Acroy

iTrader: (3)

Just bought a nice S5 na and looking to control the fuel better.

Mods:

Streetport & 3rd gen housings
Full Rb exhaust
6-ports work with stock air pump
Cold air intake
Injectors recently cleaned & balanced
Walbro 255


Car has a slight cold-start hesitation; previous owner said it started with the Walbo installation. It stinks like gas right after startup. Otherwise car is quick & drives great. I’m sure the car is running a bit rich due to mods, hi-pressure pump, and Mazda’s overly-conservative stock mapping.

I’d like to better control the fuel & lean it out for easy starting, drivability, and optimum power.

Popular options seem to be a SAFC or Rtek 7 with the ECU fuel curve mapping. Any others?

I plan to install a wideband. Aftermarket ecu (Haltech etc) is not an option at this point, I do not plan to do much more modification.

Searching the forums revealed various owners go either way. Just wanted some feedback, thanks…

sc0rp7

iTrader: (3)

Stock fuel pressure regulator? If so then your fuel pressure is climbing too high at idle... the Walbro will outflow the stock FPR. Thats why a TII has a voltage regulator to its pump, so that it doesnt overflow the FPR at idle. If this is one of your problems, then you would notice it more on startup where its already rich.

As for fuel control,

The SAFC is the easier and cheaper way to go.

RTEK isnt really user defineable unless you do a RTEK 2.0, and thats a lil bit more expensive... You do get control of alot more and get all the other benefits of the RTEK though.

If money was no issue, I would get the RTEK though...

- Chris

j9fd3s

iTrader: (3)

rtek 2.0 is the best option, imo.

blackedoutFC3S

iTrader: (7)

definitely go with the rtek2.0, theyre very easy to control and they have settings up to 720cc injectors, so definitely go with the rtek if you can spill out the money for it, itll teach you a lot about mapping and then itll be easier to do it on a Haltech system because you'll already know somewhat to map

and your probably already running rich from that bigger fuel pump, plus if you have removed cats then you'll get that rich smell no matter what from the engine

Black91n/a

I think for most NA users an RTek is all they'll ever need. True you can get better this and that with other systems, but in the end it probably won't run much if any better and you probably won't make much if any more power (well a little bit untill they can get rid of the AFM) unless you've got something pretty extreme.

Acroy

iTrader: (3)

thanks for the input!

update:
removed the Walbro and installed a used t2 pump
installed Mallory Hyfire 6 - nice CDI ignition
ordered plx wideband
ordered used SAFC

wideband & safc will go in this week hopefully.
The gas smell is GONE and the car starts much better. no hard starting now!

I wanted the Rtek but could not justify $400+ handheld vs. $130 used safc. I'll tune best as I can with the safc & see what I can get. if it becomes a limiting factor, then I'll jump into the Rtek.

the car is very strong and driveable as is. I figure leaning it out a bit will only help. Then I'll tackle the TB boring, etc maybe.

please post comments if you got em!

j9fd3s

iTrader: (3)

rtek is better, but the safc does work