ok...all i have done...downpipe and hks air filters

pfs ecu on setting 1....tuned for 10lbs with fuel cut at 13lbs

tonight i was racing in third gear...car felt great except it lunged forward with fuel cut...and alot of time i feel the car hitting above 10lbs..my defi d gauge is off a little so i think it reads a little high but im afraid to even turn my ecu up to setting 2 for 12lbs in fear that ill be hitting 15lbs...how high can my fuel system support should i not worry about it and set the fuel cut higher than 13lbs....is it better to set the fuel cut low and cut before u run lean or vise versa?

is there any risk involved in fuel cut it just feels wrong when the car cuts out....

and last...it would be a BAD idea to gut my cat or throw on a midpipe even with a little restriction plate considering i'm already creeping or peaking with only new air filters?


considering i have the stock intercooler...and catback (except louder muffler) why the hell am i going past the setting on the pfs? do i need a boost controller?

 

also wanted to add....the pfs indicates 22hgs of vac....and my gauge indicated 19...which boost gauge is correct?

 

do you mean pfc?? the pfc psi is will always give you a diffrent reading of what your gauge says.. you sure your not spiking with thos mods you really shouldn't be creeping if u have the main cat still there

 

It's not as wrong as blowing an engine. Nothing feels worse than that. It sounds to me like you need to see a tuner and get this car set up properly. It may be a boost control issue too.

Yes, an overwhelmingly bad idea.

Louder muffler on the stock catback? Do you mean then that you have the stock piping and an aftermarket muffler canister welded to it? In any case, that's not really a stock cat-back anymore.

Is there any chance that your cat isn't stock, or already gutted?

 

I had a terrible time controlling boost with the purple motor eater in the winter. I highly suggest a switch to the Power FC. Also, with your issues, derestricting your exhaust any more than it already is could be a recipe for a blown motor. GL!

J

 

Blame the cold weather. I'm seeing 16 psi in my cobra where as it would make 13-14 in the summer with the same pulley. My car is tuned for it though. Just an example for much of a difference weather can make. Get the car re-tuned and get the boost control issue sorted out before you pop the motor.

 

well, i thought creep and spike were essentially the same thing....they both hit a higher psi that you want....what is happening most of the time on my boost gauge

heatsoak or partially warmed intercooler - 10lbs stable on 1st setting
fresh intercooler temps - i hit the gas hard its normally 10/11-9-11/12 split second and back to 10...i can't get it to stay 10-8-10...last night it went 11-9-13 but its only there for a split second (my fuel cut is set there)...now what exactly is the difference between creep and spike....

creep is just boost coming on when ur asking for less that you want?
spiking is hitting peak higher than you are programmed for?

If so i just need a way to keep the boost from going over 13lbs...will a profec b do anything?

 

That's where the similarities end. Oh, and less restrictive exhaust makes both worse. Do some reading. Just general google info should be useful.

Creep takes a little time to create an overboost. The longer you stay in hard throttle, the higher the boost goes. With a cat in place you probably aren't creeping.

Spike happens suddenly, usually at 4500rpm when the secondary comes online. It sounds like your boost is spiking, and a better boost controller is the answer. The purple box has some boost adjustments, but you are exceeding it's boost control limits.

Yes, that's one good boost controller. For less money, a manual boost controller will work also.

Dave

 

Definitely better to avoid an excessively-lean condition under boost, but it's not like you want to continue driving that thing around hitting fuel cut on a regular basis. You should stop ragging it and take it to a competent tuner.

 

well...tonight i drove it half throttle on the 12lb (#2) setting....car stays at 12..but if i push the throttle to full it hit 15 momentarily (bucks at the fuel cut and comes back down)...this is definately spiking

Im going ot buy a profec b and see how it works out

 

so by porting your wastegate,,, which one does it control apike or creep. Ive ported my wastgate but noticed i still get spikes in the cold especially.????

 

seriously you should get your wastegate ported bigger or get fuel to accomadate those high boost levels, maybe even adjust timing or else that doesn't sound good for your motor.... I wouldb't be driving around hitting fuel cut all the time, 12 psi is high boost for the stock turbo anyway, that'll fry your utrbo if done often enough.

I have fresh rebuil that i can't even drive really becuase I'm afraid of creep/spkie in boost that will result in lean conditions----> detonation----> blown motor. Right now I am getting turbo rebuilt/balanced/blueprinted and wastegate ported to 30mm. Also whole new fuel system is underway, everything from pump to x4 720cc, w/new injector connectors and clips/ all the braided steel and -6AN fittings you could ever need........

I am just too aprehensive about blowing the motor, and god knows i didn't want to put a cat back in....... don't quote me though, thats just what i have gathered so far.....

 

There's nothing wrong with running 12lbs. on stock twins, many people go higher than that.

Edit- Provided you have the supporting mods.

 

profec B should do it considering the couple of mods. Dont count on it though. G

 

Not necessarily. He's getting boost creep, not boost spikes. A boost controller will only help him out if it's spiking momentarily.

 

just thought i would let everyone know...profec b spec II setup version 2 with the electric uim wastgate and pca solenoids unplugged = MUCH IMPROVED boost control...creeps 2lb at top of redline....added a restriction plate to the exhaust (purchased a universal 2 bolt flange 2.5 inch sandwiched it) car pulls harder than ever on the primary with the version 2...the violent transition is quite fun....pulls to redline great

 

Most of you guys still have no clue what creep and spike and elevated boost levels are. This is not difficult. Do a search using my username and boost creep and you should find a proper explanation of the three terms....

Unless you have a downpipe and gutted cat, there is NO WAY IN HELL you are creeping whatsoever. You have elevated boost that is not properly being controlled.

 

Glad to hear it. Those spikes are dangerous not only for the motor, but for car control.

Dave