Roll On Performance

[William Quantrel]

To pull it back on topic, I was asking how a GT40 would stack up against modern cars from a roll due to its aerodynamics and high power to weight ratio.

200 mph barrier isn't a concern.

 

[Mike]

If I remember right this is a pulley & tune Ford GT so I would say the 40 would fair pretty well.

GT40MFEST - YouTube

 

[roaldin]

Cliff has a Ferrari so no wonder he thinks 200 mph is hard to hit. ;p

Tim.

 

[Jim Glickenhaus]

There are road cars that can hit 200 and it's true that a MKIV went 223 in 67 but there's a HUGE difference in how safe it is to do it in a GT40 or a modern road car that
makes much more downforce. In 67 at speed the MKIV's produced 953lbs. of LIFT. A modern LMP1 makes 3800 lbs. of downforce at 185. Driving a modern race car is a totally different experience than a MKIV. You literally go flat out through turns at twice+ the speed. A lot also depends on gearing. With Le Mans gearing (2.99/1) a MKIV takes a long time to reach VMAX and are pretty slow 0-60. On the road I run 4:58/1) which makes it a bit more lively but you do have to remember to crank in opposite lock before you stand on it in first.

 

[roaldin]

Screwed up, only looked at the first day's official results. Apparently a lot of the cars picked up 15kph on the second day... Weird... Some have no speed recorded at all now, I have no idea why... Anyway, I was still officially faster, just not by as much.
Fantastic event, a credit to the organizers - a bit more care with the speed checks and recording would be nice though.

Anyway William, I think that as the GT40 is relatively light and slippery it is likely to fair pretty well against most of the modern supercar field in roll on tests if it has a half decent engine.

Just saw Jim's post, wish I had a wind tunnel at my disposal, given the ways my various cars behave at speed I'd be prepared to bet that my GT is better lift-wise than my modern GT-R, front end anyway. My car, and I suspect a lot of replicas would be similar, has had some modern thought given to making
aero better. Certainly not perfect but I'm pretty happy with how mine behaves. I'm not trying to compete with a Radical around corners.
BTW Jim, kudos for using that car on the road, fantastic! I use that pic of it on a bridge as a wallpaper.


Tim.

 

[roaldin]

So anyway, roll on comparisons...

Tim.

 

[René]

sometimes I wonder how did they measure their top speed...there was no GPS back then and the speed indicator wiggled all over the place perhaps
so 200 could be 180 or something...?

 

[Seymour Snerd]

"We" do know this? Who's "we" in that sentence if you don't mind me asking?

"I" know what it takes to get to 200mph in a road car. As in first hand experience...me personally. Have "you" taken a road car to 200mph so you "know" it? Better yet, any first hand top speed experience with a GT40?

The vast majority of car folks dramatically underestimate what it takes to get a road car to 200mph. It's easy getting to 150 or 160, even 170 with some finesse. 200 is a whole different ball game however.

Calm down Cliff... "easy" could have meant "easy for the car". It isn't all about you.

 

[Mike]

Calm down Cliff... "easy" could have meant "easy for the car". It isn't all about you.

I wasn't quite sure what Cliff meant by hard? Hard to power it to 200? Hard to handle it at 200? I had my GT to ~180 going up a hill on a short on ramp to freeway pull(6am Sunday deserted freeway). It was take your hands off the wheel easy. I have no doubt 200 would be effortless given a little more room. Not sure I will ever try that in the 40 but it will be interesting to see how it feels at more pedestrian speeds say 140ish.

 

[Seymour Snerd]

I wasn't quite sure what Cliff meant by hard? Hard to power it to 200? Hard to handle it at 200? I had my GT to ~180 going up a hill on a short on ramp to freeway pull(6am Sunday deserted freeway). It was take your hands off the wheel easy. I have no doubt 200 would be effortless given a little more room. Not sure I will ever try that in the 40 but it will be interesting to see how it feels at more pedestrian speeds say 140ish.

I'll let Cliff answer the implied first question.

My understanding of the GT is that it was heavily "engineered" for aerodynamics, downforce and stabiliity. On the other hand, if you read and believe some of the personal accounts from the drivers in the 60s of how the GT40s behaved on the Mulsanne straight, you'd have to be somewhat of an idiot to try it yourself. So based on that, as a human effort I would agree with "hard" as in "difficult or requiring talent and skill to do well" or "having a definite or sudden ending." Or both.

