I've seen so many HP gains, such as XERD's which gave 17hp, but only 3tq gains.. personally I rather have as much, or more torque than HP since thats what's basically "pushing" the car..

which mods are putting the best TORQUE gains out there? I dynoed 249tq (baseline is roughly 235 by what I seen), but want to kick it up another notce without doing any internal work such as cams..any suggestions?

 

Another example is ati's supercharger, i was hoping to see high tq gains, highest i seen was in the 310's, which is only a 70tq gain (even though thats a LOT) compared to over 100hp gain.

this reminds me of peter farrells IS300 which has 610hp, but 626tq, compared to SRT's 700hp IS300, but with only 500tq. I'm mainly trying to get tq mods, so any suggestions would be appericiated.

 

Crawford's Headers made 15.1 HP & 12.4 Ft-lbs of torque @ 6500 RPM.

The chart starts at 3K rpm, so there is most likely a loss of torque unde 3K rpm.

And Crawford's headers come with cats too.
XERD's headers elminates the cats.

 

I agree. Torque is far more important to me. There is nothing better than alot of low end torque.

 

greddy TT 334rwhp 339rwtq


http://www.turbomagazine.com/features/0307tur_350z/


read about it. thats over 100lbs rwtq. thats also why I am waiting on these turbo kits. Granted the ati procharger puts out more hp but turbos will have the advantage on tq

 

We made no loss of torque on the dyno.

We don't hit it on the dyno until 2000 rpm, which by 3000 rpm is when the logging begins.

What we DID get was a nice gain between 3k - 4k, then from 5500rpm up gains went up and up!

As for the XERDS making that little torque... WOW. I don't know what to say.

 

First off, let me state that I'm not flaming at all. I just have a couple of questions that maybe you could answer.

Why does the baseline dyno start at ~2300rpm, but your post dyno at ~3000. If you were going to lose torque, I suspect it would be below 3000rpm, so it seems that this is a pretty critical part of the dyno to omit. Even if you did lose bottom end, I don't think it should be a big concern since you'll only be affected by it in 1st gear, whereas you'll reap the benefit on the top end in every gear.

I think the numbers Ricky was quoting had to be peak HP and TQ gains. A 17hp gain has to be at least 13lb-ft with our rev limit, so either he's quoting peak gains or he mistyped the HP or TQ numbers for XERD.

So, if he's talking peak TQ gains, you shouldn't be suprised about a 3lb-ft gain, since you're headers didn't change the peak TQ at all.

Have you guys dyno'ed a Z with both the plenum and your headers? I'd love to see if these two mods are additive on the top end. It must absolutely scream if this is the case.

 

Correction, the procharger puts out more PEAK horsepower. We haven't compared power curves or acceleration times.

 

Ricky, the Stillen exhuast gains more torque than our Borla.

 

Also the greddy kit is only putting 5.6psi in kit form. Add boost controller to about 7,8,9psi. Damn I wish the kit was out

 

A couple comments:

Remember that HP = TQ*RPM/5250

Therefore, @ engine speeds below 5250, all mods will gain more TQ than HP. Above 5250, all mods will gain more HP than TQ. There is simply no way around this.

Also remember that the Z already has very good low end torque, but the top end drops off after 4800 RPM.

Also, most cars are tuned quite well from the factory in the mid RPM range, since that is where most people drive.

So, on the Z you will most likely see gains primarily at the top end, since that is where we have the most room for optimization. Therefore, most mods on our car will gain more HP than TQ.

The easiest way to increase low end TQ, especially on the VQ35 which already has a very high TQ for its size, is to increase the displacement. This is effectively how S/C, T/C, and N20 increase the torque.

So, if you want more torque on the Z and want to avoid FI, a stroker kit might be a very good mod. Does anyone know of something like that?

-D'oh!

 

mabe in the future when the VQ40DE comes out.

 

I would like torque too, but at the same time I want traction... I would rather have a car that is fast on the street/track running at high RPMs than one that kicks off a good 60', but only when using ET streets...

 

As far as absolute numbers are concerned that's a correct statement. But the ratio of HP gain to TQ gain is the same below or above 5250 RPM. Double TQ and you double HP.

 

HP sells cars..................
TQ wins races!

 

You know honestly, about the signal not picking up pre-3k on the run. Couldn't tell you. It really is dependant on when you "hit-it" on the dyno. Traditionally we get on throttle between 2 - 2.5k rpm. Typically 500rpm later logging will start.

Good point on the XERD headers, if he is STRICKLY talking about peak numbers. I'm impressed. Where's the dyno chart? I'd love to see 17hp gain at PEAK! The redline gains must be SICK!

Dougs car with the plenum, cats, and headers gain 40+ at redline... so yes it pulled like a mad dog up top!

 

Speaking of dyno runs I've noticed the overall trend of most everyone's charts, weather from a member or from a company touting a part, that they ususally don't start till 2.5K or 3k. Their was one instance where numbers were published below that, but ironically it was for a company selling exhaust system parts and it showed a loss of low end, enough of a loss that thier's no way on earth I'd put those parts on my car (no comment on whom).

To that end I called a dynojet shop I entend to do a dyno run at and I specifically pinned them down on them being able to give me dyno results starting at 1.5K. He said that would not be a problem that he could do that.

And another thing, in listening to the dyno shoot out mp3's. I noticed as the car's are shifted into the gear where the dyno readout is taking place. None of the cars were allowed to have their rpm's drop as to read from a level lower than 2.5k or so. That explains to me why the charts are starting so high.

 

Gcoupe35

you are not going to get a good read out on the dyno if you do a 5th gear pull at 1500rpm thats why most people do them at 2 to 2.5k. Not to metion that if you were racing you would never be at that rpm at no time(unless you mess up on a shift). I know I am going to get bashed on this statement but most of the time when you free up the exhaust (headers, exhaust, off road pipes) you will loss hp and tq at the bottem but the gains were you need it out benifits the loss on the bottem end.

 

Good point, no bashing.

I cannot think of ANYTIME in racing, when I am at this RPM.

Hell, I'm rarely there on the street daily!

 

I don't really care if I lose 20ft/lbs in normal driving rpm because it's not hard to rev the engine an extra 200-300rpm to regain that if I really need that power. Also, how often are you really at WOT below 3,000rpm? If you aren't at WOT then just give it some more gas. I am only driving 2.5L of fury right now and almost never floor it below 3,000rpm. Beyond the fact that there is just no power there in the first place, I just don't need to.