My SPF2202 against a 650 hp Ford GT

[Jack Houpe]

Dave, theres a thread on it already, we've been talking about you. Tell us what happened. Did the GT lift the throttle at 130? It looks great.

 

[Dave-SPFGT40]

He lifted I believe around 140 mph... as I was pulling away he said he didn't want to get rock chips hitting his car so he pulled off... I kept going hitting 170 mph... But weight plays a huge part in this cuz the ford GT is about 1000 lbs heavier plus he has a guy in his car weighing around 150 lbs taking the video.... I do have a solid roller which allows me to get to 7000 rpm... helps out on the pull....

 

[Jimmy P]

Maybe the GT deployed a chute at speed because the SPF left him for dust. We really need to know the back-story on this race. Dave, I'm with Jack...please tell?

 

[Jimmy P]

That answers that...thanks.

 

[Rich E.]

Re: SPF vs Ford GT

To all the skeptics who talk about the GT's better aero and say "If the race would've gone on the outcome would've been different", I say strap a supercharger or turbo to a SPF and run'em again:thumbsup:

Rich.

 

[Keith]

Re: SPF vs Ford GT

I would qualify my earlier comment then - the GT has been wind tunnel tested and although you can't easily see it - there are small but nor insignificant aero tweaks and as a production vehicle the confidence factor would have been much higher for the GT driver plus it is probably geared for 200 ish. That's what I meant.

I assume that a "stock" replica has NOT been wind tunnel tested, or taken to 200mph or has Type Approval etc etc and so forth. Not that the SPF isn't capable, far from it, but without extensive engineering checks - would you wanna go 200 in your replica?

Course you would! :thumbsup:

 

[Cliff Beer]

Re: SPF vs Ford GT

Here's the aero difference....

You can go 205+ in the GT on a level and straight road without add'l aero effects nor a lot of experience piloting super fast cars. It'll be steady and track true.

Try going 205+ in your GT40 replica and here's some of the stuff you'll experience: windshield wipers lifting and then launching themselves, external rear view mirrors launching, door tops getting sucked up and out, plexi-door windows sucked out and launched, exteme light front end with very real risk of complete loss of steering and launch (of entire car), tire blow out (if using a 15 inch wheel).

There's a very big difference in the two at these insane speeds, and that's why there are loads of YouTube vids of GTs at 200+, but none of GT40s.....

 

[Jack Houpe]

Re: SPF vs Ford GT

I know this is tread jump but I am willing to bet that a pan underneath the engine of a GT40 and all the way back to the rear would knock the CD way down and increase speed and gas mileage. There is way to much pressure under the rear deck lid and I feel considerable amount is buffeting up from underneath the car.

Thanks for the heads up Dave! How did your car feel at 170? I have had mine to 165 which with my ring and pinion is 6200 RPM with 15 inch avons, it felt good but sounded like the motor was doing 10,000 rpm. What RPM where to doing at that speed?

Cliff I open road raced with a guy who is not on this forum, his name is John Tiemann, he is trying to bust the 200 MPH flying mile with his car. He encountered many problems and once left the road, unhurt but still OFF the road. He has an Australian build 40 with Porsche transaxle with cooling for the long distance we race. He added the diffusers from the GT on his car which made it stable. I have pictures which I will post.

 

[Trond]

Re: SPF vs Ford GT

Hi

I have not yet reached the 200miles barrier, but drove my SPF MKII with Roush 427R at 305km/h this summer. That is about 190miles/h. This was measured by GPS (and by the Porsche 997 Carrera 4 that was being passed driving 295km/h)

We were driving mostly straight forward at a new motorroad in Poland (yes, they have SOME good roads also) between Sopot and Poznan. At that speed you have a lot of noice and earplugs is essensial, the doors is pushed up towards the eyebrows, but that is about it.

The car is remarkably steady to drive, and through wide turns on the road the car still feels in good contact with the road. My car is standard as delivered from Superformance, exept 17" rims instead of the "original" 15"

It did not feel like that the last 10 miles would make a big difference, but at that speed you never know. I still had some rews left until the maximum 6500rpm, so I think it shoud have been possible to reach 200 miles but we went out of road.

 

[Jim Craik]

Re: SPF vs Ford GT

Cliff,

Thanks for clearing that up. I appeard to me that you were implying that the GT should be much faster due to it's "MUCH SUPERIOR AERO", now it appeas that its the windshield wipers, rear view mirrors, door tops, tires and a light front end that will slow the 40 down.

I'm not implying that I'm even close to brave enough to go those speeds, but there were very brave men in the 1960s' who went 200+ mph with a light front ends, plexi windows and 1960s' tires.

 

[Mark]

Amazing pull away speed....what motor are you running?

 

[Dave-SPFGT40]

Thanks Mark. I got a 427R (Roush) solid roller... Gives a great pull at high rpm....

 

[Dave-SPFGT40]

Re: SPF vs Ford GT

Hi Rich, if the the ford GT was stock 550 hp then the race would have been totaly one sided in my opinion... he claimed to have had 650 hp and i was still pulling away from him at 140 mph and still pulling at 170 mph... i was just getting nervous about hitting high speeds with the wind conditions that day... I have to give to Mark at Roush for building me such an amazing motor and Erick Voss for the install... They did an amazing job.

