I have a greddy profec B spec 2, and I was wondering if anyone else here has played with it much.

Basically, I've got to try and keep my turbo building boost at higher RPM without upping it too much at lower RPM.

I don't know if it's possible due to turbo design, or my engine possibly out-flowing my turbo, but I just figured I'd ask and see if anyone's had any luck keeping the turbo pumping, and if so what settings they used etc.

 

If you want the turbo to be less responsive and you want to build boost slower, then lower the SET GAIN.

SET GAIN determines when the wastegate starts to open, so the lower the value, the sooner the WG opens and the slower you build boost.

Mind you, you are pretty limited with what you can do with the stock S4 WG...

 

Yah, the turbo is actually off of an S5.

I don't want it to build boost more slowly, I want it to maintain boost at higher RPMs.

 

the boost controller can only raise boost, it can not make it any lower. if before the ebc the car was boosting too much (if you have a 3" exhaust it will do that on a stock turbo) the boost controller will not be able to lower it. this is called boost creep and can only be fixed with a bigger wastegate or porting of the stock one.

 

I'm not having an issue with too much boost, I'm having an issue with not enough boost at higher rpms. I guess I didn't make that clear or something.

 

that boost control could be alittle confusing to use. there is a setting of what the actual boost will be if you just turn the **** from the main menu without going into any settings. that is your boost adjustment. the boost adjustment in the menus is what your target boost is and gain is how fast the turbo will spool up and what it will hold up top. so check to make sure that your target boost is right and then try to play with the gain.

if you are on a stock turbine, and you have a full 3" exhaust and a front mount, u will have a hard time having the boost over 9-10psi over 5k rpm, the stock turbine is just too small to flow that much air so teh boost wil drop off even with a boost controller.

 

hmm i was having no problem boosting 13 psi on stock s5 turbo all the way to redline ... i was using a manual boost controllor.... i have hte full exhaust and tid mod, but i am still using stock IC

 

yes that was with a stock ic, with a large front mount it will be much diffrent.

 

To quote the Manual:

If the Boost falls off at higher rpm, increase the GAIN adjustment 2 increments at a time until it stabilizes.

 

Man, those manual thingys are handy!

Thanks

 

That s5 turbo is running out of breath. That thing cant hold high boost levels to red line. you can go ahead and yank the wastegate line and you still wont hold much more boost up to redline.

And some profec B spec 2 101:

set boost = boost above spring pressure in %
Set gain = level (in PSI) where the profec will begin to modulate the wastegate
gain = amount of modulation, in percent, that the wastegate is modulated.

 

You guys never listen...
If you've gotten an AVC-R, this wouldn't be an issues cause the AVC-R can do RPM dependent boost control!


-Ted

 

That still wont make an S5 Turbo hold like 15 pounds to redline, that turbo just aint got what it takes.

 

Im suprised about hearing everyones boost falling off.....My S4 Turbo holds 13psi all the way to redline WITH Full 3" exhaust, 3"TID, and 3" Intercooler piping to a MASSIVE FMIC....

 

Yep, and its SUPER efficient at 13 PSI too! and is that measured before or after the IC?

 

:P


hehe Well, I'm stuck with what I have now

I don't need it to hold 13psi till redline, I just need at least 6.

I don't have a very free-flowing exhaust, it's only like 2.5 inches. I still have the stock tmic.

But, I think with the ports I have and the rotors I'm using, by the time I get to higher RPM my engine just pulls more air in than the little turbo can flow out:S