 

[Cliff Beer]

Odd question to ask Cliff. Are you not aware that in the late 60's Ford raced at a place called Le Mans and their cars, the GT40, reached 200+ mph down the main straight?

"We" means "the collective of all those who are aware of this fact" over the last 40+ years. "We" is used in this context. As for answering the rest of your questions, I haven't a clue where to begin. I am not sure why you are implying I am some type of arrogant or elite member of the 200 mph club or acting as a poser.

Almost as if you are attacking me for asking a simple question. Have I offended you in some way?

Where on God's green Earth do you get that I have gone 200 mph in a GT40 or otherwise? On what grounds do you ask if I have first hand experience? What's your angle here? What's your beef?

Did I hit a nerve here? I am at a loss.

Thanks. I stand corrected. I had no idea that GT40's went 200mph at LeMans in the 60's. Appreciate the heads up there.

My frame of reference in terms of modern cars is broad. The new porsche GT2RS for example has 620hp and manages 205 (not limited by gearing) and is an exceedingly slippery design. My own first hand experience has been that it takes at least 450hp to get to 200mph with a very slippery/aero shape, and more hp for most other road cars, a lot more, in fact.

Incidentally, the Spain book clearly shows that the Mark I cars top out between 170 and 197 (check the Gulf/JWA Race Record section) with various version of the 289/302 back in the day. Elsewhere in this book, and in other reference materials, you'll note that these Mark I engines were putting out closer to 450hp, not 400. The Mark IIs certainly topped 200mph with the 427 engine but, again, these engines were putting out well in excess of 500hp.

i'm not trying to be difficult, I just don't see a 400hp GT40 doing in excess of 200mph anywhere in the picture. I'm a stickler for fact, and factual detail, particularly historical detail. However, I'm glad to hear your experience is different as I'd love to think my lowly 302 could do it!

Thanks.

 

[Howard Jones]

Wow........easy 200, 180, 170mph, pediatrician speeds of 140............geese you guys need to DRIVE one of these things!!!!!!!!!! at 150MPH some day and then call it easy. You better pay attention because at those kinds of speeds you will not get a chance to catch up on a fuck up. Just because some guy posts some wild claim on the internet doesn't mean it happened.

As far as 200MPH goes. I don't believe that ANYONE on this website has had their self built GT40 to in excess of 200 MPH. Dan, Mario, Mark, and AJ don't count unless you think you are as good as they were/are and your race car building and prep skills are as good a FMC. Not to mention their budget

There have been a few valiant tries by people who have a hell of a lot more talent that I do building these cars. High 190's is where I believe Frank Catt left off last time. He had a POWERFUL car and a fair stretch of runway to work with and it is HARD!!!!!

Jump right in Frank if I have this wrong, but taking one of these self build cars in excess of 200MPH is not EASY!!!!!!! and damn dangerous. Crash one at a buck forty on public roads, in the mist of telephone poles and trees and God help ya, because without the help you are going to end up DEAD!

 

[Mike]

Wow........easy 200, 180, 170mph, pediatrician speeds of 140............geese you guys need to DRIVE one of these things!!!!!!!!!! at 150MPH some day and then call it easy. You better pay attention because at those kinds of speeds you will not get a chance to catch up on a fuck up. Just because some guy posts some wild claim on the internet doesn't mean it happened

I have not driven a 40 so cannot speak to how it handles. I certainly will take my time becoming accustom to the car before ever approaching even moderately high speeds in the car. In regards to the GT or any other modern supercar, you most certainly have never driven one yourself. Mine with a pulley and tune was just a short blast through 3rd to 140. I can't even count the number of times I had it there. It certainly takes exponentially more room as speeds go up but it was pretty undramatic at that speed and higher. Coming out of a corner at 30mph on cold tires demanded much more cautious attention than pointing it in a straight line and standing on it at 140. Regarding "wild claims"... I don't claim anything.

 

[roaldin]

Doesn't take much to fire this forum up these days.
William, this happens every time someone talks about speed in a GT40 for some reason.

