vortec tpi

Just picked up an 89 IROC with a 5spd trans. Is stone stock except the hooker cat back exhaust. See from the spec section that a little over 20,000 iroc's made but doesn't list how many were stick cars. Anybody got any info on production numbers for 5spd cars? Thanks

yaj15

iTrader: (3)

Ask Chaz to see if he knows. He is a real expert on thirdgen history and he has a black 1989 IROC with the G92 option and a 5-speed with only 11,000 original miles and he is the original owner! Ha ha many of us are jealous of him for that car. It's very nice.

Does your car have the G92 option as well? That would make it more rare among the small amount of 5-speed cars that were produced in any given year compaired to the production numbers for automatic transmission equipped cars.

AmorgetRS

iTrader: (6)

Nobody knows how many were produced as GM didn't keep track of combinations of options.

navy02ws6

...or so they say. You can thank Ralph Nader for this. I'm starting to wonder how long it's going to take before we can forget the whole "unsafe at any speed" lawsuit and just release the numbers.

vortec tpi

Has all the option listed to be a g92 optioned car. Dual cats,16" wheels 4wd brakes etc. I expect that it is but need to verify somehoe to be sure

chazman

iTrader: (4)

If it has dual cats, then it's a G92. Post some pics and get one of the SPID sticker inside the center console and we'll verify. I don't know how many 5 speeds were made in '89, but only 1500 G92s were made.

yaj15

iTrader: (3)

Yes if you have the G92 option package for 1989 IROC with the 305 TPI you should also have the following options as well:

LB9 (the G92 cars got the same cam that came in the L98's). From 1989-1992 to get the higher spec L98 cam in the LB9 you had to select the T-5 transmission and G92 option. That mandated some other factory performance related hardware. For these later years (1989-1992) G92 became more of a performance option package rather than just a set of steeper gears in the rear end as it was with the 1982-1988 cars.

N10 dual cat exhaust

PBR calipers and 11 inch rotor - rear brakes

T-5 trans with the G92 spec 0.73 overdrive gear ratio instead of the non-G92 0.63 overdrive gear ratio
The first-fourth gears are the same in both cases.

Aluminum driveshaft

9bolt Borg Warner rear axle with posi-traction and 3.45 gears.
This was the steepest rear gear option that you could get from the factory with an LB9. The L98 cars were also equipped with the same rear axle but only 3.27 gears (with the G92 option) and all the L98's were paired with the 700r4 automatic.

I know I probably left out some other options like the engine oil cooler but you get the drift here. The G92 cars had the factory speed parts that most of us are looking for or are upgrading to if our cars didn't come equipped with some of these options in the first place.

I wish that all the higher level performance cars (Z28's, IROC's, Trans-Am's, GTA's, Formula's, etc.) over the entire 10 year production run of thirdgens got a combination of G92 and 1LE factory speed parts to start with. I know that the performance minded folks like us would have liked that. I am sure though that the money folks at GM would have stopped that idea if it came up. Higher asking prices for all the factory performance thirdgens would have cut in to their profit margins - at least that's what I think the money folks at GM would say.

eseibel67

You are correct about the business end. A car that has high performance looks will always be more profitable because the aveage Joe with the checkbook doesn't have the faintest clue what he's looking at. In the era when 3rd gens were new, there weren't more than a hand full of GM dealership salesmen that even knew that G92 or 1LE was even available.

An IROC with a TBI and high MPG gears that the dealership had in stock was the profitable sale.

yaj15

iTrader: (3)

That also explains why there were so many LB9/700r4 cars with the non-G92 spec cam - I assumed that was a money driven choice too.

I get that the L98 was not going to be the bread and butter with respect to the fastest money making engine option that was available. The L98 was an expensive engine option compaired to the L03 or the LB9. Still I just wish that they had given the G92 spec cam (for whatever year we are discussing) in the LB9/700r4 cars as well.

