ive been having some boost issues with my greddy b. the other day it was cold and in 4th gear i hit 1.05 kg/cm2 as per the pfc. right when i did i felt what felt like fuel cut. power went away, i got out of it immediatly and it drove fine after that and still does. i dont think it was detonation, but i may be wrong. my pfc is tuned by bdc. do you think he set a boost cut to 1.05? ive never used a pfc before, so im not real familiar with how it cuts fuel and such. any input is great.


also, i think i may be running too rich in mid throttle point. i can feel it cutting out at around 10.0 afr under partial throttle. is it easy to tune the mid ranges in? again, ive never used pfc. just aem ems and hks.

 

The PFC will cause a fuel cut if boost hits a value of 0.25 kg/cm2 above its (PFC) boost setting.

 

is this with or without the pfc boost controller? cause i dont have that. im guessing there is a limit bdc set for this?

 

With or without. It is not a "pfc boost controller" function, it is an ECU function for overboost control. Up your boost limit in the PFC to .25 over what you are targeting. Can be done with commander.

 

Do you have the modifications to support running 15+ psi?

 

yes, supra pump, 1600 cc secondaries, fmic, etc, etc. im not ganna run over 15 psi though. and only 15 psi when on at least 50/50 mix race fuel. im a conservative guy.

 

1.05kg/cm^2 on a stock map sensor is way more than 15psi. It's probably more like 18psi

 

dude, your way way way off. its 14.6 psi. 1.00 kg/cm2 is 14.22 psi.

 

1) On paper you are correct when simply translating psi to kg/cm2.

2) Everything else you need to listen up and fly right: Steve is right in that you are nearing the upper limit of the stock 2-bar sensor and unless you have real world testing or experience to back up that yours is exactly 14.22psi...appreciate what Steve is trying to tell you and be careful.

3) Appreciate what everyone else is trying to tell you and make sure you have the supporting mods or we'll all call you names after you post in here that you blew your engine.

 

yes, i have all supporting mods. i have gauges saying boost is right. unless both are wrong? anyways. i know im getting up to the end but im only running 12 psi now. i never even meant to run that high it was a cold day out.

 

9 days late?

IIRC the stock map sensor tops out at 17psi. He should be fine doing 15psi on a stock sensor.

Also, that boost could have been creep from the WG... and thent he PFC could have ran into the fuel cut area (like mentioned before .25kg/cm² over set boost). I set my boost limit to max, I think it's like 12.5 or something.. and I just use my boost controller.

I am not too familiar with the profec b since i use an AVC-r - but it might have a duty control setting and it may be a bit to high causing the boost to go over the desires limit. Try reducing the duty cycle so you hit your exact boost at WOT.

Just my $.02

 

yes, i was saying that about the map sensor. i havent hit the end of that yet. i truely dont want to be running 15 lbs now, i tuned it down to 11 because spark break up is making any more boost useless. i have a hks twin power on the way, so that should clear things up a bit. also should prolly change the trailing plugs. im still working through boost issues, but mostly because the non seq. twins werent completly converted to parallel by the previous owner.

 

that wasn't the original argument. Stock map sensor isn't accurate w/ the pfc. Have you ever notice that when you run 12psi on the boost gauge, the pfc only shows .7-.75kg/cm2? It should be at least .8kg/cm2 if anything. Once it hits 1.0kg/cm2 on the map sensor, its no longer a linear function. I have seen 17-18psi on the gauge when the map sensor was only showing 1.05kg/cm2 (approx 15.5psi) on the pfc.

if you guys trust the stock map sensors reading, go ahead and knock yourself out.

 

Touche

Steve, I never got a response about your tuning. If you look in the thread for the socal tune ont he 29th, you'd be able ot respond. (if you dont mind)

Thanks
-Darren-