xa0s
Banned
Registered: 4th Mar 08
Location: Dartford, Kent Car: Turbo'd Fabia vRS
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I've often wandered about torque to weight ratio. For example, would stripping out a car and saving 300kg be more beneficial on a car with say 150ft/lb than a car with 350ft/lb?
Compare these two cars (a random example, figures just made up)...
2.0 petrol turbo, 250bhp, 150ft/lb, 1,400kg
2.0 diesel turbo, 200bhp, 350ft/lb, 1,400kg
Both doing identical 0-60, 0-100, 1/4 runs, etc...
If you were to then save 300kg on both cars which would it improve the most? I presume the one with the least amount of torque but how much would it really matter? Does the more torque you have make weight less important?
Sorry for the random question. 
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ed
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Registered: 10th Sep 03
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Power is the amount of work done in a time frame, so torque/second in this case. In this example the petrol engine would probably get off the line faster in the first few gears but then the diesel could catch it up in a 1/4 mile race as the higher torque figure helps in the higher gear ratios.
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3CorsaMeal
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Registered: 11th Apr 02
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i'd say the exact opposite to Ed.
i reckon the diesel might get a nice start due to more torque low down the revs, but as soon as the petrol reaches high revs it will have peak bhp and therefore win
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xa0s
Banned
Registered: 4th Mar 08
Location: Dartford, Kent Car: Turbo'd Fabia vRS
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I find launching is very difficult in my car, it literally either just bogs down or spins up, there's a very fine line and it will happily spin in 3rd and sometimes 4th just off the power in a straight line so it makes quick launches a pain. People suggest launching in second but I dunno about that, seems harsh on Mr. Clutch.
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Robo C20Let
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Registered: 22nd Feb 10
Location: Somewhere inside your mom !!!
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i disagree with everyone
drop them off a cliff at the same time and they will both fall at around the same speed lmao
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Robo C20Let
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Registered: 22nd Feb 10
Location: Somewhere inside your mom !!!
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quote:
Originally posted by xa0s
I find launching is very difficult in my car, it literally either just bogs down or spins up, there's a very fine line and it will happily spin in 3rd and sometimes 4th just off the power in a straight line so it makes quick launches a pain. People suggest launching in second but I dunno about that, seems harsh on Mr. Clutch.
i had a c20let corsa and i did a full throttle launch in 2nd and it just gripped (was on racing slicks tho)
[Edited on 06-01-2011 by Robo C20Let]
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BarnshaW
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Registered: 25th Oct 06
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agree with 3CM, think diesel would go off the line and then petrol would catch up
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Russ
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Registered: 14th Mar 04
Location: Armchair
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quote:
Originally posted by Robo C20Let
i disagree with everyone
drop them off a cliff at the same time and they will both fall at around the same speed lmao
"around".. 
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Nath
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Registered: 3rd Apr 02
Location: MK
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quote:
Originally posted by Russ
quote:
Originally posted by Robo C20Let
i disagree with everyone
drop them off a cliff at the same time and they will both fall at around the same speed lmao
"around"..
Terminal velocity for diesel's is higher m8...
[Edited on 06-01-2011 by Nath]
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antnee
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Registered: 30th Dec 07
Location: Cov Drives: Clio 197
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quote:
Originally posted by xa0s
I find launching is very difficult in my car, it literally either just bogs down or spins up, there's a very fine line and it will happily spin in 3rd and sometimes 4th just off the power in a straight line so it makes quick launches a pain. People suggest launching in second but I dunno about that, seems harsh on Mr. Clutch.
You need some new/better tyres! My 2 friends running hybrid set ups (1 is 230bhp 380lb/ft, the oother is 245bhp 410lb/ft) don't have any problems in 4th, it would have to be quite wet for it to happen in 3rd.
And on this topic, the 2 friends I mentioned above, were both running the same power figures, but nearly the same 1/4 miles times. One has NO interior (not even a dash), the other just had rear seats stripped. So approx 100kg difference made about .1 second difference on high 13's 1/4mile times.
