Track Characteristics of the SPF?

Kim Petersen · 02-21-08, 05:24 PM

Well, I'm within a month of receiving my SPF Mk I from Olthoff Racing, after waiting almost a year for a transmission. Dennis & Co. have been great, and are as much hostage to the ZF shortage as anyone else. (Hopefully a reliable source will come from Quaife and their ZFQ, but that remains to be seen.)

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

Ross Nicol · 02-21-08, 10:27 PM

The cheeky side of me suggests you'll be off at the first corner but seriously your'e asking how long is a piece of string. Your car will have it's own unique characteristics that other 40s even among SPF's may or may not exhibit.As you go faster on the track, handling issues present themselves,even the way you drive can create different responses from similar cars.Nothing wrong with excitement and anticipation though.

Ross

SpyderMike · 02-22-08, 01:08 AM

Hi Kim,

Did you ever live in Southern California? Just curious...

Mike

Alan in Nevada · 02-22-08, 01:41 AM

The only information on the track characteristics of the SPF's that I'm aware of are in the thread back one page intitled "SPF GT40 handling" posted by me a few months ago to elicit the same information that your looking for.

One "Jeff" responded that he and his father have been playing around on track with a Ford GT and a SPF GT40 that they owned, which revealed some valuable information, but that's all so far.

It appears that to get optimum handling from a SPF GT40 one will have to do a lot of "sorting out" in the areas of wheel and tire size and type, suspension stiffness, shocking, and so forth (The way it's been done since forever). Should be fun, but will involve a lot of track time, parts switching, and some $$$. First, I would get some good and reliable alignment specs, set my car to those, and go from there.

Good luck. And do have fun.

Steve C · 02-22-08, 08:04 AM

Guys,

Dennis Olthoff has been running his red 40 pretty much stock at a number of track events...Suggest you give him a call and report back...Also go to "Olthoff Racing Perfection.com" and see clip of him racing the stock car.

Steve

Kim Petersen · 02-22-08, 08:38 AM

Quote:

Originally Posted by SpyderMike

Hi Kim,

Did you ever live in Southern California? Just curious...

Mike

Mike:

As a matter of fact, yes. I lived in Malibu for four years back in the mid-90's and was active with FCA and PCA. Had a chance to drive at Laguna Seca - fabulous course!

Kim

Jeff · 02-22-08, 10:28 PM

Kim,

My Dad and I have had a couple track days with the SPF & Ford GT. Nothing too scientific, no g-force numbers or lap times but street tire to street tire the Ford GT wins hands down. There is no comparison except in acceleration where the two are almost dead even. The SPF makes around 520hp at the crank vs 650? from the GT.

In my opinion a damper upgrade is necessary to track the SPF at any real speed. Maybe someone with superior driving skill would be more comfortable? The stock spring rates are fine but the compression/rebound damping is way too soft. We fitted some adjustable Qa-1's and despite spending time getting them dialed in are happy with the results.

We have plans to get some track tires for the SPF, and probably make some camber adjustments. I really think it will make a substantial difference in how the car feels on track...and hopefully get rid of the terrible understeer.

BTW, 608hp isn't too much of an over kill... just need to resist the urge to stomp the throttle! Or just spend some time brushing up on your drifting

Congratulations on the car! Your going to love it!

Alan in Nevada · 02-23-08, 05:12 AM

Quote:

Originally Posted by steve c

Guys,

Dennis Olthoff has been running his red 40 pretty much stock at a number of track events...Suggest you give him a call and report back...Also go to "Olthoff Racing Perfection.com" and see clip of him racing the stock car.

Steve

Interesting videos.

But at neither track is the car is being driven anywheres near really hard:

The engine isn't being taken up anywhere near redline, no hard braking on corner entry, no complaining tires through the corners, and not the slightest hint of wheelspin or fishtailing indicating an attempt at fast corner exits (although at Kershaw it may be because the track appears to be wet), so I don't think the videos are telling us much.

But certainly Olthoff's set-up would be a good place to start for sorting out a SPF GT40, barring any other information.

