# Bigger injectors?



## Qnko (Jun 8, 2014)

I am thinking of finally getting my car a dyno tune. I got a tune from the guys that sold me my engine parts and put it with my budys EFI live. Car runs great but I know that this kinda tunes are far from perfect. 
Car has trickflow 225 heads, cam is 240/244 .605/.598 112+4 , fast 102, NW102 longtubes etc. A guy with same heads and cam made 485rwhp.
When do you have to replace the stock injectors and what is the max power they can support? From some online search they say I need 42# ones. I did a log though and the max I see is 87% injector duty cycle (I know I should upgrade at 80%). 
Will there be a noticable difference from properly sized injectors and a real tune? Car runs great now and it goes to 87%idc only at WOT. 
Just trying to justify my expense.


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## JeffM (Jan 27, 2014)

*Injectors*

I wish someone knowledgeable would weigh in. I don't mean to highjack the thread but I have a similar question. I have LS3 heads/intake with LS2 fuel rails and injectors. I am considering going with LS3 injectors and fuel rail for a Fast intake in the future. I just wonder what size injectors to go with and what the upside or downside would be besides tuning for the injectors themselves. Is there any benefit to larger injectors other than increased fuel delivery?

Thanks


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## svede1212 (Nov 1, 2005)

I wouldn't worry about someone else's "dyno number". Who knows if it's accurate? Larger injectors probably won't give you more power. Yeah, you should have bigger ones as the control of them at 87% means they are pretty much static and open all the time but if your AFR is correct it's correct. The reason to run below 80% injector duty is to make sure at some point you don't run too lean of a condition and melt a piston or break #7 ring land from detonation. BTW slightly too lean usually gains you a little more power at the expense of safety. You should be tuning with a wide band O2 controller to verify AFR


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## Qnko (Jun 8, 2014)

Thanks for the reply. I will probably do the injectors and tune. I don't wanna risk melting a piston and my current AFR is probably just a guess. 
What is a good brand injectors for the ls2 (fit and ease of tune)?
Will the tuner have a problem if the car was tuned with EFI live and he uses HPtuner?


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## svede1212 (Nov 1, 2005)

He should be able to tune it. FAST and DeatschWerks 42lb LS2 Injectors are popular


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