3rd Gen GM F Bodies - Need some help

Ron Earp

Ron Earp

Administrator
I'm writing an ITR proposal to class the Mustang V8 in ITR. I would like to include the 3rd Generation GM F Bodies too, the ones with the 5L motor and five speed. I need help selecting a couple of years to put into the proposal. Problem is, I'm not much of a GM man and I know the 5 speeds weren't exactly common.

Is there anyone interesting in possibly racing one of these cars that knows some details? I know there was a 190hp 5 speed for a couple of years that would be perfect. I *think* it had rear disc brakes too, which would make life easier for the racer.

Any help would be appreciated.

Ron
 
Ron:

Check out this link: www.thirdgen.org/tech-data

It has a year by year breakdown of the engine/transmission combinations. I don't know if it's 100% accurate, but it looks pretty close.

Bob Clifton
#05 ITB Dodge Daytona
 
Hi Bob,

Thanks for that, extremely helpful!

I think what I'll do is pick a pair with specs close to the Fox4 Fords, and go with those. They can be expanded later, the main goal is to get a selection of pony cars in as a start.

Ron
 
Ron,

As much as I'm a Chevy guy, and like the idea of the third gen Camero in IT, I think that classing them will be problematic at best. Especially when there are two LE9's with two different horse power, based on which cam it got and no way to trace it. Do you class the 150hp 305, the 190hp 305, or the 210hp 305, and which cam belongs to which? I think it's going to make an ideal cheaters paradise as who knows which cam belongs?

James
 
Ron,

As much as I'm a Chevy guy, and like the idea of the third gen Camero in IT, I think that classing them will be problematic at best. Especially when there are two LE9's with two different horse power, based on which cam it got and no way to trace it. Do you class the 150hp 305, the 190hp 305, or the 210hp 305, and which cam belongs to which? I think it's going to make an ideal cheaters paradise as who knows which cam belongs?

James
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Hey James,

It might not be as hard as you think. The 150 doesn't fit in R, the 190 and 210 do. The way to do it is to class the higher hp car and possibly put the others on the same line. The user needs to figure out which motor/cam/induction they need.

It is more of an ITAC issue and some of us doing the new R cars are facing this exact problem. I don't know what the answer will be, but we'll find one.

Policing and cheating is not the problem of those classing the cars. If that were the case we couldn't class Mustangs or Camaros due to "aftermarket support and ease of cheating".

BTW, didn't the 150hp LE9 car have a throttle body injection which is responsible for the lower hp rating? I'm not a GM guy, but vaguely remember the low hp ratings on some Ford and GM V8s was precisely this. Not sure it'd be an issue for IT though and might could make power.

Ron
 
Ron,

Do you class the 150hp 305, the 190hp 305, or the 210hp 305, and which cam belongs to which? I think it's going to make an ideal cheaters paradise as who knows which cam belongs?

James
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Tracing it is easy...write the paper and off to the cam doctor. If we didn't spec cars because they had easily swappable parts, we'd have single car classes. How many old ITC Rabbits out there ran ITB Rabbit throttle bodies and cams, etc? Not many at the ARRCs, but tons around the country. Cheating is a choice, and enforcement is a choice as well.....
 
Cam issues are a possibility in any piston powered IT car. With the Pony cars, there are other possibilities which are even worse. A decked 305 with a 400 crank is 334(IIRC)...If you can cut if far enough, Sleeve it and you can find 383 CID. As Ron knows, the possibilities are there for 347 and larger 5 liters that look stock also.

Cheaters will always find a way.

The 150 HP F bodies had a terrible electronic quadrajet carb(of sorts). The 170 hp cars were TBI, essentially two large injectors mounted on a 2 bbl style intake manifold. The TBI cars didn't like to rev over 5000.

As an aside, I owned a 93 5.0 LX, and an 89 305 TPI/5spd F body at the same time. Certain friends(cough cough Junktech) used to help me do some, unofficial "comparisons" between the two. The F body was a little slower in the typical drag race stuff, handled better, but felt substantially larger and heavier than the Mustang. I think either one would be potent enough to destroy the front brakes without some serious cooling. They could be made to be similar in lap times to each other..but how will they fit in ITR???


Jim "where did my torque go?" Cohen
 
Jim, good points.

On the displacement issue, this -- risk of cheating -- is true of most piston cars. You've been in rotary land for too long!

On my car, there are no visible outside differences between a 3.5, a 3.9, a 4.0 and a 4.6 Rover V8 block. If I was cheating, you couldn't tell by visible inspectin - at least not until you saw the car on the straightaway.

