Ben G
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Registered: 12th Jan 07
Location: Essex
User status: Offline
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you're so geeky paul  
[Edited on 13-09-2009 by Ben G]
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Nic Barnes
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Registered: 5th Apr 04
Location: nowhere near ginger people
User status: Offline
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quote:
Originally posted by Paul_J
Thing is... believe it or not a F1 car only has 203 lb ft of torque
but that torque is carried all the way up to 18,000 rpm - which gives such a high bhp figure. Remember (torque * revs) / 5252 = bhp figure.
So (203 * 18000) / 5252 = 700 ish bhp.
So why is it so quick with such low torque I hear you cry?
Obv the car is light, but by having a engine that revs to 18000 - you can run really short gear ratios (which require less torque force to rotate and thus accelerate quicker).
for example, if you imagine a F1 car in 1st gear does say 50 mph (no idea what they do in 1st to be honest)
Then 50 mph @ 18000 in 1st means 2.7 mph per 1000 rpm. Imagine this on a normal car, at 5,000 rpm you'd only be doing about 12 mph in 1st gear.
im not convinced with anything you've written. there are no youtube videos to back up your theory.
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Ben G
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Registered: 12th Jan 07
Location: Essex
User status: Offline
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his thoery was based on a live 10 minute show on terrestrial television, therefore it must be true.
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jr
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Registered: 20th May 02
Location: Kent
User status: Offline
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quote:
Originally posted by Mattb
quote:
Originally posted by DizzyRebel
the old turbo bmw engines were about 1200bhp iirc
and 1.5 litres!! lolololol.
with a road car based block
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AK
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Registered: 5th Jul 00
Location: Aberdeen City
User status: Offline
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.... that was left outside to 'weather'
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Tom G
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Registered: 4th Aug 08
Location: Cheshire
User status: Offline
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... and pee'd on
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jr
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Registered: 20th May 02
Location: Kent
User status: Offline
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with the pissing thing knowones really sure if thats true or not
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RCS
Member
Registered: 26th Jan 05
Location: Lichfield/Dundee
User status: Offline
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quote:
Originally posted by Paul_J
Thing is... believe it or not a F1 car only has 203 lb ft of torque
but that torque is carried all the way up to 18,000 rpm - which gives such a high bhp figure. Remember (torque * revs) / 5252 = bhp figure.
So (203 * 18000) / 5252 = 700 ish bhp.
So why is it so quick with such low torque I hear you cry?
Obv the car is light, but by having a engine that revs to 18000 - you can run really short gear ratios (which require less torque force to rotate and thus accelerate quicker).
for example, if you imagine a F1 car in 1st gear does say 50 mph (no idea what they do in 1st to be honest)
Then 50 mph @ 18000 in 1st means 2.7 mph per 1000 rpm. Imagine this on a normal car, at 5,000 rpm you'd only be doing about 12 mph in 1st gear.
I would expect the 2.4L engine's to produce around 240-250 lb ft maximum torque.
And power is the rate at which torque is produced - so the engine produces a reasonable amount of torque (250 lb ft - A 2.0L engine could produce 200 lb ft) but it does so at an extremely high rate because of the operating speed of the engine - 18,000rpm.
In other words, at 18,000rpm the engine will be producing a torque of 250 lb ft at the crankshaft 300 times per second. The 2.0L producing 200 lb ft at 5000rpm will only producing this torque around 83 times per second.
Think of it like how you pedal a bike and the effort it takes.
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Paul_J
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Registered: 6th Jun 02
Location: London
User status: Offline
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interesting  good way of explaining that.
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sand-eel
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Registered: 15th Mar 07
Location: carluke/braidwood--IRNBRULAND
User status: Offline
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quote:
Originally posted by saxo_tom
there conrods a tiny so it revs more
A bit more complicated than that but yeah the stroke is tiny.
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RCS
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Registered: 26th Jan 05
Location: Lichfield/Dundee
User status: Offline
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quote:
Originally posted by sand-eel
quote:
Originally posted by saxo_tom
there conrods a tiny so it revs more
A bit more complicated than that but yeah the stroke is tiny.
Con rod length determines the angle of the rod during operation which influences the magnitude of inertial forces. Smaller means less of an angle.
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SVM 286
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Registered: 13th Feb 05
Location: pain
User status: Offline
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quote:
Originally posted by DizzyRebel
the old turbo bmw engines were about 1200bhp iirc
The engine utilised for qualifying in the 1986 1.5 litre V6 turbo JPS Lotus that Senna drove made approx 1bhp per cc  Going up the hill at Monaco, it's just ludicrous. 
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dhdev
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Registered: 22nd Dec 05
Location: Midlands
User status: Offline
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quote:
Originally posted by RCS
quote:
Originally posted by sand-eel
quote:
Originally posted by saxo_tom
there conrods a tiny so it revs more
A bit more complicated than that but yeah the stroke is tiny.
Con rod length determines the angle of the rod during operation which influences the magnitude of inertial forces. Smaller means less of an angle.
Just to clarify smaller conrod = bigger angle, smaller stroke = smaller angle.
The smaller conrod also allows block height to be shorter, does it not?
Watched an F1 dvd last night and they showed the difference between a V10 F1 (BMW E41 iirc) crank and a BMW E46 M3 crank. They were approx the same length even though the road car has 4 less pistons, but the F1 crank was half the weight!
[Edited on 16-09-2009 by dhdev]
[Edited on 16-09-2009 by dhdev]
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gez bay
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Registered: 14th Feb 08
Location: South Wales drives: Vxr
User status: Offline
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was looking at the new focus rs the other day and the sales guy said that the engine is completley different from the ST engine. its gone for a small stroke and a bigger bore rather than an bigger stroke and a small bore. that where they are getting the torque from.
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ed
Member
Registered: 10th Sep 03
User status: Offline
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If you think of the crank as a lever, you'll understand how it all works. The longer a lever the less force required to make moment so you get higher torque. So the greater the angle on the conrod, the more torque produced. However, engines with lots of angle tend not to rev as well because of the reciprocation of forces in the engine hence why F1 engines can have the living shit revved out of them.
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lee303
Member
Registered: 1st Jul 08
Location: under the nova usually
User status: Offline
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quote:
Originally posted by jr
with the pissing thing knowones really sure if thats true or not
i do, and its not!
was reading about the BMW turbo engine in racecar engineering, and they had an interview with the team leader for that engine, the idea was mooted that a high mileage block would have all lost all its stresses and be very strong, they built one just to satisfy curiosity and it didnt even get fully warmed up before it failed on the dyno
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