Fwd chassis versus RWD Et
 

When it comes to advantages or disadvantages, how much does it appear using a FWD conversion is better than older RWD chassis. I have heard some report as much as .15 improvement when they place drive train in FWD from their older RWD cars.... Any input?

Re: Fwd chassis versus RWD Et
 

Kinda depends. As for GM cars, if you don't need to be under 2900/3000 lbs it would be hard to beat a '93/'02 Camaro/Firebird at that weight. 101" wheel base, with the engine set back. Half the engine is under the windshield & dash. Pete Peery told me that my driveshaft is like 8" shorter than his little GT car. You can run smaller tires with more air. When it gets hot, and my friends with the "jellybean" fwd GT cars start spinning & talking about the track going away, my car can't tell the difference. Likely not as easy a car to work on, however.
The reason you see so many running GT classes with carbs, ain't because they came from the factory with fuel injection. :-)

Re: Fwd chassis versus RWD Et
 

This is another one of those questions that depends on who you ask. Jimmy Boburka had a VERY nice, well beat to death F-Body Camaro. He built a really nice Cobalt and did exactly as you mentioned . Everything he could use he did. Motor, Trans, 3rd member, ...everything. Of course the headers had to be changed. He then headed to a track that he new like the back of his hand. He told us it was 7 to 8 faster.

But ,I've had one good friend swear that it is not nearly that much.. And they also have had both platforms.

Re: Fwd chassis versus RWD Et
 

Five to seven

Re: Fwd chassis versus RWD Et
 

Hard to think where it would come from, if we are talking about a 4th gen. Especially when the track goes away.

Re: Fwd chassis versus RWD Et
 

You should know !

Re: Fwd chassis versus RWD Et
 

Gotta wonder where it is. A 3rd gen, I could understand.

Re: Fwd chassis versus RWD Et
 

Five if conditions are the same. A little more if there's any headwind. The front wheel drive cars are just more aero than the rear drive cars, Ed.

Re: Fwd chassis versus RWD Et
 

Learn something every day. Don't understand aero making that much difference in ET, no faster than we run, but I don't understand how bar codes work either. LOL

Re: Fwd chassis versus RWD Et
 

I know the one to get you a double shot for the price of a single, but I ain't telling...

Dale

Re: Fwd chassis versus RWD Et
 

With all the variations on factoring because of stick, auto, Gt versus SS would there be reason to give a Wt break to standard RWD cars versus FWD cars in same class, or should factors apply only to FWD if that is the fast car? Leaving the HP the same on RWD?
Seems a Camaro gt versus a SS chevelle are different should it apply to this difference also?

Re: Fwd chassis versus RWD Et
 

From all of the numbers I've seen, the 3rd gen Camaros/Firebirds are actually more aerodynamic than the 4th gens. The 3rd gen Firebirds are actually a little bit better than the 3rd gen Camaros as well.

Re: Fwd chassis versus RWD Et
 

I'm hoping it goes the other way for me, when and if I get this vette done. Adding 280 lbs and losing .35 on index. The Vette is lower, wider, with only slight engine set back as compared to my number 3 cylinder at spindle centerline on my FWD. On paper I'm calling a good exchange.

The only advantage I can see in a FWD car is the weight factor. Lighter is faster. There are a some aero bodies out there RWD also, so don't see much there.

Dick, what are going to build?

Ernie Neal
SS354

Re: Fwd chassis versus RWD Et
 

Slightly off topic,

the last fast bracket car I build was a 1990 Firebird. It was an excellent platform, easy to work on, very very consistent.

When I began the GT project I strongly considered using another 1990 Firebird and I think it would be a good package. Then became interested in the S-10 platform and went that direction.

I still have thoughts of another 3rd gen Firebird before I retire or die. In my experience with 100" wheel base, strut front and easy access to engine it is a valid choice for several combinations including GT. It would also be a good IHRA Crate Motor platform.

Re: Fwd chassis versus RWD Et
 

here is my 2 cents, if you own a rear wheel drive car, you can run normal SS, GT and the modified classes, if you own a FWD conversion car, you can only do GT and modified classes, so that's another pro and con of looking at both body styles.
Just my thoughts

Re: Fwd chassis versus RWD Et
 

Good Discussion. THanks. Have a friend who in a rwd car and feels there is a benefit to moving to FWD for Aero dynamics. Maybe but same wheel bases or longer when see beretta.103. Cavalier is same as Camaro at 101. I feel you chose what you feel is beneficial. When I built my Camaro I really loved Dave Colberts Monte carlo but knew it wasn't going to win on Aerodynamics and pure MASS so I chose CAMARO. Then built a cavalier and it is very competitive.... but cant measure the advantage.....

Re: Fwd chassis versus RWD Et
 

A Cobalt has a .34 Cd and there are RWD cars such a 3rd Gen Firebird which has a .31 Cd.
The aerodynamic effect will vary, no matter if it is a FWD or RWD, based on the amount of rake and the behavior of the car down the track. Also, too much rake, can create other issues such a ground effects since there will be an area of high pressure between the ground and the undercarriage of the car. That is the reason why many cars improve when the belly/undercarriage in enclosed or sealed.

Re: Fwd chassis versus RWD Et
 

If you do not think Areo makes any difference...........Try Dialing my O/SA
Dodge Pickup in changing wind conditions!:eek:

Re: Fwd chassis versus RWD Et
 

A little more difference there, than between a Camaro and a Cobalt. LOL

Re: Fwd chassis versus RWD Et
 

Yes, the Camaro is dirtier than the Firechiken! ;) A 3rd Gen Camaro is around .36 ~ .38 depending on the aero package.

