TwinTriangles

Well Ive been hitting fuel cut now everytime in 3rd or 4th probably 5th but right about 6k-6500rpm, The car will not get by it I must shift or it will buck all the way down the road, Im working with the PFC to solve it but Im wondering how dangerous this fuel cut really is...?

Its happened to me many times and my car is perectly fine, Its just real annoying when it cuts and im not ready to shift yet...

Maybe I should be more careful when it happens but how else are you supposed to know if the problem is solved if you dont try...?

I'll post my boost settings and mods as soon as I can go write them down, maybe Ive got something real screwed up there but I've been upping the "target boost" value with no prevail and upping/lowering the WG duty %'s with no prevail either.

I dont want to change my boost pattern at all because then i would have to be retuned, I just want the fuel cut to go away...

Ive read many old threads and got a few more ideas but looking for some personal input here also...

Thanks guys!

cewrx7r1

iTrader: (2)

Have you read page 28, last paragraph; of the PFC manual where it warns about fuel cut?

Your boost must be running 3.6PSI higher than you think it is set at in the boost setting table.

TwinTriangles

I havent noticed it spiking at all, when I peek hold on my commander it shows it holding the same spot everytime. I'll take it out later and check the peek hold again

cewrx7r1

iTrader: (2)

Nothing to do with spiking. Has to do with the boost set point in the table. If I have it set for 10PSI but actually are running about 14, then fuel cut.

Target boost must be higher than you are actually running.

TwinTriangles

Ok I had a chance to do a few hard runs today, And I was at a little warmer intake temps and didnt get any fuel cut. So it must be that the wastegate is having truoble controlling boost when its cold out. these are my settings:
0.95 58%
0.95 80%

Now 80% is right about 14psi what we were shooting for when I got tuned tuned last summer. Now peak hold today I saw the highest 1.10, 3 hard runs 2 1.09 and the 3rd was the 1.10. Im not sure what Im hitting exactly at fuel cut, but if I up my tartgeted levels but leave the duty cycles the same, is it going to up my boost at all ?

rynberg

No, it shouldn't. The PFC fuel cuts at 0.25 over the target, which would indicate you were hitting 1.2 bar, if even momentarily. I would raise your duty cycles a little bit to lower your boost.

TwinTriangles

So I should raise the duty cycles a little to say 62% pr & 84% sec or so, Should I raise my target level up to like 1 or 1.05 ?

rynberg

Set the target level to whatever you want to run at. Adjust the duty cycle until you are consistently hitting the target. You should be adjusting duty cycle via a boost gauge and NOT the PFC, because there is a well known issue with the Commander displaying a lower boost reading than what you are actually hitting.

TwinTriangles

Ok well .96 Bar is what I want and usually am hitting but I was unaware that I was creeping past that, And I guess it only happens if air temps are too cold, So .95 is a good target.
But doesnt the PFC take into affect the target level and the duty cycles and come up with an avg. ? Maybe Im wrong there. So I should keep the target value at .95 & raise the duty cycles so that after it creeps the highest it will creep to is my target value right ?

Say Im hitting 1.10 but I only want .95 so I raise the duty cycles so I should only be hitting .80 and then when it creeps or whatever it should hopefully only rise to around .95 ?

cewrx7r1

iTrader: (2)

I personally do not use the PFC to control my boost.
Tried it and it did not work on my car.

I use a Blitz DSBC which has an overboost function that prevents overboosting by dumping more exhaust gases via the WD.

I can set it at 15.5PSI and boost will not go over it and the engine keeps on running fine. No fuel cut.

I suggest it to all!

particleeffect

yeh but don't "ineligent" BC's have problems with the sequential system because of the unsteady boost levels at transition?

cewrx7r1

iTrader: (2)

I run non-seq and maybe that is why I could not get the PFC to control my boost properly. Thus no problems with transition.

A friend used the Apex-I AVC-R to control boost on his SEQ turbos because it does it better than his PFC. It controlled both PC and WG better. His boost was almost perfectly flat with no noticeable spiking or dropoff during transistion.

Since his car was heavily modded, he later went non-seq like me. He now prefers non-seq over seq.

Seq is good for stock or lightly modded cars.

The owners with heavily modded engines that I know, prefer non-seq or single over seq.

TwinTriangles

Ive got an AVC-R but I cant put it in because I would need to have my fuel map retuned because of how it was tuned last year real strange to help smooth out the power curve. I would put it in but the PFC does pretty well controlling boost for me usually and I cant find anyone in the area who can tune my PFC anymore... So Im just holding onto the AVC-R until I go single then Ill put it in

jpandes

I have the PFC and it doesn't control my boost at all. I use the good old spring and ball manual boost controller to keep boost down to 14-15.

TwinTriangles

I just realised my only problem with creep is when intake temps are cold and Im above 5k rpm. Im still running sequential, is there a way I can hook up my avc-r to just have it control the secondary turbo or control just secondary boost because I dont get any spiking or creep before the transition ?