With the high performance thirdgen cars there were more LB9/700r4 cars produced than any other engine and transmission drivetrain combination. The LB9 (even with the peanut cam) was a step up from the L03 yet it didn't have the over $800 option cost of the L98.

Also GM allowed some of the peanut cam LB9's to be paired with the T-5 trans as well so that was another way for GM to make more money in a peformance car while still not loading it up the way they would a G92 optioned car.

vortec tpi

Thanks for all the info. Car will be going up on the rack tomorrow to ck for the aluminum shaft and oil cooler. Does have the PBR brakes on the rear. Will post up some pics too. Car is red with the normal pealing clear coat paint. Car was bought local and has been here all it's life. Guess you could call it a barn find since it was stored in a garage for the last few years.

chazman

iTrader: (4)

It will have a steel driveshaft. The Al was only on the 1LE or highly optioned cars which were at risk for surpassing their EPA weight class.

Slater126

iTrader: (1)

Are you certain that the 1989-92 non-G92 LB9s (including 5-speeds) got the peanut cam? We had a dispute over this in this thread, where I took your position but many told me I was incorrect.

https://www.thirdgen.org/forums/hist...iroc-best.html

Read post #s 20-30. What is the basis of your knowledge that G92 LB9s had the hotter cam?

yaj15

iTrader: (3)

For 1989-1992 the G92 option package also required you to get some other manditory options when you selected the L98 or the LB9. I still think that for the 1989 model year the cars with the LB9's that got the G92 option still got the L98 style cam. Although some of the information that I have found doesn't support my assumption 100%.

https://www.thirdgen.org/1989-chevy-camaro

http://www.streetshowdriftdrags.com/Camaro.html


1989 Chevrolet Camaro History


Sport Coupe dropped, replaced by returning RS model. 1989 Chevy Camaro RS now available with LO3 V-8. Headlight pockets on RS no longer painted black. '89 Camaros now came with rear shoulder belts. The Corvette PASS-KEY ignition lock system was adopted for all 1989Chevrolet Camaros.The base 15 inch IROC wheel was restyled to have the appearance of the optional 16 inch wheel. P245/50ZR-16 tires replaced the P245/50VR-16 tires on the IROC-Z when equipped with the 16 inch wheels. TPI motors got better performing `Multec' fuel injectors. The exterior of the TPI plenum changed slightly: the ridges on top of the plenum did not extend as far forward. Calibration refinements eliminated the cold start injector.Four wheel disc optioned (J65) IROC-Z's rear brakes were increased in size from 10.5 inch rotors to 11.65 inch rotors with PBR Australian built aluminum calipers and more reliable parking brake actuators. Front discs still had 10.5 inch rotors with Delco-Moraine single piston calipers.

G92 option included: N10 performance exhaust system (dual catalytic converters) which increased power output by 13% on cars so equipped. For 1989, G92 also required the following options:

• 5.7 TPI motor (B2L) or 5.0 TPI motor (LB9) with 5 speed (MM5) manual. 16 inch wheels (N96) P245/50ZR-16 Goodyear Gatorback tires (QLC) Limited slip differential (G80) Rear disc brakes (J65)
• Engine oil cooler (KC4)

G92 and J65 (rear disc brakes) no longer available on IROC-Z convertible.G92 and J65 (rear disc brakes) no longer available on LB9 automatic IROC-Z.1LE performance package option (option level 0 IROC-Z) became more well-known.

1LE package was obtained by ordering the following:

• Level 1 IROC-Z with 5.0 TPI engine with 5 speed or 5.7 TPI engine Optional axle ratio (G92) (305/3.45, 350/3.27) and its required options.
• Air conditioning delete (C41) (standard heater)

Then the 1LE performance package was installed consisting of:

• Fog lamp delete Aluminum driveshaft (JG1) Performance exhaust system (N10) (dual catalytic converters) Special deflected disc shocks Aluminum spare wheel with smaller spare tire (N64) Larger (11.86 inch) front rotors with Girlock or PBR Australian built HD front dual piston aluminum calipers Special swinging fuel pickup in gas tank and special 18 gallon baffled fuel tank for fuel pickup down to .5 gallon reserve to prevent fuel starvation in hard cornering.
• Some came with special 16x8 light alloy mesh wheels. (XWL)

111 1989 1LE IROC-Z's were produced.

