Doing a little math (GT40 quickness)
- Thread starter darrinps
- Start date
Forget all your theorising for now and just get on with it and build one.
How fast is a GT40 replica? How much money do you have is the answer. Mine has a 380 RWHP (dyno dynamics) 347 motor and weighs 1110 kg wet. I don't have any 1/4 mile times (it's on my list, but not at expense of other events). I've done about 150 runs down the 1/4 in my old car, so I've got a feel for what you need to do to get down the quater. And this one will go deep into the 11's at close to 130 MPH is my best estimate.
What I do have is heaps of youtube incar footage at various events. Search 200MPHGT40 and you'll get a feel for how quick it goes. Short answer is it goes pretty well. At a recent supersprint it had similar top end pull down the straight to a racing 996 GT3 (up to 230 k's before braking down hill at Wanneroo circuit). But better punch out of corners.
Straight line performance is the least of your worries, as mentioned several times above. Getting everything else balanced for best performance on any given course is what sorts the men from the boys.
How fast is a GT40 replica? How much money do you have is the answer. Mine has a 380 RWHP (dyno dynamics) 347 motor and weighs 1110 kg wet. I don't have any 1/4 mile times (it's on my list, but not at expense of other events). I've done about 150 runs down the 1/4 in my old car, so I've got a feel for what you need to do to get down the quater. And this one will go deep into the 11's at close to 130 MPH is my best estimate.
What I do have is heaps of youtube incar footage at various events. Search 200MPHGT40 and you'll get a feel for how quick it goes. Short answer is it goes pretty well. At a recent supersprint it had similar top end pull down the straight to a racing 996 GT3 (up to 230 k's before braking down hill at Wanneroo circuit). But better punch out of corners.
Straight line performance is the least of your worries, as mentioned several times above. Getting everything else balanced for best performance on any given course is what sorts the men from the boys.
Everyone is entitled to their own opinion. In the US, we value balance as it relates to straight line performance as well as everything else.
As for quitting theorizing and getting on with a build, I will just as soon as I get the kit in hand. It's been ordered and is supposed to ship within a few weeks.
Not all of us in the US are concerned with straight line performance.
Even with my past life as the owner/driver of an old Top Fuel digger, I place a much higher value on balance and braking/acceleration in/off corners..
Anyone can go fast is a straight line. Making it turn in at speed and in traffic is where the rubber hits the road..
Even with my past life as the owner/driver of an old Top Fuel digger, I place a much higher value on balance and braking/acceleration in/off corners..
Anyone can go fast is a straight line. Making it turn in at speed and in traffic is where the rubber hits the road..
True, not all are. I'm actually not that big into it but as a general rule, a 0-60 or 1/4 mile time gets a lot more emphasis here than does a lap time around Watkins Glen for example.
To me it's about balance. Acceleration is a big part of the equation in evaluating a car's overall performance.
As you say, to each their own, however, balance is exactly what you lose when you start to chase 0-60 and 1/4 mile times.
Acceleration is acceleration, not launch. Setting up specifically for best launch will cost you in overall balance.
Enough from me, people build what they want, as long as it meets or surpasses their expectations then all is good.
If you want your seesaw to always fall to the right then go for it. ;p
Tim.
Acceleration is acceleration, not launch. Setting up specifically for best launch will cost you in overall balance.
Enough from me, people build what they want, as long as it meets or surpasses their expectations then all is good.
If you want your seesaw to always fall to the right then go for it. ;p
Tim.
The original GT40 (Mk-I) was very good for its time and is a car designed for Long Distance Road Racing (Lemans) at it won in 68 and 69 against "better" and up to date cars. The brakes, tires, wheels and horsepower can not match a modern sports car. My first ERA GT was 330 C.I Ford with a single 4V carb. I took the car to several tracks and could not keep up with a modern BMW M5, Mustang Cobras or Corvette. The second time around the car was built with bigger wheels (which helps on tire selection and bigger brakes), power assisted brakes and 409ci Ford engine with a much bigger 4V. I could run at events without the issues of being too slow or difficult to drive due to poor brakes and low on power.
Last year at Goodwood I saw the Le Mans winning Audi. The drivers position, controls, wheels, tires, engine, brakes make the GT-40 an antique (a very good looking antique). You can not compare a 47 year design with a modern street sports cars. In 2013 we have a factory Mustang with a top speed of over 200MPH. The same applies to 1960's computers against today desktop/laptop etc.
Last year at Goodwood I saw the Le Mans winning Audi. The drivers position, controls, wheels, tires, engine, brakes make the GT-40 an antique (a very good looking antique). You can not compare a 47 year design with a modern street sports cars. In 2013 we have a factory Mustang with a top speed of over 200MPH. The same applies to 1960's computers against today desktop/laptop etc.
Agreed about the driver's position but as for the rest, that's up to you and only the case if you want to keep it original though. Mine will have a modular Ford V8, Wilwood brakes, Michelin Super Pilot Sport tires and forged 19" wheels and should be easily capable of 200mph (although it will never see with me driving) and a 1/4 mile time in the low 11's (and maybe a wee bit better).
