Spoonie

I know I'm going to get called a troll but here it is. I saw Car and Driver television. They loved the RX-8 but said that it needed more power in the 3k-5k rpm range. Everyone in the world Acknowledges that the RX-8 has limited torque. But mention that here and you get shot down. You guys need to come to the reality that the RX8 has flaws, namely the lack of low-end grunt.

I have not posted here in about 2 months. I was considering the RX-8 but its S2000 like torque characteristics turn me off. It's a legitimate gripe. Rather than shoot everyone who mentions the RX-8's shortcomings, people here should acknowledge that fact and stress the RX8's strong points. Some folks respond respectfully, but most of the responses to RX8 criticism usually ends with the word "troll"

Personally, I'm waiting for the supercharged version to see if the RX-8 is for me. The normally aspirated RX8 does not have the Low-End torque that many people (Car & driver included) would like to have. Call me a troll, call me whatever, but at least I'm man enough to admit shortcomings in a vehicle that I love. It seems that if anything is said negative about the RX8, people here take it very, very personal. The RX-8 is a very nice car. The RX-8 has advantages and disadvantages over the competition. No car is perfect but if the RX-8 had about 50lbft more of torque it would be perfect for me. For people who do not need the low-end torque the RX8 more than delivers. I can understand the extreme enthusiasm for the RX8, it is a sweet car. I just wish it had G35/ 330i low end torque characteristics instead of S2000 torque characteristics. Everyone knows and acknowledges that the S2000 is a Dog down low.

RotorGeek

I am one of those guys that could care less about the torque. I love the 8 for it's looks. The rotary, the carbon fiber drive shaft, the handleing, the seats, the 4 person seating, the freestyle doors. The knowledge that I will own the only Production 4 door 4seater rotary in the WORLD ha ha ha

shahpor

That is your opinion and there is no reason why you can't express it.

I think that if you have a reasonable complaint that is fine. It is just these people who come here and say 'The RX-8 is crap' simply to annoy people that should be banned.

By all means, if you have a specific complaint I want to hear about it. I came here to learn about the car, good and bad.

I personally like cars you have to rev to get the best out of, but I can understand that that is not for everyone.

So if you want to complain about the lack of torque, please do so cause I want to hear it.

RXhusker

I think everyone well understands the power and torque characteristics of the Renesis. I believe what the guy on C&D TV said was that when you are cruising in top gear at 3-5k and punch the accelerator -- it just doesn't seem to have a lot of pull -- doesn't pin you to the seat (ala the Z). That is a reasonable comment to make. I really don't care because I know how to downshift :D and realize that 6th is for highway gas mileage not high speed passing.

I too find myself dreaming of a higher power RX, but then I remind myself that it is just human nature to want more -- no matter what you have. I loved my first gen RX-7 and it would be considered pathetic now in the power department. I am not sure that many people here will ever really push the performance limits of this car as it stands -- much less one with substantially more power. For most it is just always wanting more and thinking someone out there has more (Z).

KayakDaddy

I don’t think you are alone in your concern about the RX-8 being torque deficient, though I am pretty confident that whatever it has will be plenty for me. I enjoy rowing the gears so shifting will not bother me. If the engine will rev into its power band as quickly as we are told, I don’t foresee a problem.

Considering that none of us have actually driven the RX-8 (that I’m aware of) and no one has driven a production RX-8, it’s really too early to make a judgment anyway. I haven't driven a S2000 for that matter so I can't really compare it to that either. I’ll wait and drive one for myself and make up my own mind. I haven't pre-ordered, so I have the flexiblity of not buying one if I don't like it. That being said, I expect to LOVE it and expect to buy one in early 2004.

Midnight Flyer

Why don't you just wait and drive one before saying yeh or nay. I like the look and the concept of the car but I have no plans to put any money down, sight unseen. The way I test a car to see if I like the power is to take it out on the highway, at my normal cruising speed and see how well I can pass other cars. I have not found any cars that throw you in your seat without downshifting to pass.

My 01 Miata only has 140hp, my 91 Miata has about 100hp and I have no problems driving them or passing other cars, they are just a ball to throw around. The thought of 250 in a car just a bit bigger then the Miata should more then meet my needs even if it does have a roof.

Spoonie

I have, that's why low end torque is important to me, you don't have to downshift. The power is always there.

Try test drivng a 330i or a G35/350z. You can still feel the power in high gear @4000 plus RPM. I like effortless power.

DrKillJoY

all this banter about torque... many people here haven't driven one.. ask some of the people who have. Dan and Bern from rotarynews... Derrick Berg from Texas.. and other who have driven it.. trust me.. noone I have talked to has been very sad about the lack of torque.




enjoy.. and good luck..

