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Discussion Starter · #1 ·
Hey guys! I'm a long time car guy and recently I've been looking into getting into stage rallying. I'd call myself a die-hard RWD guy, so with the provisional license I'll compete in Gp 2. Once a full license is achieved, I plan move up to Gp 5 in an RWD car.

So here's my thought: I bet a prepped C4 Corvette would make a kick ass rally car.

When I say prepped, I mean it - relocated suspension mounts and strengthened A-arms in front to raise the ride height and increase suspension travel, a fabbed double A-arm setup with big travel coilovers in the rear, and of course a full cage (and then some). Within the rules, a pushrod engine can be up to 6.375L, which would allow me to run a hopped up LS3 or similar, easily over 500 hp, hopefully with a sequential tranny. I'd aim for a 50/50 weight balance with a foot of wheel travel all around, a race weight of about 2600 lbs. Throw on some mud flaps and dirt tires and hit the stages!

The real question is this: do the Rally America rules allow competition in a C4 Corvette? I can't find a single example of it having been done other than some cryptic Finnish rally forum threads. The biggest issues I can see are the fact that all the 'vette panels/bulkheads are fiberglass, and that all the C4s have bolt-on targa tops. Here are a few examples fromt he rules:

"Fuel pumps and filters shall also be isolated from the driver/co-driver by
a metal bulkhead or the fuel cell case." - Will stock fiberglass pass muster as a "metal bulkhead?"

"Eligibility is restricted to street licensed, closed-bodied, four-wheeled
vehicles. Fabric tops and side panels are prohibited." - Will the bolt-in targa top work?

Alright, I'll shut up and listen for a while. Anyone have any thoughts?

PS - I'm not interested in hearing how RWD is worse than _WD, how I won't be able to control the car, how 500hp is too much, etc. I get it - you're scared. :D
 

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don't cut
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Fiberglass is frowned on at Rally America headquarters. But you can fabricate metal parts if you want. Or run a Camaro instead. We run a Mustang.
 

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Not sure on the legality in RA with fiberglass body, but NASA events might be game, plus with NASA you don't have to start in G2.

You don't need to worry about getting that much travel, 8" would be plenty.

You will need to fit 15" wheels, so smaller brake calipers would be needed.

Does the C4 have a steel frame to weld cage stuff onto?
 

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Discussion Starter · #4 ·
Fiberglass is frowned on at Rally America headquarters. But you can fabricate metal parts if you want. Or run a Camaro instead. We run a Mustang.
Camaros carry an extra 600 lbs, poor weight distro, and a solid rear axle I figure I could live without. But if fiberglass is a showstopper, that may be the fall back plan. When you say 'frowned on,' do you mean like "let's make really sure every other aspect of the car is up to spec" or "no way will that touch a stage on my watch!" I'd prefer to avoid fabbing steel firewalls and floorpans, although its an option.

You will need to fit 15" wheels, so smaller brake calipers would be needed.

Does the C4 have a steel frame to weld cage stuff onto?
Actually, according to general consensus at corvetteforum.com, a 15" wheel will fit over stock calipers (barely). Drag race guys apparenly do it regularly.

And yes, the C4 still ha s a full steel frame. It's wrapped in 'glass in alot of areas but the frame is there.
 

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Not Ideal
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corvette is a no-go in Rally America according Mike Hurst, the technical director unless you get his boss to ok it.

http://rally-america.com/forums/showpost.php?p=15072&postcount=10

M. Hurst said:
If you want to run a corvette or other glass bodied or removable roof car, you'll have to go over my head to do it.

The SCCA granted the owner of the corvette permission, but required him to install a steel roof underneath the fiberglass t-tops.

I will not allow anything like that to run without a directive from the boss.
 

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When you say 'frowned on,' do you mean like "let's make really sure every other aspect of the car is up to spec" or "no way will that touch a stage on my watch!" I'd prefer to avoid fabbing steel firewalls and floorpans, although its an option.

...
While I and many others like your style, The guy you have to convince is Mike Hurst at Rally America (if you want to run RA). He is very much in the "Not a fan of rally 'glass" camp.

If you are willing to put tons of effort into a C4; moving pick up points, mounting some tiny V6 or heaven forbid a 4 cyl, Putting a camaro on a diet shouldn't be that big a deal. The roundy round guys do it all the time.

Now that we've rained on your parade, See pics in the "unusual rally car" thread for yummy Stingray action.
 

