If your serious about that, and can give me an idea how much time/effort your looking at.. I'll finance some of the features for the benefit of the community..

 

Oh also, MAF scaling becomes difficult for very large injectors due to the dead time of the injectors, but also something everyone overlooks.. If your MAF value drops below 20hz or so, the car drops into open loop operation and runs in a very rudamentary speed density mode and is very rich.. (you can hear the relay in the engine compartment clicking on and off as idle hunts too when that happens, thats the IAC trying to adjust)

 

Whoa! Cool.

--Dan
Mach V
MachEVO.com

 

I agree on the first two, but it seems like to eliminate the rev limiter you'd have to somehow clamp the crank sensor signal to the stock ECU. That is - engine is doing 8500, and you tell the stock ECU that it's 7500. If you did that, you would have to also drive the ignition, because the stock ECU wouldn't fire at the right time. Clamping the crank sensor seems like it might have other bad side-effects, like screwing up the knock sensor gating. I dunno - seems like a bad idea to me.

I'm working on the P0300 issue now, and I'm pretty confident that the closed-to-open loop transition isn't the problem. Some folks with stock injectors get the P0300 as well.

Tom

 

One thing that's interesting is that the larger dead time of big injectors means that you usually don't drop to those really low MAS frequencies. Example: if stock uses a 40 Hz MAS frequency and you double the injectors, you'd think you would be running at 20 Hz to compensate for them. In fact, at idle, the dead time and low on-time means that the injectors appear to be a good deal less than 2x the size, and you have to goose up the MAS frequency to compensate.

Tom

 

Interesting thread. My 720's are on the way, and I just started getting the P300 code since I installed the ECU+ about a week and a half ago. I've never had it before now (stock injectors).

 

I will be trying 880's this friday my ecu is flashed for the stockers. Any suggestions in order to make the car driveable as the max is 780's? It will be around 2 weeks before i take the car to be flashed for 880's in the mean time i want to start playin with it and maybe try to tune it for now for WOT runs.

So scaling for 880s is overkill from what i see. Would something like 650cc scaling and adjusting from there make the 880's driveable would i be able to reach my target air fuels?


Thanks in Advance
Joel

 

I would start with something around 700-750 and see how it idles. I ended up with 680's (long story) and I have the scaling set to 600cc and idle is near perfect.