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. All sports cars are geared to run from 0- ~150 mph. Yes having more of an aggresive gearing will give you better acceleration but it sure won't drop the 1/4 mile time more than a few tenths of a second. Do you really think that Mazda did something special to the gearing that no one else in the sports car industry knows about? the 350z/G35 and the rx8 are all 6 speeds and both going for high performance. The gear ratios chosen will be the best suited for each engines power band.

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).

wakeech

not really... if you LOOK at the NUMBERS (especially accounting for the final drive ratio) you'll see that it's not very similar... "close" is too subjective a term to really say "they're similar because their gearing is close"

AW, don't take this personallly, but why do you persist in prolonging your ignorance?? please read the articles/posts/info i've outlined for you: you are wrong...
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.

yes, we are all extremely aware of this... it has ALWAYS been this way with RX cars, and it'd better always be. this is how you drive ANY car fast, torque down low or no, but because the characteristics of this car reward in such a strong fashion true, correct, and active driving so charismatically is why we like it. This is the tradeoff we want: small, light, you put in a little more, you get a little more out of it through the corners AND down the straight.

lefuton

no words will ever seem to convince you.

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.

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

lefuton

gross generalization or not, that's a good way to explain why gearing matters.

AbusiveWombat

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.

AbusiveWombat

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:


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.

Gord96BRG

Interesting calculations. Should the real effect of the gearing be considered - speeds in gear? For example, if I'm cruising along at 45 mph in my RX-8 in third gear and floor it, what torque is available vs. 45 mph in third gear in my 350Z?


I guess it's how you read between the lines. Aside from CAR magazine (which claimed that the RX-8 torque was fine but that the 350Z lacked low end torque!), magazines have commented that the RX-8's torque isn't great at lower rpms. Have they actually used the word 'flaw' or equivalent? Nope, most have not. Some might have called it a weakness, but most have just said that low-end torque isn't a strength (which doesn't automatically make it a flaw or weakness).

Regards,
Gordon

BlueAdept

Well, I don't think any of us are actually trying to argue that it's a torque monster... but I think you'll agree that a lot of people here who are going on about "keeping up with traffic" (OMG, what are they thinking).. would be a lot happier is they saw a 200 ish number... even if it was calculated as you have done to give an impressition of the effects of gearing and the high revving engine..

Again, I don't see anyone argueing that the 330 is "Low torque"... certainly it's not as high as the 350z, but I don't think anyone would argue that it is... Mazda are trying to give the car a more refined feel, the power IS there, you just have to wind the engine up to get ALL of it... somthing that with a rotary is no hardship!

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..

lefuton

Just dandy. I think blueadept has it right about people just not liking to see 159 ft-lb. By no means was i trying to imply that a 3 banger geo metro could be turned into a dragster with proper gearing. All I was trying to say was that just looking at the flywheel output numbers, yes these other cars are faster, but gearing does make up for some of it.

evel333

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.

AbusiveWombat

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.

vipeRX7

.

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 ) to rest.

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...

wakeech

that's not quite it... the track they were at (Willow Springs??) was clearly a horsepower track, where the SVT (with +400hp) beat out the RX-8 only by seconds... the difference between the RX-8 and the G35C was tenths or something...

RacingDynamcs

thx for clearning that up because i was seriously considering that magazine test drivers need driving lessons...wooh!:D

Hercules

Not much to do with it actually... I think the real problem was that the high power ports weren't opening.