A/F ratio for LS-Turbo
 

I have a ls-turbo with 450 injectors,apexi v-afc, and I just got my LM-1 wideband. I was wondering what was the best a/f ratio to run. Should I shoot for the same a/f ratio across the board???? And also im running a V-afc which advances your timing should I retard my timing some or just leave it at TDC????? I was also wondering if when street tuning will the A/F ratio be different in every gear or if you tune for one you tune for all??????? Thank for anything

Re: A/F ratio for LS-Turbo
 

14.7 at cruise, light load
13.5 - 14.0 under a bit of load and acceleration conditions
13.0 at you cross the Vac/Boost threshhold...
12.0 - 12.5 in boost up to 5 psi
11.7 - 12.0 from 5 psi and up (to 10psi)

Those are 'safe' recommendations...

Retarding the base timing at the distributor will help slightly with the advanced timing the Hack creates...not optimal IMO though

Re: A/F ratio for LS-Turbo
 

OBD1 and newer... yes.

OBD1 has a gear ratio table that has "multipliers" for each gear you're in. These multipliers are geared for the stock transmission that drives that ECU (I.E., P28 -> Z6, P30 -> B16, P75 -> LS) so on and so forth.. Dan, Nick, and I had a good conversation about this table, and possibly disabling it, or at least "zeroing" it out so no correction is made, however, at this time, we do not know the impact that doing this will have on the fuel interpolation routine, and overall drivability.

Re: A/F ratio for LS-Turbo
 

oh my motor is OBD0. I was also wondering where the best spot to put the wideband o2 sensor? I heard closes to the turbo is best. And thanks to both of use you have answered all my questions great.

Re: A/F ratio for LS-Turbo
 

Anyone?? ??

Re: A/F ratio for LS-Turbo
 

12" - 18" from the exhaust outlet on the turbo...

Re: A/F ratio for LS-Turbo
 

werd

Re: A/F ratio for LS-Turbo
 

how will i know if im running to lean in a certain RPM??

Re: A/F ratio for LS-Turbo
 

look at the wideband (or do a datalog/record session to be safer while driving) and then compare your a/f to the values xenocron posted earlier.

personally i wouldnt really take time out at the dist, especially anything over a couple degrees. conversely, i might make the a/f in boost just a little bit richer to attempt to compensate for the increased timing, perhaps somewhere around 11.5:1 or so

Re: A/F ratio for LS-Turbo
 

Rich AFR will bandaid for a split second AT BEST for too much ignition timing. Best to get the ignition timing correct in the first place.