Rookie

iTrader: (4)

I think your #'s look pretty good and safe. I don't believe you want to be any higher then 12.2 on a NA engine from what I have read.

I also like my LM1. isn't the LM2 dual recording for both banks?

raeburn

I think the a/f ratio at wot looks okay, but seems rich at idle and low rpm's. I'm going out again tomorrow and will record #'s at specific rpms.

The LM2 is single or dual. I went single (odd cylinder bank) because it would be a tough squeeze getting an 02 bung in a dry spot on the exhaust on the even side - I have exhaust diverters. There's more room on the odd side but it's still really close to where the water enters the exhaust. My CMI Sport tube headers don't have much tailpipe before the diverter valve.

raeburn

Had a great day on the lake yesterday. I still can't figure out how to recall the air/fuel ratio data logs, it keeps coming up "invalid data file". I will have to phone Innovate on Monday-I'm sure it's something simple that I'm missing.
I got the wife to write down the a/f ratio's at 500 rpm increments, made four runs. Seems rich at idle/low rpm, not sure about the rest, what do you guys think?
5000 rpm is the most I could get with a labbed 28p bravo.

BenPerfected

My thought is your AFR is safe/typical but rich. The pro-engine builder has little motivation to put the AFR ratio any leaner especially not knowing each use/load and the fuel being used.
If you leaned out your set-up a full 10%, how many fuel $ will you save in a season?,,,$150-300? Is it worth it?
Having said this, I haven't stopped working on my to get it right on the money
Do you have set a target AFR at each RPM? How many test runs is your wife good for?

raeburn

I don't have a set target for the AFR, but I have a lot of transom soot that I would like to reduce if possible.
The wife will do more AFR test runs as long as the beer cooler is full and she gets some time behind the wheel!

Smitty

iTrader: (1)

BenPerfected--

Getting the AFR right is also about making horsepower. When it is too rich, you are wasting fuel and available horsepower.

IMO for N/A motors, you are a little on the rich side and you confirm that with the black transom.

BenPerfected

Smitty,
I agree and believe that an engine in tune will make more power. Rich leaves the plugs half fouled and cuts the life span of the oil and may increase wear. On our mid-July trip, I am targeting 13.4-13.6 from 3000-5300 RPM and from 12.6-12.8 at 5300+ (PV's open).

jeffswav

I just tuned my engine last month, I have a NA 489 stroker, Holley MPI with wideband O2. I set the target at 13.5 from idle to 3500 RPM, I ran the mid range at 13 and 12.5 at higher RPM's. No soot on the transum and runs perfect.

Big Block Billy

Hi ! Is there a part number for the FAST kit or components needed ? I would like to get setup to use the 1/4" NPT threads on stock Mercruiser exhausts, as well as the CMI headers. I would love to use this on a 383 I just installed in a buddy's boat to get it jetted perfectly. Thanks, BBB

raeburn

The black transom shows up at all rpm's and at idle the exhaust definately smells a little rich. I was also thinking 13.5 at idle/low rpm's and 13 mid range and 12.5ish for high rpm. The spark plugs always look clean, but that could be from the high energy ignition on the 496's.

I will talk to Dustin at Whipple - I'm running Whipple's Stage 2 ECU, so hopefully he can retune it leaner.