I'm currently using the PFS Purple Box ecu and I'm thinking about switching to the pettit unlimited. I'm currently running all bolt on + midpipe and using the fuel pump 12v rewire. Rewiring the fuel pump completely messed up my first tune with too much fuel.

Has anyone run the 12v mod with a preprogrammed ecu like the pettit? Did you notice too much fuel across the board?


Maybe I should just go with PFC

 

Exactly where in the map did you notice the problems? I ask because I did this mod on a similar setup years ago with no problems including the rewire & a Supra Denso pump. In my experience, closed loop operation during cruise/light load will pull the extral fuel and ecu fuel trims will store the corrections and apply that info to [at least] those portions of the map--until you reset the ECU.

You might want to verify fuel pressure and FPR operation. And O2 sensor as well. Do you still have the 2nd FP (boost) relay and resistor installed?

 

I've ran the pettit ECU with rewired pump the last two years without issue (street and track).

 

I remember having to back out almost 1.0afr worth of fuel on everything including idle, it still drove but broke up under boost

Im not sure what the relay is you speak of, I will look into it.

Iv had the car for 7 years and its always run very rich with a crazy pp port sounding timing overlap until it hits 140f strangely

 

I would see it as nothing but a positive. I have ran the Pettit ECU well outside the boost range that most would believe is acceptable. The Pettit does seem to run a few points richer at idle than the stock ECU(all emissions removed) and seems to sit around 11.2AFR at a 900rpm idle with a very small street port and heathly engine.

I ran it up to 18-19lbs on stock injectos with the stock twins and AEM water/meth injection and air/fuel ratios would be in the mid 12s at high rpm and would hear occasional audible knock(ALS seals for the win). At around 15-16lbs never heard knock and the AFRs stayed in the high 11s to low 12s at all times.

I have also ran the Pettit ECU with a Apexi rx6b with 61mm compressor wheel and 60-1 with the 58mm wheel and at 10-11psi the AFRs were in the mid 11s and those setups were a lot of fun for street driving. Mid 300rwhp and a nice smooth 900rpm idle at all times. Really nice option for those who dont have a tuner near by and arent power hungry.

This is all more info than you asked for I know but felt it somewhat relevant.

 

I'm a fan of going PFC

 

The pettit ECU runs much safer AFRs above 10psi vs a PFC untuned. It idles a million times better with our without AC. You do get the "3k hesitation" sometimes and it does run a little richer at idle with the Pettit. It really is a great option for those on stock twins wanting to run more boost safely.

 

Althoguh this is all true , the usefull ness of the PFC with the commander's million gauges and options , and the ease of enriching it up a little for more boost , ithink its well worth the investment , I play with my PFC almost every day my lunch break is spent in the car adjusting my cells to get perfect afr's

if you like to tinker . i'd go with hte PFC the gauges alone on it are awesome

 

Thanks for the info im strongly considering, but like I said im concerned w closev loop base map driving. Yes ill be able to run 16psi. I ran on dyno w stock fuel and made 340 rwhp at 11.3afr. However doing the fuel pump rewire made normal driving insanely rich until I dialed back a lot of fuel.

Only reason im wanting to ditch pfs box is im getting high rpm fuel cut at random explained times which has been reported to be the pfs box

 

Here is a question for you guys who run the petit ECU , and those other pre tuned systems.

How are your cruising afrs?

I was told they generally ran quite rich when cruising

 

Sore subject or no one knows? lol

 

Generally, people who are using non-tunable ECU's are not monitoring AFR's. Why would they if they cannot adjust anything? That's kind of the point with one of those types of ECU's is just put it in and go. You might be able to look back in the archives as someone may have been curious in the past just to see what they are, but I doubt you'll find a lot of info in that space.

 

I figured to know how far and how safe you are running , I dont think I could Live without my wideband LOL I look at it almost as much as my tach

But a friend of mine was interested in maybe getting one of these since its quite a bit cheaper then a PFC and well like you said comes tuned . but wanted to know how the cruising was .