For? You don't need bigger injectors in an NA unless its not NA mostly. Or if you have a huge port job done. Get an s-afc and some dyno time.

 

yeah i definetly plan to pick up a s-afc

its nice to have and looks sweet in action

 

Ryde _Or_Die is using 2 720's though. Why would i need 4 850's?

 

hey a s-afc is pretty much universal right?

so could I just grab one cheap off ebay or do i have to buy the expensivly overpriced one from rx7.com ?

oh yeah im referring to the second gen apexi s-afc's with the vacum florecent display

thanks

 

Yes they are universal and no they aren't cheap even off of ebay .. plan on around 250 or so for a used unit.

 

 

Good ol 550/1600's here.

 

Cause with TO4 and a 3" exhaust, 720s will max out. 850s are questionable. When I think TO4 I think no less than 1200 cc secondaries. Dont want a lean condition.

 

so what's the deal with primary injectors???
should you go bigger?
or is it a good idea just to upgrade the secondaries.??

I'm on the initial stages of modding my s4 turbo

plans
full exhaust system
air induction
no emissions
remove ps
Larger fuel pump
fcd

should my stock injectors hold up?

 

I'm with chuch. I'm tryin to figure out what injectors I need. I have some leaking now I think so they need to replaced anyway. My mods are in my sig.

 

from what i understand most people just go with 720cc secondary injectors unless they have an upgraded turbo i still don't know what size im going to run Input is welcome guys.

 

If you don't have any fuel control, its better to just upgrade the secondaries, since you only need the extra fuel under boost.

Large primary injectors will cause idle problems (too rich) unless you have a way to reduce the injector pulsewidth.

1FastT2 is a primary example that you can run stock primary's in a high HP car.

 

mine willl be the same as 1 Fast T2,
550 primaries
1680 secondaries,
Microtech Lt8 to control the fuel,
I don't understand why you would need more than 550's in the primaries, if you have a stand alone, there is not need, rich iddle, gas guzzling cruizing conditions... etc.
IMOP 550/1680 is perfect for my setup!

 

While you guys are on this subject maybe you can give me some feed back about my set-up! I have a 60-1 TO4B P-trim, HKS manifold and external wastegate, Walbro 255lph, 2 Greddy 720's, and only the S-AFC to run this for now. My secondaries are supposedly 610cc by RC ( came with the car ) so I was planning on using them as my primaries. The only reason that I bought this stuff before the stand-alone was because I had planned on going with a bigger turbo anyway and my turbo needed to be rebuilt, plus got a really good deal on the 60-1. My question is basically what am I looking at with this set-up in terms of hp numbers and boost levels, SAFELY!!! I also have the Greddy 2-row FMIC, and a custom HKS full 3" exhaust, plus the motor is rebuilt with 3mm seals and a mild street-port. Thanks in advance for any info.

 

bump

 

Where did you guys with s5's get your aftermarket injectors? I want some 720cc's but looks like i'll have to change my plugs and add some resistors.

 

1680cc X 4 w/ perfect idle

 

Yes it is universal. Sorry no one got to your question quicker.


Oh and I am running 4x720s now.

 

im running 550cc 850cc theres no stumple like everybody say or maybe the remaped ecu took care of that who knows. all my friends are running 720cc and want to switch to 850cc for more boost

 

Well im planning on running that same Turbo you got.
With that Turbo, your looking at any where from 370-400 RWHP more or less depending on the compressor size, and the A/R housing size you have, amd also that turbos Efficency is good for 14-15 PSI, no more than that. It's easily a legitament 11' second Turbo-II. I know this for a fact cause my buddy has that Turbo, but running a Holley Blow Through Set Up. he put 375 to the wheels @ 14 PSI, and the car was a consistent 11' second street car, "Smokin those 5.Slow Stangs"



Well the first thing I would do if I were you is sell the S-AFC, and with that money, add some more money to it, and go with a MT LT8 or, another aftermarket EMS, were you have availability to a good tuner. Dont get me wrong the S-AFC is good, or rather ok for what it is, but IMHO its limited to a certain point, "Its a Band Aid Fix" The way I look at it is I can go with a MT LT8 for a little more money, but have something sweeter, and better than the S-AFC, any aftermarket EMS is more versatile than the S-AFC. Then again correct me if im wrong, "Ive yet to see a Turbo 2 running consistent time slips with that kind of Turbo charger a TO4B/E putting down 370-400 RWHP on a Air Flow Meter, using a S-AFC". Now for Fuel, you can keep the 720's for the primaries, and 1600's in the secondaries. Or you can do like "1 Fast Turbo2" go with the 550"s in the primaries, and sell the 720's, and with that money get 1600's for the secondaries, with either one of these two setups you cant go wrong at all. Also for the 1600's your going to need a Fuel Rial, the one from KRD is the one to get actually, they sell a very nice Fuel Rail/Injector Upgrade Combo, which is what you need my friend
Also if you want to do it nice, and save time, and money, and headaches in the future, I strongly recommend you go with the SS Braided Oil,Fuel, lines with the Nice AN Fittings that cost $$$. Also last but, not least your going to need a Fuel Regulator, and gauge to monitor your Fuel Pressure, once everything is said and done as far as upgrades are concerned its time to hit the Dyno as well for some fine tuning. If I left anything out people please fel free to post away.

 

4x720cc

Mods in the sig