96 12Valve stock boost performance.
 

Ok folks, I know there is loads of information on this forum and scattered around on the internet about second generation 12 valve, but most of it is related to tweaked/modified setups.

I am having trouble finding basic stock performance specs.

My truck is a basically stock '96 12 valve auto. My primary question is regarding boost. I am seeing a max of ~18psi boost under WOT @ ~2200RPM. At that number I am starting to smoke a little. Everything up about 70% throttle is pretty clean to about 15-18PSI, after that it just adds a more fuel without adding more boost providing very little more power and more smoke.

Is there something that is not adjusted right? Does this turbo have a waste gate? I have seen a lot of talk about boost elbows to add more boost, but it seem that all they allow is more fuel to create more boost which doesn't seem to be my issue.. Shouldn't the stock turbo be capable of more boost than this?

Also, down around 1500RPM, is there a way to get the turbo to spool more, all I get is ~10PSI...

Enlighten me :)

the stock wastegate is set to about 17-19psi. manifold pressure determines when the gate opens and how far it opens. its just a diaphram. a boost elbow has a very small orifice in it which retards the reference signal (pressure) to the diaphram of the wastegate, keeping it closed longer and thus making more drive pressure 9PSI) on the hot side and more PSI on the cold side of the turbo. it is placed anywhere in the reference line from the gate to manifol PSI. a boost elbow has absolutly nothing to do with fuel. i hit 52lbs of boost with my stock turbo before i decided it was time for an upgrade.

Hey guys im looking at buying a 1997 f-250 powerstroke diesel its an automatic with 180,000 miles it is 4x4 its a regular cab long bed. Its all stock except for a straight pipe. They are asking 4500 for it is that a good price or does it sound like a problem truck?

your in the dodge section friend

oh im sorry i just made this thing today and i aint to sure how to work it yet

lol :)

once you get a hang of this forum you will definately find it useful ;)

Ok, I temporarily capped off the boost feedback line that goes from the compressor housing to the waste gate controller. In theory, this should give me 100% of available boost.. The most boost I am seeing is about 20PSI. I am assuming this is because of lack of fueling with the stock setup.

The question I have, is that at about 2000RPM I can get about 19PSI of boost, if I bury the peddle I get some smoke, but almost no more power or boost. If I increased the fueling, how would that be any different? What I am really asking is why do I get smoke? Is that un-avoidable?

Thanks

I don't know, but my truck made 22psi bone stock. I got a few more psi out of it with the BHAF, and a few more with the straight pipe exhaust. Right now with a filter and exhaust I'm making 30psi at WOT, so I'd say something isn't working right for you.

^Did you change your fueling from stock at all? 3k/4k GSK, etc? What year?

with no mods i'd say your truck is acting normal, if you want better performance i suggest grinding your fuel plate and play with it a bit until you like the outcome.. #100 & half way forward should be ok for a all stock truck to make it go a little more than stock.. and for more boost down low you can alter the starwheel.. giving that your truck doesn't smoke in the low rpms...

Does your turbo have end play?