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Rallying a C4 Corvette has got to be one of the worst ideas that I have ever heard! The topic of rallying big American cars has been discussed quite a bit recently. They can probably be made to work ok, but in general they will suck compared to the "standard" cars. You really need to do some research about the sport that you want to enter.

Just for fun you should go over to http://www.rallyanarchy.com/phorum/ and post the same question.
 

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your other left, you idiot
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g*dd*mnyellowcorvette

I absolutely hated the original g*dd*mnyellowcorvette (yes, all one word), in its original incarnation back in the 1970s.

It would inevitably crash, scatter fibreglass all over the woods, and block the road.

It did teach us the meaning of force majeure....................

(Very loosely translated as - tough sh*t)

press on,
 

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Lesse, the one way back that Jimmy ID'd did 'splode a bit when brushing any tree. And the one at MFR just few years ago did not look too good after a roll...but, then more cars don't! And it did manage to go on. But I don't think that was a fast roll. The fiberglass IS a concern to some degree. I would not feel that a a bolt on targa top is acceptable.

Much more HP than you need; I would put in a small block engine to save weight and get better balanced that will buy you a LOT more on stage than another 100 HP. No, not scared; I drive a 600 ft-lb truck around all day and on gravel roads. Common rule-of-thumb is that it's just hard to hook much more than 100-125 HP per tire to a gravel road. It works if the stage road is pretty clear of gravel, but if you have a light weight, that is HP all by itself.

The cage would take a lot of consideration, and may be the real killer for this idea. The big problem is that you only have the frame to tie to. Rally cages are closely integrated into a unibody car shell, and are designed to work that way; tieing A pillars and B pillars to a cage structure increases the assembly strenght sever times over. Taking the same cage basics and hanging them onto a frame only car is a whole different story. Just changing a cage mounting to tie to the frame of a P/U truck and tie in the metal cab is a different enough, but you don't even have a metal cab.

Where you at? If you are in a part for the country where there are enough NASA events nearby to make sense for you to run those events, I'd be willing to run it up the flagpole. Won't gurantee a positive answer, though I have no idea what the reaction would be. Send me a PM if you're serious. We just kicked around another odd vehicle request lately; that did not go anywhere, but the guy did not act like he wanted to work with anyone, would/could not provide any documentation of the vehicle, and he just wanted to be tricky about getting a carte-blanche ruling to go ahead.

If you want to get anywhere with this, understand that we are concerned about safety and are good guys. My advice: Just work with folks if you want to get anywhere with this.

Regards,
Mark B.
NASA Tech guy
 

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pressing on tirelessly
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I absolutely hated the original g*dd*mnyellowcorvette (yes, all one word), in its original incarnation back in the 1970s.

It would inevitably crash, scatter fibreglass all over the woods, and block the road.
So, was that a result of some kind of inherent instability with the car, or with its occupants?
 

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Discussion Starter · #14 ·
Sounds like I've struck a nerve :cool:... a few rebuttals:

Rallying a C4 Corvette has got to be one of the worst ideas that I have ever heard! The topic of rallying big American cars has been discussed quite a bit recently. They can probably be made to work ok, but in general they will suck compared to the "standard" cars. You really need to do some research about the sport that you want to enter.
If you'd take the time to learn a bit about vehicle suspension dynamics, you'd realize that a car's handling potential is largely dependent on only a few unmodifiable parameters of the car - weight distro and CG location primarily. The rest can all be modified with suspension design changes and appropriate setup, which I am willing, capable, and educated enough to perform. While I would agree that a large, heavy, street-tuned car is a poor choice, your blanket statement that 'they will suck compared to "standard" cars' suggests a certain level of ignorance. [/rant]

Also, before you associate a Corvette too closely with other "big American cars," realize that C4s had a curb weight less than the last few generations of STI (a "standard" car, I presume.)

Much more HP than you need; I would put in a small block engine to save weight and get better balanced that will buy you a LOT more on stage than another 100 HP. No, not scared; I drive a 600 ft-lb truck around all day and on gravel roads. Common rule-of-thumb is that it's just hard to hook much more than 100-125 HP per tire to a gravel road. It works if the stage road is pretty clear of gravel, but if you have a light weight, that is HP all by itself.

