I am wondering what kind of performance difference can be seen by raising the boost by about 3 pounds? I have the ATI 9# pulley on there now, and would like to know what to expect if it is replaced with the 12# pulley. Would 10 different motors see different numbers depending on how they are set up? Who has done this, and what difference did it make to your truck? How much torque and horsepower did you gain. Any help will be appreciated.

 

You don't give all the specifics of you're set up but depending on inter-cooling and original HP#s, fuel octane availability, etc. you should see an increase of 30 to 40 HP

 

Is there an average horsepower gain for each pound of boost added, or does it differ upon setup?

 

I think I read somewere that it's somewere around 10 to 13 HP per #

Phil

 

Is that gain at the rear wheels?

 

Yes, figuring 10 rwhp gain per pound of boost increse is acceptable.

 

I forgot to ask after it was installed, could a tuner like Mike get more than 10 horsepower per pound of boost out of it? BTW aren't most of the 12# pulley's costing 300 bucks or more? Not sure if I would notice the difference except in my wallet.

 

One word, TORQUE! The biggest difference you will notice going to the 12lb pulley is an increase in lowend power, and it is worth the upgrade.

 

If that's the case, I can sure use as much low end torque as I can get. Now, how much would you say it could add compered to the 9#er? Remember Mike is going to be tuning this truck at his shop.

 

It is not so much the amount added, but that the torque curve ramps up lower in the RPM range, you get into boost sooner, and thus into the power. With my 12lb pulley I see well over 400ftlbs at the rear wheels, and I have 90% of that by 3500rpm

 

Are you changing the upper or lower pulley?

If you change the lower, the idler pulleys spin a bit faster and may wear out bearings quicker.

Changing the upper won't do this, but you may get a bit more belt slip at higher revs.

Note: I haven't done this upgrade, this is just what I've read from others. I put Mad's intake on and got an extra 1.5 psi from this...something to consider, though the gains will be about half of what you'd see with a 3psi pulley swap.
(I'm a math genius )

 

Not sure what pulley would be changed, cause Mike Troyer would be doing the install. As far as I know, he will install 9# first to see how much power it makes. If he doesn't see the numbers he expects to see, then he said he might try the 12# pulley. If it is going to put more torque to the ground at lower rpm's, then I expect he will use it. I guess it would be worth the extra money for that.