- 1,155
- artic_zap
But the Z06 will out accelerate the ZR1 over 230ish, and reach a higher top speed.
Power to Weight VS actual acceleration
- Thread starter XDesperado67
- 43 comments
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But the Z06 will out accelerate the ZR1 over 230ish, and reach a higher top speed.
Rotary Junkie
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- 9,810
- Canton, MI
- RJs_RX-7
Powerband vs gearing.
dr_slump
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- 7,425
- Switzerland
- the_dr_slump / GTP_dr_slump
And this influences top speed?
shirakawaa
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- 5,034
- GTP_shirakawaa
Of course for top speed you need power. Speed is only very marginally related to the car weight (due to the increased tire resistance).
- 3,359
- California
- PumpinNumbies
Like I said previously, it has to do with the power band.
Despite popular belief the Z06 actually has the bigger motor. It breathes better and the old saying goes 'There's no replacement for displacement' (spare me the debate, I'm just making an example).
On top of this, the Z06 reaches max Torque at about 700RPM later than the ZR1, so despite the ZR1 having more power, the Z06 appears to have more 'pull'(Acceleration) based on the torque curve.
I can't say for sure, because I've only driven the Z06 in real life, but in GT5 if you assume both cars are accelerating to 230mph and they're both at 4900 rpm, the Z06 will continue to 'climb' it's Torque Curve until 5600rpm, whereas the ZR1 has already begun on it's downslope of torque.
That's the best logical explanation I can provide, and I can't guarantee it to be 100% accurate.
- 3,359
- California
- PumpinNumbies
Effective power is more important than 'more' power. (To a point I should say)
If you're looking for a more specific reason, then it again, probably has to do with the powerband and what happens each time you shift.
Where the ZR1 RPM drop, is probably already beyond where max torque was made, while the Z06 drops down under max torque and climbs its curve through every gear. I can't really comment much further on it, as my Z06 isn't within a reasonable range of my ZR1 to do any valid tests and more importantly I don't see any useful information coming out of the conclusion. If you think I'm wrong, that's fine, because I'm not even claiming I'm right, just offering a possible reason for the result articzap has mentioned above.
- 3,359
- California
- PumpinNumbies
For top speed, I would say it had to do with overall displacement.
But displacement can only overcome so much power, and I'm not positive of the differences between a maxed ZR1 and Z06.
But displacement can only overcome so much power, and I'm not positive of the differences between a maxed ZR1 and Z06.
- 1,945
- Treviglio
- PAPPACLART
- PAPPALCART
If we were to compare the peak rear wheel thrust measured in lbs of an engine that has 200 ft/lb at 4000rpm with an engine that has peak a torque of 100ft/lb at 8000 rpm, potentially both would produce exactly the same thrust/accelerative force at that point at the wheels. The reason why this is the case is because the engine that revs to 8000rpm, as it is able to rev double (8000rpm vs 4000rpm) it is possible to use half the gearing while still being able to equal the in gear top speed of the 4000rpm motor. If the 8000rpm motor lowered its gearing further, so it was greater than half the ratio of the 4000rpm motor, the 8000rpm motor would have even more thrust at the wheels but would loose top speed in each gear to the 4000rpm motor. So half the torque but double the rpm can = same thurst/acceleration at the wheels if gearing is utilised properly. If the 100 ft/lb motor peaked at 4000rpm, then it could still match the 200ft/lb for thrust, but would again have to half its gearing, which would mean half the speed etc.
Remember gear ratios are a multiplier of torque, the higher revving motor is able to capitilise on using lower gear ratios without loosing to much speed in each gear.
Your average big lorry may have 14 gears, with a huge turbo diesel engine that makes massive torque. 1st gear in a big lorry may only have a top speed of between 5-10 mph, just enough to get it moving, but as the lorry engine makes huge torque and revs soo low and has very low gearing, it has massive thrust at the wheels that enable it top pull big loads.
A current f1 engine has only about 210 ft/lb of torque, but as it revs to 18000 rpm, it is able to have very low gearing, making thrust at the wheel huge.
Imagine riding a bicycle, when you go up a hill, you use lower gears, as this multiples the torque that your legs produce, the reason why you can't cycle at 25mph in the lowest gears has nothing to do with your lack of torque in our legs, but you legs ability to rev/spin being a limiting factor, so to go faster you change up a gear, and are able to achieve a higher speed, but by doing so you now have less thrust at your disposal to accelerate.
Like I said, a 270bhp car @ 400kgs traction permitting, should accelerate like a sportsbike, even if the engine is peaky and it has 5 gears it should still fly regardless.
Many people here do not understand torque and power, Power is torque and torque is power. Power is just a multiplication of torque x rpm. Produce a particular amount of torque at a particular rpm and that gives you power. Put simply, torque is a force, and power is how often that torque is applied in a given time.
