Meth, timing, and psi

[hellcat]

I haven't tuned my car for a while now and was thinking about trying another tactic. Currently I spike to 30 psi, hold it for a bit and fall to 25 at the top of 4th gear etc. I was going to lower the boost and up the timing a little up top to see if that feels like there is a little more power there. Maybe even make the lower psi, higher timing map and my current map, and run them back to back at the track to see if the numbers show any obvious advantages. Have any of you gona back and fouth with maps like this? If so did you notice any real advantage to running more timing and a little less boost? Im on stock turbo, stock cams.

[SlowCar]

it will be nice to see this done on a dyno - for safety and you get quantifiable results

[hellcat]

I agree. I have talked to a few people and I hear diff. stories. Some people prefer more boost, some like to up the timing and raise the boost less.

[cpoevo]

Boost is what makes more power. When people run a lot of timing they are usually running the engine pretty rich, like low 10's. I tune my car for 11.5 down to 11.2 at redline on 91 oct alone. On 50/50 12.0 afr is good.

[hellcat]

Im running 100% m1 and i notice at peak boost if the afr is above 12.5 I start to see counts of knock. I keep it about half of a point lower than that for safety. My timing map has only increased 2 degrees at most through a small portion of my rpm range. With that little increase it "seemed" to pull better. I only road tune so its really hard to say. What works with me on my car is setting psi, then afr, then tweaking the timing a degree here or there, usually not much.

[10sectalon]

deff. do on a dyno to get a fo sure tune

[cpoevo]

Originally Posted by hellcat

Im running 100% m1 and i notice at peak boost if the afr is above 12.5 I start to see counts of knock. I keep it about half of a point lower than that for safety. My timing map has only increased 2 degrees at most through a small portion of my rpm range. With that little increase it "seemed" to pull better. I only road tune so its really hard to say. What works with me on my car is setting psi, then afr, then tweaking the timing a degree here or there, usually not much.

12.5 AFR for straight meth is too lean in my opinion. For straight meth I would tune to the same AFR as gas. With straight water you want a 12.5 AFR so you arent literally putting the fire out in the cylinder.
For Straight H2O I would tune to 12.5 AFR, 50/50 tune to 12.0AFR and straight meth tune to about 11.5AFR. These are the AFR's I use in CA where we run 91oct. If you have higher oct maybe go a little leaner. Straight meth will make more power than 50/50, but you are closer to knock with straight meth. The water cools better than meth does.

You can street tune and measure the results by looking at your logas and seeing how long it takes you to accelerate from a certain mph to a certain mph. For instance say you tune in 3rd gear and at 3000rpm you are going 30mph and at 7500rpm you are going 90mph. You look at your log and see how much time elapsed from 3000 to 7500 rpm. If the amount of time is less you are making power gains.

[Ultimate CC]

It really varies from tuner to tuner and car to car...either way I would either go to the track or hit a dyno or both for tuning...