vtol28

I got into a heated discussion with a nissan 350 guy over torque and how much more he seems to think it matters. I,m wondering if any you tech guys can shead some light on this subject as I know our rotory engine does suffer from lack of torque. Give me something to shut this nissan guy up!
thank guys

zoom44

hp/weight. T times gearing etc etc. trhere are a ton of threads on here to educate yourself. find bugers posts on gearing and look at the t x gearing comparisons between the rx-8 and some torque monsters

Vizacar

Forget about torque....ask him to follow you up a mountain. That'll shut him up. :D

Sigma

Which is more important depends on what you want to do.

If you wanna get off the line fast, torque is very important. The faster that you got, the less torque matters and the more horsepower matters.

But one thing your buddy seems to be forgetting is Gearing, and also Weight. Ask your buddy this -- if torque is so important, why can an RX-8 with about half the torque run respectably against a 350Z? Or how can an RX-8, with less torque than a Honda Civic, blow the crap out of one in a straight line? Or how does a Turbo'd RX-8, doing 'just' 200ft/lbs (still a good 30% less than a 350Z) outrun a 350Z?

Obviously it's not just about torque. For that matter it's not just about horsepower either. Gearing and Weight can easily play a larger role than either of those numbers.

Your Gearing multiplies your Torque. Well, work through the gear ratios and the RX-8 has significantly better gearing. Here's the RX-8's advantage per Gear:

1st Gear -- 24.37%
2nd Gear -- 22.58%
3rd Gear -- 27.50%
4th Gear -- 17.50%
5th Gear -- 25.49%
6th Gear -- 32.77%

So, yes, the RX-8 has almost Half the Torque but it's got a 25% advantage in 1st gear, narrowing the difference. Couple that with over 200lbs less weight to pull along (not about to do the math on that effective gain) and you end up with a car with 150ft/lbs running moderately close to one doing almost 300, and why the RX-8 when pushed to 200ft/lbs will outrun the one doing almost 300.

vtol28

Thanks Zoom44 I read Bugers thread and thank you Sigma, now I,m going to go slap some info on this Nissan guy =)

CERAMICSEAL

What ever happened to Buger?

StrokerAce

horsepower = rpm x torque / 5252

priscilla ls1

Well torque is very importent. lets say u are at a red light or on a drag strip there are two cars with the same weight and Hp but car 1 has more torque then car 2, car one is going to beat it off the line and eventualy win the race. This is why domestic cars have a huge advantage, they have lots off torque to through there *** across the line faster but in a longer distance the car with the longer power band and less weight will have the win. But also there is low end torque and high end torque. I will give u 2 examples My 01' formula and an RX-8, at low rpm's such as 2500 to 4000 the formula will have the advantage because it is already at it's low end torque at the line and the RX-8 can't reach it's torque tell it is higher in the rpm range like 5200 to 7000, this is high end torque that RX-8 will have. So now u are wondering how can I beat this lower end torque car at the line, well first u need some slicks and a torque converter, then have the converter stall at a 5000 and you will beat the formula and deffinitly leave the 350Z in the dust. But this is just my $0.02.
:D

StretchSJE

This uses an S2000 versus a 350Z for the example, but you get the idea:
http://mazda6tech.com/index.php?opti...id=9&Itemid=52

When I wrote that article, I had originally used an RX-8, but unfortunately the engine and power/weight wasn't quite good enough to illustrate the point. The 350Z is indeed the more powerful car in any gear at any RPM, but it also doesn't have nearly the practicality, nimbleness, or precision. The 350Z is more of a Japanese muscle car than a sports car, in my opinion. The design is bloated and rubbish, an effect of using the huge FM shared platform designed for large vehicles such as the FX45. But enough of my opinion....

Torque isn't important at all without analyzing gearing. The numbers are meaningless without looking at the big picture. Horsepower is a little more meaningful because it incormporates engine speed into the measurement. Power to weight ratios are most meaningful, but even they are just an approximation of speed, as you still don't know the curve of the torque band.

More torque isn't necessarily better for 'off the line' performance providing the "smaller" engine has just as broad of a torque curve. The problem is, most high-revving engines aren't very strong down low, thus the torque curves are not equally broad.

Normalize two dyno charts (the torque curves) and measure the area under the curve for the RPMs you'll be at. That's the more powerful car. Don't forget to factor in weight when you're done.

zoom44

priscilla is aparrently saying i need a torque converter?

priscilla ls1

I'm not saying anything, But it could help.

Sigma

Um. No.

zoom44

priscilla i have an MT not an AT just poking at you a little

priscilla ls1

Um. yeah.