RX8Lover

TROLL

Spoonie

LOL, My post was mature your response is childish. Grow up.
But hey, I was expecting stupid comments like yours. Trolls are people who write threads to upset people. All I did was state the truth about the RX8's shortcomings. I guess you can't handle the truth. I don’t know what's worse, people who cannot or will not except the truth or trolls.

I’m hoping that you were just joking, if not you need to learn to accept a little constructive criticism. Later

RX8Lover

It was meant as a joke. I would have thought someone would have beat me to it. But since no one did, I thought I would be the first.

Spoonie

Sorry, You should have put a smiley face :-) after your comment. Sorry again.

quicks8

I like everything about the 8 but the torque issue concerns me. I worry that I will wind up voiding my warranty be engaging in aftermarket modifications to fix an obvious issue that should have been addressed by Mazda initially. Of course that is just my naive opinion what do I know.

Jimmylove

What bugs me the most is when the word "S2000" gets mentioned in any Rotary forum, it gets constantly gets blasted for having "no torque". But the same people who criticized the powerband on the Honda, are suddenly defending the characteristics of the RX-8. Leads me to believe there is strong brand bias on Mazda boards (as there is on other boards).

For me, I'm a huge fan of the RX-8 because of its peaky powerplant. I see it as a compelling reason to buy rather than a downside. I've run out of breath trying to defend the F20C on message boards, and it seems like Renesis owners will be picking up where I left off.

kittychester

I am not sure what you all are talking about --what is torque and how will effect by ability to go from 0 to 60.

DrKillJoY

I didn't write this, but it looks like a reasonably unbiased account of the 2 forces of motion.


The Case For Torque

Now, what does all this mean in carland?

First of all, from a driver's perspective, torque, to use the
vernacular, RULES :-). Any given car, in any given gear, will accelerate at a rate that *exactly* matches its torque curve (allowing for increased air and rolling resistance as speeds climb).

Another way of saying this is that a car will accelerate hardest at its torque peak in any given gear, and will not accelerate as hard below that peak, or above it. Torque is the only thing that a driver feels, and horsepower is just sort of an esoteric measurement in that context. 300 foot pounds of torque will accelerate you just as hard at 2000 rpm as it would if you were making that torque at 4000 rpm in the same gear, yet, per the formula, the horsepower would be *double* at 4000 rpm.

Therefore, horsepower isn't particularly meaningful from a driver's perspective, and the two numbers only get friendly at 5252 rpm, where horsepower and torque always come out the same.

In contrast to a torque curve (and the matching pushback into your seat), horsepower rises rapidly with rpm, especially when torque values are also climbing. Horsepower will continue to climb, however, until well past the torque peak, and will continue to rise as engine speed climbs, until the torque curve really begins to plummet, faster than engine rpm is rising. However, as I said, horsepower has nothing to do with what a driver *feels*.


Fine. Take your non turbo car (turbo lag muddles the results) to its torque peak in first gear, and punch it. Notice the belt in the back? Now take it to the power peak, and punch it. Notice that the belt in the back is a bit weaker? Fine. Can we go on, now? :-)


The Case For Horsepower

OK. If torque is so all-fired important, why do we care about horsepower?

Because (to quote a friend), "It is better to make torque at high rpm than at low rpm, because you can take advantage of *gearing*.

For an extreme example of this, I'll leave carland for a moment, and describe a waterwheel I got to watch awhile ago. This was a pretty massive wheel (built a couple of hundred years ago), rotating lazily on a shaft which was connected to the works inside a flour mill. Working some things out from what the people in the mill said, I was able to determine that the wheel typically generated about 2600(!) foot pounds of torque. I had clocked its speed, and determined that it was rotating at about 12 rpm. If we hooked that wheel to, say, the drivewheels of a car, that car would go from zero to twelve rpm in a flash, and the waterwheel would hardly notice :-).

On the other hand, twelve rpm of the drivewheels is around one mph for the average car, and, in order to go faster, we'd need to gear it up. To get to 60 mph would require gearing the wheel up enough so that it would be effectively making a little over 43 foot pounds of torque at the output, which is not only a relatively small amount, it's less than what the average car would need in order to actually get to 60. Applying the conversion formula gives us the facts on this. Twelve times twenty six hundred, over five thousand two hundred fifty two gives us:

6 HP.

Oops. Now we see the rest of the story. While it's clearly true that the water wheel can exert a *bunch* of force, its *power* (ability to do work over time) is severely limited.