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xa0s
Banned
Registered: 4th Mar 08
Location: Dartford, Kent Car: Turbo'd Fabia vRS
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Toyo T1-R's, I haven't driven it in warm weather yet though so it's always cold or wet but yeah it spins up in 3rd off the power most times and it's only running 199bhp at the moment.
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antnee
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Registered: 30th Dec 07
Location: Cov Drives: Clio 197
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Ahh that makes sense then if you haven't had a dry day yet.
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sc0ott
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Registered: 16th Feb 09
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in not clued up on the diesel side of things but why cant they give them higher revs with more power?
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3CorsaMeal
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Registered: 11th Apr 02
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quote:
Originally posted by sc0ott
in not clued up on the diesel side of things but why cant they give them higher revs with more power?
i was told diesel doesn't burn that fast
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taylorboosh
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Registered: 3rd Apr 07
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The petrol surely is a vtec to have torqe that bad
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3CorsaMeal
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Registered: 11th Apr 02
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quote:
Originally posted by john-d
The petrol surely is a vtec to have torqe that bad
i was going to comment about that, turbo as well 
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Graham88
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Registered: 16th Apr 07
Location: South East Kent Drives: E46 M3
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Diesel faster off the line but petrol will beat it in higher gears...
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sc0ott
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Registered: 16th Feb 09
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depends if the petrol car is a corsa xe.
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taylorboosh
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Registered: 3rd Apr 07
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A corsa xe doesnt need a turbo to beat 250 bhp turbos....
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Mertin
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Registered: 12th Oct 05
Location: Scotland
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quote:
Originally posted by xa0s
I've often wandered about torque to weight ratio. For example, would stripping out a car and saving 300kg be more beneficial on a car with say 150ft/lb than a car with 350ft/lb?
Compare these two cars (a random example, figures just made up)...
2.0 petrol turbo, 250bhp, 150ft/lb, 1,400kg
2.0 diesel turbo, 200bhp, 350ft/lb, 1,400kg
Both doing identical 0-60, 0-100, 1/4 runs, etc...
If you were to then save 300kg on both cars which would it improve the most? I presume the one with the least amount of torque but how much would it really matter? Does the more torque you have make weight less important?
Sorry for the random question.
I know its random figures aswell but comparing weight and torque, diesel engines weigh more so the diesel car will have more weight unless stripped to same weight as petrol
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antnee
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Registered: 30th Dec 07
Location: Cov Drives: Clio 197
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I think what he's asking is if both cars were to loose say 400kg, which (if any) would gain the most advantage.
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Fonz
Premium Member
Registered: 12th May 06
Location: Newbury, Berks
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quote:
Originally posted by xa0s
Toyo T1-R's, I haven't driven it in warm weather yet though so it's always cold or wet but yeah it spins up in 3rd off the power most times and it's only running 199bhp at the moment.
that maybe yoru trouble, T1-Rs although grip in the wet are no good when pushed hard and by the sound of it that is what you are doing.
i have T1-Rs on my MX5 and they grip and grip in the dry, and i have no complaints in the wet. that doesn't mean she doesn't step out. i was at the recent WR rolling road and she performed with 100bhp and 89 torques but spinning the wheels isn't difficult from a standing start if done so in a "heavily spirted fashion" (racing start) or when enjoying some roundabouts and i press the pedal on the right!
you're running twice the power so imo with my experience it is no surprise!
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sand-eel
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Registered: 15th Mar 07
Location: carluke/braidwood--IRNBRULAND
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Saying that both cars had the same engine characteristics and grip the diesel would get off the line faster but the power of the petrol would take over and since the petrol revs faster there will be more "powers" and "torques" per second than the derv.
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Rob R
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Registered: 31st May 03
Location: Kent
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quote:
Originally posted by john-d
The petrol surely is a vtec to have torqe that bad
still more than an XE 
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