What does RX-8 acceleration compare to?
#51
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Originally posted by BlueAdept
Torque needs to be measured at the wheels... (assuming they are the same size)... and so if you want to get a real measure for comparison then you've gotta take the gear ratio's into account, and perhaps weight...
Torque needs to be measured at the wheels... (assuming they are the same size)... and so if you want to get a real measure for comparison then you've gotta take the gear ratio's into account, and perhaps weight...
There is no way that the gearing of the RX8 will make up for the low torque. The only way to do this is to either have the RX8 have a ton more gears (12 speed) or reduce the top speed so that the range the gearing runs is from 0-100 instead of 0-150. It's not going to happen.
So...get used to the idea of down shifting to get acceleration rather than a blip of the gas pedal. It's just a different solution that the engineers at Mazda chose.
It's very similar to my '98 Prelude versus the '98 Mustang GT. The GT had the big V8 with 225 hp and 305 ft-lbs of torque and the Prelude had 200 hp and ~160 ft-lbs of torque. Both ran the 1/4 mile around the same time but the Prelude needed to be rev'ed to get that speed where the Mustang had the power on tap low in the rpms. So during normal driving you would swear that the Mustang was faster because of all the torque compared to the Prelude.
The RX8 and the G35 are very similar. They are both run very similar 1/4 miles but the G35 will feel faster during normal driving because of the torque advantage. It's not until you get above 5k in the RX8 that you'll feel the difference. The RX8 will keep accelerating (linear torque) while the G35 will drop off in acceleration (torque drops off after 5k).
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Originally posted by AbusiveWombat
The reason that I say you don't need to take gear ratios into account is because all of these sports cars are geared very close to eachother.
The reason that I say you don't need to take gear ratios into account is because all of these sports cars are geared very close to eachother.
Originally posted by AbusiveWombat
There is no way that the gearing of the RX8 will make up for the low torque. The only way to do this is to either have the RX8 have a ton more gears (12 speed) or reduce the top speed so that the range the gearing runs is from 0-100 instead of 0-150.
There is no way that the gearing of the RX8 will make up for the low torque. The only way to do this is to either have the RX8 have a ton more gears (12 speed) or reduce the top speed so that the range the gearing runs is from 0-100 instead of 0-150.
not only does torque count, but the rpm that amount of force is at, the rpm range of the motor, the gears in the box, the drive ratio in the diff, and the diameter of the drive wheels... not to forget the mass of the vehicle, which is another point of discrepency between the two cars you mention.
Originally posted by AbusiveWombat
So...get used to the idea of down shifting to get acceleration rather than a blip of the gas pedal. It's just a different solution that the engineers at Mazda chose.
So...get used to the idea of down shifting to get acceleration rather than a blip of the gas pedal. It's just a different solution that the engineers at Mazda chose.
#53
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Originally posted by AbusiveWombat
The reason that I say you don't need to take gear ratios into account is because all of these sports cars are geared very close to eachother.
There is no way that the gearing of the RX8 will make up for the low torque. The only way to do this is to either have the RX8 have a ton more gears (12 speed) or reduce the top speed so that the range the gearing runs is from 0-100 instead of 0-150. It's not going to happen.
The reason that I say you don't need to take gear ratios into account is because all of these sports cars are geared very close to eachother.
There is no way that the gearing of the RX8 will make up for the low torque. The only way to do this is to either have the RX8 have a ton more gears (12 speed) or reduce the top speed so that the range the gearing runs is from 0-100 instead of 0-150. It's not going to happen.
rx8
Horsepower
250 @ 8,500 RPM
Torque (lbs/ft)
159 @ 5,500 RPM
Weight 3029
Final Drive Ratio
4.444
1st 3.760
2nd 2.269
3rd 1.645
4th 1.187
5th 1.000
6th .843
350z
Horsepower
287 @ 6,200 RPM
Torque (lbs/ft)
274 @ 4,800 RPM
Weight 3188 (lightest of the models)
Final Drive Ratio
3.538
M/T
1st 3.794
2nd 2.324
3rd 1.624
4th 1.271
5th 1.000
6th 0.794
not gonna bore everyone with the math, it's been done before with these numbers, buger has a thread somewhere about it.
https://www.rx8club.com/showthread.p...&pagenumber=11
there's a good graph on there comparing the rx8 to the g35 and some renesis vs f20c curves too.
here's a good little ditty on why gearing matters
https://www.rx8club.com/showthread.p...hlight=gearing
http://www.rx8forum.com/showthread.p...9309#post19309
and one last one, http://www.rx8forum.com/showthread.p...9309#post19309 scroll down a bit til you see 2 graphs, and that is torque applied through gearing.
by no means will an rx8 be, say, easier to drive, and sure the g35 is faster but in response to one of your comments above. what advantage would having 12 gears do the renesis? 12 gears would begin to make sense if it had a peaky narrow powerband...but that torque curve, as low as you think it is, looks pretty darn smooth to me.
