I think that I have figured out the low end problem. Here is the pulley setup that I am running. I have an 8.75" lower which should be a 4lb. The top pulley is a 3.5" KB pulley. So If I am correct I should have around 11.5-12.5 PSI at redline, this would be less than I had with the Eaton. I was running 14 on my Eaton. So that would explain why my top end HP was way higher, but my low end torque felt VERY WEAK. I am going to a 8lb lower and keeping the 3.5" upper. My thinking is this, this should net me ~ 16-17 PSI, am I correct? I will have it retuned, will I need the following

** Upgraded Injectors **
** MAF extender **

Thanks for all of the help, I love my L!!!

 

 

I up graded to 60 lb injectors ,SCT 2400 MAF,255 Fuel pumps ,better safe than sorry right.

And im running the 4 lb lower and a 3 1/4 upper 14 -15 pounds boost is what kennebell told me we will should see so next week when we get everything done,and dyno tune will tell all.
Bob

 

To be safe, you will need injectors, MAF, and pumps. I have a 6# lower with a 3.25 upper it makes 15#'s.

 

Please remember that heads, cams and exhaust also effect boost, not just pulleys. A better flowing engine will actually cause your boost to go down, while airflow will remain the same or improve.

 

What size is the stock KB upper?? Is it 3.5??

 

Here is the dyno sheet, note where the peak HP RPM is ~5900. Boost would hit 13-14 at this level. I am going in tomorrow for a 8lb lower and a new tune...

 

What was your setup on 1/24? Your torque and HP take nosedives after 4.4k on that pull.

 

It was the eaton with a 4lb lower

 

What year is your L? I have a JLP 8# pulley in the garage $100. My brother lives in Mesa and hes coming down this weekend.

 

Are the only changes b/w the 1/24 dyno runs and the recent ones ... the KB blower? If so, this REALLY shows a great comparison between them. Yes, at 14psi the Eaton keeps up til ~4200rpm then "bye-bye" the KB outshines it in a big way, even with a little less peak boost.

Impressive!

But this should tell you that your "butt meter" isn't lying. You felt it was a little sluggish down low and you were right.

However, if you'd raced the truck even with only 12-13psi from the KB it would have smoked the times you ran with the 14psi Eaton setup.

Good luck with it!

 

Looks like you have the car itch like me. I have had several Z06's all S/C .etc and Vipers. etc. Yes it does show how mutch better the KB is, and I cannot wait until I pick it up tonight, I am having a 8lb lower put on...... TICK...TICK..... NO BOOM...... I HOPE!!