I'm trying to run about 13-14psi, with a Neo S-AFC as my piggy back... and I was wondering if 550cc prim 1000cc sec is a bad combo w.o a stand alone? I read something about the transition point from primary to secondary injectors causing a point where the engine might lean out and cause it blow. I was also thinking for now using just 550cc prim and 750cc second, is this enough fuel at 14psi? Any opinions on this?

I have a s5 13bt with stock port, stock turbo, TMI.
-ported wastegate
-3" full exhaust (no kitty)
-stock N370 ecu
-AEM wideband
-walbro 255

 

http://www.rceng.com/technical.aspx#...tor_Worksheet_

this may help a little. as far as your individual setup it is all about tuning. im no expert but i dont know that the safc is capable of keeping up with that boost. stand alone is your best bet for sure. I personally think that the 550/720 combo would be fine, but without control, the larger injectors wont help.

 

Well I've been running 12psi with my current setup, no S-AFC... just the stock ECU, and with stock 550cc prim and second. I havn't had any problems and it's been almost a year with this set up (drifting and all). So, with a S-AFC and larger secondary injectors I should be able to run about <14psi and be fine... I hope. Past that PSI I know the stock turbo won't be any good.

 

If you raise the boost you will get some more midrange but not a lot more topend because the boost will fall off. You're also really pushing the limit of the stock TMIC. If your 750's are supplying enough fuel, stick with them. Use the AFC neo if it is running too lean, but the AFC won't help you if you are out of injector and fuel pump.

I would just stick with your current setup. You are about maxing out the stock turbo anyway... probably dynoing 220-240rwhp.

 

what you didn't read is that the fuel system they where using wasn't parallel. use a parallel fuel system and you'll be jim dandy.

 

or get your ecu chipped (its a cheap bandaid), the rtek 1.7 lowers the sec. turn on so there is an overlap

 

rtek is only for s4. i have an s5, they don't have any chips for s5 turbo ecus (in us anyways).

Will I even need 750cc secondary injectors running 12-14psi on a stock set-up? Or should I just keep running 4x 550cc? I will have a wideband and a apaxi safc to adjust and tune for fuel with the bigger injectors?... I just wanted to know if upgrading the secondaries with my current setup is pointless or not.

Thanks.