TC injectors and boost

[cdydjded]

Based on the experience of LTNoogie, Garm & ChinoCharles Iv come to the conclusion that that TC injectors are too big & the factory ECU can not control them. They all suffered from the same simptom, CEL, Rich Condition & high RPM misfires. I also know from experience that ECU's of most car today can only handle 10-20% larger injectors. Considering that the stock injector is +/- 190cc & the TC injector is +/- 380cc the problem is obvious. I feel that right now the best injector to use for boosted aplications with a factory ECU is the 1ZZ injector since LTNoogie has had positive results since he installed them.

[mario98c]

Good to know it! Thanks

[Tamago]

Originally Posted by cdydjded

Based on the experience of LTNoogie, Garm & ChinoCharles Iv come to the conclusion that that TC injectors are too big & the factory ECU can not control them. They all suffered from the same simptom, CEL, Rich Condition & high RPM misfires. I also know from experience that ECU's of most car today can only handle 10-20% larger injectors. Considering that the stock injector is +/- 190cc & the TC injector is +/- 380cc the problem is obvious. I feel that right now the best injector to use for boosted aplications with a factory ECU is the 1ZZ injector since LTNoogie has had positive results since he installed them.

obviously the stock ECU should not be used to control them.. are you trying to run a boosted engine on stock ECU alone?

injector scaling is imperative if you're using a piggyback controller anyway, hell, you could run 550cc injectors and a piggyback.

mathematically, at 10psi, WOT and redline, i was running the "tC" (2azfe people, camry, Rav4, Highlander, Corolla XRS, etc etc etc etc etc etc) injectors at around 70% duty cycle. that's pretty ideal actually. you also must consider that as the boost increases, your duty cycle must go down. why? because your fuel system is now fighting the natural compression PLUS the boost pressure in the combustion chamber. 10PSI of boost on top of natural compression, vs stock 50psi fuel system means your injectors need to stay open longer to inject enough fuel to achieve proper air/fuel.

so, in conclusion, the "tc" injector is NOT too big for the 1nzfe. in closed loop, the stock 1nzfe ECU has absolutely no problem maintaining 14.7:1 a/f without a piggyback. i know this because i drove my 1nzfe on 2AZFE injectors for 2 months sans-piggyback. open loop is a different story however.

[Tamago]

Originally Posted by Tamago

you also must consider that as the boost increases, your duty cycle must go down. why? because your fuel system is now fighting the natural compression PLUS the boost pressure in the combustion chamber. 10PSI of boost on top of natural compression, vs stock 50psi fuel system means your injectors need to stay open longer to inject enough fuel to achieve proper air/fuel.

i should clarify this, because it doesn't sound right..

as boost increases, to maintain duty cycle (regardless of fuel usage) you must increase the size of your injectors.

[cdydjded]

I found it hard to put down the words for my comment of the TC injectors. So I did a little search & found this from the MSD Fuel Injection web site:
Bigger Isn't Always Better
Stock, street driven EFI engines using an O2 feedback, closed loop control system rarely exhibit a performance gain simply by installing higher flowing injectors. During closed loop operation, the stock ECU will try to adjust for the greater amount of fuel being delivered. If the replacement injector is not too large (about 10 - 20% greater flow at most) the ECU might be able to make the correct compensation. If the induction system has been left stock and the ECU cannot compensate for the increased fuel volume, unburned fuel will all but pour into the exhaust. This in turn will cause the Check Engine Light to come on, the catalytic converter could overheat and other problems will occur. In applications looking for just a little more performance it my be easier and more cost effective to raise the fuel system pressure to get a 10%-20% fuel flow increase at the injectors.
Remember that installing larger flow injectors only has technical merit if substantial modifications have been made to the entire induction system. Plus, the stock ECU will undoubtedly have to be re-programmed for the increased injector fuel flow.
Tamago: You had the TC injectors installed on your xA? Yes right now Im boosted on the stock ECU, No Piggie back, stock injectors. I have not put it on a dyno, I know its running lean at WOT. I have a set of 1zz injector that I will install while I dyno the car. But overall the car drive perfect, no hesitations, no problems & no high RPM miss.

[Tamago]

Originally Posted by cdydjded

Yes right now Im boosted on the stock ECU, No Piggie back, stock injectors. I have not put it on a dyno, I know its running lean at WOT. I have a set of 1zz injector that I will install while I dyno the car. But overall the car drive perfect, no hesitations, no problems & no high RPM miss.

you even admitting this should cause ANY reader of this thread to disregard any so called "knowledge" you're trying to spread here.

let me dumb it down for you buddy:

how much more power over stock do you want to make? 50% ? that'd be roughly 150whp.

wouldn't it make sense to maintain "stock" duty cycles, you'd want 50% larger injectors? even higher considering you want a much richer a/f than stock, so 60%+ larger injectors?

please, stop spreading misinformation here, someone might follow in your footsteps.

[cdydjded]

You know what Im going to end this right now. Im on the way to the dyno. I will do the following pulls with AFR's:

Stock injectors, 3-4lbs
Stock injectors, 5-7ilbs
1ZZ injectors, 3-4lbs
1ZZ injectors, 5-7lbs

[Tamago]

Originally Posted by cdydjded

You know what Im going to end this right now. Im on the way to the dyno. I will do the following pulls with AFR's:

Stock injectors, 3-4lbs
Stock injectors, 5-7ilbs
1ZZ injectors, 3-4lbs
1ZZ injectors, 5-7lbs

to make it fair, you should be including 2AZ injectors in this..

you can't prove 2AZ injectors are the problem by NOT trying them ;) that's like saying pie makes you fat.. which it can, but only if you eat it...

btw, to those of you lurking, let me explain the OP's logic pattern with a following "hypothetical scenario"

garm, chino and ltnoogie all eat pie
they're all overweight
i don't eat pie and i'm not overweight
so therefore the reason garm chino and ltnoogie are overweight is because they eat pie
so pie is the problem here
and nothing else can be considered
i am going to end this once and for all, and go to my doctor. i will be taking cake and ice cream with me. i am going to eat a little of cake and weigh myself, and see if i'm overweight. i am also going to eat a little bit of ice cream, and do the test again. however, i am NOT going to eat PIE and weigh myself, because pie has already been proven to be the cause of obesity.

i will post my results here later

[cdydjded]

Ur right, Ill find a set of TC injectors.

[Tamago]

Originally Posted by cdydjded

Ur right, Ill find a set of TC injectors.

no matter WHAT injector you install, whether it's 1zz or 2AZ, make sure to let the stock ecu learn the duty cycle after install. you cannot do this sitting on a dyno. you'll need to let the car go through a few heat cycles with each injector installed before testing on a dyno.

also, it's important to note that a dyno pull isn't going to tell you anything about closed-loop behavior, which is much more important than open loop behavior. full throttle pulls will undoubtably be in open loop, and the stock ECU isn't going to be monitoring AFR's.. at low boost the 1ZZ injectors will most likely get you closer to 11:1 than the 2AZ injectors, but again, this has nothing to do with your original argument about tC injectors vs "missfire codes".

good luck, post your results. dyno sheets only tell us so much, street tuning with each injector size installed is far more valuable in the real world (street tuning while monitoring AFR's of course)