Indeed it is important to have a good spread of power and torque to help with in gear and overall acceleration. If a car made power and torque equivalent to your average 2000cc NA engine, then between 6500 and 6501 rpm it made 1000bhp, this car would not accelerate fast at all, as it makes the same power and torque up to 6500rpm as a typical Na 2000cc engine then for the spread of a single rpm jumps to 1000bhp, you get that power for only 1rpm, not even in the blink of an eye. Obviously there is not engine like that but some crazy small motors that have big turbos kicking out 1000bhp can be very peaky.
2 vehicles that have the same weight, rolling resistance, aeor, gears and peak power can accelerate differently, with one being faster in/through the gears than the other.The faster car A being the one that makes more power before peak power is reached vs car B.....So as car A changes gear after reacing peak power, as revs fall and the next gear is engaged, car A finds itself with more power to accelerate the gear toward peak power. These differences are marginal, and it would take a very peaky engine to be much slower than a car that produces equal peak power, or it would have to have less gears, 5 speed vs 6 speed, or be geared longer overall.
Essentially, when lowering either final drive or individual gear ratios, what we are actually doing is increasing the thrust but condencing it over a narrower speed range. (as speed decreses in each gear if we lower it) If we increase gear ratios we reduce thrust in each/single gear but the thrust although now less is available over a greater/wider speed range within each individuaul gear. Gearing is a fine balance.
Torque and power curves only tell us one thing, we should all be looking at thrust curves if we really want to see in gear thrust/accelerative potential at any speed in any gear.
Remember gear ratios are a multiplier of torque, the higher revving motor is able to capitilise on using lower gear ratios without loosing to much speed in each gear.
Your average big lorry may have 14 gears, with a huge turbo diesel engine that makes massive torque. 1st gear in a big lorry may only have a top speed of between 5-10 mph, just enough to get it moving, but as the lorry engine makes huge torque and revs soo low and has very low gearing, it has massive thrust at the wheels that enable it top pull big loads.
A current f1 engine has only about 210 ft/lb of torque, but as it revs to 18000 rpm, it is able to have very low gearing, making thrust at the wheel huge.
Imagine riding a bicycle, when you go up a hill, you use lower gears, as this multiples the torque that your legs produce, the reason why you can't cycle at 25mph in the lowest gears has nothing to do with your lack of torque in our legs, but you legs ability to rev/spin being a limiting factor, so to go faster you change up a gear, and are able to achieve a higher speed, but by doing so you now have less thrust at your disposal to accelerate.
Like I said, a 270bhp car @ 400kgs traction permitting, should accelerate like a sportsbike, even if the engine is peaky and it has 5 gears it should still fly regardless.
Many people here do not understand torque and power, Power is torque and torque is power. Power is just a multiplication of torque x rpm. Produce a particular amount of torque at a particular rpm and that gives you power. Put simply, torque is a force, and power is how often that torque is applied in a given time.
Indeed it is important to have a good spread of power and torque to help with in gear and overall acceleration. If a car made power and torque equivalent to your average 2000cc NA engine, then between 6500 and 6501 rpm it made 1000bhp, this car would not accelerate fast at all, as it makes the same power and torque up to 6500rpm as a typical Na 2000cc engine then for the spread of a single rpm jumps to 1000bhp, you get that power for only 1rpm, not even in the blink of an eye. Obviously there is not engine like that but some crazy small motors that have big turbos kicking out 1000bhp can be very peaky.
2 vehicles that have the same weight, rolling resistance, aeor, gears and peak power can accelerate differently, with one being faster in/through the gears than the other.The faster car A being the one that makes more power before peak power is reached vs car B.....So as car A changes gear after reacing peak power, as revs fall and the next gear is engaged, car A finds itself with more power to accelerate the gear toward peak power. These differences are marginal, and it would take a very peaky engine to be much slower than a car that produces equal peak power, or it would have to have less gears, 5 speed vs 6 speed, or be geared longer overall.
Essentially, when lowering either final drive or individual gear ratios, what we are actually doing is increasing the thrust but condencing it over a narrower speed range. (as speed decreses in each gear if we lower it) If we increase gear ratios we reduce thrust in each/single gear but the thrust although now less is available over a greater/wider speed range within each individuaul gear. Gearing is a fine balance.
Torque and power curves only tell us one thing, we should all be looking at thrust curves if we really want to see in gear thrust/accelerative potential at any speed in any gear.
Last edited:
- 5,814
- Hillsboro Oregon
- XDesperado67
- XDesperado67
Great pic
And actually the Anglia's much like the Mini's were frequent racers. They were some of the favorite "tuner"
cars of their day.
http://www.anglia-models.co.uk/saloon-photor00.htm
Here's a site with a lot of great photos of these little monsters. And yes they can both accelerate and have a high top end
