initial turbo tune with 10% ethanol.

[thebeewantsboost]

i've got a 2001 camaro 3.8 series II. the turbo is garrett. tb0348. with a .63 exhaust side and .60 compressor. motor is stock except it will be getting 42# ford green top injectors.

am i correct in assuming i should put the injectors in and tune for them first thing?

i'm at a loss for what base afr and PE afr i should be aiming for.... all of the gas here has "up to 10% ethanol" i've seen so many different numbers that i thought i would ask.

ALSO do i need to tune it to run richer at all before i install the turbo. i've heard people say you can run drive it with a stock tune as long as its low boost (5lbs) but the idea of the initial wide open run is a little scary without any modifications to a tune.

i've been away from the tuning world for a while. trying to get back in, thanx guys

[thebeewantsboost]

anything?

[oakleafresin]

You want to be between 11.5 - 12:1 on a gasoline calibrated WB, closer to 12 is making more power but heat too. Do a quick MAF tune and you should be good to go. Make sure IFR table is right

[thebeewantsboost]

thanx for the response. i'm really confused if i should use that 11.5 -12.0 scale range or go lower because im running 10% ethanol...should i drop it .4 from what i choose? what about stoich?

[murphinator]

stoich for e10 is around 14.1 , I have seen 14.11 and 14.13 listed in different places....

Ive had better luck in the 11.2-11.5 range with FI 3800's but others like 11.5 to 11.8

starting on the richer end should give you more cushion dialing in your setup than on the known lean end of the FI window (12.0)

[oakleafresin]

If you take a stock tune and put 100% gasoline into the tank, the car will achieve 14.7:1 using XXX amount of fuel. If you add 10% ethanol to the tank, it's going to require roughly 3.8% MORE fuel to achieve this same 14.7:1 AFR. The o2 sensor will account for this, as would a simple MAF calibration. Don't worry about the whole stoich thing, just look at what the wideband says... you want to see 11.5:1 regardless if it's gasoline or e10 or even e85 to a certain extent, you know?

Non-IC m90 cars will like the lower end of the 11's to offset the hot air but really you should shoot for good timing first, and if you can't run an AFR in the low-mid 11s, pulley up or IC I don't know anything about turbos so I don't know if they suffer from the hot air that the too-small m90's do

[thebeewantsboost]

thanx for the responses.
oakleafresin, you broke it down pretty nice.

one more question. obvioulsy the reason we do maf tuning is to get less fuel trims.
how does that really benefit us?

the answer to that question will tell me how important setting up the correct stoich is.

[oakleafresin]

Good fuel trims is a side effect of maf tuning. The real reason you "tune" the MAF is because WOT fueling is arguably completely dependent on it. Anything below like 4k hz will get taken care of with fuel trims anyway so it's sort of pointless to tune maf in this range but once you hit PE, the PCM uses the maf table to determine fueling.

The maf table tells the pcm how much air is entering the engine per maf hz. If you have 40lbs of air entering your engine per minute at 6000rpm, the engine knows to squirt xxx fuel to reach your PE table AFR (whatever you have it set at). You use the maf table to make sure your commanded AFR equals the actual AFR your wideband is showing.

[thebeewantsboost]

i've bee doing some reading trying to answer my own questions. and found this.

The reason people watch their fuel trims when tuning idle and low load operation is because if it goes too far one way or the other, the pcm effectively loses contol of a wide range of response to changing conditions. This basicly means it can't react as it should to the change in barrametric pressure or altitude.


what i get from that is........ there isn't a performance improvement from getting your fuel trims (maf tune) closest to 0. but a maf tune is necessary, when changing injectors or something along those lines or else, the computer will struggle to compensate for the extra fuel. am i correct?

[thebeewantsboost]

once again, good insight. i posted the last post before i read your last post btw.
the more i research the more questions, i have. Since i'm going from NA to turbocharged. is my stoich still 14.7 (or whatever i decide with compensatin for ethanol 14.4/14.1) until i go into PE.?