Im running 94.5% on the injector duty (as shown on my PFC)

I know I have to either get it tuned or go with the fuel upgrades....

If you know, What would you guys suggest for fuel upgrades?
as far as
injectors, fuel pump, RRFPR.....???

What should I do? Let me hear your thoughts or what you did.....

 

easiest way is to get better fuel pump,1200cc secondaries,and sx fpr. you will still need tuning though but you can run upto 1bar. if you want to go excessive like me get 1600cc bosch injectors and custom fuel rail

 

Anyone else have an opinion?

 

Drop in a Cosmo fuel pump

 

You definitely don't want to run the injectors past 85% duty cycle, you're liable to burn them out. Don't know much about 3rd gens, so I wouldn't want to give you bad advice, but here's my thoughts: upgraded fuel pump, bigger injectors (which might require an upgrade to your ecu, either an addon like the Apexi Super-AFC or replacement like a Haltech) and possibly a boost dependant fuel pressure riser.

 

You'll need a fuel pump upgrade and it would also be a good idea to upgrade your secondaries to atleast 1200cc's. Once you do this you'll be fine. I have this setup and the max duty cycle I see on my Power FC for the injectors is 65%.
Ernie

 

I agree with ErineT. You can program the P-Fc for 1200 CC injectors.

YOU NEED A FUEL SYSTEM UPGRADE NOW. Don't run 95% duty cycle on injecotrs. they never get a chance to cool down. Some poeple on the forum has said they do it but, like gambling, no one ever talks about what they lost.

I think the Bosch FP is best (M2) followed by the Walbro (Rx-7 store).

Another cheaper way to go is put 800 CC secondaries in the primaries. I'll bet this leads to some driveability problems as the duty cycle around town would be really small and require better control.

 

Where is a good site to look for a fuel pump?

Where and what is the address for Wade's site (the guy who sells FPs)

 

1200cc how much hp can it handle?

 

What's a good place/brand for the 1200cc injectors? Any advantages to using Toyota's Supra FP rather than the Bosche? Does a 1200cc injector upgrade require a new fuel rail, or is it a drop in and go upgrade? Okay, that's my three question limit.. Oh yeah, here's a link to rx7.com's fuel calculator.. very handy for the "how much hp can these injectors handle" questions..

http://www.rx7.com/cgi-local/3rdgencalc.cgi

 

Just send your stock injectors to RC Engineering. They clean and bore them out so you can drop them right in.

 

What about new pump, and variable regulator, as to bump up the fuel pressure and just spray more fuel through existing injectors. I haev heard that this is a nice way to do it, and it promotes a much better spray pattern and lends to more complete combustion. although 95 is too high I think 55 would be way to low.

WHat do you guys think? I know this would probably screw all the entire PFC maps. opinions?

 

Try Here:

http://www.k2rd.com/Online_Catalog/FD3S/FD3S-index.htm

Fuel injectors, custom fuel rail, and Walbro Fuel pump kit.
Hope that helps....

 

If you only get a fuel pump and do not upgrade your secondaries, you won't do yourself any good. It doesn't matter how much pressure you have, if the injectors only can spray 850cc's. This is why you should atleast go to 1200cc secondaries. This setup will also do just fine for a single turbo setup. And no, a fuel rail upgrade isn't needed. It helps for a single setup, but is overkill for the stock twins.

 

Thanks, Im looking into 1200 or 1300 injectors now....Thanks for your input..

 

ErnieT,

That's not totally correct about the 850's... if you raise the pressure on the 850's they will delivery more fuel than 850cc. Pressure does matter.

Wade

 

I just made a web page that does some useful calcs that you guys might want to check out:

http://www.maxcooper.com/rx7/how-to/...tem/calcs.html

-Max

 

Max, I tried your rwhp calculator and got some interesting results. I left everything the same except the duty cycle, I changed that to 95% and got a reading of 387fwhp / 329 rwhp which seemed a little low. I went to the rx7.com link above and used thier calculator and with the stock fuel and 95% duty cycle it showed 401.5 fwhp which at 15% loss is 341 rwhp. The 341 seems more in line with what I've seen from dyno sheets but I wonder what the difference is??? Should i have changed some of the other info or left everything the same except duty cycle? I'm trying to determine the rwhp capable of the stock fuel sys at 95% inj duty cycle.

Thanks,

 

dont you need to use an upgraded fuel pressure regulator with the 1300cc injectors from RC???

thats what i was told at least....

thanks

 

No, you don't need a fuel pressure reg. w/ the larger injectors.

 

dammit.....i just got a pfc on its way and i was trying to decide whether to put the injectors on the list and ended up deciding not to.

how easy is it to reprogram to use them??

i know you change the injector size from 850 to 1300 on there....but isnt there a lag time number and pulse correction value or somethin like that??

what would the numbers be for the 1300cc injectors???

and are you SURE it doesnt need a different pressure regulator?
can someone else back him up???

 

SPOautos,

I think the rx7.com one does not account for fuel pressure, and uses 0.63 as the BSFC for the car. Also, there are a lot of variables that can effect how much power the car makes that are difficult to account for in a tool like this. BSFC is different from car to car because of the compression, alignment of the manifolds & hoses, etc. Duty cycle can change, too, depending on the intake temps and boost pressure.

95% duty cycle is equivalent to 100%, because the injectors will just stay open if you give them a 95% signal. You basically cannot tune effectively above about 85% because the injectors stay open. If you have a good enough fuel pump, you might want to raise the fuel pressure and lower the duty cycle.

Thanks for the feedback. I updated the calculator page with some more info and options. Check it out.

-Max