I have a 02' LS6 Stage III head and cam + LT headers and I still only make 10% more torque than a stock car? Stock 02' LS6 should be in the 345- 350 RWT and I am only at 375 RWT. Why is it that the push rod mustang motors (5.0) can make tons of torque and the LS-x blocks are kinda wimpy of the torque side (without Nitrous)?

 

Looking at your combo I am missing something. Your setup puts down 415rwhp and 377 rwtq which in my book is way low. Most H & C cars put down 420+ and 390+ respectively. I noticed that you dont have your cam specs listed within your sig. Are you still running the stock cam(LS6)? If so that's your problem.
Phillip

 

I am by no means an expert at any of this but I agree with Phil in that the answer to your question is probably the CAM.

I believe to get big RWTQ numbers one has to go to a more radical/aggressive cam. The more aggressive you get with the cam the more you probably lose street drivability of the car.

With the proper tuning some of these extremes can be pared down.

BTW I am not sure a stock LS1 puts down 350 RWTQ while only putting down 298 RWHP for a MN6. I would like someone to chime in on what a stock LS1 RWHP/RWTQ numbers are and also what a 2002 LS6 block would put out.

Chuck


[Modified by chucschramm, 12:59 PM 10/3/2002]

 

My stock LS6 put down 358.1 hp and 348.1 lbs/ft.


[Modified by Argetni, 6:53 PM 10/3/2002]

 

Well, it is because that is the way engines are. You can get about 1 ft /lb + of rwtq per cubic inch of displacement max. So an LS1 can get about 400+ rwtq tops.
Torque is how hard the engine presses on the crank. Horsepower is how much "work" the engine can do. If you increase the rpm's the engine can do more work, even though the torque stays the same or even goes down. This is saying the engine does the same torque, but produces it faster.
So all we really do when we mod our engines is that we make them do more "work", by making the same torque faster.
This is because the rpm's go up, always, to get more horsepower, if the cubes stay the same.
If you want more torque you must increase the cubic inches, or you must supercharge, which artifically increases the cubic inches.
Torque is the pressure you feel when you break loose a lugnut on a wheel lug. Horsepower is the power it would take to keep turning that lug at that ft/lbs continuously.
This is why it is so hard to increase torque, it is built into the cubes of the engine in question.

 

GREAT info and simplified explanation regarding torque and horsepower! :cheers:

Nitrovette

 

If you are using factory specs for the LS1 Vette motor, the specs are based on the flywheel HP & TQ. You can figure roughly 15% loss to the rear wheels. Typical stock 405hp Z06 put down about 347hp at the rear wheels. I don't remember the TQ figure, figure ~15% less then the sales lit..

With nothing but the mods in my sig, my LS1 is putting down 337RRHP & 347lb/ft. That would give me ~ 395hp and 40?TQ at the flywheel. Stock or factory specs were 345hp 350TQ.

Why you're not getting the numbers you think you shoud, check some of the other responses, hopefully they'll know more about it then I do. I don't have any experience with the level of mods you've added. Have you improved the intake and exhaust along with the H/C mods. With out improving the air flow in and getting rid of the exhaust, you're doing your H/C work a dis-service. You've got to be able to feed A/F to the mods and let them get rid of the exhaust.

You're on the right track, keep after it. :cheers:

 

My engine is brand new, only 1600 on the ticker. My cam is a 'competition cams'. I used to have the specs on it, but I lost the paper. It is supposed to be a pretty aggressive cam. It lopes like no ones business, and screams about 3500. I will post cam specs or if Bill or Nate from Xtreme can chime in. Xtreme did the work.

I can also say that of the dyno's I have been to, Xtremes puts out the most accurate numbers IMO. Other dynos are not calibrated for altitude which can give higher numbers.

 

I do not have the cam specs... but I bet Mike knows them... give us a call tomorrow :)

 

vararam/not learned in, with B&B exhaust with x pipe
01 auto coupe
past saturday at Colvins in Austin,Tx
Chassis Dyno 299rwhp & 320 tq :rolleyes:

 

My two numbers have always been similar: stock 298 rwhp, 301 rwtq; now about 317 on both.

 

Check my sig. for hp/tq no.s

 

HP is about breathing and revs.

TQ is about displacement and compression. Since you didn't change the displacement, and maybe only the smallest tweek to the compression, it is not surprising that the TQ only increased by a small smount.

Incidentally, in order to get the high HP in stage III heads, the intake and exhaust ports have been massaged. This increases breathing in the high end of the rev range, but often hurts in the low end of the rev range as the ports are not flowing with enough velocity until later in the rev range. A big cam may hurt TQ in the lower end of the rev range also.

 

If you have such high flowing heads, you will lose quite a bit of torque potential. My 346 C.I. engine produces 435 ft/lbs of torque while making 448 RWHP. I made sure my heads weren't too big for the cubic inches. Usually the stage 3 heads are good for stroker engines. They can adequately use the extra airflow.

 

Here are my cam specs

Stage II Katech
Intake
581 lift - 223 duration
Exhaust
588 lift - 227 duration
114 degree lobe separation

 

Some thoughts...

First, the Mustangs use incredibly long runner intakes which help to overfill the cylinders at lower rpms, giving them higher than you'd expect torque numbers.

Second, I've always found the water wheel story useful in helping me to understand the relationship between torque and hp:

The Case For Torque

From a driver's perspective, torque 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*.

You don't believe all this?

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.

(12 x 2,600) / 5250 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.

The article is fairly long and I pnly posted part of it, for the rest you can go to...
http://vettenet.org/torquehp.html

Written by: rba@augenstein.ultranet.com

 

TTT