GMs in IT

[erlrich]

With the Mustang discussion last week I noticed that we don't have much GM participation in IT. However, I think there are a couple of places where the General can come out and play.

The 1993, 1994, 1995 4th Generation Camaro has an engine option that would fit well into ITS, the 3.4L 90 degree V6. Stock the motor is rated at 160hp and 200 ft-lbs of twist. Looks like it'd drop into ITS at around 2580 lbs before any adders for torque, so maybe a mid-2600 spec weight.

The only problem with that (well, not the only, but the major problem) is the same problem its younger cousin has in ITR, but worse; the weight. All the 4th gen cars all weigh about the same - ~3300 lbs. Add a cage and a driver, and you'll need to drop almost 1000 lbs to get to the ITS weight.

I'm pretty sure the ITAC & CRB don't agree (we should find out this month), but I think those cars should be classed in the lower class at a heavier weight, i.e. the 3.8 should be in ITS at ~3200 lbs and the 3.4 should be in ITA at the same weight. Even then I think they would both be mid-pack cars.

[Ron Earp]

The only problem with that (well, not the only, but the major problem) is the same problem its younger cousin has in ITR, but worse; the weight. All the 4th gen cars all weigh about the same - ~3300 lbs. Add a cage and a driver, and you'll need to drop almost 1000 lbs to get to the ITS weight.

I'm pretty sure the ITAC & CRB don't agree (we should find out this month), but I think those cars should be classed in the lower class at a heavier weight, i.e. the 3.8 should be in ITS at ~3200 lbs and the 3.4 should be in ITA at the same weight. Even then I think they would both be mid-pack cars.

I'm not a 4th generation Camaro guru and I'm assuming your not quoting marketing/magazine/web curb weights, but the Mustang hasn't played out as badly as predicted. With the stang it is more a question of dropping few hundreds of pounds, not many hundreds of pounds. Any chance of a real-world V6 T5 Camaro in street trim coming in at 3100-3200 lbs with a light driver sitting in the seat?

I haven't been asked but I don't think a 3.8L V6 Camaro in ITS at 3XXX lbs would be that attractive. It'd have the juice though. I'm not much up on ITA, but I wouldn't fancy my chances with a 3XXX lbs weight in ITA either. I think I'd rather race a 3.4L V6 Camaro a couple of hundred pounds over spec weight in ITS than race it in ITA at its curb weight. But, there again, I don't have much Camaro experience. Is the CRB/ITAC considering re-classing the Camaro?

I do like the Camaro classed in ITR though at around 2800 lbs. That weight seems obtainable, the chassis has some good features, and the motor should be able to make power needed for the class. Bummer that the 3.4L ITS version has rear drum brakes - I swore those off when I sold the Z.

[erlrich]

I'm not a 4th generation Camaro guru and I'm assuming your not quoting marketing/magazine/web curb weights, but the Mustang hasn't played out as badly as predicted. With the stang it is more a question of dropping few hundreds of pounds, not many hundreds of pounds. Any chance of a real-world V6 T5 Camaro in street trim coming in at 3100-3200 lbs with a light driver sitting in the seat?

I haven't been asked but I don't think a 3.8L V6 Camaro in ITS at 3XXX lbs would be that attractive. It'd have the juice though. I'm not much up on ITA, but I wouldn't fancy my chances with a 3XXX lbs weight in ITA either. I think I'd rather race a 3.4L V6 Camaro a couple of hundred pounds over spec weight in ITS than race it in ITA at its curb weight. But, there again, I don't have much Camaro experience. Is the CRB/ITAC considering re-classing the Camaro?

I do like the Camaro classed in ITR though at around 2800 lbs. That weight seems obtainable, the chassis has some good features, and the motor should be able to make power needed for the class. Bummer that the 3.4L ITS version has rear drum brakes - I swore those off when I sold the Z.

Ron - not a guru either, but I did stay at a Holiday Inn...err, scratch that - I did take my car ('02, V6, T5) across the scales at Summit a couple of years ago just to see what I would have to lose to get to ITR weight. With my 250 lb backside in the seat, and about 1/4 tank of gas (~4 gals) it came in at 3535 lbs. That was in full street trim - spare tire, jack, full interior, etc.

