yep thats right, i can hit 50psi all day long but i want more, i have talked to many people from turbo shops and performance places, and with the high tech 71 series 64/14 turbo thats on my truck. the turbos efficiency range is 55-65psi, but i cant get more than 50psi out of it, i have even plugged off the wastegate but nothing works, is a stock 95' intercooler holding me back?? please help, and yes at 50psi im still rolling a decent amount of smoke so i now i have enough fuel, check my sig. thanks


jason

 

Maybe your head has some small cracks and it internally bleeding off some of your max boost. What do your valve guides look like? Do you get alot of blow by out of the breather tube when you hot rod it? If the head is fresh and you've got plenty of fuel, I'd say you've got a small boost leak. My intake plate had blown out a small piece of the gasket and was holding my stocker back to 30 psi. Now with the leak fixed, I can hit 35psi.

 

more is not better, and the efficiency of that 64 is probably between 40-50 not 55-65.

more boost doesnt mean more air, at this point spinning a 64 that hard, more boost will be more heat

 

Well said!

 

ohhhh....... i thought the efficiency range was higher than that, at least thats what i was told, but im still curious, will my stock intercooler hold me back if i decided to go for twins in the future??? thanks

 

the intercooler wont hold you back at all.

 

You should check your drive pressures. This way you will know if its overworking or not.

 

I've heard the 64 compressors are efficient to a higher pressure ratio than the 62 or 66, but I'd say at 50psi you're probably on the edge of the map.

 

i'm makin 52psi on my 71 series 64/14.... i have the tst boost elbow i got with my plate.... FWIW my drive pressure is 1:1 @50psi.....

 

Does anyone have an actual map to see the turbine speed at 50 Psi? I would be concerned about overspeed of the turbine as well as TIP.

The head is the flow restriction..

 

well i talked to some people who had a friend with the same turbo as i and enough fuel for 500+rwhp and he said that when he adjusted his turbo to push 55psi he cleared up more smoke and made a bit more power, i don't now how much more but it was definatly running cooler egts and making more ponies, so im curious to try it to see if their is a difference. just cant seem to push more than 50 and i can't figure out why, thanks


jason

 

Almost everyone runs too much boost pressure...... I did a ton of dynoing to see what would work best and found it to be much lower than guys would expect. On a PS62 the best was around 42 lbs, going to 50 gained 5 RWHP but increased egt's by over 100*. We also dynoed over 600 RWHP on a single 63mm turbo @ 43 lbs boost. I haven't tried the HTT 71 64/14 but I would expect to do its best around 48-50 psi.

 

when i installed my 64/14 i left the wastegate set at 40psi and it got hot and real hazy quick.... i could peg the pyro almost as fast as i could with the stock charger..... upped it to 50psi and all is well...... dropped egt's ~200* cleared up the smoke to just a haze at WOT..... i think 50-55 may be the limit for this charger.....

 

How much power you got? Maybe your set-up can only pull 50 psi, regardless of which turbo. Check your drive pressure? Leak check everything. I presurize with 50psi air tank and look. If funny what will leak and doesn't. I have a leak in my intercooler. So I can only pull 70-75psi at 3500ft. At sea level, who knows. 50 psi is about max for a stock head gasket, no o-rings, no studs. Fixing blown head gaskets aren't fun. As Jetpilot mention higher boost isn't a ticket to bigger HP. Less smoke and egt's maybe