When Ford designed the new Ford GT it took a old GT-40 and tested on a wind tunnel and spend a million dollars blowing air to it. It found how unstable the car was and added a rear diffuser and a front spoiler to reduce the up lift of the car. It is not only to add a big engine, brakes, and tires. A modern race car suspensions and everything is very light. Last year I was at WilliamsF1 and purchased a wheel nut. The wheel nut was very light almost no weight. Aero plays a very large part on the speed of a F1. Check this year how close they are and all improvement comes from aero updates they make at every race.
Car and driver did a test of the 2013 GT500 that Ford claims 200mph. They did a calculation that they would need a straight line of 15000 feet to reach 200mph. After testing in a oval they found that they reach 190mph and the car had almost zero acceleration. they would need a 30000 feet straight line with a very good tail wind to reach 200mph. It is not easy to reach 200mph of anything and I would not like to be on a GT40 at that speed.
I do not understand quoting drag strip times as a comparison for an Endurance racer. I know there is a new Ford GT 1000bhp shown on Utube out gunning all opposition. But with sometimes not out accelerating at the start but catching them before the quarter mile.
The GT40 even in 1968/69 was a detuned endurance car that was reliable by then but heavy by those days standards (they were geared for 205mph and had a 3 mile straight to attain this speed). And in 1969 Jacky Ickx hands it was the driver that gained the win over the Porsche 908. Le Mans was a race of attrition you had to be running after 24hours to stand a chance of winning. The fastest did not win look at the Porsche 917 Langheck!
Regards Allan
The GT40 even in 1968/69 was a detuned endurance car that was reliable by then but heavy by those days standards (they were geared for 205mph and had a 3 mile straight to attain this speed). And in 1969 Jacky Ickx hands it was the driver that gained the win over the Porsche 908. Le Mans was a race of attrition you had to be running after 24hours to stand a chance of winning. The fastest did not win look at the Porsche 917 Langheck!
Regards Allan
Seymour Snerd
Lifetime Supporter
We in the US do tend to distill things down I suppose. We are kind of utilitarian as well...practical. There are reasons why we use those measurements....
I do agree we value HP in the US more than in other places around the globe it seems. Maybe that's because we make some reasonably good performing engines.
If by "we" you mean "US auto magazines" the British and European ones all have some equivalent measurements (0-100 kph, etc.) l don't see much difference there.
If there is more interest in straight-line acceleration in the US it probably has its roots in two places: much cheaper fuel than in Europe, and the origins of the hot rod movement which occurred in a geographical area (southern California in the '50s) where it was quite practical to fully exercise a high-power vehicle. Cheap fuel and "wide open spaces" encouraged development of larger, therefore heavier, therefore more powerful vehicles than were optimal for the cost of fuel and road conditions in Europe. I don't think you can argue that American engines were or are generally more "good performing" than Europe's. In fact until relatively recently, at least in terms of specific output (eg power/weight or power/displacement), European engines were superior.
The other thing to remember about straight-line acceleration is that of the three basic parameters (acceleration, braking and cornering) acceleration is the easiest to experience "in the limit" on the street with "normal" levels of driving skill. I suspect that is why many people tend to focus more on it than the others.
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That's probably because you reside in London and not L.A.! :nice:
"Darrinps" pretty much nailed it IMO when he suggeseted the hot rod/drag racing background over here is at the root of our 'preoccupation' with 1/4 mile times. It's what the car community has grown up around since the very beginning of the hot rod/custom car hobby here in the U.S. :thumbsup:
I dont recon it will handle or ride that well on 19" tyres.
Profile is part of your spring rate and also allows the tyre to conform to the road and grip.
Low profiles are ok on a controlled surface.
Unfortunatly smaller rim sizes reduces brake size which many seem to make that a priority.
Or you may just like that LA look.then that is ok as it is your car, but if you are looking for all round performance 19" may not be a good choice on these vehicle.
Just my experiance.
Jim
hahaha 19" wheels on a 40...the thought of it makes me gag..
That's your opinion. Not mine. The Ford GT looks just fine with them.
Not sure why you would say that. Larger, taller, yet lite wheels are the norm for high performance cars. Several reasons behind it.
Probably should have mentioned that I am having a front spoiler added to mine from the factory.
Not too many every day driver engines from Europe came close to those built in the US. I can list numerous examples. Pure race engines, agreed. Europe had some good ones for specific applications, but for mass production, come on. There really is nothing that has matched American muscle en mass and certainly now with the GM and Ford engines of today that cannot be argued unless you want to talk exotic ultra high dollar motors.
Seymour Snerd
Lifetime Supporter
Please do, along with the measurement for which the American engine is superior.
F1 are on tall profile,dosnt hurt them.
I know the reasons but thay are not always ideal Darrin.
Surface condition plays a large part on how a tyre performs.
A race track is controled but not always perfect,out on the road where you will spend 70-90 percent of your time are not.
I run 15's by choice I was told they move an squerm around ,I have not had an issue with that but it is very forgiving.
Passengers are always supprised at the quality of the ride.
When I go to the track its times are well into cace car territory.
I think it was the Ozi top gear did an experimant on a late model ford ,STD profile and low profile on taller rims and it was slower on the low profile.
Other things may have effected that I admit but that was the outcome.
I know of targa road rally cars that have gone faster on taller tyres
Like I said it is my experiance.
Jim
