how much boost before fuel cut???
 

Aight i have an 88 turbo 2 with a manuel bc and was wondering when does the fuel cut happen on these i have a walbro 255 large streetport three inch intake just in case thought i would let yall know thanks guys

What kind of engine management are you using?

Stock ecu

If you haven't already experienced fuel cut, you might have a blown turbo....
Its supposed to cut at around 8psi, which you could easily hit w/ any ONE of your modifications.

8.6 psi

Na i havnt boosted on it yet fresh rebuild on turbo and motor i was just wondering for after break in and what happens if bc is on back wards

Do you have a fuel cut defender? I have two if you need one LMK

I do not i do need one though how much how much would u want for it and is it ok to boost about 2500 miles on motor cause i did it today and held at 3 psi and droped it to 0 psi i have another thread about that its called "boost issue"

He has an S4, isn't fuel cut for S4's 5psi or 5.5psi?

No. You're thinking of the max boost. BOTH S4 and S5s have a 5.5psi wastegate spring. S5s use a factory boost controller to reach 7.5psi, and if either boost creeps to 8.6psi, fuel is cut to the rear rotor.

So how well will the wastegate hold past stock boost that kinda sounds dumn for mazda to do that lol

So to be able to run 10-12psi on stock engine, stock turbo, you obviously need a fuel cut defender, right ?

Look up how a boost controller works. The wastegate spring makes little difference when you adjust how the actuator sees pressure.

With a stock ECU, you need an FCD or an Rtek chip.

Nice, so lets say with everything stock and a FCD, whats the maximum psi you can run on a s5 turbo2 engine before the turbo blows up or something :) ?

I would not run more than 9 psi, which is approximately where fuel would cut normally.

fuel cut at 8???
my buddys will spike up at 13 and still no fuel
cut and every thing is stock just a bc and down pipe

Either his car is not Really hitting 13 OR the ECU is not seeing the signal from the boost sensor. One or the other.

Will putting a fcd on my car cause bad boost creep cause i really dont wana blow my motor lol and hailer where in fort worth u live?

If your exhaust is free-flowing, as well as your intake, boost creep is pretty much guaranteed. Instead of hitting fuel cut, you'll overboost instead. Also, FCDs alter the boost signal to the ECU, which means negative effects on fuel and timing. Honestly, since the Rtek chips became available, there's no reason anyone should be using an FCD.

No it won't cause boost creep. Mods will cause boost creep. FCD will prevent you from blowing up your motor from fuel cut when your boost creeps.

Which Rtek chip are you talking about?

Thanks for the clarification RR.

Incubuseva, I don't think fuel cut will actually kill a motor. And all the rtek chips have FCD's now.

Also, n0ferz, there's no real point to run that much boost on a stock turbo. You're basically just overheating the turbo at that point or close to it.

Car manufacturers have been employing fuel cut protection on turbo cars for a long time. If it were somehow safer to allow the engine to overboost, they would have done that instead. If all fuel is cut, there can be no detonation. It's when you have a lean mixture that you have a problem.

Rtek 1.x chips are cheap, don't fool the ECU by changing the boost signal, and have many other nice features. http://www.pocketlogger.com/index.ph...age=1&ecu=S4T2

^I looked those up after I posted that. I think most people have FCD's because you can easily find one used for less than half the price of the Rtek.


I think I'll go with a 2.0 instead of my neo.

hey sorry for reviving this thread idk if anyone will even see this. I have a s4 na car with s5 t2 with stock s4 t2 ecu. But my gauge shows its hitting 10 psi i havent hit fuel cut. I do have a 255 pump and my afm is rewired to the s5. So my pump is always on when the key is on. Is it bad to hit 10psi? I do have a 3inch exhaust complete emissions delete. It runs and drives really great. Running 97 Premix and fmic. I do have an aftermarket boost controller turned all the way down.