The Jense was teh same way. A simple crank change and the motor becomes a 2.2.

THe point is we can't class based on a fear of cheating. We just have to get better at policing.

But your second point is valid. Do the cars really fit in ITR? I think they MAY, which means, let's class them up and let some one try to make the brakes work. Because they may.....
 
Ron,

While I enjoy running my IT7 car, I would think heavily about letting my inner redneck out and running a bitchin' Camaro in ITR.

Can you PM me a list of data that you need for the Camaro? I will gladly scurry around and dig up what I can.

Thanks,

Jim Hess
IT7 #11
2007 MARRS IT7 Champion
 
Cheating is cheating. James, you could be running a 3.2 in that Z car - I'm pretty sure the 3.2 shares the same bore spacing with the 2.8s, just a matter of rods and crank. Can't not class cars based on cheating potential.

Jim, release the inner redneck! I know I will if the proposal is accepted.

What I need are two GM stable mates (Camaro and Firechicken) that have the following:

*Rear disc brakes (I think GM always got this right)
*Mutliport EFI
*5 speed tranmission
*No more than 210 stock hp, that is the upper limit
*No more than 5L displacement, so all the 350s are out
*No special models, odd balls, etc.

What I need for the proposal are basic specs you'd find in the GCR and good estimates of power and torque. Cam specs would be useful for evaluation. Some knowledge of the heads or other limitations would be good. We don't want a 5L GM motor that was underrated, or under performed because of a crappy single exhaust (I know some F bodies had singles and saw large gains with a real dual system) and things like that.

I'd want to use these two, along with the 1994-1995 5L Mustangs, to get the ball rolling. I know I'm being somewhat restrictive, but I'm trying hard to have a good handle on the proposal. I know the 94-95 Fords pretty well, but I don't know the GM cars at all.

Thanks for the help, it'll really be appreciated.

Ron
 
I think I have hit a stumbling block finding a great fit. To me the TPI 5.0L would be a great car to race. I makes bags of torque, but as I recall the TPI runners choke the motor at high RPM. You can get plenty of low end torque, but things tail off pretty quick as the RPM’s climb.

The best manual trans numbers for the LB9 (engine code) cars looks like:
1987 LB9 215hp@4400 / 295lbft@3200
1988 LB9 220hp@4400 / 290lbft@3200
1989 LB9 230hp@4600 / 300lbft@3200
1990 LB9 230hp@4400 / 300lbft@3200
1991 LB9 230hp@4200 / 300lbft@3200
1992 LB9 230hp@4200 / 300lbft@3200

Those cars are already over the Hp limit you mentioned. It is pretty hard to find a Camaro with less Hp than a Mustang. (I can see where having Ford and Chevy guys joking with each other might be fun)

All these years came with a 5 speed. All years were 9.3:1 compression ratio. There was also an automatic version of the LB9 each year that had a few less Hp and a little more torque. Disc brakes were at least an option each year (not finished looking at this).

The only real oddball options were the 1LE and BC4 Camaros. Oddly enough most of the 1LE stuff is already allowed by IT rules. The two gotchas for the 1LE package were bigger front brakes and an aluminum driveshaft. The bigger brakes were 11.86” diameter jobs. I assume that by listing the allowable brake sizes on the spec line you could eliminate the 1LE and BC4 cars. The BC4 was the police pursuit option.

If someone knows more about these cars, please correct me. I gathered this by surfing around the internet. Mostly from: www.thirdgen.org and www.iroczone.com

I assume the Firebirds are similar, I did not dig into those yet.


Ron,

Should I keep digging or should I look for something a little pokier in the engine bay? The important thing (to me) is that whatever car get specced it fits the formula and is a good fit into the ITR spectrum.

Hope this helps,

Jim
 
The 3rd gen f-bodies would be a good match for the fox bodied mustangs. The performance differences between the two should be able to be balanced with weight . IIRC, the Firebirds were rated 5 or so HP less due to the intake configuration. IIRC, the later 5 liter sefi engines were rated at 225 hp. They revved easier and higher than the 5 liter f-bodies. The Fox cars were apporx 200 lbs lighter to start with, had lesser brakes(10.25 or so front, and drum rear). All the later F-body rear discs were the same as the 1LE cars had. The f body suspension is better, but the Mustang felt pretty nimble due to it's size/lower weight. I don't know the SN95 cars that well, but IIRC, they lost 10 hp or so for some reason. I'd guess they are heavier than the fox cars.

Both cars have a HUGE aftermarket support system with exhaust stuff, pulleys, gears(more so mustang) and more.