The cage would take a lot of consideration, and may be the real killer for this idea. The big problem is that you only have the frame to tie to. Rally cages are closely integrated into a unibody car shell, and are designed to work that way; tieing A pillars and B pillars to a cage structure increases the assembly strenght sever times over. Taking the same cage basics and hanging them onto a frame only car is a whole different story. Just changing a cage mounting to tie to the frame of a P/U truck and tie in the metal cab is a different enough, but you don't even have a metal cab.
Thanks for the input, Mark. I'd hoped I could get an experienced tech guy to weigh in on this.

First, on the power issue, it all depends how fast you're going, just like on asphalt. Pretty much any amount of power will break tires loose from a stop, it's just a question of how fast you can go before the available tractive force is greater than the torque your driveline can apply to the ground. Higher power just means I can maintain peak accel for longer and thus end up faster. Of serious use in rally?... likely not, but since an all-aluminum LS3 weighs ~100lbs less than the stock L98 and would have in the upper 400s of hp, I can't see a reason not to have it in case there's a long straight. :D

On the cage - I had assumed that having a full frame was an advantage. All the cage regs I've dealt with have been NHRA ones for drag racing, which frown upon unibodies since the cage mounting points are inherently weaker. It seems odd that a properly implemented frame-mount cage would be looked down on, but it must be possible to have one meet rally spec. Something to look into.

Oh, and I'm signing up for an account on rallyanarchy now. Get your popcorn ready!
 

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Mark Utecht here in MN, and for that matter, Mike Hurst before him, have experience with running a large, very powerful RWD car in the form of a Mustang. After Mark did the stroker engine in it, he said the tires didn't really hook up until about 80mph...

Ridiculous fun, but certainly not the most direct path to fast stage times.
 

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If you can come up with a design to satisfy Mike, and you really want to build a vette, do it!

Pop and I have considered a 308 or 328 for many years. Of course, we've never pulled the trigger, because we had other cars that worked better, but in terms of silly fun, sweet lookin' car, and awesome sound, hard to beat it. Now the price of the things has climbed again. Probably not gonna happen...but if it does...
 

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Trogdor
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Also, before you associate a Corvette too closely with other "big American cars," realize that C4s had a curb weight less than the last few generations of STI (a "standard" car, I presume.)
I don't think anybody is suggesting that an Impreza is not a big car, either.

One thing that always gets me about Corvettes, especially the C4s, is how incredibly cramped they are. Every couple years I get the itch to buy one for autocross/track day duties, and then Realization sets in. They're just plain tiny on the inside. I can't see being able to wear a helmet in one, and sit below a roll cage in one, without spinal reconstructive surgery. Impreza maybe large car, but it's large in useful ways.

A rally rollcage is far more space-intensive than an NHRA cage. A car with an NHRA cage can be driven as a street car with minimal fuss, I don't think the same can be said for a rally cage.

Don't get me wrong, I am sympathetic to the wedge shaped RWD cause. Personally, I love playing with early RX-7s, but these have a lot more interior room than a C4, and if I had to stick a cage in there too, I'd just park the car and get something with more interior room like a Neon or a Golf/Jetta.

since an all-aluminum LS3 weighs ~100lbs less than the stock L98 and would have in the upper 400s of hp, I can't see a reason not to have it in case there's a long straight. :D

Oh, and I'm signing up for an account on rallyanarchy now. Get your popcorn ready!
You'll just hear the same things as here: 400hp in a 2wd car seems like a tire retailer's dream. 100-125hp/tire is a realistic figure for loose surface.

If you go to RA, after the initial "is the guy serious?" and "just get an XR4Ti" (not a bad idea, if you can find one that isn't rotted) comments, you'll probably hear stories of 450hp Mustangs and 550hp turbo Volvos... and how they still aren't as real world fast as something that weighs 2000hp and has maybe 150hp...
 

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With all respect to the naysayers, or to put it another way "the practical people", there is still lots of room in performance rally for those who want to have fun their way. If we regularly saw fully subscribed fields of AWD cars then the decision to build and rally something different might be suspect. But that's not the case. On this continent this is still a sport that has room for and welcomes the garage mechanic and if trying something different is what scratches that person's itch, then who are we to throw up roadblocks? Will they ever win a rally overall or perhaps even their class? Perhaps not, but does that matter to someone who is doing what they want and is interested in facing and conquering the challenges that lie before them?

Best of luck to those that want to dream of a Corvette build or of any of the other "unusual" options for rallying. We don't all need to have a Subie to be a self-satisfied rallyist.
 

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Build it as a euro rally cross car and show what real American power can do! :D Id like to see a corvette going over the big jump at x games!
 

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