I'm in the process of building three inch exhaust for my S5 TII, I'm concerned that I may run out of fuel with all the excess boost pressure I may encounter.

Are 720cc secondary injectors just plug and play? Do I need a fuel controller, or ECU piggyback? Will the stock ECU compensate for larger injectors? Any recommendations on the type I should use?

 

Ok, did some reading on Rtek's website. Looks like the rtek 1.7 is what I'll need if I decide to run 720cc secondaries. Do I have to send it in? Seems like a pretty simple install....

Will I also need an upgraded fuel pump?

Will this mess with my emmissions?

 

you will have to upgrade your fuel pump.

make sure the injectors are high impedance or you'll have to run inline resistors

you can do a 1.7 install yourself if you're comfortable with soldering

 

Suggested fuel pump?

Would it be smarter/dumber to find someone with a used ECU with an Rtek 1.7 already in it?

Any suggestions on injector brands? Someone has some venom injectors for sale on the board, but I've heard bad things on those.

 

walbro 255 pumps are the standard most people use. you can get them for about $100

it depends, do you need your car every day? if you can't afford to send you ECU away than you can either do that or buy another stock ECU and send that one away, but ECUs can be pretty pricey even used.

it doesn't really matter much on the brand. Most of them are just re-branded nippon denso injectors. I'm running injector dynamics injectors which are nice because they're high impedance

 

Whats the benefit to high/low impedence? Does the ECU just require high impedence?

 

simple answer: they're just different types, and your ECU requires high impedance or low impedance with inline resistors.

http://www.rx7store.net/product_p/in...20resistor.htm