At The Dragstrip
OK. Back to carland, and some examples of how horsepower makes a major difference in how fast a car can accelerate, in spite of what torque on your backside tells you :-).

A very good example would be to compare the current LT1 Corvette with the last of the L98 Vettes, built in 1991. Figures as follows:


Engine Peak HP @ RPM Peak Torque @ RPM

------ ------------- -----------------

L98 250 @ 4000 340 @ 3200

LT1 300 @ 5000 340 @ 3600


The cars are geared identically, and car weights are within a few pounds, so it's a good comparison.

First, each car will push you back in the seat (the fun factor) with the same authority - at least at or near peak torque in each gear.
One will tend to *feel* about as fast as the other to the driver, but the LT1 will actually be significantly faster than the L98, even though it won't pull any harder. If we mess about with the formula, we can begin to discover exactly *why* the LT1 is faster.

Here's another slice at that formula:


Horsepower * 5252

Torque = -----------------

RPM


If we plug some numbers in, we can see that the L98 is making 328 foot pounds of torque at its power peak (250 hp @ 4000), and we can infer that it cannot be making any more than 263 pound feet of torque at 5000 rpm, or it would be making more than 250 hp at that engine speed, and would be so rated. In actuality, the L98 is probably making no more than around 210 pound feet or so at 5000 rpm, and anybody who owns one would shift it at around 46-4700 rpm, because more torque is available at the drive wheels in the next gear at that point.
On the other hand, the LT1 is fairly happy making 315 pound feet at 5000 rpm, and is happy right up to its mid 5s redline.

So, in a drag race, the cars would launch more or less together. The L98 might have a slight advantage due to its peak torque occuring a little earlier in the rev range, but that is debatable, since the LT1 has a wider, flatter curve (again pretty much by definition, looking at the figures). From somewhere in the mid range and up, however, the LT1 would begin to pull away. Where the L98 has to shift to second (and throw away torque multiplication for speed), the LT1 still has around another 1000 rpm to go in first, and thus begins to widen its lead, more and more as the speeds climb. As long as the revs are high, the LT1, by definition, has an advantage.

Another example would be the LT1 against the ZR-1. Same deal, only in reverse. The ZR-1 actually pulls a little harder than the LT1, although its torque advantage is softened somewhat by its extra weight. The real advantage, however, is that the ZR-1 has another 1500 rpm in hand at the point where the LT1 has to shift.

There are numerous examples of this phenomenon. The Integra GS-R, for instance, is faster than the garden variety Integra, not because it pulls particularly harder (it doesn't), but because it pulls *longer*. It doesn't feel particularly faster, but it is.

A final example of this requires your imagination. Figure that we can tweak an LT1 engine so that it still makes peak torque of 340 foot pounds at 3600 rpm, but, instead of the curve dropping off to 315 pound feet at 5000, we extend the torque curve so much that it doesn't fall off to 315 pound feet until 15000 rpm. OK, so we'd need to have virtually all the moving parts made out of unobtanium :-), and some sort of turbocharging on demand that would make enough high-rpm boost to keep the curve from falling, but hey, bear with me.

If you raced a stock LT1 with this car, they would launch together, but, somewhere around the 60 foot point, the stocker would begin to fade, and would have to grab second gear shortly thereafter. Not long after that, you'd see in your mirror that the stocker has grabbed third, and not too long after that, it would get fourth, but you'd wouldn't be able to see that due to the distance between you as you crossed the line, *still in first gear*, and pulling like crazy.

I've got a computer simulation that models an LT1 Vette in a quarter mile pass, and it predicts a 13.38 second ET, at 104.5 mph. That's pretty close (actually a tiny bit conservative) to what a stock LT1 can do at 100% air density at a high traction drag strip, being powershifted. However, our modified car, while belting the driver in the back no harder than the stocker (at peak torque) does an 11.96, at 135.1 mph, all in first gear, of course. It doesn't pull any harder, but it sure as hell pulls longer :-). It's also making *900* hp, at 15,000 rpm.

Of course, folks who are knowledgeable about drag racing are now openly snickering, because they've read the preceeding paragraph, and it occurs to them that any self respecting car that can get to 135 mph in a quarter mile will just naturally be doing this in less than ten seconds. Of course that's true, but I remind these same folks that any self-respecting engine that propels a Vette into the nines is also making a whole bunch more than 340 foot pounds of torque.

That does bring up another point, though. Essentially, a more "real" Corvette running 135 mph in a quarter mile (maybe a mega big block) might be making 700-800 foot pounds of torque, and thus it would pull a whole bunch harder than my paper tiger would. It would need slicks and other modifications in order to turn that torque into forward motion, but it would also get from here to way over there a bunch quicker.

