Im putting my 850 seconds in my primary slot. What should I go with for the secondary though? I have a PFC w/ Commander but I dnot have a data logit.. so should i go for 1600's and get a datalogit (or borrow) or just get 1200/1300's? Anyone have some sell..

haha.. im just going with 850x4.. with a walbro fuel pump =]



should this work for 14lbs on pump and 16-17.5psi on race?



josh

1680's for secondary and then just keep the 850's for the primary!

what exactly are your mods?

850/1200 should be more than enough for what I am guessing is non-seq twins. 850/850 is not going to be enough for 14psi and up.

what about just the 550pri and some 1680 sec. ones? i just ordered a rail....wiating for the bonus in 2 weeks for the injectors.....

Yeah 550 with 1200 and up is plenty. I ran 550/1200 on my old apexi single turbo running 18psi keeping the duty cycle below 90%. 550/1600 is the same as 850/1200.

wont the PFC whack out though? with the 1600's in? or am I on crack..

I think theres a way around it, but you'd need to ask in the ecu section probably for better details.

well isn't it better to run a smaller one up front, for tuning sake.....i mean, wouldn't you have to tune more with the larger injectors up front, rather than bulking up the secondaries....??

Well you have to retune your trims anyways, so wether its primary or secondary its the same either way. If you go too big on your primaries than drivability can suffer from side effects, but 850's are proven to be perfect for the street. Stock injectors are 550/850, so its not like the primaries are going to be bigger either, you wouldn't want 1200/850's or anything, but 850's all the way around is a good setup for certain mod setups.

From everything I have read I would keep the 550 primaries and just put bigger scondaries in. Sounds like a fairly good number of people have trouble getting the idle tuned smoothely with 850 primaries. When I finally get around to upgrading my turbo I will probably go with 550 primary and either 1200 or 1600 secondaries, probably 1600. The 1600's work but because they are low impedance and the PowerFC expects high impedance, you must add a resister in-line with the injector.

I have heard that the pfc has a hard time with the 850 primaries unless you have a datalog kit to fine tune it better. With the haltech or something similar to really fine tune 850's work great. Just another reason why i'm glad I ditched my pfc and went haltech, cause at the time 1600's were out of the question and 850's were hard to tune. Now with the use of the datalog kit its posible to use bigger injectors.