what? a 64mm S300 charger should be fully lit in the 1600-1800 range.

 

ah ok all these fancy names for turbos are getting a bit excessive ... so 300ish RWHP

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really depends on the turbine choice

 

my 71's going in the 1500ish range his was a 74 its not gonna be that much slower.

 

its at full tilt at 1500 or starting to build boost by 1500?

My old silver bullet could only make 10psi at 1800 but was at full song by 2000-2200 and that was with the 74 turbine 14cm housing

 

starting to really get going by then ide say full lit my 1800 in the right situations. SS13cm

 

Yeah I had a 64/74/14 I think. It wouldn't start spooling till 2000 and then it would set you back in the set by 2200 or so.

 

I got a similar question, any comments would be appreciated! I haven't got a chance to dyno mine yet but would like to get an opinion on how much u think I'm putting down. Got a 98 12v with a 0 plate all the way back. 191 delivery valves, 370 marine injectors, marine pistons, marine cam, 4 inch turbo back, dodgezilla turbo, pushes about 48 psi, and head studs. Any suggestions? Thanks.
Originally Posted by jkidd:
your boost is an indication of extreme drive pressure. You will probably gain 20-30 hp alone by letting the front 3 cylinders wastegate at 32-35psi. Unless you have modified the divided in the turbine housing the rear 3 cylinders will not gate.

your back pressure must be like 2:1 compared to boost.

Suggestions:

1) get a bigger turbo with at least a 68mm turbine. Prices start about $1300

2) if you can't/won't spend money on a turbo upgrade lower boost to 32-35psi, remove the turbo and drill or cut the divider to allow the exhaust to wastegate all 6 cylinders.
--- you might as well have a 2" exhaust as your system is NOT free flowing with that much restriction in your turbo.

Im not really into buying a turbo as of right now, probably more likely in the future. But this whole drive pressure to boost pressure has kind of got me on edge now because i don't wanna screw anything up. So from what I have gathered is to fix this problem i should pull the turbo off and cut the divider out in the manifold that separates the front and back 3 cylinders? Btw forgot to add i have 4k governer springs and 75 ILB valve springs

 

higher rpm will increase drive pressure as you have more air trying to escape the engine.

drive pressures above 1.2:10 bost will start to kill HP. So many people are leaving 20, 30 50hp or more on the table because they refuse to wastegate properly or choose too small of a turbine housing and wheel. A wastegated housing on a s300 can add 25% more flow making a 14cm flow like a 17cm while open.

 

don't cut the divider out your best option is to drill through the divider. Remove the plate that covers the wastegate, take the clip holding the gate flap off, drill the same size hole through the divider as the origonal hole, than enlarge the OEM gate hole. If memory serves me right max you want to go is about 7/8" I think the stock hole is about 3/4".

 

Ok that definitely makes sense Jkidd an sounds like i might be one of the guys.. So now from what I understand you don't have to take the turbo off? Just take off the wastgate cover and you can drill a 3/4 to 7/8 through the divider from there? Btw how does a guy go about adjusting the waste gate? Don't know as much about this stuff as I'd like to.. Thanks for helping me out here! Much appreciated!