How fast a GT can go?

[Jack Houpe]

Your a jewel Kirby!

I would like to see an SPF do the Texas mile and join the 200+ club but don't know of anyone who has tried.

Dennis gave me the front canards I just haven't put them on, he says there is an improvement at very high speed, I forgot to ask what speed that was.

 

[Jack]

Re: How fast a GT can go?<!-- google_ad_section_end -->

How tight are your shorts, and how deep is your wallet?

 

[René]

I'm not a fan of those, although they might help a few kilo's downforse...
also, are those aloud? it cuts legs ;-)

I think this front lip/spoiler will be better for say 200mph>>

http://www.gt40s.com/forum/all-gt40/12875-gt40-evolution-carbon-fiber.html

 

[Howard Jones]

A couple of things. If you look at the 2nd B&W photo of #73 it is clear that the front is getting light. These cars made a couple of hundred pounds of LIFT at Le mans speeds. Everybody who raced them tried to fix it. You see all manner of canards, chin spoilers, and rear spoilers in the period pictures, and in the end real applied scientific aerodynamic work proved the shark nose design obsolete.

As to how fast.......... street car, street car build budget, Z rated tires, and pump gas 400Hp motor, I would think that 160 is pushing it. 200MPH? well....... your are going to need a LOT of power. 600HP at least. But more than that, a LOT of development work by someone who knows what they are doing. Amatures (like us) don't have any business trying to drive a home built car that fast.

And........have a look at a real modern race car like a NASCAR stocker. That's what it takes to survive a mistake at 200MPH. I have NO doubt that if I lost my car at anything like that speed and hit something it would be the last time.

Lastly.......... check out what it takes to run in the 200 club with SCTA land speed cars. Not many street car there. Maybe there is a good reason.

Fantasy discussions on the web always sound like it is just a matter of pointing it straight, putting a lot of power down, and ........... walla! 200MPH. The reality sets in when it is attempted. VERY, VERY few cars of any kind car can attain those speeds. And even if you could do it there are few places safe to try. You are going to need at least 9 or 10 thousand feet and dead salt-flat smooth.

Please don't end up on Utube!

YouTube - ‪Nissan 350Z high speed crash‬&rlm;

another, http://www.youtube.com/watch?v=yS1NU6xjTSY&feature=related

 

[Jac Mac]

I see Iain Pretty in RF 117 has nudged 288kmh/179mph in the video of his last outing at Bathurst, ssemed to have plenty of RPM in reserve, car was getting 'light' over the crests on this circuit and this car runs quite a few 'aero' extras. Check out his build thread Rf117.... for the video link in last post or go to ' straight eight racing ' on vimeo..........


'If 'BURT' can do it surely a GT40 can..............

 

[David in Durango]

My prediction (based on some experience and a lot of research) for 1 mile and 200mph you will need:

800 rwhp
good weather
good engineering YouTube - ‪Underground Racing Twin Turbo Gallardo Crashes At 200+MPH Texas Mile‬‏
and spectacular attachments [1]

Ford GT w/ twin turbos (1000hp?) 225mph
Lambo w/ twin turbos (1800 whp?) 240-250mph
After an agricultural excursion my Pantera did 148mph (325 whp) in a mile without the front spoiler - an exciting drive and not recommended.

Two miles would give more speed for the underpowered - don't forget you need to stop!

cheers,


[1] attachments = Huevos, 'nads, balls, courage

 

[Howard Jones]

More Math!

The Mayfield Company Homepage - Coefficient of Drag Tables and Curves

 

[Jack Houpe]

David, did not John Tieman break 200 in the speed trap at bborr? His car was built in Austraila and is geared real tall. I see no reason a proper built car with 600 HP can't touch the 200 mark on a mile.

 

[René]

here in the Netherlands I life next to Germany about 30km from the border
the first Autobahn wich is limit-free is the A31 and that one is about 43km from my house...and then I can drive at least 100km on that road to try and there were the road alouds it when their is not so much traffic.
But still I only visit Germany 2 or 3 times a year, next month though we go with some fast cars and do a 700km trip mostly over those speedlimit free roads, will cost some fuel I'm afraid sadly no GT40 will be their to see how fast that could go on a safe way, safety comes first.

 

[Jack Houpe]

Howard, have you ever done Silver State, Big Bend or Sandhills? There is a special license you must have to open road race and you must pass a driving skills test at speed before its issued to you. Then you can increase your speed every race till you get to the unlimited along with the required safety equipment as your speed progresses. I don't think there were armatures at the wheel when those accidents happened. The 350Z looked to be a blow out, and the Lambo was the stupid idea of a parachute.

If the GT40 did 200+ in Le mans then it will do it now, SPF cars are built close as possible to original and with aluminum blocks which is 200lbs lighter and EFI which can make much more reliable HP I think the car would be a front runner in the 200 MPH club. Lets not forget how many cars are 200+ off the showroom floor which are much heavier.

 

[Dalton Veitch]

I note that Iain Pretty in RF117 has done 179 mph in racing, but this car is highly modified in every detail to a modern specification, has serious aerodynamic aids, serious power, and enough safety cage to make it difficult to enter. Your typical GT40 replica isn't on the same page.

 

[J. Salmon]

I thought "speed220mph" got his screen name at Bonneville, confirmed, in his ERA.

I have heard the canards really do help keep the front down. I have been wondering about fender louvers on top of the front clip, certainly not done on any original or replica I have seen. I think a deep splitter would work too, and the RCR chassis has a great setup to build a removable one.