 

[Rich E.]

Dave, I'm in complete agreement. Yes the SPF suffers from a bit of lift at the higher levels but........IF we had the same aero improvements as the GT ie, a splitter, diffuser, etc, it wouldn't have even been a contest. For me I'd install a good set of canards, a good set of hoosiers, and I'd have no problem trusting my car to 200+. Personally I've been 166 mph (mathematically calculated) in its current configuration and that was just at the top of 4th. Felt pretty good too IMO.

As for the statement that our cars would come apart at such a high level. Well someone might want to tell Dennis, Trond, Alan, and I'm sure others that have been there that they are driving desintegrating cars........... BTW, I don't think any of that has happened yet but I could be wrong.

My comment about adding power was to level the playing field. With a turbo or supercharger, like in the GT, you would've been so far ahead I think it just might have been laughable.

Added power can overcome alot of things, cases in point:

These cars were essentially aerodynamic bricks but with properly managed airflow and huge power they were pretty quick. Imagine the possibilities with our little lightweight land bullets.


my .02
Rich.

 

[Cliff Beer]

Dave, I'm in complete agreement. Yes the SPF suffers from a bit of lift at the higher levels but........IF we had the same aero improvements as the GT ie, a splitter, diffuser, etc, it wouldn't have even been a contest. For me I'd install a good set of canards, a good set of hoosiers, and I'd have no problem trusting my car to 200+. Personally I've been 166 mph (mathematically calculated) in its current configuration and that was just at the top of 4th. Felt pretty good too IMO.

As for the statement that our cars would come apart at such a high level. Well someone might want to tell Dennis, Trond, Alan, and I'm sure others that have been there that they are driving desintegrating cars........... BTW, I don't think any of that has happened yet but I could be wrong.

My comment about adding power was to level the playing field. With a turbo or supercharger, like in the GT, you would've been so far ahead I think it just might have been laughable.

Added power can overcome alot of things, cases in point:

These cars were essentially aerodynamic bricks but with properly managed airflow and huge power they were pretty quick. Imagine the possibilities with our little lightweight land bullets.


my .02
Rich.

Rich, I totally respect what you're saying here. And, I'm sure your car is nicely developed and ready to go super fast. What I might suggest here is that in my personal experience there's a world of difference between mid-160's and 200+. It might not seem like a big deal addig another 35+mph but personally speaking, that's quite a big deal indeed. That may not be the situation with you and your car (hoping that's the case) I realize.

Several years back my brother and I did some high-speed runs in his highly modified Lotus Esprit S4S (1997). Stock top was around 170-172, with roughly 350hp. His mods added about another 175hp, and this increased the top end to about 195-197, but not quite 200 as measured on the on-board GPS. At 165 the car was relatively stable and fairly quiet. However, by 195 all hell was breaking loose - the doors and windows were being visibly sucked out of their holes (as in, big gaps), the front end was so light that steering corrections were on the order of 25 degrees of steering wheel motion, the windshield wiper launched, both rear views launched, and the car developed a pendulum motion which was just plain spooky (road was dead straight and billiard smooth). The later Esprits are highly developed modern supercars with a lot of suspension and aero work going into the design. I just can't imagine doing 200+ in a 1960's design, even with canards and buttoned up windows and extra locking on the front and rear clamshells. Guys die when something goes wrong at those speeds. You don't just coast to a stop. Here's a couple interesting YouTube vids...

YouTube - Porsche GT1 Flip

YouTube - Flying Mercedes?!

I recall hearing somewhere that the Veyron takes something like 260hp to push it to 150mph, requiring an extra 400hp to get it to 200mph with the final 350 to get to 240. I'm not positive on those numbers but it's something along those lines.

So, be carefull!

 

[roaldin]

Sounds like some serious cabin pressure.

Tim.

 

[Pat Buckley]

"Lotus - highly developed modern supercars"......I'm sorry but you made me spray coffee all over my keyboard!

 

[Jimmy P]

The question that keeps running around inside my head is all the stuff I've read about the GT40 running at 200+ on the Mulsanne in the 60's. Most of us are driving replica's and SPF claims their car is 95% interchangable with the original so why would the car be unable to do 200+? What am I missing?

 

[John Lowe]

'Ello all

The (I think Mk1 bodied) big block prototype driven by Ken Miles achieved well over 200mph (205 from memory) at the Ford Romero(?) Test Circuit on a quoted 485bhp. Partly by luck with the original shape and partly by racing development the drag factor would have to be very good even by modern standards to achieve that speed with that power. Clearly, as many have identified, it would not be as good as a modern car at producing any downforce through ground effects. A tray under the engine combined with a rear defuser and lower front airdam would make a big difference to downforce without adding too much drag.

Ruin the period looks mind which, given that its aero performance is pretty good anyway, seems very silly to me.

If you want modern bye modern.

Just my pennyworth on a great thread

John

 

[Tom]

Jimmy,

I'd bet $ the answer to your question "what makes them different..." is the chassis set-up. The most obvious part is ride height. I remember reading a comment from Dan Gurney regarding the mark IV, that they had to run them in slightly illegal spec (front ride height lower than reg) in order to keep the front end planted. I don't imagine that running street spec 4" ride height front and 5" back is the way to make them stable at 200 mph.