650cc Injectors and 120% duty cycle at WOT

[dirtbike_79]

I just recently put a 2g maf in my car and 650cc injectors.Now that I can finally do a WOT pull(becuase of boost creep to 23 psi) I am getting 120% duty cycle and I still have up to 23 counts of knock and my afc is set to +25 in high throttle. None of this is making much sense to me so any help would be greatly appriciated. Oh and I have even set my timing to 0 degree's to try and get rid of knock.

 

[silver bullit]

You need to fix the boost creep, and it is impossible to run your injectors over 100%.

 

[dirtbike_79]

I have tryed to fix my boost creep, it states in my profile that my turbo is ported and polished, and I have also tryed to put a restrictor in my exhuast. Nothing works. I am basing my duty cycle on what the Mmcd program on my logger tells me, and that is 120%.
I decided a long time ago to get supporting mods to deal with the boost creep becuase that is the amount of boost I would like to run. Oh and this is all happening on 94 octane pump gas.

 

[tbonitz301]

No it is not impossible to run over 100%idc. If you have a stout fuel feed and fpr you can run over 100%. snoboarder714 is running at 124%idc

 

[matt98eclipse]

Have you checked for any boost leaks??

 

[VelocitàPaola]

I have tryed to fix my boost creep, it states in my profile that my turbo is ported and polished, and I have also tryed to put a restrictor in my exhuast. Nothing works. I am basing my duty cycle on what the Mmcd program on my logger tells me, and that is 120%.
I decided a long time ago to get supporting mods to deal with the boost creep becuase that is the amount of boost I would like to run. Oh and this is all happening on 94 octane pump gas.

The logging cycle is only reporting what the IDC is based on a mathematical formula... in reality, the injectors cannot be run at higher than 100% because 100% IDC simply means they're held open constantly. You should take the necessary measures to keep the maximum IDC at 85% or less... running them at higher duty cycles is a good way to burn out the coils.

 

[dirtbike_79]

Yes I did check for boost leaks, but I also figure that a boost leak would make my car run rich, and my afc is set to +25 and its still lean. Dont forget that these are 650cc injectors, why arent they flowing enough fuel for a evo 3 16g.

 

[secondnature]

have you tryed running a o2 dump? i ran one on my big 16g with a ported 7cm housing and ran about 17psi and it helped alot with creep for me at least.And as far as the idc Sounds like you do have a boost leak somewhere. when you have a boost leak the car is adding more fuel to compensate for the the loss of air .

 

[lasthope05]

Have you ever heard of rich knock?

 

[tenn-gsx]

Change your fuel filter. You may be able to maintain correct fuel pressure at idle or while the engine is off, but running lean because of a bad filter or pump at higher rpm/boost levels. Even your fpr might be screwed up.

 

[hdoerr]

Reset your fuel trims and start from scratch. Take into consideration that phantom knock will ruin your power because of timing pulled. The duty cycle situation looks strange but I am willing to bet you need to start from scratch (Tuning).

 

[dirtbike_79]

I changed my fuel filter yesterday, becuase that is what I thought the source of the problem was. I am going to test for boost leaks this morning and then I will reset my ecu and start from scratch.

 

[JayRolla]

Why you adding so much fuel. You should actually be pulling fuel. The 2gmaf makes you run about 15-20% lean and usually 550's will bring you close to normal. But you have 650's, you should be pulling 5-10% fuel, you are running way rich.

 

[oldman420]

Sounds like your turbo, my hrc super16g is wicked. No boost creep. Sorry it's not really help but i thought i might mention it, just incase no one has any ideas how to fix your problem. Also i was thinking if you went to an external wastegate with a low pressure spring that might help as well.

 

[steve]

No it is not impossible to run over 100%idc. If you have a stout fuel feed and fpr you can run over 100%. snoboarder714 is running at 124%idc

This just shows that you don't understand what going on.

IDC is the percentage of time the the ECU wants the injectors open for to achieve the programmed AFR divided by the amount of time available at the current RPM.

Actually delivering >100% violates the laws of physics. Running >85% is asking for trouble.
Depending on the injectors and electronics the behaviour is undefined as you approach 100%, you may get the injectors turn on for the whole time or they may become erratic.

 

[JayRolla]

Ohh also like everyone else said you are running way too much boost on that turbo for pump gas unless you are pulling a lot of timing with some type of timing control. Thats why you are seeing knock.

 

[dirtbike_79]

So I guess I'm going to be buying an external wastegate. I realize that my car should be running way rich, but even my low settings are at -9 +2 +2 0 0 0 0. I am trying to tune using my dataloggers o2 trims and fuel trims.

 

[dirtbike_79]

Why do you suppose that my fuel and 02 trims are wanting to be this rich?

 

[JayRolla]

You can port the turbo for free and that will fix the boost creep issue. Fuel trims can be a pain sometimes, a wbo2 helps so much with tuning.

 

[dirtbike_79]

I have already ported my turbo and yesterday I tryed to extend the wastegate accuallor housing as per the other post on the forum. It may have helped a little bit but not too much. I am thinking that maybe i should pull out my turbo and try to port it some more, but I thought that I already ported it enough. What is your opinion, and I also have full 3" exhaust with a test pipe(no cat).

 

[JayRolla]

It needs to be ported correctly by the wastegate outlet on the exhaust housing. So there is a straight shot to the flapper instead of just flowing right by it. You must not have ported that area enough.

 

[dirtbike_79]

Ok I have finally got an update. I just finished putting my turbo back in may car after porting it for the second time, and my car still boost creeps to 20psi. So this thing is still creeping that high even with an extended wastegate actuator and alot of porting and polishing. Do you think that I could get away with 20psi on 94 octane? Also I still have the stock 1g bov so I am thinking that it could be leaking. If it is leaking and I got a better bov would the boost pressure increase even more? I am stumped on what to do now, so any help would be greatly appriciated!

 

[50trimmed1g]

Probably rich knock. Do you log your o2-v on your logger. Try to get them around 90 for a start and see if you still knock.

 

[dirtbike_79]

At WOT my o2 voltage does not go above .87 even if it is running extremely rich.

 

[dirtbike_79]

Any help?