A new progressive throttle linkage was added to give smoother initial acceleration. The throttle had a smaller rate of advance at beginning of travel, and a larger ratio as the throttle was depressed





Unlike the 1985-89 models, G92 option in 1990 (I think that should also apply to the 1989 models too) was expanded and purchased as a full "performance package" rather than requiring other options and simply being a performance axle option.

G92 could be ordered two ways:

with or without air conditioning. Ordering G92 `without air conditioning (C41 standard heater)
added the 1LE . The G92 package was only available with 5.7L 350ci B2L code or 5.0L TPI 5-speed LB9 code. All 5.7L 350ci IROC-Z's were required to have the G92 package in 1990 and 1991-92.

G92 with air conditioning (C60):

- Optional axle ratio (5.0L 305ci w/ 5-speed = 3.42 ratio and/or 5.7L 350ci = 3.23 ratio)

- Rear disc brakes (J65)

- Performance exhaust system (N10) "dual Y-pipe w/ dual catalytic converters"

- Engine oil cooler (KC4)

- 5.0 liter TPI (LB9) with 5 speed gets revised and more aggressive cam for 230hp rating

- Weight saving spare (N64)

G92 w/o air conditioning (C41) in addition to above adds 1LE "Road Racing" performance package consisting of:

- Fog lamp delete

- Aluminum driveshaft (JG1)

- Larger (11.86 inch) front rotors and PBR Australian built HD front dual piston aluminum calipers

- Special swinging fuel pickup in gas tank and special 18 gallon baffled fuel tank for fuel pickup down to .5 gallon reserve to prevent fuel starvation in hard cornering

The 1990 model year was only a half year of production. Due to the termination of the Chevrolet IROC contract, no IROC-Z's were produced after 12/31/1989. Instead, the

1991 Camaros were introduced early during last half of the normal 1990 model year...

1990 IROC's are easily identifiable: 1990 was the first
year for the updated interior which included drivers side airbag, redesigned instrument panel, yellow lettering on dash, rounded controls, etc. So 1990 IROC's are the only IROC's with the new interior...

In 1990, the base engine for the IROC was finally the higher horsepower LB9 TPI 305 rather than the base lack luster economy version TBI LO3 V-8.

However, G92 had to be specified now to get the more aggressive cam and 230hp LB9 motor in the 5 speed LB9 IROC-Z.

Previously, all 5 speed LB9 IROC-Z's got the higher output LB9. One other difference between a 1989 5.7 IROC and a 1990 5.7 IROC are the pistons.The 350 (only) received lighter weight pistons thus a slight horsepower increase of 240 (1989) to 245 (1990).

In 1990, TPI Camaros switched from MAF air metering systems to MAP systems. This eliminated the mass airflow (MAF) sensor...

IROC-Z convertible now came standard with 16 inch wheels and P245/50ZR-16 tires.

G80 limited slip differential became standard equipment on IROC-Z.

The Borg-Warner HD rear end was dropped and replaced with the old 7.625 (7 5/8) inch rear end. Because the Borg-Warner axles were no longer being used for the G92 option, optional axle ratios changed slightly:

LB9 305 TPI 5 speed went from 3.45 (1989) to 3.42 (1990)

and the B2L 350 TPI went from 3.27 (1989) to 3.23 (1990).

