Why did I hit fuel cut in my S5 TII?
 

Why did I hit fuel cut? Is it my downpipe and straightpipe. I was told it would be ok, took it for a drive and got fuel cut. Engine pulls really good once turbo kicks in at full boost though. My first time driving my fc turbo, and im impressed even when fuel cut kicked in.

likely the downpipe and straight pipe are causing boost creep. port the wastegate and report back.

its funny, because a lot of people on here said it would be ok. Well, I will port wastegate anyways.

Stock ecu fuel cut for boost is 8psi I think, just get a FCD, FC's can easily handle up to around 10psi with stock turbo + cooler.

Porting the wastegate is more effort than it's worth in this situation imo

Who was the idiot that told you it would be okay???


-Ted

I'm curious to know, also. Even a downpipe, with stock cats, will *probably* cause you to hit fuel cut. Seriously, give us a name.

And, you say you were impressed..what sounded like.."during" fuel cut. Tell me you didn't continue WOT during fuel cut >.<

And uhh, porting the wastegate, more effort then it's worth? WTF? What other situation would you port the wastegate in? Downpipe and straight pipe..with an air freshener? WTF?

Don't remember who, I asked a long time ago when I was barely starting the swap like 4-5 months ago. Yea, I will install my fuel cut defender, if I can figure that out. as long as I dont get uncontrollable boost creep that would be koo. I guess tommorow, I will install my boost gauge, then install my HKS FCD and see what kinda boost I get. if its too much then I will port the wastgate since I already have a MBC. Then I can try to figure out why my stupid black magic fan wont turn on, and why my radiator had a lot of white smoke on the driverside of it.

And I was impressed of the power when it hit full boost at 3800 rpm and was impressed until I hit fuel cut. What I mean is even though I didn't feel all of its power to 7000rpm, I still was satisfied with the power I felt before fuel cut-off.

What else you running?

-S5 13BT Engine - low mileage JDM engine, Stock Turbo, Stock Intercooler, 2.5" Downpipe with straight pipe, HKS Intake with 2.5" TID, , Koyo Radiator, HKS SSQV Bov, Walbro Fuel Pump, Black Magic E-fan, Mazdaspeed Motor Mounts, SS Oil lines, Eibach Springs

I haven't installed HKS Pfc F-con, HKS FCD, HKS Turbo Timer because I still have a bouncy idle problem.

If you want to confirm it's definitely overboost fuel-cut, just unplug the boost sensor at the electrical connector.
So long as you're not going crazy boost, like over 14psi, give the engine more load slowly and see if you can replicate the bucking.
If you get no bucking, that just confirms it was overboost fuel-cut.


-Ted

hmm

weird
i run 2.5" downpipe, midpipe, testpipe, into RP catback
no fuel cut here....

i agree with what ted said... give that a shot???

Well considering he'll be making maybe 2-3psi more than usual TOPS I fail to see the logic behind going to the trouble of removing a stock turbo to port it's wastegate when he could just as easily install a FCD and run it at ~10psi, which results in more power and at that level of tune is quite harmless.

If he is getting boost spiking then, yes porting the wastegate might be the best option, but if he is just creeping up to 8, 9 or 10 psi, why not just run it?

but he does have intake and exhaust, kind of. I would port it anyway, just to be on the safe side and so you wont have to deal with it later..


Gil

with that f-con though, he would be safe...

The point of porting a wastegate is to have the freedom to do mods, without boost creep..Boost creep = unreliable, unsafe, etc..

I'd rather have a boost controller making me get more boost, rather then my system simply not being able to flow enough to NOT be creeping.

Well, I haven't exactly put that in yet, because I still have a bouncy idle, and figured I'd throw that in once my car idles right. I already have an extra wastegate that has been ported in my room of parts. It won't be hard bolting it on the the turbo. and I believe it was fuel cut, because the car pretty much didnt even want to push anymore, it was like at 5500 rpm, and I know hesatation is at 3800 with bad grounds but mine picks up quick until 5500rpm. I remember someone on here said I would get 1-2 psi with the 2.5 dp, mp, and HKS filter and TID, and wasn't fuel cut at 8.7psi? Oh, well, I guess I would do it all anyways, just to be safe for now and in the future since some of you stated. thanks for the help and opinions.

do what ted suggested... you would find out forsure if its fuel cut
if not... it *could* be boost leak....