SAFC Street-Tuning with LM-1/RPM

[BlazedGlory]

I just installed my Innovate LM-1 with the RPM-converter. First of all, the RPM seems to be logging double my actual rpm, but when I try and program it, it tries to re-program the rpm converter at the same time, but obviously the cable isn't hooked up because I'm using a desktop - do I have to have a laptop to program it correctly?

The real reason though is about the tuning. I've done a little searching, but I can't find a real good thread that tells me everything I really need to know.

I'm not sure what a/f ratios are optimum for idle, no throttle, cruising throttle, etc. At WOT the car holds pretty steady around the low 10s, and even drops down to like 9.9 or 9.8 afr! I think I want my WOT afr to be around 11.5 or so, correct?

Before I go any further, let's check my basic air/fuel ratio knowledge. The higher the number, the leaner the mixture. My SAFC-II manual tells me that if you alter the correction values, the fuel percentage should directly correspond to that number. For example, if you increase the correction by +10, the fuel should increase about 10 percent. Is this correct?

So I dropped all the values on the high throttle map by like 1 or 2 and gave it a little run again. It seems that the afr stayed pretty much the same or perhaps dropped a little bit more, so I set it back to where it was and decided I'd make sure I'm modifying the numbers in the correct direction before I did anything else.

With the car running as rich as it is (around 10.1 afr avg), am I going to need to subtract the values by like 10 percent or more before I actually see any change?

Thanks in advance - Sorry for the silly questions I just want to make sure I have a basic knowledge of what I'm doing before I overdo it and destroy my engine =P

[RBS14]

Are you tuning a boosted engine or n/a? that determines what WOT afr's you should have. For n/a you want between 13:1 and 13.5:1. For turbo engines you want between 12:1 and 12.5:1. With turbo engines you don't have as much room to fudge with, so I wouldn't recommend much leaner than that. For Idle you can run any afr you want. A lot of people run stoichiometric, however, I've found 16:1 works well. It saves you gas that you don't need to waste. your car will idle at a bunch of different afr's. It's just what feels best to you. For cruising you want no richer than stoich, but not much leaner than 16:1. 16:1 is like super cruise. Best is about 15:1 to 15.5:1. Decel is preference again, most nissan engines stock run near no fuel on decel. I'm running around 18:1 and it backfires like a mofo.

The thing with an AFC is that you can't tune accel seperate from decel. If I recall correctly it's just based on RPM. So get the WOT afr's where you want them, and see how the engine acts while cruising, decel and such. If it's acting funky, change the settings again.

The bottom line with tuning is give the engine what it wants. so In the end, do what makes the car feel the best.

And for the probs with the LM-1, go ask on the Innovate forums. There's guaranteed to be someone on there that can help you.

[BlazedGlory]

Thanks for your help. This is on a turbo engine - SR20DET on the stock turbo... I think I'm going to have to just drop the numbers down by like 10 at a time or something until I see some results. Right now my idle is between 800 and 1050 rpms or so, and the afr is between like 16 and 20. Like I said on throttle is like 10, off throttle is like 20, and cruise is random. You are correct that you can't modify the deceleration values, but it will take into account your tps, and there is a different map for hi throttle (I think mine is set to 55%) and low throttle. I'll play with it some more and see what happens.

Thanks again!