Fuel cut

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Bensk8s

:
Mazdaspeed Protege 2003
So I just had my MSP on the dyno and tuned, but it still gets fuel cut in 2nd or 3rd at about 5500 to 6000 rpm. The guy who helped me tune it said I should run stock boost, since I have stock fuel injectors, and stock internals. I only have 10psi on the engine and I know the most these engines can take it 12. I'm just wondering, instead of lowering my boost. Is there any other way I can help stop the fuel cut?
 
what engine management are you using to tune? And these motors have been known to blow at 10psi too. What are your supporting mods to run 10 psi?
 
Well I've got a split second piggy back tuner on the factory ecu, I also have a 626 intake manifold, hi-boost intercooler setup, injen ram air intake, synapse bov, hi-boost exhaust manifold, tial f38 wastegate with a spring rated for 10psi, with a turbonetics t-60 turbo. I'm almost thinking of going with the stock turbo or garrett gt2860r turbo later on.
 
Any tuner worth their salt should be able to provide a decent tune with a piggy back. The only reason I could see them not being able to tune out the fuel cut is if you are hitting the max duty on the injectors.
 
True that's what I'm thinking, would I be better off going with bigger injectors, or lowering the boost?
 
I would talk with the tuner again and see why exactly he couldn't tune the fuel cut out. And then make your plans based on that.

If you do need bigger injectors, a lot of people use the wrx 440s on our cars, since they are drop ins and flow way more than stock. Since you have the AFC already, you will be able to tune for the increased fuel flow. You will need a complete re-tune if you go with bigger injectors.

Also, just noticed you are not running the stock gt25 turbo, so you could be moving a lot more air at 10psi with your turbo. I'm not too familiar with your turbo or its size, so can't say for sure.
 
People have a very poor understanding of fuel-cut and what they're experiencing...

Give more information- what are you meaning when you say fuel-cut?

Are you overloading the MAF, maybe?
 
He is running a 60-1 turbo. This is a large T3 turbo capable of big power. Odds are that at 12 psi he is maxing out the injectors and what a stock engine can handle. I'd turn the boost down and enjoy it while it lasts.
 
Yeah I'll just lower the boost, it'd be alot cheaper for my budget. Just out of curiosity though. Would I be more at risk if blowing the engine by leaving the boost at 10lbs, and going with 440cc injectors?
 
Well I think it's fuel cut I. get on the throttle, and the car hesitates at 5500 or 6000. Like the RPMs quit climbing for a minute.
 
Bensk8s said:
Yeah I'll just lower the boost, it'd be alot cheaper for my budget. Just out of curiosity though. Would I be more at risk if blowing the engine by leaving the boost at 10lbs, and going with 440cc injectors?
Click to expand...

8 psi is probably even pushing the limits of the stock motor.
 
I don't think 10psi is a problem if you have a good tune, I know of more than one stock MSP at stock boost that have blown the stock motor. It's more based on the tune and the condition of the engine and how it has been treated/maintained. I do recommend finding some 440 injectors, I got a set for about $100 and they are easy to find.

Fuel cut is not a hesitation, it's a full on cut of the ignition. As if you slammed on the brakes for a split second.
 
Even with the increased air flow of the big turbo he is running, you don't think 10psi is a problem? I do agree with the tune having a lot to do with the longevity of the motor, but 10psi on a large turbo with stock internals is just asking for trouble - no matter how good your tune is.
 
Yeah I think I'll just go with the gt2860rs to be on the safe side, since it is my daily for now.
 
I think you are having another issue since it happens only above 5500 rpms. For me on those rare occasions its below 40*, Ill get the MAF based cut instantly as soon as I go to take off and its way below that rpm. I doubt your bigger turbo spools that late.
 
I don't think changing turbos will solve your current issue. You need to speak with the tuner and see what is exactly going on and address the problem from there.
 
I did talk to one guy, he said with the 60 trim turbo, I'd have to go with rather large injectors to help fuel cut. Other wise he said a smaller turbo would be better for how the engine is. Like a 35 or 40 trim
 
The gt28 will not bolt up to your current setup. The flanges are different t2 vs t3. If you go with a gt28 you will have to get a new manifold. Or you can get a smaller turbo with the t3 flange that is on your current mani.

And I just looked up your turbo, that is way over sized for any protege application, especially one that is close to stock.
 
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