hks 272's maxing stock injectors....

[terminaltsi]

ok, first off don't worry about why i have 272's before i've upgrade my turbo....i had them from another car, so i dropped them in the current one. my question is this, would the 272's max the stock injectors at 14 psi, stock turbo, 255 pump, 3" turbo back, fmic, safc?

i'm thinking the additional airflow afforded by the 272's is drastically increasing my need for fuel, causing a nice stutter around 6k rpm, even at +15% on the safc....

anyone think it's true?

 

[nine5raptor]

With cams, you will flow more air at a lower psi. What happens with knock and ipw during the stutter?

 

[terminaltsi]

i can't really see what happens with knock and pw when this happens because my natural immediate reaction when i first hear the stutter is to shift....there is nothing BEFORE that point though that woul d indicate anything abnormal.

i guess i'll make a run and try to stay in it just a little bit to see if the logger will pick up something i can use.

 

[nine5raptor]

Is it a stutter or does it feel like you locked up the tranny and hit a wall at the same time? If so, then it is probably fuel cut being induced by too high airflow levels.

What kind of plugs are you using and what is the gap on them? Also how old are they?

 

[terminaltsi]

it's definitely not fuel cut, it's a stutter

plugs are bpr7es, gapped at 030 (because of the lower boost i'm using, otherwise i'd go to 028 for higher boost), they're 1300 miles old.

 

[terminaltsi]

injector pulse width at the onset of this "stutter" is 18.4ms at around 6krpm. that's pretty close to the edge isn't it; as far as duty cycle goes?

 

[hostile]

I doubt your getting that much more airflow out of the 14b.

Are you still using a stock 1g mas?

 

[terminaltsi]

yes i'm on a 1g mas, honeycombs removed. just installed 650cc injectors, trying to get them tuned using the safc. stutter still present, logger doesn't show anything helpful at the time the stutter occurs. 02's at 0.90v, no knock, boost at 1.2bar, pulse width now around 12.8ms, max airflow according to safc approx. 1900Hz, timing at approx 22deg.

any ideas?

 

[djpast]

regap your plugs to 28, see if that helps... or try change out your plug wires... that seems to cure alot of problems...

 

[terminaltsi]

regap your plugs to 28, see if that helps... or try change out your plug wires... that seems to cure alot of problems...

yeah i'm going to pull the plugs today and gap them. i don't think however that it's a gapping problem, i'm sure the ign. can light up 1 bar boost on 030" gap, but i'll try it anyway.
plug wires are 2k miles old.