Meth Tuning Question
BTW - I'm doing the tuning on the car. I have everything dialed in, but it's going to be shot to **** once we boost reference the fuel pressure lol. It is currently falling off to about 50psi at the rails under WOT.
The main thing I was wondering about was what AFR to look for while the meth kit is on. The car felt like it picked up 50rwhp going from 16 to 20*. It showed NO knock, even leaning out a bit on the first try.
also since the stock computer isnt dropping timing with boost, i would leave that alone and just add fuel (meth) with the added boost.
all together it may work itself out without even retuning.
the referenced regulator will just mean you hold the last injector value across all the ifr table, as it is now held constant being compensated by fuel pressure fluctuation with map.
We contacted LPE about tapping into the output on the MAP (running a 3-bar on the car already) for the signal so we wouldn't have to run an extra sensor, and they said they haven't tried it and that iit may interfere with the signal received by the PCM.
The 3-bar SD HPTuners custom operating system has a boost-enrichment table. I can set it up so that it will command a certain AFR until a certain X MAP value. If set the meth to come on at X+1 MAP, I can come off on the enrichment value and let the meth go to work.
I want to make it all happen automatically lol. We have the boost controller in the car already at arms reach. It would be nice to reach down, crank the boost, and it automatically pull timing, correct the fuel, and hose the meth in one fluid motion.
We will need to know what your combo is before we can give you real sound advice. I will however say that it sounds like you could get another couple of #s of boost as well as more timing.
Logging as you go up will be helpful, Depending on how much meth you are spraying will dictate you A/F. I would start at around 10.5:1 or 10.7:1 to start. Meth has more O2 than gas so you'll need tune a little on the fat side.
My 347 ran 8#s w/meth and 42# inj at 90% dc and 21dg timing made 500/510 w/ a maggie.
Doug