The V6 currently runs in SSB at 3300 lbs, and the V8 version is classed at 3530 lbs in both AS and T2. To the best of my knowledge, other than things you can change in IT trim (springs, sway bars), the suspension, diff, and brakes are identical on both V6 and V8 versions. I know 3300 lbs sounds heavy to us in IT-land, where 2600 lb cars are considered pigs, but I think that car will work at the higher weight. That said, I really don't think this will be a great car in either class; I think Andy summed it up well...something like "you can put lipstick on a pig, but in the end it's still a pig".

And yeah, I put in a request to have the V6 Camaros & Firebirds moved to ITS months ago; I just received an email that the ITAC & CRB have reviewed the request, and the decision should be in the next FT.

[Ron Earp]

I know 3300 lbs sounds heavy to us in IT-land, where 2600 lb cars are considered pigs, but I think that car will work at the higher weight. That said, I really don't think this will be a great car in either class; I think Andy summed it up well...something like "you can put lipstick on a pig, but in the end it's still a pig".

Time to get some pigs in IT. What are they making these Camaros out of, Tungsten?

I bet the car can make ITR weight with some serious work. Dick got his RX7 to make ITA weight, against all the naysayers, and it was apparently a lot of work. I can get Dercole's ITR stang to minimum weight and I think he's convinced of that too.

I can't get my ITS stang down to weight, but I think I can get close enough to weight that it'll be a threat in ITS, at the expense of many man hours of work, but it might just be possible. The Camaro could be a similar situation in ITR.

So in ITS trim the 3.8:

200x1.25x12.9 = 3225 (no "torque adder" applied, does it get one?). Dang ol. No doubt the 3.8L can make some power, but that is some serious weight to haul around. About 600 lbs heavier than the RX7, more than 700 lbs heavier than the Z. I've always liked those GM 3.8L engines. Powerful workhorses that didn't complain much. Man ol man, talk about parts aplenty.

In ITR trim it is considerably lighter, 2815 lbs. Let's say it can't make 2815 lbs and has to race at 2950 , still seems like a good package for ITR. I'd be surprised if they moved it to S, but you never know. S or R, I'd love to see some of them on track. High time to move away from the Mazda Car Club of America.

Earl, how user friendly are they? I haven't poked around them much, but the ones I have looked at seem like a definite "front mid-engine" design. The motor seems to live under the dash between the two occupants. Definitely a slick exterior. And, from the times I spent in the back seat of the 3rd gen cars in the 80s I know there isn't a lot of room there. The Mustang seems like a more usable package although maybe at the expense of handling.

[Andy Bettencourt]

Letter ID Number: #6637
Title: 1984 C4 Corvette Classification
Class: ITR
Request:
I would like to request the classification of the 1984 C4 Corvette. Specs are below needed to classify the car per the ITCS:

1984 Chevrolet Corvette
205hp@4300 / 290 lb-ft@2800
Curb weight 3200lbs
V-8 OHV
Bore and Stroke: 101.6mm x 88.4mm
Intake valve: 1.94”
Exhaust Valve: 1.50”
Compression Ratio: 9.0:1
Wheelbase: 96.2”
Wheel sizes: Base: 16”x8.5” Z51 package: 16”x8.5”F, 16”x9.5”R
Transmission ratios: 4 speed, 2.88, 1.91, 1.33, 1.00
Brake size: 292.1mm F&R (11.5”)
Independent front and rear suspension with transverse leaf springs.

Using the classification process, I would see it playing out like this:
205 x 1.25 x 11.25 = 2882.8 rounded to 2885lbs.

If you care to research these cars, you will find out that they share the ‘cross-fire’ injection with the 1983 C3 L83 cars. Horrible for revs but decent torque. Pre tuned-port-injection. Single year on a single spec line.

We have a build pending the weighting of the car. Thanks.

