This is the only thing i am really worried about with the RX8. i currently drive a MX6 V6 and i LOVE the low end torque of the KL. Instant acceleration at any rev range, never requiring a downshift. awesome feeling. so i heard from one of the magazine test drives tat the midrange torque on the RX8 is not bad. i really hope thats true. think they rated RX8 torue at 160lbs/ft, which is the same as the MX6's KL. so as long as RX8's torque distribution is just as even as the MX6's, ill be happy :D

 

This was discussed to death on the discussions page. Here's the link:

http://www.rx8forum.com/showthread.php?threadid=361

 

need some high end...Boost!!!!:D

 

need to get rid of that sig:D

 

I posted this at AutomotiveForums.com:

Hey guys, I hope you realize torque doesn't mean too much.. at least not from where I'm standing. Look at the Honda S2000. Does 0-60 in 5.3 seconds, with a weight of 2810 lbs. The torque is 153lb/ft@7500, with a horsepower rating of 240.

The RX-8 has a weight of 2970lbs (probably Mazda is trying to trim some more, last I heard). The torque is at 162lb/ft@7500, horsepower rating of 250.

With only about 170lbs of difference in the cars, but greater torque on the RX-8, I wouldn't be suprised to see the RX-8 make its way into the mid 5s for a 0-60, keeping up with the Nissan Z.

The Z is nice for a lot of people, personally I love the interior of it, the seats and all. But the exterior still looks like a retarded Audi TT, and there is no back seat, and little trunk space. That's what makes the RX-8 an easy choice for me. That, and I feel it will be a more agile and tossable car than the Z, because of its special LSD, and 50:50 weight distribution.

Of course, time will tell in this area. But let's not rule out the RX-8 as a non-contender to the Z.. I think the Z will get a run for its money yet.

 

thats the second time i've read that on this forum. what's "special" about the limslipdif?

 

Dunno. But people that sound like they know what they are talking about mentioned it, so I figured I would as well

I know there is something special about it, I hope somebody can clear it up for us.

 

i'll try to take care of this one, fellas!

okay, there are 3 main types of differentials.... open, posi, and limited slip....

in an open differential, both left and right wheels have the ability to turn, but when one wheel starts spinning, the other wheel starts spinning and the first one stops. this is most common because they're cheap, and still effective for the normal driver.

in a posi differential, both wheels spin at the exact same speed at the exact same time. therefore, more power to the groudn than with an open differential. the problem is when you take turns and accelerate.... because the inside wheel is still spinning at the same speed as the outside wheel, but has less distance to travel before it's in a straight line again. good for drag racing, but will burn your tire off faster than you can say drag slick.

in a limited slip differential, both wheel turn, but each turns at the speed it needs to connect to the ground, basically it's like a posi dif because power is transferring through both wheels, however it's better because if one wheel needs to slow down or speed up, it can. this way, during a high speed or high degree turn, you can transfer the power needed to the ground without killing your transmission, tires, clutch, etc etc etc....

the limited slip is by far the most expensive to produce. a limited slip dif is made for most autos on the road today, and range anywhere from $500 to $2000 for the complete differential set.

(BTW: if any of you think i got this wrong or this is not the answer you're looking for, please correct me so i dont sound like a moron next time i try to explain this to someone.)

 

I dunno about you guys, but my 325i has ~170 lbs/ft of torque. I find that plenty fine for driving in my car which I'd estimate is around 3400 lbs with all my other options attached. While it doesn't have a really strong pull, it still has enough grunt to make your eyes pop it you floor it. You're not going to mistake it for an econo engine.

A 2900 lb. car with just 10 lbs/ft less torque and a hell of a lot more HP is going to feel and be much faster. Maybe it's just be, but I woudn't worry too much about having too little torque.

 

you got it right renesis rex. but what i'm asking about is the "special" lsd that people have mentioned for the rx-8.
what makes this one "special"?

 

The concept's spec sheet shows it having a Torsen (TORque SENsing) limited slip differential, a type of LSD typically used on performance cars. The S2000 has a Torsen LSD as well, for example. There are descriptions of the various tipes of limited slip differentials available on the web

 

thanks B!

 

by the way...a posi is a limited slip. it uses clutches to distribute torque between the two axles. a locker locks up and forces both wheels to spin at the same speed....also a limited slip

 

hey zoom44, i just wanted to add on to what others have said and maybe explain why a LSD would be considered "special" as compared to the other types of differentials. as stated earlier in this thread, open differentials really only transfer power to one tire. this is why they are sometimes called "one leggers" because when one peels out in a car with an open differential, usually only 1 tire breaks loose and leaves a tread mark. with an open diff., the tire that spins most easily is ironically the tire that gets the most power transfered to it (easier to get stuck in the mud, etc).

thus, if a person wanted to have more performance out of his car, he really wants his tires to stick to the ground as much as possible that way his car actually goes somewhere when he punches the gas instead of breaking loose and screaching. or, if he is just looking to burn up his tires, then at least he will want to burn both tires equally since it's somehow more stylish that way. im off topic. performance-wise, an LSD is "special" because it allows the best acceleration out of any other of the mentioned differentials (then there was jaguar who had a silicon based lock up mechanism that was supposedly pretty cool too, but thats a whole nother kettle o' fish). and when i say "acceleration" im refering to the deffinition we got in physics class, meaning change of velocity (speed AND/OR direction). thus, a LSD would not only be optimal for straight-line acceleration (only change in speed, but not direction), but it would also be great for corners because it allows some slip on the inside tire so that it will turn more slowly as needed. you will possibly still hear a chirp when making corners with a LSD, but its not as bad as a posi.

