I can get my hands on 2 greddy 720cc secondaries...to put in place of my 550cc stockers....how much HP will theses 720cc handle?? or should i just spend money and get the 1600cc secondaries

 

Question's been asked a lot, but off the top of my head I'd say 300whp would be the absolute max... Like dangerously maxed out, lol. I've seen a dyno-sheet recently posted and the guy dyno'd at like 304whp with 720cc's... It's not recommended to stretch any injector that far though. Maybe 270-280whp is a good maximum number.

The 1600's would be around the same price, but there might be a little injector/fuel-rail modification necessary. I think FC3Spro.com has some reading on this, but I'm not *quite* sure.

Try searching.

 

yoiu have to also figure what are u using to control these injectors?? you MUST have a standalone to use some 1600cc, they are huge 3x the stock size, ive heard of people running 720 on stock ecu and they are just somewhat rich

 

Will a piggyback be able to lean it out a bit after getting 720's?

 

Absolutely or you could get a Rtec 1.7 and it will do it for you

 

thats what im goin with a rtec 1.7 and 720 secondaries....i could always put my 720s to primary too.....would that allow me to obtain a higher HP?? and of course tune it with my SAFC

 

Ive read everything i can....on fc3spro.com they say 4 x 720 for their fuel that they use all the way to 400hp.....im not goin that far....but i want to be able to hit 350 without changing injectors.....would 4 x 720 work?

 

will greddy 720 fit my injector clips?? i have a 88 t2....or will i need to get different clips??

 

Using that equation but substituting .7 instead of .6 because it's a turbo and you want it to be a little richer, with the 550 primaries and 720 secondaries you should be good for about 265 to the rear wheels. That's being safe. I'm sure you could really push it if you wanted to upto like 300 but like was said above that's probably not safe and might not last too long.
Dom

 

Whats the largest injector i can get without having to modify my fuel rail and get a Stand alone....all i have to tune it is a SAFC.....

 

i have been wondering if i can go with 550 primaries and like a 920 or something between 720 and 1600 or should i just run 1600 secondaries with a s-afc??

 

You can get 1600's from Marren, and they are drop in. May need a resistor pending you Series.

From what I read, 720's....

Now, you dont need a stand alone to put in 1600's. Greddy has a great piggyback computer. It will handle any size you throw at it.

 

would running 4 x 720 give me enough fuel to get to 350hp?? i would first only run 720 secondaries...but in the future get some 720 primaries....would that be enough fuel for my goal???

 

350 hp on what turbo?? stock?? NO, you will not get this amount of power if your planning to use your stock turbo no matter how big injectors you put into your motor.

I would stop thinking about fuel injector size and plan your setup first with the right turbo for the right injector size, and most importantly fuel management.

Why spend money on bigger injectors if you could just run your stock turbo at 11-13 psi. with good tuning (SAFC you already have). You gonna have hard time tuning injector setting and the results will not show anything. Forget a greddy piggyback. For the money you'll spend on safc, injectors, greddy piggyback, rtek, etc. you could just get a standalone. In the meantime I would suggest running an aftermarket fuel pump perhaps a 255 walbro (cheap and easy to put in).

My theory is go big or go home. If you want 350hp, it might cost you some bucks so I would suggest you do it reliably right the first time. By the way, you can run 1600cc injectors without modify stock fuel rail.......all you would have to do is just simply modify the actual injector which is very easy.

87 GXL
91 j-spec TII motor
TII tranny
TII rear
Racing beat downpipe
Racing beat pulleys
Apex n1 dual exhaust
Greddy 24v front mount intercooler
HKS mega flow intake (custom made with honda prelude CAI)
HKS super sequential BOV
10 mm magnecore wires
Boostvalve.com ball/spring boost controller
Racing Hart C2 3 piece 17 inch wheels
TII side view mirrors
TII round tailights
Microtech ltx-8 (not yet installed)

 

i know im not makin that power on a stock turbo....im not stupid.....BNR stage 2 is whats in the mail....im just wondering if 4 x 720 will work for 350hp

 

Use that equation I posted earlier. . seriously It's easy. 720x4 divided by 7.7 The answer will be home much bhp that setup can handle at about 80duty cycle of the injectors.
Dom

 

thanks man....finally an answer i was lookin for

 

I'm planning to do 4 x 720s in the future too. I heard 1600s can have problems.

 

problems with fitment and controlling those bad boys.....4 x 720 seems to by more what power range im lookin for

 

anyone know of any other 720 injectors other than the greddy ones that are cheap too....or anyone selling some?? all i need are 2 right now...but if u have 4 ill take em

 

Try looking around at google or some tuner magazines for injectors. I think that Greddy doesnt actually make the injectors they just restamp their name on them.

I'm sorry a can't be much more help but I'm in the market for 4 720cc injectors too.

good luck,
TR