Engine/Transmission (1994 - 1998) Boost ?

[pete97]

What should my boost reading be for my truck with the mods that I have? The #10 plate is in the stock position and the AFC is slid all the way forward.

 

[PRattenbury]

15-20 pounds max, 4 or so just cruising at highway speed.

 

[Dieseldemon]

The rule of thumb is 1 psi of boost = 10 HP

 

[bmoeller]

The rule of thumb is 1 psi of boost = 10 HP

Well, at least it works on a stock truck. The 10 plate was my first fuel mod as well. With the adjustable boost elbow, and not altering it from stock, I could peg the 30# gauge I had. Have no idea how high it really got. Have a 60# gauge now.



Stock, you should see 18 or so. With the elbow adjusted properly and the 10 plate, I think 25# would be plenty to keep the EGTs in check.



Cruising on the flat, 7-10# is what I saw with the stock turbo. 12# at 70+ and 4. 10 gears.

 

[NHays]

20-25psi Max, I could peg a 30lb gauge with the plate forward. cruising I saw 5-7psi at 70 mph, with surges to 12psi up hills empty. the stock wastegate should open around 25psi. I put a 60lb gauge on before i did some other mods and lost my turbo. The max i got was 37psi with 100 plate all the way forward with the stocker. With my Super-B i see 43psi max and i tow alot. don't see anything above 1300*F, even if I try to. The stock HX35 is efficient below 30 psi, anything above that and you get really hot air. However, ALL of this is with a standard not an auto.

 

[tp0d]

Pete:



Your wastegate is relieving all your exhaust pressure. Get a set of small vicegrips and clamp em on the rubber (not ss braid) hose on your turbo. That will block the wastegate bellows, if it isnt already stuck open. You can safely run 30-35psi thru your stock HX35 turbo. (the vicegrips is only a temp fix though, and over 35psi is bad)



-j

 

[KingS]

I agree with that. I could push 30 and sometimes tap 32psi with the stock plate slid full foward afc full forward. and I did do that used visegrips to pinch off wastegate line. these number though were with a afe stage 1 which help with the 5 to 7 psi hire the the 25 psi that you would get with stock air filter.



And with my #5 plate I had 40 42 psi everytime I stepped down on the pedal and I only ran 2 psi or so at 70 80 cruisen. My stock turbo gave out after four times of 55 psi before I took out the fins and bearing with my setup now.

 

[pete97]

I usually run no higher than 20-25 now. I was just checking. If the wastegate was stuck open, what would that do to performance? If it is stuck open, can it be fixed?

 

[tp0d]

If the WG was stuck open, it would allow your turbine drive pressure to bypass around the 'hot' side of the turbo, and not generate much pressure. If you dont have black smoke right off idle with min foot pressure, it isnt stuck. Yes it can be fixed. . I`d say yours isnt stuck tho.

 

[pete97]

I guess it isn't stuck open then because I only have smoke if I really get on it which is still not too much smoke. If I lug it with the TC locked up it will smoke much more.