150 isn't easy now? Er, yeah it is... In my GT40 that I own and drive (occasionally).
I dunno, these Americans and their famous can't do attitude... No, hang on... ;p
Reminds me of those famous words of Sir Edmund Hillary - 'Climb that! You have to be kidding!'.
Get a grip guys, read the first post again, try not to lose the context... Sheesh!
Forgive William if he should have said with some difficulty 197 with 450...

FWIW I think RF1 took a 40 to an officially timed event and did 186 mph before they ran
out of room with a 400bhp 306. Could be wrong but that's
how I remember it.
There are 40s out there with a LOT more than 400 bhp, some of them with worryingly more.
I haven't been to a UK airstrip VMax event but footage I've seen of it seems to
indicate that speeds are track length limited.

The quality of these replicas will obviously vary but there are some pretty good ones out there.

It'd be interesting to hear any other stories of roll on comparisons if someone could sneak
one in occasionally.

Lastly, for the old and nervous, I prescribe a quiet room and a dose of "Worlds
Fastest Indian". Take until symptoms cease. ;p

 

[Mike]

I did locate a video of G-Man's uber GT40. I did hear through the kangoroo that he was planning to roll race the big overweight Ford GT TT in video numero dos. Maybe when he returns he will post video of the outcome...

Georgie's mega carbon fiber GT40

The competition

 

[roaldin]

I did locate a video of G-Man's uber GT40. I did hear through the kangoroo that he was planning to roll race the big overweight Ford GT TT in video numero dos. Maybe when he returns he will post video of the outcome...

:lipsrsealed:

Tim.

 

[Cliff Beer]

For clarity, the OP was indicating that it's commonly understood and agreed that a 400hp GT40 can achieve in excess of 200mph.

I have no idea what a uber hp (600?) GT40 achieve as far as top speed. My comments are limited to the OP's original thesis, which I believe is incorrect by a fair margin. It didn't happen in the 60's and it ain't happening now. Add 100+ hp and maybe you'll make it....on a very nice flat piece of road. Wear your helmet and make sure your will is up to date.

Howard Jones' comments above are spot on.

 

[Mike]

Old people smell funny

 

[roaldin]

For clarity, the OP was indicating that it's commonly understood and agreed that a 400hp GT40 can achieve in excess of 200mph.

So instead 197mph with 450bhp. You'd have to be an accountant or a lawyer to worry about that sort of detail in a cheery, offhand, incidental comment designed (I think) to steer people away from top speed discussion and toward a comparison of roll on performance.

BTW, Cliff I'm just poking. oke:

Think 200 in a 40 is dangerous? How about this - http://www.youtube.com/watch?v=HKSCoDKxXe8
(Warning, it might take a bit of effort to get past the absurdly Hollywood wrapping.)
Yeah yeah might (I have no evidence either way) have bigger sprocket etc I know, but it's still nuts.
His roll-on performance looks like it might be quite impressive.

Congrats Michael on post 22, on topic!
An amazing feat on this forum these days.

Life is for living, the rest is for lawyers.

Tim.

 

[Pete McCluskey.]

Fact is, GT40 shaped cars with 400 bhp managed it at some place called LeMans, in Europe somewhere I think, about 40 years ago. I'm pretty sure that's right...

I know whatever project you were working on was difficult Cliff, on the other hand there are a number of people that have managed it without too much difficulty in cars far less slippery than a 40. Modified GT-Rs manage it quite often. There is plenty of evidence about for this. (I think I've posted links on every other thread I've seen here that goes this way.)

Wouldn't like to try it in one of those Italian or German jobbies though, shudder, scary thought... Well the Italian ones anyway...

Anyway, these threads always get dragged in this direction.
Yeah it's possible, it's been done. How many replicas could do it? Who knows, but I bet some of them can and I'd suggest some may have done it. Not
everyone is willing to say "yeah I did 200MPH on a public road" on a public forum. Finding a racetrack to do it on is not as easy in some places as it is in others.
GPS devices give a good enough reading, much better than a conventional speedo.

To be fair to William, I think the 200MPH comment was incidental to his question.

Tim.

Tim I don't think there is a race track in Oz where 200MPH is possible, but we do have some nice salt lakes. All a bit damp at the moment. But when they dry out it would be a fun project no?