The time has come...I'll be getting the trans built soon, and the only reason I can think of NOT to get more boost would be......well, traction

I'm looking at either the 3.25 or 3.10 pulley, does anyone have any dyno or track times with these vs. the 3.4? Or basically the SOTP feel after the swap from the "stock" 3.4? Allen was saying that the "15-20hp increase" from each 1psi that people talk about is a bit exaggerated.....and I'd like at least 20hp if I'm going through the trouble of swapping/tuning (might even go to san antonio to dyno tune).

What was the formula for blower RPM again?

 

7.5 (crank pulley size) * RPM / blower pulley size = blower rpms

I say 3.1 I got a pretty good difference al around from that one.

 

How fast can you spin the blower until you have significant dimishing returns? 3.0? What is the max magnacharger says the blower can spin?

 

I think the 3.0 is the best to go with. Thats what i had the best luck with

 

sent you a pm, talk to you soon,

allen

 

14k, but the L boys have been known to spin theres up to 18k no problem.

I'm spinning mine just over 16k. What you really need to look out for is if you're spinning the motor passed 6500 or so.

 

I'm thinking about a smaller pulley as well. At want point do we need to change belts? Stock pulley is 3.3 for me so can i keep the same belt at 3.1 or will I have slippage?

 

Your altitude is about the same as mine in Ontario and I am using a 2.9" pulley and this gives me 9.5-10lbs of boost. (Hard to tell from the little boost guage) This works very well.

 

I have an '04 Silverado SS and a Radix with a 2.9" pulley. Other engine mods are LS6 heads (long story), LPE GT2-3 Cam and JBA headers. TR6 plugs and a 160 t-stat tocool things down.

The 2.9" pulley is the smallest most people go. There are a few folks using the 2.75" but at over 6000 RPM you're starting to overspin the blower. Diminishing returns set in with extra heat and only small gains in boost.

 

I ended up going the the 3.25 pulley for now, and so far I've seen 9.2 just before the shift....my boost numbers seem slightly higher than alot of people's which may or may not be the gauge.....alot of variables (exhaust, intake etc)

Truck feels great, its about what I expected with a .15 drop in diameter - more part throttle boost as well

Track times to come - mid January