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Which engine accelerates faster? (All Other things Equal)

  • 150 Lb/Ft @ 8,000 RPM = 228.48 HP

    Votes: 0 0.0%
  • They perform about the same!

    Votes: 0 0.0%
  • I don't know.

    Votes: 0 0.0%

What is more important in terms of acceleration?

26K views 174 replies 52 participants last post by  dad 
#1 ·
*Assume that both vehicles are geared to obtain the same top speed*
Yes there is a correct answer! Please answer and discuss your position; this is always a fun topic.
 
#6 ·
more torque quicker start, quicker to the end speed
 
#7 ·
Originally posted by Dissident@Nov 27 2004, 05:49 PM
I don't think you can answer it form a peak torque number.  What rate does the torque rise at?  The second engine could be making 299 HP at 8000 rpm, which would mean it's making almost double the hp of the first one....

It doesn't matter, the illustration is the same. I'll chime in with my opinion once there are more votes.
 
#11 ·
Hold on I change my opinion..looking at where in the powerband the both engines produce peak TQ and peak HP I say they perform the same if your comparing straight line acceleration..One engine will get going faster the other engine will catch up on the top end..THERE THE SAME!!!
 
#12 ·
That's what I selected. What do I win?

Don't say fruitcake.
 
#13 ·
:bump:

Continued till tomorrow night. I must say I had hoped that this would spur more discussion! Anyway, I'm sure we'll have more to discuss once the correct answer is in...complete with explaination of course

Get those votes in you trolls!

Nick
 
#16 ·
The question is which engine accelerates faster.

Assuming that it is a 1/4mile, I would still say that the car with 300ft/lb torque at 4000 rpm. More torque is being delivered at low rpm while the car is starting from a standstill. Also, once the car is already moving it will be easier to keep it accelerating especially in higher gears at lower rpms. If the gearing on the car is such that it will be in 5th gear at around 4000 rpms by the end of the 1/4 mile, then the car will have the advantage because it was able to use more of its available torque as opposed to the other car because it will still be in 4th.
 
#18 ·
Those numbers could come from the SAME engine. For example, an engine could produce 300ft/lbs of tq at 4K rpm's, and remember, these are non-linear figures. The curve could drop off past peak up to 8K rpm, and in fact, equal 150ft/lbs.

Now if you asked what is better for acceleration: an engine with 300ft/lbs of tq and 150hp, or an engine with 150ft/lbs of tq, and 300hp then the results would be different (favoring the higher tq numbers for acceleration).

In conclusion, the question you posed does not contain enough information to make an informed decision, which could be why not many voted. Fun topic tho..
 
#20 ·
Ok, more importantly, which accelerates faster, a 2004 Track 350Z or a 2005 special edition? ;)

I thikn if torque was the only thing that mattered in accelration, we'd all be driving diesels that make 350 lbs of torque (and 150 hp). Harleys make more torque than most sportbikes, but good luck making one quicker, gearing or not...
 
#21 ·
Dissident nailed it on the head! Horsepower NOT torque is the determining factor in acceleration! The correct answer is both engines perform about the same. I appologize for the simplistic illustration, but I was just trying to make the illustration as easy as possible to understand without getting into things like the area under the power curve (no not area under the torque curve).

Anyway, since I am new to this forum and the fact than most of you seem to think that torque "owns" I figured rather than give my thoughts on Horsepower Vs. Torque I would let someone else provide the proof. This was the best written article on the topic that I could find on the net, enjoy.

Courtesy of Yaw Power Products
 
#22 ·
Beergoggles,

I look forward to hearing your opinion of the answer and the article since you feel so strongly about torque. In fact I found the article after I read your post:

This one is simple. Torque creates acceleration. Period. If you're going for a high topspeed then HP is the thing you need, but torque is what makes you feel acceleration.

Horse Power sells cars...

Torque wins races.
The article refutes the false statement "horsepower sells cars torque wins races" directly.
 
#23 ·
Originally posted by thrlskr@Nov 29 2004, 11:25 PM
Beergoggles,

I look forward to hearing your opinion of the answer and the article since you feel so strongly about torque.  In fact I found the article after I read your post:

QUOTE
This one is simple. Torque creates acceleration. Period. If you're going for a high topspeed then HP is the thing you need, but torque is what makes you feel acceleration.

Horse Power sells cars...

Torque wins races.
The article refutes the false statement "horsepower sells cars torque wins races" directly. [/quote]
It's not an opinion. Horsepower is a measurement derived from torque. It also depends on how far you are racing. From 0-60mph the higher Torque will kill the lower torque engine, but then you have to factor in gearing. Are you gearing this car to give the advantage to which one?

It's not really an issue. You need both, but it's Torque that will throw you're car forward. Take a look at the S2000, High HP, Low Torque and the Z will eat it alive on the strip. It's also the reason the Ford Gt with 500hp/500lb ft will accelerate to 60 in 1st gear.

