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Discussion Starter · #1 ·
For all those of you experiencing fuel cut, what mod finally led to your experience with fuel cut? I realize their are a number of possible combinations of mods that would cause fuel cut so please state the following:

1) vehicle modifications before you experienced fuel cut
2) modification(s) that finally led to fuel cut

examples

1) CAI, cat back, dp, bov, mbc (17psi)
2) TMIC

or

1) SRI, DP, EBC (16psi), cat back, FMIC
3) larger turbo

or

1) stock
2) L-A TMIC, MBC (18psi)

I tried to develop a poll for this but the number of combinations was too great. Please keep your answers to the 2 requested. If you would like to start a new thread discussing the possible reasons for fuel cut, there are already plenty around. For this post, i'd like to keep it clean with just the answers to the question. Thanks in advance to everyone that replies.

PS. mods, if this is better suited for engine/drivetrain section please move it as i don't have the capability to do so.
 

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Mods to my car are listed in sig below so i'm not going to retype all of them.
Fuel cut appeared when i put the MBC on... even tuned down all the way the car still spiked to 20psi when rolling into the throttle in any gear above 3rd. The car holds boost fine if i launch it and go WOT 1st-4th.... but low rpms / high load driving cause it to cut fuel. Since then i have added the TMIC and DP which obviously haven't helped the fuel cut issues... i just be careful with my right foot and modulate throttle to control boost. One of these days I'm going to tap the MBC input into the intake manifold instead of the stock boost control location (the stock location has that restricted opening and concensus is that it doesn't allow the wastegate to react fast enough to prevent the boost spike).

I have a feeling that even if I remove the MBC that the car will still cut fuel because of the additional flow from the TMIC and DP so I'm hoping i can tune the MBC to hold 14lbs of boost with very little spike until tuning becomes available. Even with tuning, I'd be happy with stock boost until 6k falling to 12lbs at redline and just some timing advance with better AF ratios. Should make for a fun car without overworking the tiny stock turbo too much.
 

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1) My first experience with fuel cut was from using an MBC, but that was controllable. I used to have a Fujita intake, Magnaflow exhaust, 1G BOV, and the MBC, and I could run up to 16-17 psi before hitting feul cut (that is boost post intercooler, so 19-20 psi coming out of the turbo).
2) I now have the ATP GT3071R turbo kit and the Magnaflow catback. I do not have the MBC anymore since the boost can't go below the wastegate's opening point. I do not get fuel cut in first gear, boosting at 15.5 psi, but in the other 5 gears I spike to 18-19 psi and settle at around 15, but the spike causes fuel cut so I only settle if i control the boost with my right foot. Yet if i control it at 15 psi I will hit feul cut at the top of gears 3-6. I'm soooo ready for a feul cut defender/tuning!
 

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With the catback, intake, BOV, and engine mounts, I never experienced fuel cut. The catless DP had me see fuel cut rarely, only when Im floored it at really low rpms. With the cutout, I hit fuel cut in the top of 5th and 6th, anywhere above 5000 rpm.
 

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Whats with the fuel cut issues anyway? i helped a friend put on his cp-e downpipe and he put on the cp-e cai and while driving hard we experienced some fuel cut it wasnt cool lol.
 

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Fujita intake, catless CPE dp, no fuel cut, then MBC and 17 psi with no fuel cut. Anything higher would hit fuel cut. Then the TMIC and it fuel cuts above 15 psi, the TMIC obviously worked wonders, put the stock boost control back on since cannot use the boost above wastegate spring pressure anyway. Then winter set in and at any ambient temp below 50 or 60 degF it fuel cuts at 15 psi with stock boost control. Evidence that these mods do flow more air, therefore more hp potential.
 

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Discussion Starter · #9 ·
great, thanks for the responses guys. I was debating on whether or not to hold off on the TMIC and DP until a FCD was available, but i think i'm still going to pull the trigger on both. CP-E seems to have an idea of what's going on with the throttle plate as well, so the future looks promising for the tuning of this platform.
 

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Before: CAI, BOV, EBC, open stock DP, and nitrous innercooler sprayer.

After: CAI, BOV, EBC, catless DP, custom cat-back, nitrous innercooler sprayer.
 

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Before: CAI, 30+ degree F weather

After: CAI, Catted downpipe, sub 30 degree F weather

Had the downpipe on about a week before my first instance of fuel cut, temperatures dropped to 15 or so that week and I hit it on the way to work in the morning, motor not totally warmed up, low RPMs in high gear. I have hit it since only when temps have been below 30, so that seems to be the break point for my car.
 
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