My SAFC2 Trim Levels (w/ meth, 5.5psi, 305cc)

[SirThomas88]

Figured I'd share my SAFC2 trim levels and my corresponding AFR for general discussion and so others can compare to their own trim levels. It's been said by many before but I'll repeat it here, keep in mind every car is different so don't use my trim levels for your car expecting the same results.

My setup stats to consider:
-5.5 psi pulley
-meth injection (125 nozzle before the TB) (snow performance meth juice)
-305cc Supra injectors
-Walbro 255 pump
-jim's fuel mod
-Injen w/ UPFD CAI

My SAFC2 Hi-Throttle settings are as follows:
RPM - 800 1,200 1,800 2,400 3,000 3,600 4,000
Trim - 0% -5% -11% -16% -19% -22% -25%

RPM - 4,400 4,800 5,200 5,800 6,400
Trim - -26% -29% -29% -28% -28%

With that, my AFR is around
12.0:1 at 4,000 RPM
11.0:1 at 5,000 RPM
10.5:1 at 6,000 RPM

It varies some and those are rough numbers. I'm going to bump up 5,800 and 6,400 RPM to -29%. I've heard your not supposed to trim such a large amount with the SAFC2 so I don't want to go higher than 30%. Besides, it's safe to be richer around 5,000 to 6,000 RPM so I guess it's not so bad.

I've had a long history of running rich with my car. Even at n/a with stock tune and injectors I would rich up to 10.5:1 top end. Putting the supercharger on at 4.5 psi, I didn't even need a tune because it leaned it out almost perfectly to 12.5 AFR as if my car was meant for the S/C lol.

Anyways just figured I'd post the info for anyone who was interested.

[SirThomas88]

bump.

curious to hear if anyone has any interesting info or remarks concerning my trim levels.

[Akfahad]

I would definitely say you could lean it out from 5k on up (probably 11.5 to 12.0, somewhere in there for some more power if you want to). I'm around 12.5 towards the low end and 12.0 on up around 3400RPMs on 7lbs. Now I'm assuming your correction values are a positive (+) number and not a negative (-) number? Reading what you posted, looks like (-) correction values, just curious.

[Eye8Pussies]

^ the values with the injectors and especially with the meth on top would definitely be (-)

if he went positive with his setup, he would bog and bog and bog and probably flood his motor :p


but going with what akfahad said, you can definitely lean it out on top for more power. In fact, running a 10.5 is rather rich and not great for the motor either. Where did you do the tune? Is it a street tune?

[SirThomas88]

^ the values with the injectors and especially with the meth on top would definitely be (-)

if he went positive with his setup, he would bog and bog and bog and probably flood his motor :p


but going with what akfahad said, you can definitely lean it out on top for more power. In fact, running a 10.5 is rather rich and not great for the motor either. Where did you do the tune? Is it a street tune?

Thanks for your comments and questions guys.

Indeed they are negative numbers and I have to trim fuel because I have the Supra 305cc injectors (22% larger than stock).

Yes it is a street tune I did myself over a few weeks, slowly pulling more and more fuel to get it where I wanted it. I would lean it out more on top end, however I've been warned that with the SAFC2 you should not pull/add too much fuel and it could cause problems, and that 29% trim is already dangerously high. So, to minimize anything going wrong, I refrained from trimming more fuel. I also figured it'd be safe to run rich around the top, so I wasn't concerned about it too much.

If I hear that it's really not a problem to trim fuel on the SAFC2 higher than 30% and if indeed it is not good to run so rich like I am, then I'll have to rethink my position and perhaps adjust my tune further. The only problem I've heard with running to rich is that it can foul the injectors. Is there another negative effect on the engine itself from running rich? I always thought it was simply safe that way.

[Akfahad]

^^you are correct, it is my understanding as well that being too rich can hurt the injectors, not to mention wasting some gas in the process as well. But, its ultimately a personal preference, richer is safer on the top end, but even when I was 6lbs. I wasn't running that rich and did a compression test before going to 7lbs and was still fine. Again, you have to make the call with what you personally feel is safe. Keep in mind your driving style too. If you drive aggressively all the time, maybe you don't want to change anything. I don't and only get on her when its relatively cool with low humidity (hard to do now in southern AL).