Can higher octane help with fuel-cut?

[FINETUNED]

I would like to if I can get another pound or two on higher octane than I can on 91 pump? If not than what will I gain with race gas at the same boost?

 

[snoopnoon]

Do a search of how and why fuel-cut is what it is first next time, and understand the concept. You could have answered your own question easily.

Fuel has nothing to do with fuel cut. "fuel cut" is caused by the ECU seeing to much air and saying, hold on. i dont think i can take this much air, i am shutting down now. Now if you have some sort of fuel control like SAFC MAFT or VPC to "tune out" or delay fuel cut then you can use higher octane. TMO also is a fuel cut defenser.

 

[RACER-X]

wouldnt going with larger injectors instead of the factorys remedy the problem he's having with fuel cut?

 

[echo]

not really. from what i have read. as he said it isn't fuel related. the ECU see too much air and doesn't think it can handle it, so it shuts it down. the ECU doesn't know if you have bigger injectors or not. that's why you buy a piggy back fuel management system or a standalone.

 

[FINETUNED]

OK so will a fuel cut defencer trick the ecu safely for track use with C-16? How will C-16 help me for a better 1/4 time or will it at all?

Thanks for the help

 

[echo]

you need to get a logger atleast (if you don't have one). fuel cut isn't there for no reason. it's letting you know that your stock fuel system can't handle it. if you have bigger injectors and fuel pump then a fuel cut defencer would be ok. until you upgrade the system then i wouldn't bother with one.

c-16 will allow you to run more boost safely without blowing something up. this is were you will need the logger to decide when your knock is getting too high and when to stop adding boost.

 

[snoopnoon]

Stock injectors or capable of low 12''s. there are alot of people on this forum that do not have a fuel cut defenser but have done the "free mods" to help delay it. You can remove the lower honeycomb, back out the screw (it is under a coat of jelly like substance), most likely you have a boost leak somewhere. I do not knw what you are running for times but a boost leak will also let you see premature fuel cut.

 

[ItsStockOfficer]

Yes, their capable of low 12's, I trapped 112 on srtock injectors.....I also hit 1050c egt's.....the choice is yours and yours alone.

Sean

 

[blinded]

Originally posted by snoopnoon
Fuel has nothing to do with fuel cut. "fuel cut" is caused by the ECU seeing to much air and saying, hold on. i dont think i can take this much air, i am shutting down now.

You sure about that?

I'm no expert, but I thought that fuel cut solely occurred when injector duty cycles got too high. If the ecu sees knock, doesn't it richen up the mixture, raising duty cycles? If so, then I would think that race gas through its resistance to knock would allow the ecu to lean out the mixture, which in turn would lower duty cycles and delay the onset of fuel cut.

 

[pneumo]

Not quite. The ECU doesn't adjust the AF ratio at WOT, it just relies on the BCS and timing retard to control knock. snoopnoon is correct.

 

[DrZiplok]

Actually, both of you are right.

Fuel cut happens after the ECU has decided that it can't match the amount of incoming air with a corresponding amount of fuel (ie. in the time available to it to open the injectors, not enough fuel will make it out).

You can lean the mixture out by lying to the ECU about the actual amount of air (this is what the "free mods" referred to above do, as well as by tuning with an AFC), but eventually you will use up the safety buffer that the ECU has built in, and you'll simply have to deal with the fact that you need more fuel.

Thus the only real "cure" for fuel cut is - more fuel.

pneumo - actually, the ECU will fuel dump if it detects knock, it just can't if it's already running at 100%...

 

[tsi_turboawd]

by hacking the MAS - remove lower H-comb, silencer, and screw the plug down - should help reduce fuel cut

 

[RACER-X]

well on stock injectors if i were to go past 1 bar of boost my engine starts to surge.. dropping power for a second then getting like a surge. dont really know how to explain it better.

i figured with bigger injectors and installing the 255 fuel pump would take care of this problem.. am i wrong to assume this much?

 

[greyforestgst]

i prevent it by going just a hair shy of wot when im racing.
this forces the ecu to stay in open loop mode, and realize o2's are perfectly safe (pretty damn rich too) due to my propane.

 

[RACER-X]

how do you race and not go wot?...

 

[jibberishballr]

i prevent it by going just a hair shy of wot when im racing.
this forces the ecu to stay in open loop mode, and realize o2's are perfectly safe (pretty damn rich too) due to my propane.

I had a question about this. When i am driving hard and i floor it at higher RPMS i have what feels like lag....like my turbo was kicking in and then it stops and then kicks in again but not quite as hard. Feels almost like an automatic trying to accelerate. However when i dont go all out and push down about 3/4 of the way i get a steady rise in boost and actually go faster. Any thought?

 

[98eclipseRS]

I had a question about this. When i am driving hard and i floor it at higher RPMS i have what feels like lag....like my turbo was kicking in and then it stops and then kicks in again but not quite as hard. Feels almost like an automatic trying to accelerate. However when i dont go all out and push down about 3/4 of the way i get a steady rise in boost and actually go faster. Any thought?

DO A BOOST LEAK TEST!

 

[jibberishballr]

Did one!! No leaks!! ???

 

[bastarddsm]

i prevent it by going just a hair shy of wot when im racing.
this forces the ecu to stay in open loop mode, and realize o2's are perfectly safe (pretty damn rich too) due to my propane.

hey, I hate to burst your bubble but open loop depends on more than throttle position, you go into open loop mode when throttle position is over 45%, or engine speed is above 4000 RPM, or airflow reaches a certain amount, about the time you build 2psi. and closed loop is really bad for boost b/c of the 14.7:1 it searches for is waaaaaay to lean for power and perfect for melting pistons.

 

[No_Skillz]

Did one!! No leaks!! ???

Unlikely. Please do a proper boost leak test with a compressor and soapy water and keep an eye on your boost guage. Unless you do this test regularly (as in every other month or so) you are sure to have leaks.

Getting hack happy on your maf or buy happy on your tuning equipment isn't going to do a thing to help. Fuel cut is there to protect your engine. If you have a stock turbo and you just block it out with a fuel cut defender or lie to the ECU with an AFC, you will:

1. Overspin your turbo leading to premature failure
2. Have a bad tune
3. Not be able to see if there are any really serious problems, possibly leading to a blown motor.

98eclipsers is correct. Do a proper boost leak test. It's always the first step and 90% of the time it's the only thing you need.