?? Raising the boost w/ more octane

[pickens]

Last night I decided to mix in a little 100 unleaded ocatane w/ my 91 pump. I figured I had about 3 gallons of 91 in the tank, so I added about 3 gallons of 100 octane. That probably gave a combined octane rating of 95-96ish. So I driv for a minute and let the gas mix around. Then I log a couple of 2nd gear pulls. First thing I noticed was my timing from 6-7k was 3-4 degrees more advanced than on plain pump gas. However, from 4.5-5.8k my timing curve was identical. So, I proceed to lean it out some, about 2% at a time until I my timing started dipping. On pump, I had the car tuned at roughly -16% from 4k and up. After leaning it out some on the mixed gas, I ended up at around -23%. I was still getting pretty high timing advances in the 6-7k range (20-21 degrees). So, I decided to raise the boost from 16-17psi (i.e. pump gas level) to 20psi. I hoped my timing would come down some but it didn't. I was still getting about 20 degrees advance at the top of 2nd (didn't do to many third gear pulls). Also, even though I turned up the boost about 3psi, my karman readings didn't really change at all. They were between 1800-1850, which is usually what I get at 17 psi. So is something wrong here? The car did "feel" faster though at 20psi. Also, my o2 readings on pump usually sit around .98V, I leaned it out on the mixed gas to .96V in 2nd, and .94V in 3rd. I think I can pull more fuel since my timing is pretty good, but I'm worried about running it to lean. Remember that this is only on like 95 octane. I also want to raise the boost, but if I'm not getting any more airflow by the karman readings then whats the point. I need some suggestions on where to go from here. Lean it out more, or add more boost?

Here's my mod list

small 16g
2.5" test pipe
3" catback
AFC
RC550s

Logging:
Pocketlogger

 

[gsxtacy]

How does the car feel? I bet it is pulling pretty hard huh?

I would say lean it out just a bit more.
My Big28 pulls pretty good.....but I am seeing 2150 hz on 18 psi...thats nearly 300hz more than yours.

Maybe I need to lean my out some???

Are you on the SMIC?

Hit me up with your SAFC settings.

GSXTACY

 

[pickens]

Yea, I'm on the stock SMIC and I'm also on the stock downpipe. My settings at 17psi on 91 pump are:

3.4K -15%
4K -16%
4.6k -17%
5K-7K -17%

The ecu seems to like these settings. I get about 18 degrees from 6500rpm and up, while my o2 voltages stay around .96-.98V.

 

[gsxtacy]

You know thats kinda weird. I was converting your SAFC settings vs. mine (w/ 650's) in my head and our fuel curve looks alot alike.

my settings are

3K -33 4K-34 4.5K 35 5K 35 6K 36 7K -36

30 lo
60 hi

lo settings -32 @ 1K -33 across the rest.

I never get a check engine light, it idles great with the AC on, yadayada.

I can definetly tell the difference with some 98ish octane and some more boost.

Good luck with your tuning looks like your going in the right direction,,,I am still trying to get the logging software and cable.

GSXTACY