Quote:

Originally Posted by Slater126

Are you certain that the 1989-92 non-G92 LB9s (including 5-speeds) got the peanut cam? We had a dispute over this in this thread, where I took your position but many told me I was incorrect.

vortec tpi

Car has the 9 bolt axle and oil cooler plus all the other G92 options. Does have a steel driveshaft. Also has air/pw/pdl/power mirrors/power seat. If GM put the aluminum shaft to meet weight requirements you would think it was installed in ac cars instead of no ac. http://s810.photobucket.com/albums/zz25/bbc-olds/ is a couple of pics of the car including the tag under the console. Looks like the engine is in need of repair. Spins over good but doesn't sound real great. Now the big decision is what to do with it. Options include restoring it back to stock/installing a 350 like gm should have(making it look stock)/ or sell it.

yaj15

iTrader: (3)

Thats good. Should have the RPO G92 code in the inside of the console or in the driverside lock box in the trunk.

That was the other thing that I forgot to ask. I know that for the 1990-1992 model year Camaros you couldn't get T-Tops and the L98 engine.

Also for the 1990-1992 LB9/T-5/G92 cars you were forced to get a hardtop car because T-Tops were not available with those options either.

For the 1989 cars with the G92 option - Are they all hardtop cars no matter if they are L98/700r4 or LB9/T-5 powered?

chazman

iTrader: (4)

Says G92 right on the SPID. Looks like a red twin to my black '89. This car is worth saving. Figure 1500 '89 G92 cars. How many were 5 speeds? 3-400? Less?

Slater126

iTrader: (1)

Thanks Yaj. So per http://www.streetshowdriftdrags.com/Camaro.html, you had to order the G92 package in 1990-92 to get the L98 cam. All non-G92 LB9s during these years, even 5-speed manual cars, got the peanut cam.

That is consistent with what I deduced from the lower RPM tachometer, lower horsepower and torque rating (compared to 1989 and earlier single cat LB9 5-speeds), and camshaft listing on this site.

chazman

iTrader: (4)

All 5 speed LB9s had the hot cam. Even the base ones w/o dual cats, oil cooler and rear discs. Those came with a 3.08 gear and the M39 T5 with a higher 5th gear ratio.

chazman

iTrader: (4)

What makes it more confusing is that ALL LB9s in '91-'92 came with the hot cam, even the base 700R4/2.73. On those years, the "peanut" versions came with a full LO3 exhaust, including the more restrictive exhaust manifolds.

yaj15

iTrader: (3)

Ok that clears things up. So if I got a non-G92 IROC or Z28 from 1989-1992 with the LB9/T-5 drivetrain I would get the higher lift L98 style cam. I'm also assuming that those non-G92 option LB9/T-5 cars would also get the GM 10bolt rear with 3.08 gears, drum brakes, and possibly positraction.

If 1989-1992 LB9/T-5 cars all had the L98 style cam why did the G92 option cars get the 5,500rpm tach and the 145mph speedo while the non-G92 option cars got the standard 5,000rpm tach and the 115mph speedo?

Ha ha this is a really good thread. After this we could write a G92-option chaper in a book about thirdgens.

vortec tpi

Thanks for the wealth of info. Everybody really stepped up. thinking about rebuilding the original engine but the hot rodder in me has to add a little something extra. Most likely a stroker kit/maybe a computer tune/Port the exhaust. Will look and sound totally stock.

yaj15

iTrader: (3)

Ha ha yes we all love thirdgens on here and like going in to the history of them aswell.

The important thing is that you are keeping and working on your car so that it can get back on the road!

Slater126

iTrader: (1)

The GM Heritage material shows the only difference between the 1989 LB9 single cat exhaust system and the 1990-92 LB9 single cat exhaust system was the intermediate pipe. This piece was 2.75" on the 1989 cars and only 2.25" on the 1990-92 cars. Everything else was the same.

I find it interesting that GM would simply change the intermediate pipe to reduce power. Engineers make a change like that for a reason. Anyone know what it is?

chazman

iTrader: (4)

. Do you have a link? The info I've seen had both the smaller intermediate pipe and smaller LO3 exhaust manifolds fitted.