I'm not saying you don't need either, but when you have enough of each more torque will generally make your car faster from point A to B.
 
#24 ·
Originally posted by Beer Goggles@Nov 30 2004, 01:48 PM
It's not an opinion. Horsepower is a measurement derived from torque. It also depends on how far you are racing. From 0-60mph the higher Torque will kill the lower torque engine, but then you have to factor in gearing. Are you gearing this car to give the advantage to which one?

It's not really an issue. You need both, but it's Torque that will throw you're car forward. Take a look at the S2000, High HP, Low Torque and the Z will eat it alive on the strip. It's also the reason the Ford Gt with 500hp/500lb ft will accelerate to 60 in 1st gear.

I'm not saying you don't need either, but when you have enough of each more torque will generally make your car faster from point A to B.

It's not an opinion. Horsepower is a measurement derived from torque. It also depends on how far you are racing. From 0-60mph the higher Torque will kill the lower torque engine, but then you have to factor in gearing. Are you gearing this car to give the advantage to which one?
Nope. I understand the relationship between Torque and Horspower:

Horse Power = (TORQUE X RPM) / 5252

The car faster 0-60 (not that 0-60 is very important) will be determined by the vehicle with the highest POWER to weight ratio ceteris paribus, not torque to weight ratio. If this was not the case then you would shift near 4800 (the torque peak) not around 6200+ (the horsepower peak). For the sake of the argument lets assume that in every scenario that the vehicles are geared to maximize its acceration.


It's not really an issue. You need both, but it's Torque that will throw you're car forward. Take a look at the S2000, High HP, Low Torque and the Z will eat it alive on the strip. It's also the reason the Ford Gt with 500hp/500lb ft will accelerate to 60 in 1st gear.
An S2000 has 11.81 pounds per horsepower and the 350z has 11.31 pounds per HP this why the Z out accelerates the S2000! The reason the GT redlines in first @ 60mph (your numbers not mine) has everything to do with gearing.

I'm not saying you don't need either, but when you have enough of each more torque will generally make your car faster from point A to B.
Horsepower is a function of torque, but torque doesn't imply movement. Did you read the article?
 
#25 ·
300 Lb/Ft @ 4,000 RPM = 228.48 HP [ 14 ] [66.67%]
150 Lb/Ft @ 8,000 RPM = 228.48 HP [ 2 ] [9.52%]
They perform about the same! [ 5 ] [23.81%]

No one else has any thoughts on this??
 
#26 ·
Originally posted by thrlskr+Nov 30 2004, 09:13 PM-->
<!--QuoteBegin-Beer Goggles
@Nov 30 2004, 01:48 PM
It's not an opinion. Horsepower is a measurement derived from torque. It also depends on how far you are racing. From 0-60mph the higher Torque will kill the lower torque engine, but then you have to factor in gearing. Are you gearing this car to give the advantage to which one?

It's not really an issue. You need both, but it's Torque that will throw you're car forward. Take a look at the S2000, High HP, Low Torque and the Z will eat it alive on the strip. It's also the reason the Ford Gt with 500hp/500lb ft will accelerate to 60 in 1st gear.

I'm not saying you don't need either, but when you have enough of each more torque will generally make your car faster from point A to B.

It's not an opinion. Horsepower is a measurement derived from torque. It also depends on how far you are racing. From 0-60mph the higher Torque will kill the lower torque engine, but then you have to factor in gearing. Are you gearing this car to give the advantage to which one?
Nope. I understand the relationship between Torque and Horspower:

Horse Power = (TORQUE X RPM) / 5252

The car faster 0-60 (not that 0-60 is very important) will be determined by the vehicle with the highest POWER to weight ratio ceteris paribus, not torque to weight ratio. If this was not the case then you would shift near 4800 (the torque peak) not around 6200+ (the horsepower peak). For the sake of the argument lets assume that in every scenario that the vehicles are geared to maximize its acceration.


It's not really an issue. You need both, but it's Torque that will throw you're car forward. Take a look at the S2000, High HP, Low Torque and the Z will eat it alive on the strip. It's also the reason the Ford Gt with 500hp/500lb ft will accelerate to 60 in 1st gear.
An S2000 has 11.81 pounds per horsepower and the 350z has 11.31 pounds per HP this why the Z out accelerates the S2000! The reason the GT redlines in first @ 60mph (your numbers not mine) has everything to do with gearing.

I'm not saying you don't need either, but when you have enough of each more torque will generally make your car faster from point A to B.
Horsepower is a function of torque, but torque doesn't imply movement. Did you read the article?

You realize that since you are refering to power-to-weight it makes no mention of RPM that is at. Since the S2000 doesn't make enough torque it cannot make enough HP to out run the Z. If you bump the redline up to 10K it still won't make it to 60 before the Z.
 
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