[Ron Earp]

I also wrote a letter a few weeks ago asking to class the C4 and 3.4L Camaro. Don't see any reason why both shouldn't be included in ITR/ITS respectively.

R

[StephenB]

We have a build pending the weighting of the car. Thanks.

Another ITR car for the NorthEast! Awesome We will be at 20+ car fields sooner than we know it!

Stephen

PS: Andy you should build an ITR car not that ITS miata!

[erlrich]

Earl, how user friendly are they? I haven't poked around them much, but the ones I have looked at seem like a definite "front mid-engine" design. The motor seems to live under the dash between the two occupants. Definitely a slick exterior. And, from the times I spent in the back seat of the 3rd gen cars in the 80s I know there isn't a lot of room there. The Mustang seems like a more usable package although maybe at the expense of handling.

Ron - sorry, I missed this earlier.

They're actually pretty user-friendly - the 6 can borrow everything suspension-wise from the 8, so there are plenty of suspension pieces to pick from. Somewhat less for the engine, but still enough to do a decent IT build. And yeah, the 6 sits mostly behind the front wheels, so that helps. And you can tune the OEM computer. I do think it will make 250 HP with a full-tilt build, but that's about it.

Great brakes - I've done a few track days with mine, and with just HP+ pads it has brakes to spare (at 3500 lbs I would note). The only concern re brakes would be the aluminum calipers - I've heard tales of them deforming under lots of heat. Good brake cooling would be a must I would think. The AS guys talk about replacing front hubs often, so that may be a problem area. And then there's that live axle...

In ITR trim it is considerably lighter, 2815 lbs. Let's say it can't make 2815 lbs and has to race at 2950 , still seems like a good package for ITR. I'd be surprised if they moved it to S, but you never know. S or R, I'd love to see some of them on track. High time to move away from the Mazda Car Club of America.

Obviously the ITAC agrees. I just don't see anyone in their right mind building one - when you have the choice of a 2,800 lb E46, a 3,000 lb S2000, a 3,050 lb 968, and a 2,950 lb Camaro, I think the Camaro comes dead last every time. I would also love to see one built, but my guess is if you do it will be another one of those 'sentimental' cars guys build, and not full-tilt pro build that will show what it really is capable of. Maybe when the Camaros age out of SSB next year we'll see a few of them migrate to IT.

[Ron Earp]

I do think it will make 250 HP with a full-tilt build, but that's about it.

That is some serious power for ITS, even at 3300 lbs weight.

Obviously the ITAC agrees. I just don't see anyone in their right mind building one - when you have the choice of a 2,800 lb E46, a 3,000 lb S2000, a 3,050 lb 968, and a 2,950 lb Camaro, I think the Camaro comes dead last every time.

The thing is, the same, or functional equivalent cars exist in ITS . All of those cars exist in ITS (replace S2000 with Miata, 968 with 944 S) with larger weight differences compared to the Camaro (at 3300 lbs), so using your line of thinking the car would be a last choice car in ITS too.

Don't you think you might be assigning too large of a performance detriment to the live axle? Of the few cars in IT that use them, most notably in my area the ITB Mustang and ITS TR8, the axle doesn't seem to be a detriment at all. As long as the full rear axle allowances in IT are taken advantage of both chassis are SARRC Champion winners and podium material any weekend in their respective classes. I'm looking forward to using the axle in the Mustang compared to messing around with Datsun 240Z geometry.

I think a well-built ITR Camaro sporting 250 flywheel hp at 2815 lbs could put a hurting on some ITR regulars.

[DSeefeldt]

Ron:

I'm considering building a 4th Gen Camaro for ITR. I agree with you, I think if done right, it can be a very competitive car.

Back in the day, 1984, when ITA first started out here in the San Francisco Region, I built a ITA V6 Capri and did very well with it. Although everyone said it couldn't be done, we won some races and usually finished in the top 5 - 10. We would have 20 - 25 car ITA fields with mostly RX3's.

I sold that car back in 1992 and built an AS Camaro. Raced it for a couple of years and then took 15 years off. I got back on the track last year. I now have the itch to build one more car. This one for my son. I'm thinking a V6 Camaro could be a good build. Plus I want to build a car I can run in the annual NASA 25 hour enduro at Thunderhill Raceway Park in Willows, CA that gets better gas mileage than my AS Camaro gets.

