Okay i got a quick question about upgrading injectors with the stock S4 ecu. When you upgrade the secondaries to 720cc does the stock ecu just compensate with that? i was thinking about it and wondering if the ugraded injectors mess around with the fuel distribution somehow.

 

No. The car will run rich. The ECU has no way to know what size injectors you have swapped in.

 

okay so there is no point in upgrading the injectors without the ecu then?

 

no, you would need to a way to control the bigger fuel injectors ,so yo would need some type of fuel management control system.

 

I think i remeber seeing some kind of chip that can be programmed into the stock ecu for that? am i right or no?

 

i think what your talking about is the Rtek Ecu upgrade you should go here and check it out http://www.pocketlogger.com/index.php?pid=rtek7

 

Great thanks a lot

 

ok im lookin at the rtek7 for the s4 t2 and the version 1.7 supports 550cc primaries and then 1.8 supports 720 primaries. in what case would primaries that size be nessesary?

 

^ in the case of you having a turbo bigger than stock that may require that much fuel, like a smaller hybrid (BNR stage 1 or 2).

 

would i be ok running 720 primaries with the stock turbo? just incase i decide to upgrade a bit in the future

or should i just stick with the 550 primaries?

 

You should leave the primaries alone unless you have an ECU that can control them. I don't know if the RTek will do this as I don't use RTek for anything.

 

The Rtek can do 720's on secondaries or both secondaries and primaries depending on which one. The Rtek 1.x ones are hard-coded and you have to get the chip for your injector setup but the 2.x is programmable and you get a lot of sweet tuning features with it too.

I've got an Rtek 2.0 and it's NICE, plug and play - everything works with stock wiring/sensors/etc. It also kills the AWS rev at start up and makes setting the idle correctly nice and easy. The guys over at Digital Tuning are pretty good with support too.