if im wrong on this, someone feel free to correct me.
ham'n'cheese

 

hey everybody, i just want you to thank you for the info. but really, i already knew what the different types of diffs were,what they were for and how they operated. i even knew how a Torsen lsd functioned and had read up on viscuos(SP.?) lsd's like the jaguar one mentioned above. i was really just asking for clarification on the use of the word "special" to describe the differential being used in the rx8. sorry, i should have been more clear with my question in the first place i could have saved yall some typing

 

Its enough torque for me considering that it still has more than any ricer. To me as long as its more torque than a civic.:D

 

The gearing and the shape of the torque curve is also very important. Peak torque numbers are nice but cars with "low" torque like the S2000 and the Prelude have nice flat torque curves that do not slope down dramatically in the upper ranges of the rpms. With rotary engines how does a "usual" torque curve look? Is it flat or does it peak and fall off? If the curve is flat then the car "pulls" nicely in every gear..

 

Hi quick_lude,

Below is something I previously posted. The rotary is known to have a very flat torque curve.

"The s2000 has a range of approx 2750 rpm (5750 - 8500) of 90% peak torque or greater. The vtec's first peak in the torque curve does not hit the 90% mark and the torque actually drops before slowly rising again at 4500 rpm again. This is why the s2000 has had a reputation of being "peaky".

Actually, the most amazing thing about what we have seen come out about the renesis is that it will have "90 percent of peak torque available at 3250 rpm". Assuming that the torque curve doesn't go up and down like the vtec s2000 one, this would mean that there will be 5500 rpms of 90% or greater torque in the Rx-8's powerband!!!! "

Brgds, Brian

 

Sounds good to me.. :D Yeah, I know about the VTEC curve.. but for us VTEC Honda guys we have the A'pexi VTEC controller which allows us to tune a/f ratio and adjust VTEC crossover points. To make the long story short my car does not have the big "dip" before VTEC engages, it's smooth and linear.
If the RX-8's torque curve is nice and flat all the way to redline this car should be very fun to drive. I like how my engine revs/pulls all the way to its 7.5k redline, revving to 9K rpms sounds even better! :D

 

The new RX8 is about the most exciting thing to come out of Japan in a while. Looks . . . great. Interior . . . one of the best. Horsepower . . . very good. Torque . . . good. Could and should be great though. To add more torque Mazda could consider offering a 3 rotor super high performance car to compete with the BMW M3 at a lower cost. The 3 rotor wankel has already seen production in the Eunos Cosmo in Japan, whose performance eclipsed the competion from BMW and Mercedes.

This is a viable option and I for one would be willing to pay an additional $10,000.00 for it. Keep the 6 speed manual, no semi automatics please.

A 3 rotor engine should produce around 250 foot pounds of torque, and power should be around 380 HP. Fuel consumption could be kept reasonable with a tall final drive or even an electronic overdrive. My dream car.

MAZDA, ARE YOU LISTENING.

 

The torque curve posted the other day shows just this sort of flat behavior - 110 lb-ft of torque at 1000 RPM, quick rise to 147 lb-ft of torque at 3500 RPM, rises gradually to 162 lb-ft of torque at 7500RPM, and then drops back to 143 lb-ft NM of torque at 9000 RPM. There's a slight dip in torque from 5500 to 6000 RPM (very slight - about 2 lb-ft), but that's all.

 

im getting ready to go into the Ohio State Highway Patrol, and so i have done some pretty extensive research on the perks f the job... including the infamous Ford Police Interceptor.

The Ford Police Interceptor is the engine put in Interceptor Crown Victoria's. This engine has an upgraded alternator, a second battery, high flow fuel pump, reprogrammed ECM chip, and the magic K&N air filter. All these upgrades give it 300 horsepower and 300 foot-pounds of torque. However, the most interesting thing is the distribution of the horsepower and torque. The car makes it's peak horsepower and peak torque at nearly the same RPM (5100 and 4900 respectively). This was designed so that the interceptor, when punched from a dead stop, will supply sufficient power to give one hell of a jump without letting the tires slip. FHM magazine did a story on the NYPD interceptor, and they say it's sufficient power to get the cruiser going while the "bad guys are spinning their tires"....

with this in mind, i think i'd like to see MORE torque in general, not more low end torque. it's all that low end torque that will spin those tires... high end torque, IMO, is better.

any input?

 

You can never have "enough" torque.. down low or up high.. What you want is the highest torque possible with the curve staying flat and not dropping off at high rpms. This way the engine will keep making hp all the way to redline.

 

If your taking FHM as a credible source for anything other than which food your girlfriend would prefer in bed or how to dress like a fairy than you should cancel your subscription. Their is no chance that the RENESIS will deliver too much torque. It would be nice for it to be there when you want it but if the tires do light up lift your foot its a very simple solution. As far as the interceptor goes lets countdown the top five reasons it doesn't have its own forum with people eagerly waiting just to see one (personally I hate seeing any of them how about you?).

5. Weighs about 4400 lbs
4. Solid rear axle with leaf spring suspension
3. 60/40 refers to the bench seat and the weight distribution
2. It really is a ford
and the number one reason you don't want a police interceptor is...
1. If there is ***** in the back seat odds are you're still in the front seat.

 

Actually, Mazda may very well be working on more torque as we speak. Who knows what the end engine will look like as far as power goes??