SpyderMike · 02-23-08, 01:16 PM

Kim,

By any chance, are you a private pilot?

Mike

Kim Petersen · 02-23-08, 03:26 PM

Quote:

Originally Posted by SpyderMike

Kim,

By any chance, are you a private pilot?

Mike

Mike:

I was flying ultralights out of Torrence – dodging the Goodyear blimp, scared to death that I might puncture it with my tiny plane – but that's about it. I've spent more time jumping from planes than flying them. And you?

Kim

Kim Petersen · 02-23-08, 03:34 PM

Quote:

Originally Posted by Team Jeff

In my opinion a damper upgrade is necessary to track the SPF at any real speed. Maybe someone with superior driving skill would be more comfortable? The stock spring rates are fine but the compression/rebound damping is way too soft. We fitted some adjustable Qa-1's and despite spending time getting them dialed in are happy with the results.

We have plans to get some track tires for the SPF, and probably make some camber adjustments. I really think it will make a substantial difference in how the car feels on track...and hopefully get rid of the terrible understeer.

Jeff:

Thanks for the passing on your experience. I'm going to raise your points with Dennis Olthoff (who's preparing the car). I'm hoping that we'll have a chance to bring the car to VIR soon so as to sort out handling issues, and your suggestions would be a good place to start. Thanks!

Kim

Steve C · 02-23-08, 03:58 PM

Kim,

Let us know what Dennis has to say.

Thanks, Steve

Steve Briscoe · 02-24-08, 11:31 AM

Quote:

Originally Posted by kepetersen

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.

Kim

Kim-
Thanks for the thread. Keep us posted as I can use the information about track set up as it develops. Do you have any specs on your motor? Will it run on pump gas and what is the planned compression ratio?
Thanks,
Steve

SpyderMike · 02-25-08, 02:35 AM

I used to know a Kim Petersen who was into cars (let me drive his Ferrari Testarrosa once) and planes (as a student pilot he bought a new A36 Beechcraft). This was back in 1990 at Brackett Field - Pomona area. Thought you might be that person...

Mike

Malcolm · 02-25-08, 07:34 AM

Quote:

Originally Posted by kepetersen

Jeff:

Thanks for the passing on your experience. I'm going to raise your points with Dennis Olthoff (who's preparing the car). I'm hoping that we'll have a chance to bring the car to VIR soon so as to sort out handling issues, and your suggestions would be a good place to start. Thanks!

Kim

When racing at VIR, Ron and I always wondered how a 40 would do there. You should have a great time as it mixes both fast and slow corners with a damnably long straight! Going green with envy!

Ron Earp · 02-25-08, 09:20 AM

Quote:

Originally Posted by Malcolm

When racing at VIR, Ron and I always wondered how a 40 would do there. You should have a great time as it mixes both fast and slow corners with a damnably long straight! Going green with envy!

They have some video from VIR on the webpage, but not the Full Course or the Grand Course, only the abbreviated South course. Still, it looked like fun!

Steve C · 02-25-08, 09:32 AM

For SPF @ VIIR...Go to Olthoff web site www.Olthoff Racing Perfecttion.com...click on GT40...Lower left of that page...GT40 @ VIR... (Dennis driving)

Steve

Ron Earp · 02-25-08, 09:38 AM

Here you go Steve, this should work:

Olthoff Racing Perfection

However, just for information for those that haven't driven VIR none of the videos there are the Full Course at VIR that is used in the race weekend layouts by Rolex, SCCA, NASA, HSR, and others. I'd like to try just the South loop sometime though, l think it'd be different and enjoyable, especially in a 40!

Kim Petersen · 02-25-08, 04:12 PM

Quote:

Originally Posted by SpyderMike

I used to know a Kim Petersen who was into cars (let me drive his Ferrari Testarrosa once) and planes (as a student pilot he bought a new A36 Beechcraft). This was back in 1990 at Brackett Field - Pomona area. Thought you might be that person...

Mike

Another Kim Petersen, eh? That wouldn't be me; I would never let you drive my Testarossa! Seriously, though, it definitely wasn't me. At