1/4 mile question terminal speed

1/4 mile question terminal speed

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Welshbeef

Original Poster:

49,633 posts

206 months

Tuesday 18th September 2012
quotequote all
Just having watched wheeler dealers eth the cobra kit car 6.3 ltr v8 370bhp and 600kg or whatever they achieved a terminal speed of 108 & 110mph - clearly a racing driver would have beaten that by some margin but let's say it does 110mph at that distance.

My old fiat coupe 20v turbo with 220bhp and 1200kg had a 1/4 mile terminal velocity of 98mph. So the question I have is how much faster is 12mph over a 1/4 mile? Is that a big big difference? I'm not sure how to quantify it as Ive never really taken much interest in 1/4miles apart from knowing a 11 second road car is pretty nippy while run of the mill GTI could be 18 seconds

iva cosworth

44,044 posts

171 months

Tuesday 18th September 2012
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Why would a racing driver do a much improved 1/4 mile over an amateur ?

Not like there are any corners involved or much elseconfused

surveyor

18,148 posts

192 months

Tuesday 18th September 2012
quotequote all
iva cosworth said:
Why would a racing driver do a much improved 1/4 mile over an amateur ?

Not like there are any corners involved or much elseconfused
Better start. Better gear changes, better timed gear changes.

Pentoman

4,818 posts

271 months

Tuesday 18th September 2012
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Terminal velocity is the key measure for road cars. The stopwatch time is too heavily affected off-the-line traction. Over 100mph terminal velocity is fast, under 100mph is not so fast. And A quick time with a low MPH indicates good traction but average acceleration once off the line. While A poor time but good terminal speed indicates epic acceleration with traction problems off the line. I think I know which I prefer!

300bhp/ton

41,030 posts

198 months

Tuesday 18th September 2012
quotequote all
Welshbeef said:
Just having watched wheeler dealers eth the cobra kit car 6.3 ltr v8 370bhp and 600kg or whatever they achieved a terminal speed of 108 & 110mph - clearly a racing driver would have beaten that by some margin but let's say it does 110mph at that distance.

My old fiat coupe 20v turbo with 220bhp and 1200kg had a 1/4 mile terminal velocity of 98mph. So the question I have is how much faster is 12mph over a 1/4 mile? Is that a big big difference? I'm not sure how to quantify it as Ive never really taken much interest in 1/4miles apart from knowing a 11 second road car is pretty nippy while run of the mill GTI could be 18 seconds
Terminal speed gives a good indication of how quick a car might be from a roll. It's also not really grip dependant and doesn't require a good launch. Indeed babying a car of the line will likely result in a similar trap speed, even with a hugely different ET.

A 12mph difference in ET is HUGE. If you lined a two cars up at 20mph and one could trap 98 and the other 110mph, it'd open up car or bus lengths on you. At the strip as it's about ET's and not trap speed, then a good launch can mean the cars would be a lot closer at the line.

In real world terms a classic Impreza Turbo 2000 from a roll against a C6 Corvette.



iva cosworth

44,044 posts

171 months

Tuesday 18th September 2012
quotequote all
1/4 mile in a road car is hardly rocket science.

Launch,accelarate,change gear,accelarate,finish line.

A day at a RWYB and anyone can be an expert in their own car.

And with that .....Goodnightbyebye

Welshbeef

Original Poster:

49,633 posts

206 months

Tuesday 18th September 2012
quotequote all
I ecall seeing an MG Maestro Turbo posting over 120mph terminal speed and it was just pipped by a black 2wd cossie 125mph. Road legal cars. The cossie looked modified the Maestro looked bog standard even had standard wheels. I'd have taken the maestro out of those two.


I'd opt for the slower time but with high terminal speed.

Out of interest what does the GTR hit speed wise as that's a benchmark round these parts as a fast car and then what's the time of say a Veyron/F40?

300bhp/ton

41,030 posts

198 months

Tuesday 18th September 2012
quotequote all
iva cosworth said:
Why would a racing driver do a much improved 1/4 mile over an amateur ?

Not like there are any corners involved or much elseconfused
rofl

Welshbeef

Original Poster:

49,633 posts

206 months

Tuesday 18th September 2012
quotequote all
iva cosworth said:
1/4 mile in a road car is hardly rocket science.

Launch,accelarate,change gear,accelarate,finish line.

A day at a RWYB and anyone can be an expert in their own car.

And with that .....Goodnightbyebye
But noone would hold their foot on the carpet through a gear change in their P&J whereas a tester to max the car even if it's destroyed after it matters little to them. Hold the throttle wide open throughout the gearchange... I'd not do it so I'd be slower likewise the aggression on the clutch once in gear sure agree indifferent but say your car has no limiter a tester may push engine to nearly valve bounce to avoid time wasted in an extra gear change. You would never do that to your own car.

