How much boost?
 

ok.... a few weeks... well about a month ago i installed my turbo and a few weeks ago.... a couple weeks after the turbo i installed the injectors and delivery valves.... i had a heck of a time with the new injectors keeping EGT's in check 1500*+ before going into 3rd.... so after some reading and thinking and looking at the bank account to see how much funds i had in there if i broke my truck i installed my boost elbow that i had in my HX..... in my HX it made ~42 psi without it i made a hair over 30..... so i figured that with this turbo making 41ish that this elbow should mahe around 50 or so..... mainly i was looking to clear up my haze and lower EGT's some...... so i installed it and made a quick drive around the block (it's a country 5 mile run or so) and got her up to opperating temp and once the thermostat cycled i layed into it...... EGT's got no higher than 1300* and boost felt real good @ ~53psi..... it felt so good on my second voyage out today it blew the intercooler boot off the intercooler on the driver side..... that's another thread..... any way.... how much boost before i'm really asking for my STOCK headgasket to go? it feels SOOOOO good and pulls so damn hard...... i don't want to back it down..... now keep in mind that i don't drive like that all the time..... just when i need to put a Powerstroke or a Duramax in their place...... i'm going to be on the rollers in a few weeks..... the 28th of this month to be exact and want to know how much boost have you guys ran and had good luck with? i know i'm pressing my luck but i don't want to come up with a wammie before i'm ready to pass.....

At 40ish your already past the safe point. I won't go over 35, ever in my old truck. 35-38 is usually considered a high safe mark for the stock gasket.

I would say you might run into turbo bearing failure at that boost level. I am pretty sure they are set at around 40 psi and if it was me I wouldn't go much past that. But that is me if you like it and think it feels safe run it.

everyone i've talked to, a Pro Street driver, and the owner of the business i bought the turbo from said the turbo would be safe running @ 50-55 psi due to it being a low drive pressure turbo and what not..... i've also been told that the stock gasket will blow somewhere between 40-50 so i guess i'm gonna find out how long it takes..... it takes at least 50 psi to clear up the smoke/ thick haze....... i'll be on the dyno on the 28th so if it last that long i'll be good..... i've already talked to Plillip Palmer of Stuckey Racing about doing this head for me when the gasket blows and he said he could make my truck wake up with all the mods i have done already...... and it dosen't help he's the current Pro Street Champ and already been 9.90 in the 1/4....... and he is a machinest by trade....... so i guess i'll go till she blows and that'll give me an excuese to get it to the machine shop to get "checked"..... that's all my wife needs to know.... the other stuff will have to be replaced cause it's "worn out".....

Keep your timing down and you shouldn't have to many troubles with the stock gasket for a while. That turbo at 50psi is safer than the HX35 at 40psi due to the the lower TIP produced. Boost doesnt kill HGs timing does, however in many cases the timing comes from excessive TIP from a over spooled turbo.
If you are really worried run a set of studs in and that will help.
I would say keep the timing below 17 degrees until you can get a set of o-rings in.

Well i blew mine at 40 psi, but cummins claims they are good to 50 psi but you see how far i went(38K on truck), In stalled .10 over marine gasket and all is well so far.

Whats your timing at? Had your 12V on a dyno lately?

my timing is stock.... 14.5* or whatever it is.... are you pointing these questions to me?

Actually no..I was asking Ratsun....

ah i c

Hey Dr.
I hope to get on the rollers at the BD thing on the 21 but they limit to 60 trucks so we will see? I did a couple of pulls before doing any real mods other than the#10 plate and the 3gsk and the twins. It was 301hp and 759ftlbs @1300 degrees ( I found a boost leak of 15psi):duh3:
So since then I have done the cam, sticks and played with the pump and the SOTP meter says its picked up ALOT! I mean ALOT! Timing is set at 17.5-18 right now but dyno day might be a mystery;)

What turbo were you running?

Benjamin
At that timing and the HTT I really doubt you will have a problem, however every engine is different and there is no real hard set rules. Hell even a few stock trucks popped HGs and some never will?

stocker, with just the edge boost elbow.

Most cases the stock hg will support 50-55psi + if your drive pressure (TIP) is at or lower than 1-1 but with the stock turbo you are in the danger zone once you exceed 32-35psi.

Hey bud, check your PM's....wouldnt mind your opinion on something....

Proof that every engine is different.....I ran compounds at 60-70 psi and 16* for several months on stock HG and bolts back in my earlier days. Then I went studs and about 80 psi at 22* along with meth still no rings though. To this day I still haven't done the rings and it's holding.

My buddy, on the other hand, blew his HG at 40 psi and stock timing....his drive pressures might have had something to do with that as well.

Just proof that there is a very wide gray area, and not any hard and fast rule concerning boost and HG failures.

whats an hg a holset??? stock like whats on my 97??? all ive done is my sig and at wot in overdrive i can hit 38-40 psi

Their refering to their headgaskets with HG, your truck has an HX-35 turbo on it and yes it is a holsett, 38-40psi you better watch yourself if that is a stock turbo and your head bolts, you can overspeed your turbo and blow a head gasket with that much boost. Of course you could run it for years like that and never have a problem then again it could blow this morning

See I am after something similar. I want to upgrade my stock turbo to allow the FASS 95gph and 300hp injectors I added to work even better then they do. I posted in another thread looking for tips and opinions on which turbos where best for everyday driver needs, with weekend playtimes. I keep coming across possibly replacement of the downpipe and something about an HX40? Any help guys?:argh:

HX-40 are what are found mostly on the 8.3 Cummins, it would be decent upgrade but not your best option, i would go with a Super B 62 turbo if i was in your position