Stay Tuned!

Darryl Seefeldt
AS Camaro #22
San Francisco Region

[JeffYoung]

Of those choices, the Camaro is the cheaper build, by far, and may make the most power.

Obviously the ITAC agrees. I just don't see anyone in their right mind building one - when you have the choice of a 2,800 lb E46, a 3,000 lb S2000, a 3,050 lb 968, and a 2,950 lb Camaro, I think the Camaro comes dead last every time. I would also love to see one built, but my guess is if you do it will be another one of those 'sentimental' cars guys build, and not full-tilt pro build that will show what it really is capable of. Maybe when the Camaros age out of SSB next year we'll see a few of them migrate to IT.

Also, I agree with Ron on the live rear deal. I don't think there should be a weight break for it. Setup right, it is not, in my opinion, a real detriment. I do not perceive a handling deficit on my car to the best RX7s, 240s, etc.

[dickita15]

Also, I agree with Ron on the live rear deal. I don't think there should be a weight break for it. Setup right, it is not, in my opinion, a real detriment. I do not perceive a handling deficit on my car to the best RX7s, 240s, etc.

Interesting, so you do not think the advantage of adjusting rear camber and toe rises above the noise level in car differences.

[erlrich]

Of those choices, the Camaro is the cheaper build, by far, and may make the most power.

Agree on the cost part for sure.

Also, I agree with Ron on the live rear deal. I don't think there should be a weight break for it. Setup right, it is not, in my opinion, a real detriment. I do not perceive a handling deficit on my car to the best RX7s, 240s, etc.

Jeff - out of curiosity, at VIR are you using the curbs going up through the esses (except for the last one at the top of the hill), and going through hog pen? I don't have tons of track time on the Camaro, but from what I've done I just can't imagine those curbs wouldn't play hell with the rear end of the car.

[billf]

Of those choices, the Camaro is the cheaper build, by far, and may make the most power.

Also, I agree with Ron on the live rear deal. I don't think there should be a weight break for it. Setup right, it is not, in my opinion, a real detriment. I do not perceive a handling deficit on my car to the best RX7s, 240s, etc.

While I agree that the live axle is not in itself a detriment, the linkages to it can be. Incidentally, the Live Axle is only one of two designs that accomplish all goals in suspension geometry: constant camber regardless of chassis attitude, whether it is acceleration, braking, or cornering. The other is the De Dion. All others offer compromises under some condition, or the other. Incidentally, as we all know, the give-away with the live axle is of course the unsprung weight. While a De Dion has less unsprung weight, it still has more compared to an Independent Suspension.

Back to my statement about linkages... All live axle cars do not have the same linkage setup. The Camaro has the best, with the factory torque arm, as demonstrated in AS. The Mustang has to have the worst, with the four arm setup, which inherently binds when cornering, or under hard acceleration (when it doesn't matter). (For those who don't know, these four arms are controlling all longitudinal, and, lateral movement of the chassis...at least that's what we would like to happen.) All solutions except two, modify the bind, but do not eliminate it...just make it happen at a different time. Any bushing material replacement has the potential of increasing the bind...it cannot be eliminated because of the dissimilar arcs of motion created by three different planes of control.

The two solutions are the aftermarket three link (not four), and the aftermarket torque arm. Unfortunately, the offerings of torque arms for Mustang are enginereed for the 8.8 inch rear, not the 7.5 which the car is produced with. Thus, no aftermarket torque arm for the ITS or ITR V6 Mustang. Also, a Panhard Rod, or Watts Link must be added to provide the lateral location lost when the upper arms are removed...more weight.

Unfortunately, all solutions to the bind for the Mustang will add weight to an already overweight platform. If it ain't broke...you might find that the car can be driven without the need for additional linkages. I did for years with an ITB.

Just my two cents worth after dealing with the identical suspension in my '87 Mustang...7.5 rear also.

Bill