Are u saying that it would not help on your 60ft to put in a converter. Then u are wrong my friend, U see the RX-8 has plenty of HP but low tq and that hurts it at the line, With the converter it can quickly get into that power band in a sec. with no wait time.

priscilla ls1

oohh really.... I knew that :p
Well with an MT U R screwed. just get the slicks and hold it tell 7200 RPM's and pray they hook.

Sigma

The Automatic is so incredibly poorly powered it couldn't beat a Honda Civic off the line and is going to need a LOT more work than just a better torque converter to be competitive off the line. Get a turbo in there and then you can think about that.

priscilla ls1

Sigma come on u have to think out side the box, sure the A4 has like 50 hp less then the stick but it is not all about the power, put this in the mix A4 with 195 hp/260tq and a M6 with 240hp/150tq. Now think about it, which car is getting to that 60ft first?

Sigma

I've got some LS1, LS2, and LS6 experience, so I'm pretty familiar with what torque convertes can do. And a torque converter doesn't work those kind of miracles. If it did every drag racer in the world would put a TC with a 2.55:1 STR in their car and instantly go from 400tq to 1000tq. It doesn't work like that.

A high-stall SSF TC with a 2.2 STR on an LS2 shaves about 0.3 off the quarter-mile. You are absolutely, positively NOT going to take an ATX RX-8 from an 8-sec 0-60 to a 6-sec 0-60 with a torque converter. Not gonna happen.

And a good ratio'd high stall converter that the RX-8 would need would be a total bitch to drive around town. I mean, come on, you say a 5000RPM stall speed?? It would be virtually undriveable off the track and it would suck fuel like a motherf*$*&# even more than the rotary already does.

priscilla ls1

whoo buddy I never said that a tq converter can increase the number of tq I was giving a diff example of tq at the line but a car with a converter would not have an increase in tq just a better stall, such as racing stall ppl call it, sure I understand that for a daily driver this would be killer on the gas miles, But it will help at the line and I am not saying just like a 2/10 off a 1/4 I am talking about more 7/10 off your time.

Sigma

Actually that's exactly what a torque converter does -- it multiplies your torque by the STR. It does increase your torque number, by a factor of about 2.

Problem is it only works from the launch, and very quickly, practically within milliseconds, the multiplier goes back down to 1:1.

And yeah, I know the RX-8 would benefit more than an LS2-powered GTO would since it has more room to grow (easier to go from 16 to 15 than from 13 to 12). But I think you might not appreciate just how slow the ATX RX-8 is.

To beat just a MTX RX-8 off the line the ATX would have to gain 2 full seconds in 0-60 time and a bit more than that in the 1/4-mile.

A torque converter would help, yes. But without much power to start with, there's little reason to worry about shaving that 0.7s off the 1/4-mile -- anyone buying an ATX RX-8 wasn't concerned with that to begin with. What they are concerned about is driveability, both in daily driving and on autocross tracks -- and a high-stall TC would absolutely suck for both of those applications. LS' get really boggy with TCs even on cars with 300+tq; a high-stall on an RX-8 would probably damn near stall because it's so lacking in torque. TCs are great for off-the-line power, but they are a hinderance everywhere else, especially on an autocross track.

zoom44

somebody get me the gearing 1-4 and final for his f body so we can compare just for kicks. i catn find it with google

therm8

4L60E

1st: 3.06
2nd: 1.75
3rd: 1.00
4th: 0.70

Final drive: ~2.73 or ~3.24 depending on options, and I think there was a higher option as well.

0-60 in high 4's to 5.1 depending on tires, with a curb weight (in auto trim) around 3300-3400lbs (2002 LS1)

priscilla ls1

ok. come on we are getting way off topic. I thought we were comparing Tq to this guy's RX-8 to some dudes Z, why are you bringing in A f-body?
Let's stay in the same car's or it is just a waste of time.

Yeah I agree, A high stall TC on an RX-8 would not be good for anything but the 1/4. I mean can u imagin A stall at 5700 rpm U would have to rev it that high so u don't stall everytime u come to a stop I mean everyone would think u'd want to race them. But yeah I understand where u are coming from on this.
I just thought my input would help. :o

Sigma

Well I dunno if it "helped" (not that my input did either) but it certainly didn't hurt.

It's a discussion forum. We have discussion. And it was a good one. No reason to use the :o face

priscilla ls1

Yeah I did not think we helped at all, but it was interesting for ppl to read and maybe someone out there learned somthing



but yeah we need more Smilies. It would help as I go through about a million emotions a day.