Slater126

iTrader: (1)

Page 77 of the below PDF shows the 1989 LB9 single cat exhaust specifications.

http://www.gmheritagecenter.com/gm-h...let-Camaro.pdf

Page 77-78 of the below PDF shows the 1990 LB9 exhaust specifications, both single and dual cat. LO3 is on pages 74-75.

http://www.gmheritagecenter.com/gm-h...let-Camaro.pdf

These do not say anything about the manifolds, other than that the car has manifolds, LOL! How are the LB9/L98 and LO3 manifolds different?

FWIW, if anything, Fel Pro lists the same exhaust manifold gasket set for the 1991 5.0 Z28 and 1991 5.0 RS (PN MS9275B), and does not draw a distinction between single and dual cat.

Slater126

iTrader: (1)

Looking at it closer, I see that the wall diameter for the 1990 LB9 single exhaust branch pipes is 63.5 mm (2.5") while the wall diameter for the 1990 L03 branch pipes is only 50.8 (2"). I presume that's the part of the pipe that bolts up to the exhaust manifold outlet.

So if that's true, it would appear that the L03 does have a more restrictive manifold (specifically a smaller outlet) but the 1990-92 LB9 without N10 does not have this manifold. They have the same one as the 1989 LB9/L98, at least according the Heritage material.

eseibel67

[QUOTE=Slater126;5378947

FWIW, if anything, Fel Pro lists the same exhaust manifold gasket set for the 1991 5.0 Z28 and 1991 5.0 RS (PN MS9275B), and does not draw a distinction between single and dual cat.[/QUOTE]

Not that this is going to help much, but the head-to-exhaust manifold gaskets could very well be the same, but thd L03 outlet is going to be a smaller diameter than the LB9/L98 outlet.

Slater126

iTrader: (1)

Your hunch is correct, see above post. The LO3 manifold does have a smaller outlet. But the GM Heritage materials show that the 1990-92 single exhaust LB9 (non-G92) does not have this 2" outlet manifold. It has one with a larger 2.5" outlet.

yaj15

iTrader: (3)

I've got a question about the 1989-1992 cars that got the upgraded PBR style brakes.

I'm in the process now of saving up some money for the 2pistion aluminum caliper 12 inch 1LE thirdgen set up for the front and the PBR set up for the rear.

I've got 1988 IROC with the L98 and the J65 four wheel disk system with 10.5 inch disks and single piston iron calipers all the way around.

I know the 1LE cars used a different proportioning valve than the 1982-1988 J65 cars like mine or the cars from 1989-1992 with the stock 10.5 inch front disks and the PBR calipers.

What is the part number for a proportioning valve for a factory 1LE car?

89G92CAMARO

I like that the IROC-Z G92 Coupes that we have are Rare. We still have some of the 1LE perfomance stuff. Still Rarer are the 1LE's with no A/C.
I would rather have A/C instead. No power windows, locks and tilt steering on my vehicle. Must be the weight issue. 3-400? or Less??? Wow, I like that number. It puts us in a different category being a IROC-Z G92 Coupe LB9 TPI 305 5-Speed!

chazman

iTrader: (4)

.

Yup, in other words, it deserves being saved.

vortec tpi

This car will be saved. will be rebuilt back to it's original status with a couple of changes to suit my style. Outward appearance will be totally stock with a few tweaks underneath. Won't be a show car but will be built to be driven(good days of course).

chazman

iTrader: (4)

Thanks. I noticed that they also list the MK6 1st gear as 2.75 and describe the GM produced Multec injectors as produced by Bosch.

89G92CAMARO

Great information and I am saving this G92 Coupe for sure. I just take her out to Chevy Car Shows and do some parade work as well on sunny days. Thanks for the information Chazman.

chazman

iTrader: (4)

No problem.