Max boost before heads lift?

[bowedup2003]

Ok, I have done lots of reading on here and it seems most folks are running between 8-13psi boost w/ some venturing up to 15-17 w/ lots of mods.

What I'd the absolute max boost I can get away with before catastrophic engine damage occurs? 20psi?

The reason I ask is that I have access to a couple new takeoff wastegated turbos off of a CAT C7 370hp. Considering the turbos and my time are free,do yall see any reason I couldn't put one on. Either a compoundbound w/ my banks sidewinder or twin turbos off of each bank?

Bowedup

 

[runaway!]

Depends on how much work you wanna do, there supposedly was a 6.9 drag truck in the 90s that was pushing almost 150psi of boost but had a 9:1 compression ratio. Ran 9s in the quarter mile.

I've read that 20 psi is about the max you can hope for without machine work such as shaving the pistons.

And that 20psi might lift the heads without studs

 

[bowedup2003]

I know the engine your talking about. It was built at Hypertech and I've seen a few pictures of it. I wasn't thinking of anything crazy like that, more like 20-30psi range like a PSD.

It probably won't work, but I'm sure yall know how it is when really good free parts come your way the wheels start turning...especially like right now sitting in the cold manning the BBQ pit.

My 6.9l already has the banks wastegated setup, but I also have a 1994 F350 single wheel not listed in my sig. that is still NA. I have been debating on adding one to the banks setup or using it on the 7.3L NA.

Does anyone know of anybody that has built a set of twins for a 6.9L? I have seen a couple pics of a darn Chevy 6.2L w/ twins so the idea isn't entirely crazy...

Happy Thanksgiving to all!

Bowedup

 

[runaway!]

I was just kinda saying, you could get as much boost as you are willing to spend. But there isn't that much to be done in that area without big money.

I know what you are saying about the gears turning, this link is in my ebay watch list because I've been debating a dual turbo setup with some smaller turbos. Maybe a pair of VW TDI turbos.

http://cgi.ebay.com/ebaymotors/ws/e...0487514244&viewitem=&sspagename=STRK:MEWAX:IT

3.9 intake parts are supposed to fit on a 6.9

I thought there was someone on here that was running around with 25psi, fire ringed or something.

Maybe a custom headgasket, and ARP headstuds will keep the heads on, perhaps 500-600 bucks in cost. The stock IPs are supposed to be good up to 400hp.

 

[bowedup2003]

I agree w/ you. I have my pump maxed out and my banks turbo makes 12-13psi max, and even then I still have a pretty good black haze out of the pipes. I even plugged off the wastegate line and my boost didn't go any higher. On a long grade pulling it will run 12psi all day at 1000F.

That is kind of my reasoning for adding more turbo. Move more air to cool the egts down some when towing and get some more power in the process.

Bowedup

 

[runaway!]

Did you try an intercooler?

 

[97idi]

i have take my wastegate line off and can run way farther than the banks 15 psi gauge and even with it on i can go past 15 with no load but i have a few different mods

 

[safd1919]

now if you build a custom system couldnt you just put in a blow off valve in your system and keep from blowing you stuff apart

 

[dyoung14]

well as soon as i get the pedistal built, which i will work on today, then i will get to finish my up pipes, and buy the oil lines when i get the spare cash, then i will tell everyone if a psd turbo will lift the heads with my stuff done to my motor, but i think im going to retard the timing some and reduce the cylinder pressure some, and reinstall my glow plug deletes then i should be able to run a little more boost

 

[97idi]

now if you build a custom system couldnt you just put in a blow off valve in your system and keep from blowing you stuff apart

thats what a wasegate is for it lets excess exhaust drive pressure pass before the turbo so it cannot over spool, a blow off valve is used when say ur making 20 lbs of boost and goto shift when u get back on it ur not trying to spool from 20 lbs or what ever it is and blow off valves are mostly an import thing i havent seen one on a diesel and also that would take away the point of a turbo because u would loose all boost pressure

 

[dyoung14]

thats what a wasegate is for it lets excess exhaust drive pressure pass before the turbo so it cannot over spool, a blow off valve is used when say ur making 20 lbs of boost and goto shift when u get back on it ur not trying to spool from 20 lbs or what ever it is and blow off valves are mostly an import thing i havent seen one on a diesel and also that would take away the point of a turbo because u would loose all boost pressure

i belive a blow off valve is for a gasser, so when the throttle plate closes when you let off to shift it dont blow anything up since the boost would have no were to go when the throttle plate is closed, diesels dont have throttle plates so.... no need for a blow off valve right?

 

[97idi]

i belive a blow off valve is for a gasser, so when the throttle plate closes when you let off to shift it dont blow anything up since the boost would have no were to go when the throttle plate is closed, diesels dont have throttle plates so.... no need for a blow off valve right?

yeah i new it was something but i didnt know what exactly it was, isnt that the sound u here when the imports that have turbos shift?

 

[dyoung14]

yeah i new it was something but i didnt know what exactly it was, isnt that the sound u here when the imports that have turbos shift?

i think it is

 

[safd1919]

but if your putting a nwgt on your truck i blow off valve wont let you blow up your motor from over boosting but it really dont matter

 

[6 Nebraska IDIs]

Yea, the blow off valve is for exactly what dyoung described. And yes it is the sound you hear when a turbocharged gas motor shifts. Many of the import retards buy extremely loud blow off valves so that EVERYONE can hear that they are running a turbo. Personally I try to keep my Eclipse as inconspicuous as possible, all of my modifications are not distiguishable from a stock system. Bigger turbo CHRA is crammed into the stock looking T25 housings, but inside they are machined out to accept the larger turbines. To be honest my brown truck is by far the most obnoxious vehicle i own with the huge intercooler out front in the open and the 4" exhaust that resonates the turbo spooling up. lol