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I'm REALLY gonna keep this short, because if I need to explain it more I'll just link some VERY long threads on this subject, but perhaps for the new people....
Take 2 cars, 1 revs to 5000rpm, the other to 10000rpm. assume that the latter has half the torque.
Now, the first will have gears twice as high... giving the second a mechanical advantage of 2 times.... hence the torque at the wheels will be identical between the two cars, even though the torque at the engine was not.
It's a gross generalisation, but if the engine revs 50% higher, the gearing will need to be 50% lower, so the torque at the wheels will represent 50% more than the raw figure when comparing the two cars.
Now,,,, I don't want to stop the debate on this but understand that I won't be happy if it degenerates into a pissing match.....
So, please... if you are at all unsure what I'm talking about.... please read these articles/posts and decide then if you have anything to add:-
http://www.vettenet.org/torquehp.html
http://www.rx8forum.com/showthread.p...g&pagenumber=1
Take 2 cars, 1 revs to 5000rpm, the other to 10000rpm. assume that the latter has half the torque.
Now, the first will have gears twice as high... giving the second a mechanical advantage of 2 times.... hence the torque at the wheels will be identical between the two cars, even though the torque at the engine was not.
It's a gross generalisation, but if the engine revs 50% higher, the gearing will need to be 50% lower, so the torque at the wheels will represent 50% more than the raw figure when comparing the two cars.
Now,,,, I don't want to stop the debate on this but understand that I won't be happy if it degenerates into a pissing match.....
So, please... if you are at all unsure what I'm talking about.... please read these articles/posts and decide then if you have anything to add:-
http://www.vettenet.org/torquehp.html
http://www.rx8forum.com/showthread.p...g&pagenumber=1
#55
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Originally posted by BlueAdept
It's a gross generalisation, but if the engine revs 50% higher, the gearing will need to be 50% lower, so the torque at the wheels will represent 50% more than the raw figure when comparing the two cars.
It's a gross generalisation, but if the engine revs 50% higher, the gearing will need to be 50% lower, so the torque at the wheels will represent 50% more than the raw figure when comparing the two cars.
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I'll keep this really short. All of the reviews have stated the one flaw in the RX8 to be the low torque. Now these are people directly comparing the 350z/G35/Cobra to the RX8. So regardless of the gearing the lack of torque is felt.
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Ok now I'll end this:
Please check my math but here goes.
Let's look at the torque at the wheels in 3rd gear.
RX8-------
torque = 159 @ 5500
final drive ratio = 4.444
3rd gear is 1.645
FDR * 3rd gear = 7.31038
350z-------
torque = 274 @ 4800
final drive ratio = 3.538
3rd gear is 1.624
FDR * 3rd gear = 5.745712
So the RX8 has a 27% advantage in gearing.
Peak torque in 3rd:
RX8 = 7.31038 * 159 = 1162.35
350z = 5.745712 * 274 = 1574.32
But the Z has a 35% advantage in peak torque.
Now lets figure in weight.
a = F/m
RX8 = 1162.35 / 3029 = 0.384
350z = 1574.32 / 3188 = 0.494
At peak torque the 350z has a 28.6% T/lbs advantage.
Now if we look at the 350z dyno:
![](http://www.injen.com/webpages/special/350z_testing/RD1985%20average%20gain.gif)
So now lets assume that the RX8 is a completely flat torque curve. We see that peak torque is 230.2 for the Z from the dyno. Now at that point it is 28.6% stronger than the RX8. So if we take 28.6% off of the 230.2 we get 164.3, this is where the RX8 torque curve/flat line is. So any point on the 350z torque curve that is above the 164.3 will be a point that the 350z feels faster. Any point below 164.3 the 350z will feel slower.
Here's a break down on RPMs:
2000-6500 rpms ---> 350 is faster (100% of 350s rpms)
6500+ -----------------> RX8 is faster (36% of RX8's rpms)
But you're right the RX8 does make up quite a bit of torque in the gearing (27%). Thus giving it the impression of closer to 200 ft-lbs of torque rather than the 159 ft-lbs (when compared to the Z). So in the end does the gearing help the low torque? yes.
But here are some of the competitors.
