87_RX7_fc3s

I was wondering what would be the best injector sizes to use on my 87 rx7.

My set up: BNR stage 3, Rtek7 2.1, racing beat exhaust (Turbo back) and a FMIC.

I was hoping to push 13-15psi...

What are your recommendations for primary, secondary and brand???

lovemyRX7

RC injectors are pretty good

87_RX7_fc3s

yeah? I was thinking about running 720cc... do i need 720 for both primary and secondaries?

RotaryRocket88

iTrader: (7)

Run at least 4x 720s. I prefer to buy Denso injectors, which are packaged under names like Greddy. Always high quality.

87_RX7_fc3s

okay, thanks!

87_RX7_fc3s

Okay, what about Venom injectors, from TLF performance?

They offer direct plug in 720cc and 1000cc, Should i go with the 1000cc to be safe?

...also what is the difference between low and high Impedance?

RotaryRocket88

iTrader: (7)

Venom and TLF ebay specials are crap. Stay away. I know some people have ended up with injectors of random sizes from that vendor in particular. Stick to buying from tuner websites, etc...

Almost any aftermarket injector will be low impedence. If your engine management harness is from early '87 (not sure of the cutoff month), they'll be drop in. But if it's a late '87 harness, you'll need to wire in some resistors to keep the current levels down. Impedence = resistance. Low imp. = 2-3 ohm, high imp. = 12-13 ohm.

87_RX7_fc3s

Yeah I figured that... I hate to keep asking, but I found a set of 4 720cc Siemens injectors, Are they a suitable brand?

87_RX7_fc3s

and if not, what are some good sites to buy from?

Evil Aviator

The smaller the injectors, the better the resolution (fine tuning), especially for the primary injectors. If you want good tuning, use the smallest you can. If you just want to be safe and don't care as much about fine tuning, then go up to the next larger size. It is difficult to size fuel injectors because everybody has their own method of tuning, but here is a rough estimate for a turbocharged rotary engine:
550/550 is good for about 230-260bhp
550/720 is good for about 265-300bhp
720/720 is good for about 300-340bhp
720/1000 is good for about 360-405bhp
1000/1000 is good for about 415-470bhp

Yes, Siemens is a good brand.

http://www.kgparts.com/

87_RX7_fc3s

http://cgi.ebay.com/ebaymotors/Sieme...ayphotohosting

87_RX7_fc3s

what do u think of these... .the link above ^