adjusting fueling to compensate for 101mm maf or going sd

[Jackhammond21]

hello everyone, new to tuning currently have a boosted ls7 with alky kit was tuned to 5 psi,
I have now upgraded the system and running 12 psi and straight meth with ait safety since meth is also being used as a fuel as well

issue im currently having is maxing out the maf by 5k rpm of freq 12800 and grams of 512's
been able to adjust the commanded afr and p.e. enrichment to keep afr around 12.3
I have a 101mm maf I can install to get alittle more play out of the maf but I don't know how I would adjust the fuel trim to compensate for the lower maf readings.
my other option is to go sd with a 2 bar map that I also have available to install
issue with either choice is limited knowledge on how to tune either of them,
my knowledge is pretty much limited to tuning with just the p.e and timing tables using lc-2 wideband and data logging

would anyone would have any links or write up's that I could use to research and learn with,
yes ive google searched for leasons but searching maf to sd tuning, how to tune sd ect... just comes up with
discussion's on maf vs sd or which is better.

and yes could pay someone of course to dyno tune it and not risk screwing up my car but where's the fun in not being able to tune your own toys,
just taking it slow and safe small changes each time

[joecar]

Post your tune file and your stock tune file.

There are several ways to scale for insufficient MAF or IFR range:
- scale IFR, VE, MAF by r, and shift down any tables referencing mass (g) or flow (g/s),
- scale IFR by r and Stoich AFR by 1/r,
- scale IFR by r and one of the Injector Flow Modifier tables by 1/r,
where r is some factor (e.g. 0.5).

You will have to do the first one since your MAF table is range limited.

[Jackhammond21]

20813
20814

attached is the stock tune file
tune at 10 psi no meth and also my latest tune file at 10 psi with meth20819
also I have a set of 120 lb injectors I can install but with such a big change from current 65 lb injectors
I think it would be come a tuning nightmare to get straighten out atleast not intill I can get the air flow straighten out

[Jackhammond21]

And just got done fabing up the 101mm intake
Maf with duel m15 nozzles 1 inch farth downstream and then 2 inchs down stream is the ait, so if meth fails to spray ait goes up and timing gets pulled out20824

[Jackhammond21]

installed the new 101mm intake adjusted the maf scaling by 33% and then adjust the iat scaling for the the gm iat sensor, did acouple runs and fine tunes runs pretty good :grin:
i set the iat fail safe to start at .80 gram/s and above 30c the timing begins getting pulled and by 50c 10 degrees of time is pulled just to be extra safe if the meth fails to spary
test run with meth activated iat temp went from 32c to 7c
think I did a pretty good job attached is the final tune I installed took about 4 hours of trying and failing to get everything set right lol, it wouldn't even idle when I started it20826

and if anyone is wondering this is a stock 2007 ls7 12-1 comp, 91 pump gas,12 pounds of boost, currently with no knock with 17 degrees of timing and straight meth
so far once I get the tune cleaned up more ill push for closer to 22 degrees with a lot more meth

[joecar]

Ok, you got it running good, good job :cheers:

what did you scale, MAF and IAT (doesn't your IAT pid now read wrong...?)...?