5 PSI of boost???

[scheid6996]

well i got my intercooler on, ill post pics soon, but i noticed when i was driving, that i wasnt putting out much more than 5 psi, and then id blow a blow a intercooler tube off, but i got all them tighten down now and i dont think they will blow off anymore, but after puting on an intercooler should i have less boost, i knew i would have turbo leag, but loss of boost?

 

[94f450sd]

yes you will loose boost.as the air is cooled the pressure drops.its not uncommon to see a 6 psi drop across the intercooler.on my 95 PSD i was makeing 36 PSI of boost,now with the intercooler i get 30PSI.

 

[towcat]

2-3psi drop is not uncommon on IDI's. The nice part is it takes alot longer for the pyro to peg. So, you can turn up the feul screw just a little more. The bottom end kick should be a little harder now too with the IC in. I know it really woke up my '92. Oh yea...the highest I have gotten the boost gauge to is 5 psi on a heavy throttle going over the grapevine. Weight was at 9.5k. Speed? Passing everything on 5 except the flying J at Fraizer Park. and the Petro in Santa Nella. I always make sure I have a full load of feul going over the pacheco. You never know if you wind up sitting for half a day due to 152 being closed down for a fatal.

 

[scheid6996]

ok ya it has soo much more power now, and i havent even beenable to hold it to the floor yet, the dam intercooler tubes keep blowen off, but ill get thet handled
thanks guys

 

[ClassicIDI]

I see around 7psi on mine and that is empty on flat ground. I don't know what it was before the intercooler cause it was on the truck when I got it.

 

[Ironman03R]

If you lost boost after intercooler install, why not adjust the waste gate? I'm always told over 12psi w/o intercooler makes the air too hot, wouldnt 12-14psi w/ an intercooler make more power? Or am I missing something?

 

[scheid6996]

ya im with you, after putting on an intercooler, and haveing less boost, we should be able to turn it back up i think

 

[towcat]

ya im with you, after putting on an intercooler, and haveing less boost, we should be able to turn it back up i think

there's absolutely no reason why you can't turn up the boost and feul more. Just spuerglue your eyeball to the pyro if you do so.

 

[f-two-fiddy]

OK, here's the deal. You've lost boost by adding more volume to your turbo piping.
The problem is, your IC is to ineffcient. What IC did you use?

If you've gotta up the boost, just to overcome the added volume, then your gonna be making more heat. The IC is allready to ineffcient to handle it. Either you need a better IC, or a better (custom) turbo.

 

[towcat]

OK, here's the deal. You've lost boost by adding more volume to your turbo piping.
The problem is, your IC is to ineffcient. What IC did you use?

If you've gotta up the boost, just to overcome the added volume, then your gonna be making more heat. The IC is allready to ineffcient to handle it. Either you need a better IC, or a better (custom) turbo.

If I wasn't famliar with IC's before diesels, I might subscribe to your train of thought. Being the owner of a '85 Buick GN(non ic) and '87 Buick GN(ic'd and raced) I have a little background on IC's and their plusses and minuses.
Yes, a IC will cause a drop in pressure due to 1) the length of plumbing to and from the motor...2) the surface area of a IC is larger to slow down the air charge a little and give the alu a chance to extract some of the heat.
heck....if all these others diesels are running IC's...there must be a reason.
I do like mime

 

[94f450sd]

If I wasn't famliar with IC's before diesels, I might subscribe to your train of thought. Being the owner of a '85 Buick GN(non ic) and '87 Buick GN(ic'd and raced) I have a little background on IC's and their plusses and minuses.
Yes, a IC will cause a drop in pressure due to 1) the length of plumbing to and from the motor...2) the surface area of a IC is larger to slow down the air charge a little and give the alu a chance to extract some of the heat.
heck....if all these others diesels are running IC's...there must be a reason.
I do like mime

you also gotta remember that the cooler shrinks(for lack of a better term)the loss in boost meansthe intercooler is working correctly.

 

[f-two-fiddy]

Yes the turbo is working correctly, just as it was designed.
But you've changed the volume it needs to put out. It's now going to have to work harder to put out the same amount of boost. Cranking up the boost is going to put it much closer, or over the edge of its design perameters. Once you get that close to the edge, you're making a LOT more heat.

The volumetric effciency of an IC is prolly it's most important measurement it has.
If your IC is 60% efficient, you've lost allmost 40% over the stock Banks setup. An 80% efficent IC will give much bettter results. That's why I've allways said that an aftermarket Spearco,HKS ect. would be a much better IC than the junk that the PSD uses. Why do you think Banks & Hypermax sell $2500 IC kits?

 

[scheid6996]

well i dont agree, i have a psd intercooler with 3 in tubeing, another truck i kno of has the ATS intercoolers system, with a small intercooler, and 1 1/2 tubeing, and my system works much better, i noticed a loss in boost, witch that truck didnt, but i run lower EGT's, and since i have a bigger intercooler, the air going into my motor is colder witch means more dence, witch would make it have a loss in boost, and by turing the boost back up to 10 or 15 psi, it would be the same amount of boost as b4 the intercooler, but it now has more volume beacuse its more dence

 

[94f450sd]

That's why I've allways said that an aftermarket Spearco,HKS ect. would be a much better IC than the junk that the PSD uses. Why do you think Banks & Hypermax sell $2500 IC kits?

the stock PSD IC cant be that bad since those of us with the OBS PSD wait for the sorry saps to waste thier money on the banks junk so we can get thier stock IC to retrofit into our trucks

 

[towcat]

here's the trade off's on running a large or too large of an IC. The bad, turbo lag, pressure drop from a larger surface area. The good...in a real life situation where you are running in high summer temps, and long upgrades, the larger of an IC will soak up and get rid of the heat sooner and longer than a smaller IC. On a cool day, I see a 300deg difference between the inlet and outlet on a warm day the worst it drops to is a 200 deg difference. Keep in mind I am running a ATS IC its a half height IC. I had to deal with the AC system popping off this last summer, so i was happy that I didn't go with a full height IC. Oh yea...I am running R134a and not by my choice either. The PO put it in. R134a runs on higher pressures compared to R12 to work.
Bottom line. Either you will be sold on IC's on your truck or you won't. I am and it works well for me. Anybody who has test driven my '92 will tell you that it is a night and day difference with adding on the IC.