Mike, W/ a 6.66 and a 2.75" you are seeing 13-14 psi w/ an AFR headed 383 ci.....I wonder why I am only seeing 11-12 psi w/ the exact same pulley combo on a stock headed 355 ci....I am running the cc 224/236. W/ my S-Trim and a 2.75" pulley I only saw around 9 psi. I have a 7" waiting to go on once I hit the dyno, I just think its a little weird that I am not seeing anymore boost than I am.
Thanks
Scott

 

Probably S-trim vs T-trim difference.. there are 200CFM difference between them

 

Thats what I have is a t-trim now...I sold my s-trim and bought a t-trim and with that pulley combo I am only making 11-12 psi...w/ my s-trim i saw around 9....Doesnt this sound a little low to you guys?
Scott

 

Intake restriction? I saw a 2-3psi gain with the S-trim from replacing the "dryer hose" with a solid pipe. With the F1, running it without any intake piping gains 4-5psi.

Rich Krause

 

I do have a hard intake pipe, as well as a fully ported and bored MAF.

Something else to consider is that the Vortech bypass valve leaks over 10 psi. I replaced mine with a used Eclipse 2G unit, which is good to 15 psi.

Mike

 

Which bypass? the mondo? or the plastic one?

 

The plastic junk.

Not all of them leak, but INTMD8 picked up ~45 rwhp with his S-trim by replacing the Vortech bypass valve.

On the other hand, LJ has run 9.90 at 139 mph with the plastic Vortech bypass valve. . .

Mike

 

I think I will try both of those but first replace the bypass valve.....Do you recommend the mondo or the eclipse unit.
Scott

 

Eclipse 2G valve: $20 used (The DSM guys upgrade to the 1G valve because it will hold 20 psi).

Mondo: $240

You decide. . .

The Eclipse valve also has hose conections and is roughly the same size and shape as the Vortech so it can be adapted easily.

Mike

 

Mike, so there is not alot of fabrication to be done w/ the eclipse unit?
Scott

 

The Eclipse unit is very similar to the Vortech, but all hose connections (inlet, outlet, and vacuum) are all one size larger, so you have to play with different size hoses to make it fit.

Mike

 

You can make 20 psi thru a stock LT1 if you make the overall combo as inefficient as possible.

Realistically, if it's all about the boost numbers, I'd try to run new valve springs, straight 104 u/l, and pulley it for 15psi. I'm think you'd make about 550-600rwhp for about a summer.