Track Characteristics of the SPF? - Page 2

johann hamm · 03-04-08, 08:16 AM

[Hi Kim

In November 07 a GT40 replica was tested with 12 other modern performance cars. This was in South Africa at Upington Airport and involved sveral tests and was for CAR magazine and a TV programme. Since the vehicle is a CAV I do not feel free to discuss the outcome here. Should the moderator deem to move this elsewheres on the site I can provide more info. At best I can say that a sorted GT40 replica does run with the best.

My intention, like many on this board, is to track the car – in my case about 20% of its total miles, probably at various club events and racetracks (Sebring, Moroso, Homestead, to name a few). I'm curious: Does anyone have track experience with the SPF? What are their track characteristics? High speed oversteer/understeer? Stability at speed? Can they keep up with more modern machines like the Z06s, Porsche 996s, Cup Cars, and the like. Etc.

Obviously, I'm trying to predict how my car will perform (I've driven the car endless miles in my imagination and it always does great!). For background, it has the standard Avon tire setup (r:295/f:215); it has an all-aluminum 427W with TWM injection and 608 bhp (a tad much, I'm afraid); and, the front-end enjoys canard wings to increase downforce.

Any thoughts would be appreciated!

Kim[/quote]

johann hamm · 03-04-08, 08:29 AM

Hope I have this right to post pics

Johan · 03-04-08, 08:31 AM

Remember the Amphicar? Not a good boat, not a good car ? You will need to swap a lot of stuff to run track days and then go back to street use. Tires of course, and then there goes your bodywork. The side widows will need to be removed as most clubs require that they be down. Shocks, perhaps springs, ride height, etc.
I am not down on using the car on the track. I am suggesting that it be built as a track car first and foremost and that the compromises be dealt with on the street rather than build it as a street car and then wonder why it will not keep up with a Porsche.

johann hamm · 03-04-08, 09:03 AM

Best place to sort a car out is on the track. My 40 replica doubles as a road and track car. For track events and practice I drive it there, swap wheels to dot rated slicks purely as a costsaving measure. I prefer the feel and predictability of well worn Pirellis and laptimes are close to the slicks. No other changes are made to the car and I even run pumpfuel on track although nothing beats Avgas. I recon with a 40 you can have a piece of both pies, shouldn't a GT be as such?

speed220mph · 03-04-08, 10:11 AM

Kim: Check out Tiff Needle's drive in a SF GT40 at the Kyalami circuit. Looks as though there was no need for canards as he was hanging the back out much of the time. I don't know what the weight difference between your car and the one being tested. Looks as though this one is powered by a Roush Windsor with ci block and aluminum heads. Couldn't see what tires were on the car.

YouTube - GT40 driven by Tiff Needle

As for handling, go easy at first, then gradually build up your speeds as you get accustomed to the car. Make adjustments as neccessary. Dennis can surely help you with this.

As for how replicas handle, I ran my ERA with a 331 against a Porsche Carrera and a supercharged Z06 on VIR's 1.64-mile south course. With considerable elevation change, it's a real test of braking and off-camber, down-hill handling with some high-speed stuff thrown in. Note: As per Dennis' recommendation I installed the /CR76ZZ AVON 15-inch 215's and 295's on the car. I started in a single line behind each car in separate sessions. Result was the ERA was better than the Carrera in the curves, twistys and long straight. It was neutral in all situations. As for the Z06, he could pull me a little down the long back straight, but not so much that I couldn't gather him in under braking and in the turns. Went by when he cross it up in an uphill left hander. From then it was audios.

Be prepared for the huge smile on your face.