If I have 27-28 psi max right now, will I see any performance gains (other than lower egts) if I were to increase the boost w/ an adj. boost elbow to about 35 psi (this is the max I've heard is safe for our stock turbos.

 

No, The boost elbow will allow more flow but no one reports additional power by adding the
elbow. I just added mine last month...24-25psi without, 30-31psi with the elbow. I feel no
added power at 30psi. I do hear a little extra turbo whine now which is nice.

 

going from 27psi to 35psi may increase your EGTs

 

Pressure does NOT increase flow but actually limits it. Increasing the boost will increase EGT's

 

Most likely you will see higher EGTs witht he higher boost pressures as the more you compress the air the hotter it gets and the stock intercooler can only do so much to cool it back down.

 

these guys are right for the most part.

above the upper 20s (psi boost) the little HY-35 with 9 square cm exhaust housing is just not capable of blowing more air. remember that your boost gauge cannot distingish between more air molecules and just hotter ones, and those high boost pressures mean something different than you might think.

if the 'charger could generate more boost efficiently, and actually deliver more air molecules to the engine, then higher boost would cool EGTs and allow you to fuel harder and gain performance.

I have measured the turbine drive pressure, compressor output air temperature and have captured peak compressor temp versus peak boost on this 'charger. by the time you reach 29 psi you are generating drive pressures in UPPER 40s, and blowing 350 degree hot air into the intercooler. all you're doing is stressing the 'charger and making your boost gauge think there is more boost air when it is really just hotter air!

 

Doug, so if I'm understanding you correctly, I need to leave it alone if I'm seeing 27-28 psi. More air from this turbo will only be hotter inefficient air.

 

thats right. on this turbo I (personally) suggest avoiding the boost elbow because it forces the turbo to run outside its efficiency map, shortens its life and yields no real practical or substantial benefit.

 

Thanks Again Doug!

 

great post !! my question for is .. when i added my quadzilla tow box (65 hp) i noticed my boost at WOT will hit 44psi .. so is this a false reading ??? my egts seem very good !!!no worse than stock with the addition of the box .. but i am concerned about the high boost pressures
thanks for any info .
Gary

 

I'm another supporter of no boost elbow. With TST box I can pus 32 psi for a second or so, but then back to 28-29. I've don't have too many problems with temps, but I don't bury my foot in it long enough to get them that hot either. I know a couple of guys that added the boost elbow and theirs actually seemed to run a little hotter than mine. I don't think that small of a housing has the capability to run at high psi. It can build pressure, but not flow any more cool air, which is the key.

 

On my 04.5, with the tst you need the boost elbow, without it maxed out at 18-20 psi,

with the elbow it would stay at stock levels, 28-30, quickly though

the wastegate hookup is different then the earlier models,

 

I think you guys forgot something here. The boost elbow is an option because we added
the Edge (or another brand). This adds more heat by dumping more fuel. The turbo is already
pushing more hot air than a stock set-up. The elbow was to compliment this heat by allowing
a little more boost (psi) Hot or cold, boost is boost. I agree hot air is not efficient but we already
decided this was OK by adding our boxes and bombing our trucks. Is the stock turbo out of its
peak efficiency range while running a box ? On the upper settings you bet. When I tow my 5er
later this month I'll see if the elbow actualy hurts or helps according to what my EGT's are running.
If I see my EGT's drop slightly with the elbow then I'm sold. If it turns out they my EGT rise with
boost then I will remove it. Towing 10K lbs on a hot summer day at 8-9Kft at 12% grade should
help me decide.

 

I've already been there and Doug has done a superb job analyzing these boxes (just wish he'd update his page ) ............ if you get to where you have smoke and high EGTs, you need a bigger charger ......... the stocker works good and spools quick, but won't efficiently do over 30PSI or handle the big fuel load.

Personally ............... the same load, the same grade, the same day ........... mere minutes apart......... EZ on 6 ........... 28PSI, or disabled wastegate and 40PSI ............. 28PSI and factory wastegate ran a little cooler, not much, but enough .......... and had way less stress doing it.

I've got a pic of the 40PSI in my gallery over at TDR ............... the 10 extra pounds didn't help, it hurt.

 

hey 03CTDCO,

just for grins, the next time your in the garage, open the dran **** on your compressor tank and see how hot the cylinders get ............. then close the drain and while the pressure is building see how long you can hold your hand on the cylinder head.

Pressure does not = volume