I was oout doing a few pulls today and I only saw 13 psi on a few 2nd-3rd gear runs. I don't have a boost controller, just the PFC controlling boost - no commander either. As far as I know Dave programmed my PFC for 15 psi on my last dyno run - do I need a boost controller?

 

yes....the pfc is not accurate at reading boost in most occasions...as far as controlling boost...it sucks. I picked up a profec b and am happy.


did dave use that same boost guage to tune your car?


just wondering...cuz if he used a commander/datalogit to watch the boost than I doubt you are actually tuned for fiteen. my commander reads about a lb and a half high compared to my accurate boost guage.


jason

 

Jason, I've heard the PFC sucks at controlling boost - my boost seems somewhat irregular after the 2nd turbo kicks on - if you've looked at my dyno, my transition is basically non-existant but by gauge is reading 13-13.5 psi to redline. I know I didn't make 366 rwhp at 13 psi but my dyno runs at 14 psi show a 30 hp jump from 14 to 15 psi - after doing a few pulls, my car feels like 320-330ish rwhp - maybe I shoud pick up a Profec B...

 

Barry, it controls boot fine....except in cold weather, which any boost controller has trouble doing do their inability to read the dense air correctly. In warm temps, 60ish and up, it does fine. Most complaints are during the winter months, but my old PFS PMC did the same thing in winter time, couldn't compensate for the dense air. Do a ghost map trace and see what cell your in now (remember the ghost map scaling is off according to Glen in that you have data in cells 1 through 20, but the ghost map starts at 0 to 19....so if your in cell 16 on the ghost map, your in cell 17 in the data input cells). Bump up the duty cycles a couple of points and see what your boost looks like now. Should be up just a tad, but not out of any ranges Dave should have tuned for.

Tim

 

i disagree...tis why i went with a profec b. I found boost control to be a lot better with the profec.

 

Well, I personally never had a problem with the PFC contolling boost BUT, I'd imagine he did tune to 15psi on the dyno but it loads the wheels differently than the street so now its only 13psi. When I first got on the dyno my boost jumped up about 2psi and I and to turn it down for the dyno then back up when I got back on the street. Its probably just the difference in load, especially since our toping out 4th on the dyno.

If you have the boost setting in the PFC where you want it just change the duty% untill you achieve the boost that your set at.

Thats the main diff in the PFC and most elec boost controllers, you have to manually adjust the duty% to achieve the desired boost setting which most elec controllers do for you. This means when weather and all that change a lot you'll have to play with the duty% a little to keep the desired boost.

STEPHEN

 

Hey guys, you are exactly right - Dave lowered my duty cycle to keep from spiking (safe) but says there's definitely room to adjust and get my desired boost level for the street. I may get tuned again for 16 psi since there was a 30 hp jump from 14 to 15 psi according to my graphs and this seems to be where the sweet spot is in these turbos (around 15-17 psi) Do you think 16 psi is toom much for sequential on the street???

 

no...i think it sounds like FUN!

 

*sarcasm detecting...* *buzzz* ...broken.