B20 boosting to 8.7 psi on the full exhaust, 2.5 carsound cat, resonator, piping Magnaflow muffler no problems up to 7300rpm. Once I flip the switch for the cutout I reach about 9.1-9.2 psi at 5800-6000rpm and I hit a wall. Im currently running a Tial 38mm, Hallman MBC and the vacuum for the MBC is spliced into the vacuum for the FPR. I double checked the vacuum connections from the MBC to the wastegate and its right. Switched out the stock Map for another good one but still nada. Whats going on?

 

what do you mean wall?the car stops making power? i bet the boost cut is set at 9 psi. what management are u running?

 

He described it as hitting the revlimitter at like 58-6k. We recently switched the vacuum source for the MBC from the compressor to a t off of the FPR. this allowed us to raise the boost as b4 it was registering a bit over 7 after that it went all the way up to high 9's almost 10. I thought it was a map problem but he swapped outthe map's and the same problem persists. The car runs fine with the cutout off, but when it is opened it will only rev to the said rpm.

 

boost cut, plain and simple. who tuned the car? they set boost cut so the car doesnt overboost. rev the car up using very little load (free rev) past 58-6k with the cutout open, i bet you it makes it all the way to redline

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by I Have an STD &raquo;</TD></TR><TR><TD CLASS="quote">boost cut, plain and simple. who tuned the car? they set boost cut so the car doesnt overboost. rev the car up using very little load (free rev) past 58-6k with the cutout open, i bet you it makes it all the way to redline</TD></TR></TABLE>

yep sounds like boostcut to me too for you

 

so is it a tunning issue. The car was streetuned by pheareable and that was never discussed. I figured it had to do with either the map due to boost (10.65) or something else due to boost.

So you think it is boost cut, would lowering the mbc work. We took it to almost 10psi this weekend without the cutout. I remember it cutting out when we tried to raise it to go right at 10psi, but it never made it b4 cutting out. Isn't the ob2 map read lower psi, I think it is like 9 something?

 

ok went to pgmfi and obd0 is 9.25 obd1 is 10.65 psi. Stumped. We went past 9 psi with the ecut out off just on the exhaust. maybe the ecut out is leading to aspike messing with the MAP. I will contact phearable about the boost cut to see if he did.

 

changin the mbc isnt going to do anything....w/ the dp open the turbo is spoolin beyond the wg's control...hence the slight overboost beyond your wg spring...and the sudden spike...which is probably why your hitting boostcut....

it would be a tuning issue...boostcut is a setting that pretty much keeps the car from overboosting....by limiting it.....

used the cutout closed....and be careful by run it a higher than 9psi...see if you hit the cut....

 

after re-reading you post...im almost 100% sure your spikin...and hittin the boostcut feature....the rom just needs to be change a lil bit and make sure you have plenty of fuel int he last columns so you dont lean out when you hit 10+psi

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by drumking15 &raquo;</TD></TR><TR><TD CLASS="quote">after re-reading you post...im almost 100% sure your spikin...and hittin the boostcut feature....the rom just needs to be change a lil bit and make sure you have plenty of fuel int he last columns so you dont lean out when you hit 10+psi</TD></TR></TABLE>

Spoke with pheareable and he said he is pretty sure that he put the 10.5 boost cut, this pretty much answers the ? then, thanks fellas for the info