FDR=Final Drive Ratio
Car ----------- FDR ---------- 3rd gear ---- torque ----- T*FDR*3rd
RX8...............4.444...........1.645........... .159............1162.35
G35/350z......3.538...........1.624............274.... ........1574.32
EVO...............4.529...........1.407........... .273............1739.63
BMW 330.......3.38.............1.59..............214.. ..........1150.07
Lexus is300...3.909...........1.424............218...... .......1213.47
the RX8 seems to be on par with the BMW 330 or is300 but against the 350/G35 and EVO it's very low.
I'll leave it at that. Let me know if any of my logic is incorrect.
Please check my math but here goes.
Let's look at the torque at the wheels in 3rd gear.
RX8-------
torque = 159 @ 5500
final drive ratio = 4.444
3rd gear is 1.645
FDR * 3rd gear = 7.31038
350z-------
torque = 274 @ 4800
final drive ratio = 3.538
3rd gear is 1.624
FDR * 3rd gear = 5.745712
So the RX8 has a 27% advantage in gearing.
Peak torque in 3rd:
RX8 = 7.31038 * 159 = 1162.35
350z = 5.745712 * 274 = 1574.32
But the Z has a 35% advantage in peak torque.
Now lets figure in weight.
a = F/m
RX8 = 1162.35 / 3029 = 0.384
350z = 1574.32 / 3188 = 0.494
At peak torque the 350z has a 28.6% T/lbs advantage.
Now if we look at the 350z dyno:
![](http://www.injen.com/webpages/special/350z_testing/RD1985%20average%20gain.gif)
So now lets assume that the RX8 is a completely flat torque curve. We see that peak torque is 230.2 for the Z from the dyno. Now at that point it is 28.6% stronger than the RX8. So if we take 28.6% off of the 230.2 we get 164.3, this is where the RX8 torque curve/flat line is. So any point on the 350z torque curve that is above the 164.3 will be a point that the 350z feels faster. Any point below 164.3 the 350z will feel slower.
Here's a break down on RPMs:
2000-6500 rpms ---> 350 is faster (100% of 350s rpms)
6500+ -----------------> RX8 is faster (36% of RX8's rpms)
But you're right the RX8 does make up quite a bit of torque in the gearing (27%). Thus giving it the impression of closer to 200 ft-lbs of torque rather than the 159 ft-lbs (when compared to the Z). So in the end does the gearing help the low torque? yes.
But here are some of the competitors.
FDR=Final Drive Ratio
Car ----------- FDR ---------- 3rd gear ---- torque ----- T*FDR*3rd
RX8...............4.444...........1.645........... .159............1162.35
G35/350z......3.538...........1.624............274.... ........1574.32
EVO...............4.529...........1.407........... .273............1739.63
BMW 330.......3.38.............1.59..............214.. ..........1150.07
Lexus is300...3.909...........1.424............218...... .......1213.47
the RX8 seems to be on par with the BMW 330 or is300 but against the 350/G35 and EVO it's very low.
I'll leave it at that. Let me know if any of my logic is incorrect.
#58
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Originally posted by AbusiveWombat
Let me know if any of my logic is incorrect.
Let me know if any of my logic is incorrect.
Originally posted by AbusiveWombat
All of the reviews have stated the one flaw in the RX8 to be the low torque. Now these are people directly comparing the 350z/G35/Cobra to the RX8. So regardless of the gearing the lack of torque is felt.
All of the reviews have stated the one flaw in the RX8 to be the low torque. Now these are people directly comparing the 350z/G35/Cobra to the RX8. So regardless of the gearing the lack of torque is felt.
Regards,
Gordon
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Originally posted by AbusiveWombat
Ok now I'll end this:
--- SNIP ---
But you're right the RX8 does make up quite a bit of torque in the gearing (27%). Thus giving it the impression of closer to 200 ft-lbs of torque rather than the 159 ft-lbs (when compared to the Z). So in the end does the gearing help the low torque? yes.
Ok now I'll end this:
--- SNIP ---
But you're right the RX8 does make up quite a bit of torque in the gearing (27%). Thus giving it the impression of closer to 200 ft-lbs of torque rather than the 159 ft-lbs (when compared to the Z). So in the end does the gearing help the low torque? yes.
--- SNIP ---
the RX8 seems to be on par with the BMW 330 or is300 but against the 350/G35 and EVO it's very low.
--- SNIP ---
The cars definitely have different character, and people will buy the ones they like... if you're not convinced by the numbers, then get a test drive... when they arrive..
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Originally posted by AbusiveWombat
I'll leave it at that. Let me know if any of my logic is incorrect.
I'll leave it at that. Let me know if any of my logic is incorrect.
#61
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I'm annoyed in that replying to this worn out subject only perpetuates it. I apologize.
