Yep, if you run too much boost for your turbos (beyond peak efficiency), they fall off the table at high RPM, so your torque will be higher than HP.

If you see a Z32 with higher Torque than HP, he is most likely running too much boost.

 

Wouldn't both hp & tq fall off at that point? The VG30DE is a well balance hp & tq motor but its not designed to be a torque monster. On our engine I think its safe to say you can't have one without the other.

 

At that point, the torque is made at lower RPM, but the turbos hit the limit of the amount of air they can push, thus, higher end torque (and therefore HP) is lower.

Remember, HP is essentially a measure of high RPM torque, when you push the turbos too hard, they can't maintain pressure at high RPM (can't push enough air), thus lowering high end torque (though you are normal until then), which makes the HP number lower.

 

Throw in a 383?

I know a couple of Stage V guys running 15lbs. (or was it 16? I'm just an NA guy, don't hurt me) on stock turbos making ~ 375TQ and 335HP. 15/16lbs is very do-able.

 

16 lb is too much for the stock turbos, they go beyond their efficiency plateau. Its doable, but you cease to see the same positive gain. I believe you will see the stock turbos start to fall on their face ~14 psi, if I remember/read the charts right.

 

16 is fine. 17 is fine 18 plateau. I'll take you for a ride some time and show you. But from 16 on the gains become less and less until you hit 18 and you can feel a real difference. There is nothing left. That's what my butt dyno tells me anyway.

 

uh oh lol. this site has seen this convo many times lmao.

 

Z1 ZONLY Wrote:
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> Throw in a 383?

Translation: increase the stroke of the motor. Longer stroke will mean much more torque, but will lower the RPM redline and HP numbers. Thats actually the difference between the RB26 and the 2jz. The RB has a shorter stroke, so it revs to 9k and the 2jz has a longer stroke, thus the higher torque numbers where the RB has much lower torque.

If you didnt want to increase the stroke of the VG to increase torque, you could increase the compression ratio. The difference in low RPM torque between the NA and TT is astounding. NAs are so torquey.

"So if the NA has a 10.5:1 CR and the TT has the 8.5:1, shouldnt a 9.5:1 ratio offer the best of both worlds?"

It should. But why bother? The factory TT setup (bore and stroke+ compression) is almost dead on. The torque numbers are good, great actually, but its a sportscar. It is made to move not for payload. HP is measured in time and distance traveled, while torque is the actual strength of the motor.

If you owned a fastfood burger joint, which would you want working for you...the kid that can flip burgers with major speed or some kid that has been baling hay for 2 years?

 

Nitrous can give you all the torque you want.

 

Change your rear end out for an NA. The lower gearing will give you more torque at the wheels.

 

"Nitrous"? Makes me laugh out loud! For those who don't know how to build motors, use it.

 

Actually, one big thing you could do: change the intake hosing.

When Nissan designed the intake system, they designed them to get max torque at a specific point, which is why we have 9 feet of intake hose! I believe if you make them longer, it will lower the max-torque along the RPM range, which would lower the HP.

 

JT240Z Wrote:
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> Change your rear end out for an NA. The lower
> gearing will give you more torque at the wheels.

He already has the R200.


My suggestion would be for him to think more about being a sportscar instead of a pickup truck. Torque should take a 2nd place to HP.