playing with ignition timing

[92_6bolt_1290]

Ok, so I guess I'm looking for some imput on what I should do for my ignition timing. I have an early 92 GSX with 8.5:1 compression pistons, a 16g turbo set at 15psi, a 2g MAS and I'm running evo 560cc injectors. For tuning, I have an Apexi SAFC II. I recently upgraded to the 560's and I've been playing with the fuel trims in the SAFC but it either seems to run stoich and aquire random spark knock/preignition and such or will run rich and randomly flood the engine at idle. When the spark knock reading in the SAFC gets to 5 or higher the engine starts to idle like crap and on a very rare occasion will stall out. My base timing is set at the typical 5 degrees advance but should I make any adjustments to that?

 

[ramsack]

1. 1g turbo cars have insance timing advance. Reason: 7.8:1 is the stock CR
2. Throw an SAFC on to tune for bigger injectors and you are advancing timing even more. Why? When you tune for a bigger injector with a piggy back like that you are telling the computer there is less air going into the engine. The ECU thinks there is less load on the car so it advances timing to gain more torque and throttle response.

I always tell people an SAFC is a stupid way to tune for bigger injectors. They are fine for very minute fine tuning, but they are disastrous for compensating for bigger injectors. Especially when you are on a high CR engine... This will probably start a flame war, and there will be people here saying that it is fine what you are doing and that you have other problems, but if it was me, I would at least get a socketed EEPROM ECU and get a chip for it with the injector size you want to use. This will get you close enough to fine tune with an SAFC. If it was me I would be getting something to tune everything with. And also, retarding timing with the CAS is not the answer. This changes fuel timing as well. Just not good.

 

[92_6bolt_1290]

so is it going to kill me if I retard my timing a degree? And I would like to get DSM link but I have a non eprom ecu so it would cost me quite a bit so I'm just trying to make the most of this setup.

 

[ramsack]

I don't see 1 degree doing much for resisting knock.

 

[williillii]

Also you are pulling timing from everywhere. Not just WOT. I tried retarding mine 2-3 degrees at the CAS and the car felt like total crap.

 

[92_6bolt_1290]

well i ended up not touching timing...my friend and i went out and messed with it...turns out stupid me had the idle set a little too low, bumped it up to just over 1000rpms and no more idle issues and she pulls like a jet plane trying to take off