Is 12.5:1 too lean on A/F meter at 7 lbs. boost on MPI S/C?

[yamadooman]

Was running 137.5's and had A/F mixture of 10.8:1, dropped to 130's and now am in the 13.5 range.. I figure 132.5's should give me approx. 12.5:1.. Is this too lean? or just perfect? I could go to 133.8's and get down in the 12: 1 range.. Any advice would be appreciated.. Pretty new to this boost thing.. Chad

 

[Bossman]

12.7 is the leanest you want to go. If you can hit 12.1that is were I would go.

 

[Skydog]

not much power to gain by running 12 i have a friend with a dyno at his house he said cars with blowers only gain a few HP from 11.5-12.00

My sled is at 11.0 at 12psi at wot. Sled rocks!! I have put it to 11.8 but sled pulls the same rpm and runs the same! So i stick with 11.0-11.2 safe safe safe! This is just me! I dont need ever little HP sled is way to fast for a trail sled any way! And i have about 4-5 psi left! Every two stroke i have run i just flat out KILL!!

Skydog

Skydog

 

[bjniceguy]

Chad, could you tell a big difference when you leaned it down from 10.9 to 13.5? Did it pull any more RPM on top with jet Change?
Doug

 

[bjniceguy]

bump - come on guys - somebody should have an opinion

 

[yamadooman]

Doug, it did pull a little more RPM, and did start ratcheting the track, so I'm sure it was making more hp.. I've since gone to 135's and now it is in the 12.3:1 range.. That is exactly where I wanted.. It is pulling about 10,200-10,300 now, up from around 10,000... Should be faster... Will find out this weekend.. I'm going riding with a bunch of Mach Z's and a modded ZR 900.. Time will tell..