300bhp/ton

41,030 posts

198 months

Tuesday 18th September 2012
quotequote all
iva cosworth said:
1/4 mile in a road car is hardly rocket science.

Launch,accelarate,change gear,accelarate,finish line.

A day at a RWYB and anyone can be an expert in their own car.

And with that .....Goodnightbyebye
So you've got timeslips to prove it then?

300bhp/ton

41,030 posts

198 months

Tuesday 18th September 2012
quotequote all
Welshbeef said:
I ecall seeing an MG Maestro Turbo posting over 120mph terminal speed and it was just pipped by a black 2wd cossie 125mph. Road legal cars. The cossie looked modified the Maestro looked bog standard even had standard wheels. I'd have taken the maestro out of those two.


I'd opt for the slower time but with high terminal speed.

Out of interest what does the GTR hit speed wise as that's a benchmark round these parts as a fast car and then what's the time of say a Veyron/F40?
120mph trap is pretty darn fast. BMW M6 is like 119mph and something like a Veyron is 142mph iirc.

Most UK fast cars are more like 88-95mph trap speed unless modified. Anything 110-120mph is supercar quick.

Herman Toothrot

6,702 posts

206 months

Tuesday 18th September 2012
quotequote all
300bhp/ton said:
120mph trap is pretty darn fast. BMW M6 is like 119mph and something like a Veyron is 142mph iirc.

Most UK fast cars are more like 88-95mph trap speed unless modified. Anything 110-120mph is supercar quick.
Never got my old MX5 @ 265bhp to the strip, someone with the same turbo kit and same claimed power output posted a 112mph slip from Santapod on the MX5 forum I use to go on. Nice to see an MX5 described as supercar quick wink

Ozzie Osmond

21,189 posts

254 months

Tuesday 18th September 2012
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300bhp/ton said:
A 12mph difference in ET is HUGE.
How do you have a 12 mph difference in Elapsed Time??

Ozzie Osmond

21,189 posts

254 months

Tuesday 18th September 2012
quotequote all
Welshbeef said:
I'd not do it so I'd be slower likewise the aggression on the clutch once in gear sure agree indifferent but say your car has no limiter a tester may push engine to nearly valve bounce to avoid time wasted in an extra gear change. You would never do that to your own car.
Which is one of the many reasons why automatics are quick and reliable. It's no accident AMG don't build a manual.

Greengecko

594 posts

155 months

Tuesday 18th September 2012
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8.9 seconds at 169mph in a modified GTR must be fast then:
http://www.youtube.com/watch?v=ed2pJkuosD0

DIW35

4,160 posts

208 months

Tuesday 18th September 2012
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Google Sammy Miller. He ran a car at the Pod that posted a 3.something ET and 300+ mph terminal. Now that was quick!

Olivera

7,695 posts

247 months

Wednesday 19th September 2012
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300bhp/ton said:
Welshbeef said:
I ecall seeing an MG Maestro Turbo posting over 120mph terminal speed and it was just pipped by a black 2wd cossie 125mph. Road legal cars. The cossie looked modified the Maestro looked bog standard even had standard wheels. I'd have taken the maestro out of those two.


I'd opt for the slower time but with high terminal speed.

Out of interest what does the GTR hit speed wise as that's a benchmark round these parts as a fast car and then what's the time of say a Veyron/F40?
120mph trap is pretty darn fast. BMW M6 is like 119mph and something like a Veyron is 142mph iirc.

Most UK fast cars are more like 88-95mph trap speed unless modified. Anything 110-120mph is supercar quick.
An MG Maestro hitting 120mph on the quarter is anything but standard. If it did happen (which I doubt) then I'd guess nothing at all from the drivetrain is original, in fact it's probably a Maestro shell on top of another car.

Welshbeef

Original Poster:

49,633 posts

206 months

Wednesday 19th September 2012
quotequote all
Olivera said:
An MG Maestro hitting 120mph on the quarter is anything but standard. If it did happen (which I doubt) then I'd guess nothing at all from the drivetrain is original, in fact it's probably a Maestro shell on top of another car.
It was around 1995/96 iirc the cossie had at least 450bhp I remember that well. I've no idea on the engine or power of that Maestro but he seemed to be a regular at the time. He ran his tyres with so little PSI they looked pretty flat on the fronts I saw him decreasing the pressure. Think it was a red maestro.

I'm sure with enough money spent on that engine you could get up to serious bhp plus of course add in crazy amounts of NOS - this was huge back then I recall a friend used to have nos in his road car 150bhp shot of power.... Killed his engine in a month but my god when he hit the nos it was brillient. Engine went like the clappers.

B16JUS

2,386 posts

245 months

Wednesday 19th September 2012
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Years ago there was a guy, Andy nichols rings a bell who had a very very quick maestro something like 450bhp but as someone said was not standard in any way but looks

J

Marlin45

1,327 posts

172 months

Wednesday 19th September 2012
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