I just want to get things cleared. i've heard from my friends that tuning a turbo honda with the apexi safc/vafc/neo is bad and that it screws with your timing.

I was talking with another friend that owns a 2g DSM and he tunes with his safc and has success with it.

my question is. what boosted car can you tune with the apexi and what car can you not tune with the apexi? I have searched and haven't really got a answer to my question. so I thought i would post to get good feedback. or if anyone has tuned a boosted honda with the apexi system.

 

Here is the deal. A stock honda ecu is not set up for much more than a couple psi over ambient air pressure. A DSM ECU on the other hand, can handle actual boost that is double or more the ambient air pressure. Hondas don't respond to piggyback devices, especially in an attempt to control boost because the ecu maps themselves do not have provisions to handle anywhere near the fuel or ignition timing required of a boosted engine.

to put this in numbers, a stock honda ecu will handle up to say 2 psi of pressure above the 14 psi that is normal ambient air pressure near sea level. So at 2 psi of pressure and 7k rpm, a honda ecu will be injecting its maximum fuel quantity. An apexi piggyback will attempt to trick the ecu by sending it a higher map sensor value, basically telling the ecu that it should inject fuel for say, 10 psi above normal air pressure. The only problem is a honda ecu will see 10 psi and just interpret that to mean 2 psi at 7k rpm, because that is the highest it is supposed to go. And that is only the fuel side of things. The map sensor also determines the ignition curve, which will really be out of whack at high positive air pressure values. A chipped ecu can get around this problem, in which case an apexi MIGHT become useful. but then i would ask: why not just change the map on the ECU instead of trying to trick the ecu?

A dsm ecu on the other hand, has a map that can go up to 25 or 30 psi above ambient air pressure, and thus actually has values for fuel and ignition timing at those levels, so the apexi can modify the signal and the ECU knows what to do and actually has instructions to output to the injectors and ignition timing for the parameters being sent to it by the apexi. at certain boost levels however, even a DSM will stop responding to the Apexi.

the PGMFI wiki has some additional info on why piggybacks suck on hondas, so you can go read up about it there as well..

cliffs notes: piggybacks suck with a honda ecu because the honda ecu was never built for boost. they work on DSMs because the DSM ecu has a much wider range of acceptable parameters than a honda ECU does, and that is mainly because they were built to handle variable boost levels to begin with.

 

dude thanks for the help! that was good straight forward info. just wanting to get to know more once the car is done and ready for a tune. greatly appreciate it

 

http://www.moates.net/product_info.p...roducts_id=170
I wish somebody would have shown me this befor i blew up my first b16 turbo with a afc and dsm 450cc
use crome and freelog its not the best on the market but its free and way betterthan any afc
299.99 real tuning systems vs well over 300$ for a new or used neo that looks cool enough to bust a ringland
YOU WOULD BE STUPID TO BUY A AFC

 

I'm trying to find all the information that I need for tuning. thanks for that link too. I have a VAFC but not going to use that to tune the car with.