The Automatic LB9's(305 TPI) had a different cam than the 5 spd cars did, hence the lower HP rating. 89+ 5 spd LB9's only came with the good cam if a 3.42 or 3.45 rear gear was specified.

If the LB9's are deemed too strong for the class, the only other option would be the 5.0 HO 4 bbl cars. Terrible electronic 4 bbl carb. It had fuel starvation issues, and no matter how many people told me they knew what they were doing, I never found anyone who could make one run right. These cars were only available for a couple of years, as they disco'd them as GM got production ramped up on the TPI cars. IIRC, they were rated at about 190 hp. I'm afraid you would have to get them pretty light(relatively) to make them competitive with the 10 year newer SN95's. The 170 hp cars might make a mid pack ITS car if you could get it light enough.
 
Hey Jim(s),

This is some good info. I remember the lesser hp cars were carbed.

My goal was to get some fairly narrow year models that are well understood classified. I know there will be some who wish to get many years and models classified but I think erring on the side of caution is in order so we do not upset the fledging ITR class.

On the Ford side I’ve written the proposal around the 1994-1995 Mustang GT. The engine is more limited in power output than the 87-93 models due to the intake design. The car is also the ONLY one that has rear disc brakes besides the special models such as the SVO and the Cobra. I think most racers would choose this car over the earlier models due to this, and other changes, that make the car a bit more robust for racing.

On the GM side I’d probably opt for a two year model range such as the 1987-1989 cars without the optional 1LE and BC4 packages. Class these two cars on the same line. However, it would make sense to capture a larger range of them since the differences are so slight. Did the cam change specs from 87 to 92? I’ve a feeling those motors are essentially the same and the potential is the same between them. Ratings might be due to ECU tuning, ignition timing, etc. and these are free in IT. Regardless, we’re probably looking at a weight in the 32XX to 33XX range for these cars in ITR. Acceptable?

I will be finishing up the proposal in the next 3-6 days so any GM info or comments are welcome. I would like to have the GM cars represented in the proposal.

Ron
 
Keep in mind the current item out for member comment, which is the removal of the VIN rule. That makes it more palatable to keep the years selected narrow, as you are limiting the power and brake package, not the donor chassis.
 
Good point and a real concern if the VIN rule is the only thing that keeps one from using a say 92 camshaft in a 87 motor to make more power.

But still, cheating is cheating, right? If the spec line says 1988 Borgwald GT with 11" rotors, 5 speed transmission, and 9L V8 then that is the only year they can get those components from, including the chassis, correct? Anything else would be illegal.

Ron
 
No, that is what is changing. For example, I'll be able to build a TR8 out of a 1978 TR8 Coupe so long as I can prove that the chassis I am using is the same as a 1980.

So, Jake's point is that if a 88 body is the same as a 94, then you can use teh 88 body to build the 94 car using the 94 specs and parts.
 
Looking at the ITCS line there is some more stuff that you would need:

Bore x Stroke - 3.74" X 3.48"

Wheelbase - 101"

Wheel Dia - 15"/16"

Gear Ratios - 2.95 / 1.94 / 1.34 / 1.00 / 0.63 (I have a reference for this on the 87 and 88 years, but I did not find a source for the 88 and up cars).

Brakes - Still not clear for internet surfing - I probably need to go to the autoparts store with a tape measure. As near as I can tell:
Front 10.5" (non 1LE) 11.86" (1LE)
Rear 10.5" early years 11.65" 1989 and up

Other stuff:
(from: http://www.f-body.org/tech/tech.htm)
Cam info on 3rd Generation camaros
0.050
Tach GM PN Lift Duration Lobe
Ylw. Red In. Ex. In. Ex. Separation (in/exh)
---- ---- -------- ---- ---- --- --- ----------

1987
305 AT (LB9) 4500 5000 10088155* .350 .384 179 194 109.0 (108/-112)
305 5spd / 350 AT 5000 5500 14093643* .404 .415 202 207 114.5 (115/-114)
(LB9 / L98)
305(LM1 Police Pack.) --------- 14093640* .383 .404 291 202 112 (108/-116)

1988, 1989
305 AT 4500 5000 10088155* .350 .384 179 194 109.0 (108/-112)
305 5spd / 350 AT 5000 5500 10066049* .415 .430 207 213 117.0 (116/-118)

1990-1992
305 5spd / 305 AT 4500 5000 10088155* .350 .384 179 194 109.0
305 G92 5spd / 350 AT 5000 5500 10111773* .413 .428 202 207 114.5 (116/-116)

You asked a question about rated weight - that should be what the process calls for.

Hope this helps.
 
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