Does anyone know what HP levels would 650cc injectors sustain vs. 750cc injectors? I am wondering if 650 would be sufficient or would it be best to get the 750's? I would like to think I will eventually upgrade the turbo, but not for a little while.

Any thoughts? They wouldn't go on until the car was retuned, but I need to know what to plan for.

 

good question.. i went with the FIC 650cc and hope they are fine for 264,264 cams and either a TME, WR, or IX turbo upgrade.

 

Anything less than 700 should be sufficient for stock turbo numbers on pump gas, if you plan on running full time alky/meth or race gas ALOT then i would go with some 720s or so simply because the max duty cycle on 600s would be achieved at about 27 psi or so. This is all bench racing though and a tuner would be able to give a much better opinion.

 

I use Sard 1000cc. with KKK K27 MOJ turbo, it's ok.

 

I have the WR and stock cams. I went with 680s.

 

What engine management are you running? You are not going to have much success running anything bigger than 720cc on a flash. Most tuners seem prefer tuning 680cc on OEish type turbos.



BTW, I have a slightly used set of 680cc for sale I also run 680cc with my WR turbo...

 

I am Dynoflashed presently, but I am trying to find out how well Al can tune if I get the 750's.

Zeus you have a PM.

 

I believe Al has posted in the passed that the largest he recommends are 720cc on a flash... matter of fact; I believe that is all the OE ECU can handle. I think he has tuned larger (unknown success), but you would have to call him up on that one.

 

Thanks for all your help Zeus! I am still not 100% positive my direction, but you did help me narrow things down.

 

If you are going with a bigger turbo why not just get bigger injectors for now? Your not wasting any more fuel with the larger ones are you, isnt it controlled by the ems?

 

That was what I was thinking of doing, getting some 650-680's. But there again, what kind of power levels will they support? GT35?

I guess my dilemma is I don't know what direction I want to go it. I can go larger i/c and injectors or i/c, 10.5 hotside and manifold. I don't forsee myself upgrading the turbo anytime soon, so that is where I am presently.

I don't have the EMS. DynoFlash.

 

it all depends what you are tuning with too - you can generally get alot more out of an injector via MAP tuning than MAF tuning.

For a GT35 - I'd go at least 785 or larger - most people tend to use 1000's from what I have seen, as it gives a good margin for race gas and much higher boost.

For a stock turbo car, even one with the TME or 10.5 hotside, 660 is generally all that is needed, 720 if you want a bit extra headroom

 

Then it isn't especially necessary that you upgrade the stock injectors at this point in time. You should delay that decision until you DO know if and what turbo you plan to use as an upgrade.

A genuine 500bhp combination should use a 750cc/min injector, 850cc gets you ~600bhp. A 650cc should be considered good for up to ~450bhp or so.

 

Would Denso Style 680CC's be enough for a GT3076R or a 3037s on pump?


Thanks

 

Bear in mind that much of this discussion assumes that your fuel rail pressure will remain at 43 psi. It has been my personal experience that upgrading to a Walbro 255 fuel pump (without upgrading the FPR) will increase base fuel rail pressure to ~52 psi. If you run a fuel injector normally rated at 680cc/min @ 43 psi, at 52 psi it's effective flow rate will increase by about ~10% to 748cc/min.