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[PhilStubbs]

I just picked up a 1990 silverado with a running 305 and a rod knock. I stuck a 270hp 4 bolt main 350 in it's place. I have plans of boosting it for towing. My goals are 400ftlbs and 300-350hp spooling about 2500. I'm thinking an hx40 will do what I want. Anyone have any experience with holsets on 350's?

[dvst8r]

Started this reply and then the internet here crashed. T4 HX40, or a T40E, anything with a T4 hotside and 55-60mm compressor should do what you are looking for.

[PhilStubbs]

thats kind of what i was thinking. all of my turbo experience is 4 cylinder so its tough to really know

[dvst8r]

Those odd turbo's that 4cyl guys get like old powerstroke turbos with a WAY to big hot side, are perfect for apps like this, and can normally be found on the cheap. You will be limited by hotside before cold side on an app like this.

[PhilStubbs]

Yea, that was my gut feeling. It's to me that at the end of the day, hp is hp and. 700hp compressor will support 700hp on any engine. My boost pressure will probably be low for what a holset wants to push, but I think it will work out.

[SiFlyBy]

Those odd turbo's that 4cyl guys get like old powerstroke turbos with a WAY to big hot side, are perfect for apps like this, and can normally be found on the cheap. You will be limited by hotside before cold side on an app like this.

Like this?:

[dvst8r]

Nope the older one, with the normal T4 exhaust flange.

[92CXyD]

Like these:
 




They end up being too small for my D project.

I almost used two of them to do a twin turbo 5.0l mustang but I got hungry and sold all three.  ;D

[HiProfile]

The idea is to size the hotsize very big to keep drive pressure very low. Low drive pressure makes more HP per psi, so you stress the pistons/rods less with lower peak cylinder pressures.

[PhilStubbs]

I'm worried about spool time with a big hotside though. I want it to pull like a diesel and be able to do it for long pulls up hills and things, so I plan to stay fairly conservative with the tune to try to keep things cool.

[turbob16hatch]

The idea is to size the hotsize very big to keep drive pressure very low. Low drive pressure makes more HP per psi, so you stress the pistons/rods less with lower peak cylinder pressures.

Ok am i missing something or how does going from running 5 psi to 15psi stress rods and pistons more? Last i checked hp was what killed engines. I understand v8's on the average require less psi based on engine flow capabilities.

so far the turbo suggestion have been coming form the big turbo or it won't work crowd. a stock 350 in no way would ever "need" a t4 footprint turbo when shooting for 350 hp. there so many other turbo to suggest other then a t4 way to big turbo.

for example he could run a hx35/wh1c/hx40 with any number of larger t3 hot sides (18/22 idk the exact sizes), a p trim anything.

to suggest t4 oem app. turbo's would mean huge turbines, unlike the aftermarket where they size the wheels are way larger per housing size. ( ie: p trim t3's)