Please, for the sake of the forum, don't let this place become like some of the other ****-matching forums. To think, the damn car hasn't even been released yet! Imagine once it is...
If Mazda had somehow blessed us with, say, a 350hp, 300torque, NA rotary masterpiece, I really doubt any of these discussions would happen. Of course, there would be the possibility that the 8 would be compared to other classes of sports cars; but all the nit-picking, and splitting hairs over tenths of a second, quarter-mile-this, and on-the-track-that, all to legitimize or justify any of the 8's shortcomings will cease. If the 8 truly blew away the competition in all benchmark tests--power output, acceleration times, gearing, lateral g's, whatever--the more sensitive and touchy members of this forum wouldn't have to defend anything. Sure, I get irritated by some of the trolling comments on the boards just like anyone else, but to date, I don't think I've ever taken their bait. I have always chosen not to acknowledge their banter and remain silent in pride.
I accept the 8, and am still quite committed to purchasing one, regardless of what people may say. When I see the car, when I hear it's engine, when I imagine the ride, all I think of is that I want to own one. No other factor is a concern--that is why I'm on this forum.
Please, for the sake of the forum, don't let this place become like some of the other ****-matching forums. To think, the damn car hasn't even been released yet! Imagine once it is...
If Mazda had somehow blessed us with, say, a 350hp, 300torque, NA rotary masterpiece, I really doubt any of these discussions would happen. Of course, there would be the possibility that the 8 would be compared to other classes of sports cars; but all the nit-picking, and splitting hairs over tenths of a second, quarter-mile-this, and on-the-track-that, all to legitimize or justify any of the 8's shortcomings will cease. If the 8 truly blew away the competition in all benchmark tests--power output, acceleration times, gearing, lateral g's, whatever--the more sensitive and touchy members of this forum wouldn't have to defend anything. Sure, I get irritated by some of the trolling comments on the boards just like anyone else, but to date, I don't think I've ever taken their bait. I have always chosen not to acknowledge their banter and remain silent in pride.
I accept the 8, and am still quite committed to purchasing one, regardless of what people may say. When I see the car, when I hear it's engine, when I imagine the ride, all I think of is that I want to own one. No other factor is a concern--that is why I'm on this forum.
Last edited by evel333; 04-21-2003 at 11:27 AM.
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Look the original post asked what the RX8's acceleration would compare to. By the numbers the acceleration most closely resembles that of a BMW 330 in the sub 6000 rpms. Above 6000 rpms it's a little harder to compare because the other cars have to shift giving the RX8 the advantage. the numbers in my previous post give a good way to judge how each of the cars feel during daily driving.
I certainly realize now that the torque issue is totaly dependant upon which cars you're comparing to. When comparing the RX8 to the 350z/G35, EVO, and Cobra...yeah this car lacks a large amount of torque. I would hardly say it's "knit picking" when dealing with +20%, +40%, and +50% (respectively) more power below 5000 rpms. Now when comparing to a BMW 330 and Lexus is300 the torque is about the same and thus not an issue.
I'll agree that the first time I saw the 159 ft-lbs I was really put off but now that I've run the numbers it's not as bad as I orignally thought. So like I said, it's all in which cars you're comparing the RX8 to.
Remember...this is a discussion forum where people ask questions and get answers. I've certainly learned a lot and I'm sure that the numbers I posted will help many people understand how much the gearing helps the RX8's torque (or any car for that matter).
The best way to keep this forum from becoming a pissing match is to back up comments with factual data. So that in the end all you can say is "yes the rx8 has less acceleration throughout the 350z's rpm range in 3rd gear". That statement is not bagging on either car. It's just a factual statement. You can take it however you want. Just be objective and take an unbaised approach.
I certainly realize now that the torque issue is totaly dependant upon which cars you're comparing to. When comparing the RX8 to the 350z/G35, EVO, and Cobra...yeah this car lacks a large amount of torque. I would hardly say it's "knit picking" when dealing with +20%, +40%, and +50% (respectively) more power below 5000 rpms. Now when comparing to a BMW 330 and Lexus is300 the torque is about the same and thus not an issue.
I'll agree that the first time I saw the 159 ft-lbs I was really put off but now that I've run the numbers it's not as bad as I orignally thought. So like I said, it's all in which cars you're comparing the RX8 to.
Remember...this is a discussion forum where people ask questions and get answers. I've certainly learned a lot and I'm sure that the numbers I posted will help many people understand how much the gearing helps the RX8's torque (or any car for that matter).
