ok, ive heard my different setups as far as fuel upgrades are concerned.
obviously upgraded fuel pump.... probably tt supra pump
example:

550cc primaries
1200-1600cc injectors

550 primaries
850 sec
w/ additional 2 injectors mounted in greddy elbow

is one better than the other?

i dont want to do over kill.

im currently running 99 twins. dp, cb, hks intake, greddy fmic, koyo rad, pfc, greddy pully kit. would like to put on my mid pipe I have and turn the boost up a little, but dont want to pop my engine (again) I would like to get a good setup with the right amount of fuel.

ive done some research on this and would like some opinions
any suggestions on the best way to do this?
thank you.

 

Adding injectors is a very poor option IMO.

This leaves you with boring out secondaries to 1300cc or replacing secondaries with 1600cc Bosch top-feeders. The 1600cc option is a little more difficult to tune, requires removal of emissions, and purchase of an aftermarket fuel rail and pressure regulator. However, it is a more reliable solution than the 1300cc.

Either option would supply enough fuel to run 14-15 psi on twins.

 

why is boring out the 850's to 1300's not as reliable. Ive just heard that putting 1600's are like you said, harder to tune, and cause a hesitaion in driving. are there any higher cc injectors that would fit in the stock secondary position that would not require and upgraded fuel rail?

 

No

 

Boring out the 850's to 1300's has damaged or reduced the life of some injectors.

You also have the option of using 4x 850's. If you aren't building a 500hp monster, I would personally look into that option.

 

Sorry to thread jack...but if you were running his exact mods with the S3 BNR's you would just be better off running the 4X850's right?

 

So how would you go about running 4 850's? I deff. dont wanna have to take off emmissions just yet, and dont want to have an inj. fail. Would a upgraded primary rail be needed? What are the pro's/con's of a 4x850 setup?

 

The 4x850s requires milling down the primary rail a little bit....not that big a deal. There is some added complexity to drivability tuning with the 4x850s.

 

Thanks as always rynberg.

 

i was talking to my tech about adding 2 additional injectors. he said if I did that, that we could get rid of the pfc and use the stock ecu and a secondary unit to controll the additional injectors. That way Im getting enough fuel. But does the pfc do anything else than control fuel? I thought it helped with timing, motoring, ect....also with putting the stock comp back in, and adding the injectors, wont the primany and sec injectors still be maxing out duty cycle? How would the computer know that there are extra injectors helping out?

 

Wow, start going to a different "tech" immediately. That solution is about 6 years out of date. There are much better solutions now...jeepers. MERGING with your other thread on the same topic.....

 

first discover what u want out of the car. Recommendations that guys will give will be based on your ultimate goal. If u want to keep the twins then go supra fule pump and 1300 cc injectors. Thats what i have been running for 4 yrs or more w/o a single problem. Adding this fuel and turning up the boost is going to wake your car up nicely. I guess i also have to say make sure u get a nice conservative tune!

if u want to go single then a different route will be necessary.

oh yeah and make sure u dont get any boost spikes or creep.

 

cool. thanks, my only problem is trying to find someone in my area to tune it....pettit says they dont know how to do pfc, and japtrix reccomends a guy i know, but not that well and I have been advised not to go that route. so right now i am stuck with what to do. I just ordered the supra tt pump, now i just need the injectors and fuel rail. but still have no one to tune it.

 

Get a group to get Steve Kan out. Or make a road trip to TX.

 

steve kan is awesome but i think there are also several people in south florida that run some serious rotary beasts. contact one of them in your local section

 

most of the "beasts" run a microtech computer around here. not the pfc from what i have seen

 

If you want to push the BNRs to their potential, you'll need more than 4x850. I was running 850/1300 and it was enough (inj duties in high 80s/low 90s).

awd-rwd racer, I agree with rynberg. Your tech is living in the early 90s, going to a stock ecu is a HORRIBLE idea with your mods.

Regarding the supra tt pump, it's fine for your application (99 spec twins). But don't go much past 15 psi, based on the research I've done the supra pump nosedives as you approach 20 psi boost pressure. That's the main reason I sold mine and went with an apexi bnr pump. For more info, check out my thread in the archives, 'some fuel system ramblings'