blown 944

Part 1 complete

I removed the crossover and welded in a divider to close off 1/2 of the hotside.

I just got back from driving it. The results in 3rd gear are 5 psi @ 2200 10 psi @ 2500 and 15 psi @2700 little sooner in 4th and a lot sooner in 5th. This is with the NA head and there is a definate difference in spoolup compared to the turbo liner head so it should come down even more. I am betting it will hit 15 psi @ 2500.

I tried to run higher boost and found the crossover pressure was getting pretty high.

I turned the boost way down to 14 psi and launched it and it gets going damn quick just didn't pull as hard.

I also realized why I get pretty good mileage. When cruising with the full hotside I never get into boost much on the highway. Now with the smaller hotside I am in boost almost all the time, pretty much every time I touch the throttle to even slightly accelerate I am @ 5psi in 5th even below 2000 rpm.

Tomorrow I will try to fab up the WG bypass and set it for spring pressure of 7psi. I hope it works good, I really can't see why it won't

I am very happy, now I have quick spool and will have top end too ..

.remember this is a Holset h1E 600 hp turbo

spoolin51

Dude that is awesome.
Post some pics for us

gt37vgt

i wonder about using a waste gate as the valve to bring on the second scroll.
A big one with big can set at 7psi or even less so it stays open insted of occilating .

gt37vgt

i wonder about using a waste gate as the valve to bring on the second scroll.
A big one with big can set at 7psi or even less so it stays open insted of occilating .

blown 944

Will do W

Adam, that is the plan. I have a knockoff 46mm unit that I will be using, decent unit with stainless valve inconel housing and nomex diaphram.

I think that if I run it at low pressure opening the the turbo will still spool pretty quick.

Ultimately if all works out, I will use a 10psi hobbs switch and a nitrous solenoid with a heavy spring.

gt37vgt

i would think a inlinre check / relif / boosthancer with slow bleed of have the waste gate set to 4 psi and the check to 8 so it will not open til 8 but as long as you have 8 it will stay open if tuned by sprin alone it will creep but yeh solinoid and hose is the same thing but there needs to be a small leak so it bleeds down as it wont cleed back down through the check

TRP951

Just one thing was bothering me while thinking about it. Spooling a larger turbo earlier might put you into the surge line on the compressor.

blown 944

so far I can't hear anything and it is spooling as fast as it will, ever.

hally

So restricting the hotside inlet size increases velocity or something along those lines, is that the jist of it?
another great thread!

gt37vgt

dang were you been Gregor ??
do you want buy or swap any of my stuff posted for sale thread earlier.

gt37vgt

dang were you been Gregor ??
do you want buy or swap any of my stuff posted for sale thread earlier.

TroyN

We are talking about this right?
http://wiki.answers.com/Q/How_does_a...bocharger_work

blown 944

no that was my last project. This thread.

I haven't had a chance to use the dual crossover yet b/c of fitment issues. It will still be done. Just will have to be on my other car.

As far as the blocking and bypassing (this thread) I ran apon an issue with the WG fitment and had to put on hold until over this weekend

blown 944

Thanks
yea just like using a very small hotside for lower boost levels and a large unit for higher boost.

I am doing it with an external WG rather than the item you posted

333pg333

I think the concept of velocity increasing due to restriction is a bit warped, however I'm prepared to believe it. I think at this level it's a very inexact science, but the proof is in the spooling if you don't mind I'd say it's possible to measure the effects, not the causes in this example.
Nice going Sid. Keep 'em coming.