BASTARD

iTrader: (4)

i am running S5 street port To4E,FMI,Haltech E6K...

I just started to wire in the Haltech and am wondering if i should spend the extra money and have an additional four injectors installed in the upper manifold or just run four big injectors in the stock location...what are the pros and cons...the goal is 400hp+/- daily driver 8 Gallons Per Mile

enzo250

no need to run 8 injectors.
you'll be fine with 4 injectors.

Slipstream

In my experience with piston engines, very large injectors can't cycle fast enough to sustain a smooth idle. In that case running 2 500cc inj is preferred to 1 1000cc inj. As for rotaries, I have no idea. It would seem (in theory) to have the same effect on a rotary engine (rought idle)...but maybe some veteran rotary tuners can add some useful info.

bcty

try staged injectors if you are worried about injectors sizeing like 720's and 1600's depending on your setup!

$150FC

even with 720s/1600s you have enough fuel for like 800hp, and if you stage them, 720s will idle fine.

RX794

This is not enough fuel for 800HP. See this website for a reference:http://www.maxcooper.com/rx7/how-to/...tem/calcs.html

And this thread for another reference:https://www.rx7club.com/showthread.p...hreadid=255008

BASTARD

iTrader: (4)

I believe these are the potential horse power numbers that the following injectors "could"sustain*

Fuel Pressure @ 55psi , 80% duty cycle


1600cc is 229 hp per injector x 2 = 458
1200cc is 171 hp per injector x 2 = 342
950cc is 136 hp per injector x 2 = 272
800cc is 114 hp per injector x 2 = 228
720cc is 103 hp per injector x 2 = 206
680cc is 97 hp per injector x 2 = 194
550cc is 79 hp per injector x 8 = 632
460cc is 66 hp per injector x 4 = 264


My question isn't one of how much power will the injectors possibly make, but rather how well the engine will run as a daily driver

*these are numbers that i got off of a web site and may not be 100% correct

astrochild7

iTrader: (3)

so basically the smaller injectors allow for more precise tuning as far as the ratio's go...... i've thought about this two... like 6 x 800cc vs 2x800 and 2x1600 right

Sponge Bob Square Pants

It's not uncomman to swap the stock sized 850cc secondaries into the primaries, and get 1600cc for secondaries. That's tones of fuel for a good price.

It is true that more injectors of smaller size usually can open/close faster and result in better driveability and better idle. The effect isn't as pronounced on rotary engines. Even with tones of fuel like the 850/1600 setup I mentioned, it would idle 100% fine and drive just as good as if you had more smaller injectors.

$150FC

i know it's not really enough fuel for 800hp. Hyperbole. Especially since he's shooting for ~400rwhp.

bcty

i mean if money is really no issuse and you have time to make a crazy fuel setup with 8 injectors go for it.. it will look cool and get the wow effect..b ut save yourself some time and find a good tuner in your area and set up the staged injectors with 720's and whatever else you like.. If your only shooting for 400hp then 1000cc secondaires should be plenty fine but 1600cc's can be found cheep..

BASTARD

iTrader: (4)

i was thinking... having 8 550cc injectors would make for better drivability , but if it isn't going to make that much of a difference then i would rather save the money and buy other goodies...