opposed to 2 3/4, along with 2.73's, drum brakes, ect. in most cases. They all got the same cam starting in 1990.

 

All TPI cars from 1990-1992 had the L98 cam. Check out my Lb9's dyno numbers below. That is bone stock. So at the crank that's around 230hp and 320tq. It's a single cat 2-1/4 exhaust, but had aluminum drums and aluminum driveshaft stock. So maybe that helped things, bust still it came stock with those. Unless the 700r4 is very efficient, with less than 10% Dt.Loss.

As for the hp difference between the years, who knows. In 1985 The camaro had 215hp and the TA had 205, the next year they both had the same 190hp. I think it's just published unsupported facts and bad editing.

 

I'm still mystified by this 1990-1992 205HP LB9 that's being refered to. They just don't exist, period. You had a choice of exhausts, and that was the HP difference. You could get a single cat, or a double cat, but either way, it was a 10HP difference, not a 25 HP difference.

Even much larger, higher rev'ing LT1's only gained about 10HP with an extra cat.

 

Even still, the LT1 also had a little bit larger exhaust. I think it was 2-3/4. But nonetheless, a 2nd cat won't give you that much hp, considering it still has to go back out the same crappy pipe.

 

Well, my point exactly. That second cat should have been more beneficial (for peak HP #'S) in the LT1's case because it did go back to a larger exhaust, with a larger displacement engine, and a higher powerband.

There simply was no 205HP LB9 in 90-92.

Sorry - this has become my favorate little rant thread simply because I remember being interested in the Fox bodies back in that time period, and was always pissy that the 305 had an extra 5 to 15 horses.

 

I'm glad to known I'll be starting with 220HP not the 210HP or other wise(205HP). Godoveryou, I believe you! I looked at several 3rd gen sites and they all the same HP numbers as my topic describes. That's way I asked the question. Thanks again!

BigWhiteGTP, that's the same set-up going into my RS. 305 TPI, aluminum driveshaft and drums. Well mine's a 90. I'm adding a 3.23 posi with discs, Mac headers and hopefully a good cat-back system. That donor car had some serious huevos when I drove it home. The last owner thought it had a 350, I wish but vin "F".

Oh by the way the intermidiate from the 1990 T/A bolted right up to a 91 v6 firebird.

 

Yup, for the longest time I thought the Lb9 was a dog but I am very impressed with it. I just recently put on some headers, but have yet to run it because the piston rings are shot, therefore I haven't been able to drive it.

 

The second cat is not the point, the single 2 1/4 inch i-pipe vs the 2 3/4 inch is........ A member here (ed maher?) picked up 2 or 3 mph and 3 or 4 tenths in the quarter by just swapping from one factory exhaust to another. The gm ratings mean nothing as always

 

GMGod has it right. The difference between the 205 HP LB9 automatic and the 230 HP LB9 stick is the dual cats, AS WELL AS the larger intermediate pipe and muffler. The LB9 automatic has the choked off 2 1/4" TBI exhaust, while the LB9 stick with dual cats has the better 2 3/4" L98 exhaust. The LB9 automatic also has the smaller TBI exhaust manifolds. That easily adds up to 10 HP for the dual cat setup and 15 HP for the larger exhaust making the 25 HP difference. Believe it, or not.

 

Not all 305's came with 350 cam. Before 1990 all IROC-Z' 305 5-speeds came with the 350 cam. The 350 cam profiloe did cahnge over the years though. 305 auto still had the peanut cam because the 305 with the 350 cam would not idle well when stopped in drive.


After 1989, all 90-92 305's came standard with the 305 cam. Regardless of the tranny option. UNLESS the G92 option was specified, then the 305 got the 350 cam. G92 was a manual only option.

 

From personal experience I can tell you that you are wrong. I pulled a cam from an LB9/A4 91Z and it had the L98 cam's part number. My old 88 T5 bird was a non-G92 car, but with the L98 cam as well.

Do a search, many other members have pulled cams out of their 90-92 Auto 305's to find that part number on it as well.