We do know more about aerodynamics than we did in the 60s.

The Ricardo gearbox is easily geared for it, but I don't plan to risk my life to see high speeds.

 

[David in Durango]

Jack is correct, 205ish (can put my hands on the exact right now.) Ah, found my notes. Charlie was fastest at 209.7, John was 202 according to my notes.

But I was referring to standing start mile - not a flying mile. Of course, John's car sounds extra wonderful, too. (Jack's car seems a little muffled?)
YouTube - ‪BBORR2010 081‬&rlm; from 2010.

So says the Miata driver . . . . .

Have a safe holiday!

David, did not John Tieman break 200 in the speed trap at bborr? His car was built in Austraila and is geared real tall. I see no reason a proper built car with 600 HP can't touch the 200 mark on a mile.

 

[Howard Jones]

I have no dough that it can be done. I just think that I will take a serious and proper approach to do it safely (the parachute was stupid). There are several people on this forum that a first glance appear to have the ability to put together such an effort. On the other hand there is always also the potential to run out of talent before running out of money .

ANY shunt at these high speeds would be devastating. I guess I'm just saying a real consideration of risk to reward should be worked out before anybody goes out and sees how fast there GT40 will go.

I have though about the open (closed for the competition and sanctioned by the local police) road races in Nevada and elsewhere. Maybe one of the slower classes, 130-140, would be fun.

 

[David in Durango]

"(the parachute was stupid)." Are we referring to the Lambo @ Texas mile accident?

The parachute was incorrectlly mounted. Any parachute in a crosswind may contribute to plans going bad.

 

[Howard Jones]

Yes, as in the video above. That car shouldn't need one. They have excellent brakes. If you run it so deep into the run out/brake zone that you need a parachute then that's stupid too. Just a bad idea, executed wrong, IMHO.

The land speed guys let drag take off the first 40-50 mph at over a couple of hundred, and it will quickly. Then easy on the brakes. Above 250 a lot of them use a chute. But its pretty small 2-3 feet in diameter with a very long tether. I watched a lot of runs and many times cars at about 250-275 have em but don't use em. I think they have em as a safety system. Brake failure, car gets sideways at the high end, etc.

Over 300..........I don't think that's what we are talking about.

 

[David in Durango]

HJ,
That particular Texas Mile venue was a touch short - not quite 1/2 mile of braking area. I agree that the Lambo could probaby stop "with a good driver" - my understanding is that that particular driver was famous for "fancy dismounts," and I believe he had run off the end at a previous meet. The mount point on that car was (in my opinion and all that I talked with) WAY too low. This would cause the rear wheels to become light or actually leave the track. With the sidewind we had that day it shouldn't have been a big surprise. Remember though, 238mph is a lot of energy to control in that short distance.

SCTA (Bonneville and El Mirage) requires a parachute if the class record you are running agains is above 175 - I believe at some point they require 2 parachutes.

I have been told that the parachute will generate about 1g - and once pulled you are going to stop.

For what its worth, I saw a guy spin a Caprice (no parachute) at about 185 - I didn't think he would EVER stop!

Hopefully we can sit down w/ an adult beverage sometime and chat.

cheers,

Yes, as in the video above. That car shouldn't need one. They have excellent brakes. If you run it so deep into the run out/brake zone that you need a parachute then that's stupid too. Just a bad idea, executed wrong, IMHO.

The land speed guys let drag take off the first 40-50 mph at over a couple of hundred, and it will quickly. Then easy on the brakes. Above 250 a lot of them use a chute. But its pretty small 2-3 feet in diameter with a very long tether. I watched a lot of runs and many times cars at about 250-275 have em but don't use em. I think they have em as a safety system. Brake failure, car gets sideways at the high end, etc.

Over 300..........I don't think that's what we are talking about.

 

[Ian K]

would the little side lips like on the GT40R help a bit? they don't look really strong anough to help a lot with downforce...
btw this old 64 gt40 also has strange looking solutions...

FYI - Bob Bondurant drove a MkI, similar to the above pictures (if not one of them exactly) in the 1965 Le Mans. Using the Ford 5.3l motor in qualifying, he claims to have hit 212 mph down the Mulsanne. I suspect the Wyer/Gulf cars of 68/69 could go faster due to better aerodynamics.

Ian

 

[Fred W.]

Hi All

Is there anything that can be learned from looking at a Ford GT a very modern well thought out car that is probably faster than most of the cars that are built or owned by members here. The shape is similar (I guess).

Its a fascinating question really. You wouldn't like to find out the hard way that its a bad idea to attempt a top speed run.

 

[Ian K]

I see Iain Pretty in RF 117 has nudged 288kmh/179mph in the video of his last outing at Bathurst, ssemed to have plenty of RPM in reserve, car was getting 'light' over the crests on this circuit and this car runs quite a few 'aero' extras. Check out his build thread Rf117.... for the video link in last post or go to ' straight eight racing ' on vimeo..........


'If 'BURT' can do it surely a GT40 can..............

One thing about Iain's car - it has the split nostril. Again, the Wyer/Gulf cars went with the single deep nostril (as did the MkIIBs and MkIVs) which redirected the air coming out of the nose over the roof as opposed to either side. This should (theoretically) increase the downforce some. It would be interesting to see Iain try a single deep nosed vent and what the resulting change in aero/handling would be.

Ian