A C5 Corvette is .29 and the usual pickup such as John's, .57 ~ .59 Cd.

Re: Fwd chassis versus RWD Et
 

I've never looked at spark plugs vs spindle, but the 4th gen ('93/'02) Camaro/Firebird appears to have the engine set back further than a 3rd gen ('82/'92), certainly looks easier to work on. They share the same 101" wheel base. Most of the fwd conversions have the engine located much further forward compared to a 4th gen.
I know that goofy ricer-looking wing on the back of my Trans Am isn't helping anything. I was talking to a guy that replaced his rear hatch with one from a base Firebird, told me he picked up almost 1/2 a MPH. No ET. I'm not going to spend that money for maybe 1/2 a MPH. It was on the car when I was driving it to work. I would not have picked that car to start with to build a SS car. It just kinda grew into what it is.

Re: Fwd chassis versus RWD Et
 

I always thought the Al Hood 82 Firebird looked like a very slick car.

Re: Fwd chassis versus RWD Et
 

Cd is only half the equation. Frontal area is the other half.
And I'm sure the cobalts and other jelly beans have way less frontal area than the camaros and firebirds.

And if boburka and cour are saying its seven or so, that's what I'd believe, not a computer program estimate. ;)

Re: Fwd chassis versus RWD Et
 

Removing the rear spoiler on both the Firechicken and the SN95 Mustang (1994-1998), helps in the MPH until the car starts to exceed 150's MPH.
After 150 MPH the spoiler helps.

Re: Fwd chassis versus RWD Et
 

A bit confused because the frontal area is what is used to calculate the Cd.
There are a lot of other physical variables that can have an effect such as body rake, wheel base and CG, including sealing the belly/undercarriage of the car.

Many NASCAR, F1 and drag racing teams have been using my employer's wind tunnels for years and probably tested every contraption or device they could imagine.

Re: Fwd chassis versus RWD Et
 

I am guessing less body rake and lower to the ground would be better?

Re: Fwd chassis versus RWD Et
 

Here's a post I made a while ago regarding drag coefficients and frontal area of different vehicles used in stock/super stock. These values may not be 100% accurate but they're what I found online. You have to multiply Cd by frontal area to use this in the drag equation, Fd = .5(rho)(Cd)(A)(v^2)

Also, these numbers are all with stock wheels and ride height, a race setup would change them some.

Re: Fwd chassis versus RWD Et
 

Might need to send a Corvette to Vic Custer to put my drive train in. 'Course, somebody would have to help me get in and out. LOL

Re: Fwd chassis versus RWD Et
 

I sure don't know, but I do remember Warren Johnson (when he ran the silver Cutlass), that aero didn't amount to much (in the distances we run)

Always wondered if that was a concession to what he was obligated to run, a subterfuge or the truth

Re: Fwd chassis versus RWD Et
 

http://www.icarinfo.net/ has some good info, including drag coefficient, frontal area, and aerodynamic resistance. According to their numbers, a Dodge Stratus would be worth 15+ HP over my Volare at just 100 mph.

Re: Fwd chassis versus RWD Et
 

Aero wise at Bonneville the 4th gen Camaro looks to be better but the 3rd gen is actually the better of the two

Re: Fwd chassis versus RWD Et
 

I don't have one to look at right now, but can somebody that has looked both over tell is the engine is set back as far in a 3rd gen? Having to drag less tire down the track is equal to more hp. I would expect that to be worth more than the aero difference. The 3rd gens I see around here have some big tires. May just be for bracket mode?

Re: Fwd chassis versus RWD Et
 

I imagine the tire companies would know the rolling resistance of their tires at different pressures. It would be interesting to know that info for the commonly run tires. I bet the rolling resistance changes for bias ply tires as they grow, radials probably don't change as much.

Re: Fwd chassis versus RWD Et
 

Ed
My buddies gen 3 firebird is at my shop. I will take a look at it when I get home this weekend and let you know where the engine is positioned. It does sit back quite a bit in comparison to my gen 1 Camaro. His engine is in the near stock location

Re: Fwd chassis versus RWD Et
 

There are many of these cars that due to the engine setback with engines with a rear distributor, they have a removal cowl grill.

Re: Fwd chassis versus RWD Et
 

Next check the spindle position on an earlier vette.

Re: Fwd chassis versus RWD Et
 

I need to spend more money (no end) in a belt driven short dist up front. I was given a regular MSD for the rear. It does not come out without pulling the manifold. They come out together. Fun deal. Takes two people. Have to buy something for my Jessel belt drive to do that also. Have to buy something to run the oil pump too, don't know if it would come out alone with my Hogan intake. Easier with a single plane intake, but I could not make one run as fast.

Sure be nice to have all the money I have spent on parts that didn't run as fast. LOL

Re: Fwd chassis versus RWD Et
 

wow I always wondered how much I was giving up to one of the jelly bean modifieds, after lokking the info in this link my s10 is uses 39.2hp to just to overcome aero drag at only 60mph where the c-5 vette was listed as only using 18.6 hp for the same . not sure how much that changes at 150+ . I never really thought of the s-10 being that bad? I guess I need to re-think that.

Re: Fwd chassis versus RWD Et
 

Mark, The S10 has a pretty tall profile ..Look at yours in the staging lanes sometime.
You can always find it.