CTD2001

i have a holset Hx super 40 on my truck right now, with the comp box on 5x5, and the other mods that i have done, i can only get my boost presure up to about 28 psi, which to me seems low, the turbo is wastegated at 40 psi, i have a 35lb boost gauge and i cant even peg the needle, I though that i would be able to get the boost numbers up there well above 28psi. Do these boost numbers sound right to anyone?
Does anyone with an aftermarket turbo able to reach the psi that it is wastegated for? The turbo also has an 16cm exhaust housing, would this make a difference if it was a smaller size? I am hoping that i do not have a leek somewhere. I have checked all of the intercooler boots and they seem to be on and tight. Any help that you can give me would be great. Thanks for you time and help

SmokinFive9 4x4

That's a pretty big turbo for just a box isn't it? Not an expert by any means, but I have a 16cm hx40 with 370's, pump work, and the plate way forward and get around 40psi. I'm not real up to par with the VP44 trucks though so don't know if just a box would put out that much fuel or not. But check for leaks definately, had a boot split once that I couldn't hear(at least when the truck was sitting still) and couldn't see b/c it was on the bottom, , and how sure are you that the wastegate isn't opening at 28psi?

Oh and if you want, I'll give you a 35, that'll make alot of boost ,,,for a minute lol and take that 40 off your hands

graphitecumnz

he has Bully Dog 5's...

what happens when you turn the comp off??

signature600

He's got BD 5's there Ian...can't you read?? BTW, where you been?? Haven't noticed you on here in a while!

It's kinda lost there in the middle of his sig!

I'm sure you should make the full 40psi, I've got a B1 and less fuel and I can get 38-40psi in 4th and 5th gears. What are your EGT's at WOT? The 40 will be laggy, and may not light well at slower RPM and an auto...you may have to run up to the rev limiter in OD to met max boost.

A HX40 is a whole different animal than the HX35, that I am sure of!
Chris

SmokinFive9 4x4

Yeah I just noticed that,,,,that's me being blind lol. I've been working alot, and when I'm not working, working on the truck. It better be worth it when I'm finished lol. And yeah, I think with BD 5's that should make plenty of fuel to make more boost than 28psi. Maybe I should pay attention more lol

Scotty

Are you losing coolant? Is the overflow empty? Head Gasket?

I had a similar encounter with my 01, one night it felt like my truck fell on its face.

Boost was down by 6 psi. No leaks, did not know what was happening, then one day theres a puddle of oil from the front of the engine...pulled the head...I had 4 cracks in the head gasket which was allowing air to push back out where it shouldn't. Plus I had the big piece pushed out at the front. I figured the cracks were there for awhile.

Scotty

CTD2001

Sorry not to get back sooner, been out of town, but i do not believe that i am losing coolant, level seems to be where is should be, and i have not seen any puddles of that or oil on the ground. The boost will come on quick to about 25 or 26 psi when in O/D and then from there it will slowly build but i dont dare let it try to build much because i am going about 85 or 90 at around 26psi and i dont want a ticket. I was able to get the boost to 30psi on my ride home today, i laid into it pretty good, from about 15mph, not WOT though and it was able to hit 30psi pretty quick, then i let off of it. It pulls some hard though, boost numbers are strange though. When i turn off the comp box, the boost builds slower to about 12psi and then it will jump pretty quick to 26psi or so. Thanks again for the help

govspringbounce

Have you tried blocking off the wastegate signal/plugging the line?

CTD2001

no, i have not tried that yet, but in my previous post i said the coolant level in the bottle was ok, well i went out this morning and checked it when the motor was cold, and the coolant was at the Add more line line. What could this mean, thanks for the help

1ST GEN.

Coolant being at the add more line of the bottle is no big deal mine never stays above it, How does the supper 40 spool compared with a piers hx40

CTD2001

not really sure how spool up compares between the two, i am not sure what size exhaust housing the piers 40 has on it.

Rhino

As suggested plug the WG to see what happens.

I would also test for boost leaks.