The best way to keep this forum from becoming a pissing match is to back up comments with factual data. So that in the end all you can say is "yes the rx8 has less acceleration throughout the 350z's rpm range in 3rd gear". That statement is not bagging on either car. It's just a factual statement. You can take it however you want. Just be objective and take an unbaised approach.
#63
Originally posted by BlueAdept
I'm REALLY gonna keep this short, because if I need to explain it more I'll just link some VERY long threads on this subject, but perhaps for the new people....
Take 2 cars, 1 revs to 5000rpm, the other to 10000rpm. assume that the latter has half the torque.
Now, the first will have gears twice as high... giving the second a mechanical advantage of 2 times.... hence the torque at the wheels will be identical between the two cars, even though the torque at the engine was not.
It's a gross generalisation, but if the engine revs 50% higher, the gearing will need to be 50% lower, so the torque at the wheels will represent 50% more than the raw figure when comparing the two cars.
Now,,,, I don't want to stop the debate on this but understand that I won't be happy if it degenerates into a pissing match.....
So, please... if you are at all unsure what I'm talking about.... please read these articles/posts and decide then if you have anything to add:-
http://www.vettenet.org/torquehp.html
http://www.rx8forum.com/showthread.p...g&pagenumber=1
I'm REALLY gonna keep this short, because if I need to explain it more I'll just link some VERY long threads on this subject, but perhaps for the new people....
Take 2 cars, 1 revs to 5000rpm, the other to 10000rpm. assume that the latter has half the torque.
Now, the first will have gears twice as high... giving the second a mechanical advantage of 2 times.... hence the torque at the wheels will be identical between the two cars, even though the torque at the engine was not.
It's a gross generalisation, but if the engine revs 50% higher, the gearing will need to be 50% lower, so the torque at the wheels will represent 50% more than the raw figure when comparing the two cars.
Now,,,, I don't want to stop the debate on this but understand that I won't be happy if it degenerates into a pissing match.....
So, please... if you are at all unsure what I'm talking about.... please read these articles/posts and decide then if you have anything to add:-
http://www.vettenet.org/torquehp.html
http://www.rx8forum.com/showthread.p...g&pagenumber=1
You've got a really good point. For example, the Ferrari 308 Quattrovalvole has about 10% more torque than the RX-8, about 5% less hp, and about 5% less weight. I have been lucky enough to go for a ride in one, and let me tell you, it felt pretty darn fast. Now, the statistics I mentioned do not have everything to do with acceleration, but the 308 is *roughly* comparable (in fact it's slower 0-60 than the RX-8). Being a Ferrari, it revs fairly high ... just like the RX-8. But how often do you hear "Ferraris have low torque!"? Heck, the 360 Modena has less torque than the 350z ... but it revs to 8500 rpm. Which would you rather have? (ok ok it's not that simple, the 360 costs way more, etc. etc. etc. but you get my drift). Nonetheless, what you said shows that there's a lot more to cars than just torque and horsepower, you must consider redline, weight, gearing, etc. That should put some worries (including mine
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#64
getting back to one of the 1st posts saying that the RX8 is slower on the track than the G35...i seriously dout this statement even if its coming from a magazine...RX8 is not a regular car like the g35 it needs to be reved high all the time...and i dont think the driver who drove the rx8 on the track new exactly how to drive the rx8 properly and was more used to driving the G35 styled cars...
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Originally posted by RacingDynamcs
getting back to one of the 1st posts saying that the RX8 is slower on the track than the G35...i seriously dout this statement even if its coming from a magazine...RX8 is not a regular car like the g35 it needs to be reved high all the time...and i dont think the driver who drove the rx8 on the track new exactly how to drive the rx8 properly and was more used to driving the G35 styled cars...
getting back to one of the 1st posts saying that the RX8 is slower on the track than the G35...i seriously dout this statement even if its coming from a magazine...RX8 is not a regular car like the g35 it needs to be reved high all the time...and i dont think the driver who drove the rx8 on the track new exactly how to drive the rx8 properly and was more used to driving the G35 styled cars...
#67
Originally posted by RacingDynamcs
getting back to one of the 1st posts saying that the RX8 is slower on the track than the G35...i seriously dout this statement even if its coming from a magazine...RX8 is not a regular car like the g35 it needs to be reved high all the time...and i dont think the driver who drove the rx8 on the track new exactly how to drive the rx8 properly and was more used to driving the G35 styled cars...
getting back to one of the 1st posts saying that the RX8 is slower on the track than the G35...i seriously dout this statement even if its coming from a magazine...RX8 is not a regular car like the g35 it needs to be reved high all the time...and i dont think the driver who drove the rx8 on the track new exactly how to drive the rx8 properly and was more used to driving the G35 styled cars...
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