On the other hand, as long as we're making quarter mile passes with fantasy engines, if we put a 10.35:1 final-drive gear (3.45 is stock) in our fantasy LT1, with slicks and other chassis mods, we'd be in the nines just as easily as the big block would, and thus save face :-). The mechanical advantage of such a nonsensical rear gear would allow our combination to pull just as hard as the big block, plus we'd get to do all that gear banging and such that real racers do, and finish in fourth gear, as God intends. :-)

The only modification to the preceeding paragraph would be the polar moments of inertia (flywheel effect) argument brought about by such a stiff rear gear, and that argument is outside of the scope of this already massive document. Another time, maybe, if you can stand it :-).


At The Bonneville Salt Flats
Looking at top speed, horsepower wins again, in the sense that making more torque at high rpm means you can use a stiffer gear for any given car speed, and thus have more effective torque *at the drive wheels*.
Finally, operating at the power peak means you are doing the absolute best you can at any given car speed, measuring torque at the drive wheels. I know I said that acceleration follows the torque curve in any given gear, but if you factor in gearing vs car speed, the power peak is *it*. An example, yet again, of the LT1 Vette will illustrate this. If you take it up to its torque peak (3600 rpm) in a gear, it will generate some level of torque (340 foot pounds times whatever overall gearing) at the drive wheels, which is the best it will do in that gear (meaning, that's where it is pulling hardest in that gear).

However, if you re-gear the car so it is operating at the power peak (5000 rpm) *at the same car speed*, it will deliver more torque to the drive wheels, because you'll need to gear it up by nearly 39% (5000/3600), while engine torque has only dropped by a little over 7% (315/340). You'll net a 29% gain in drive wheel torque at the power peak vs the torque peak, at a given car speed.

Any other rpm (other than the power peak) at a given car speed will net you a lower torque value at the drive wheels. This would be true of any car on the planet, so, theoretical "best" top speed will always occur when a given vehicle is operating at its power peak.

"Modernizing" The 18th Century
OK. For the final-final point (Really. I Promise.), what if we ditched that water wheel, and bolted an LT1 in its place? Now, no LT1 is going to be making over 2600 foot pounds of torque (except possibly for a single, glorious instant, running on nitromethane), but, assuming we needed 12 rpm for an input to the mill, we could run the LT1 at 5000 rpm (where it's making 315 foot pounds of torque), and gear it down to a 12 rpm output. Result? We'd have over *131,000* foot pounds of torque to play with. We could probably twist the whole flour mill around the input shaft, if we needed to :-).

The Only Thing You Really Need to Know
Repeat after me. "It is better to make torque at high rpm than at low rpm, because you can take advantage of *gearing*." :-)

kittychester

I still do not understand--will my RX8 be faster or slower coming out a stop than my mother's escort?

miztic

Most definately will be faster unless that escort does 0-60 in under 6 seconds

kittychester

thank goodness--based on these torque discussions I was unsure. I have a 1997 Chrysler Sebring Convertible with the large V6 engine. That has a lot of power coming from a stop. Hopefully, the RX8 will have the same.

zoom44

kitty you should also read thru this thread

this thread

if you still have any questions search some of bugers posts about power. he has some great graphs:D

Elara

Kittychester, if it makes you feel better, I don't completely understand torque myself, even after having read all of the posts by buger and others about it. I have, however, picked up that in general, the more torque you've got, the faster the car is going to accelerate- but that it is so dependant on so many other factors as well (like weight, hp, etc) that unless you take EVERYTHING into consideration you're not going to get a good estimate of anything.

So, here's what I have decided:

more torque and more hp, good. Less weight, also good. And with those simple ideas, the RX-8 sounds pretty fun to drive.

Y&Y

Torque Torque Torque, everybody wants more Torque . If you want to feel that being pulled into the seat feel go to your local theme park and ride the fastet roller coaster.

Listen KittyChester you want torque go get yourself a Dodge Viper now that car has Torque. I believe it has around what 500lbs/ft of Torque. But don't burn yourself on the exhaust pipes(literally). If you read a lot of the post in this forum people are getting the car for looks, practicality, price and the cars supposed awesome handling. You want both power(Torque) and handling you go get yourself the Chevy Corvette Z06.

RX8Lover

I don't get it

Elara

Y&Y, she wasn't complaining of lack or torque or anything like that. She just didn't understand what it was, exactly. And with that, I don't completely understand the physics of it either. But it's not stopping me from getting the car!

:p