TXjeepTJ

iTrader: (8)

I have a 1970 Chevelle I installed a 2004 LQ4 in w/ a 4L80E

Tune attached, I also attached the scan log of the 1/4 mile run

Mods:
3000 rpm stall converter
232/240 .595/.608 115 cam
Long tube headers
3.33 gears (stock)

I'm running it as speed density - I do not have a MAF sensor. I'm also running it in open loop - I do not have front O2 sensors.

My best 1/4 mile time was 13.233 seconds at 104.81 MPH
60' time of 2.016


Looking through other threads, people with similar mods on the LQ4 are running low 12 second 1/4 miles.. I'm wondering if my tune is the issue. I'm somewhat of a noobie tuner. I have good power until about 60mph it feels like it sort of tops out on power (doesn't continue to pull as hard)

My tuning process:
Disable DFCO, disable closed loop, disable fuel trim, set new PE ratio

Using wideband, measure error of VE table - correct VE table

Spark Tuning - I'm not very sure how to do this without a dyno, I was told to just bump up the high MAP values to around 22 degrees

Transmission - Increased shift rpm to 6,000, increased shift time, sightly increased shift pressure. I did something for the 3000 rpm stall (disable misfire, did some other changes that I saw on a forum - can't remember exactly).

Could anyone take a look at it and see if anything is obviously wrong? Thanks!

TXjeepTJ

iTrader: (8)

Could someone at least just look at the spark table and let me know if there could be an issue there? Thanks!

2xLS1

iTrader: (25)

Yes there are issues with the spark advance. Timing goes from 28 to 17 as the rpms increase in the log. Shifting too early for a cammed engine.

TXjeepTJ

iTrader: (8)

Thanks for the reply! Yeah I saw it was pulling timing wherever it goes down to 17 - I'm sure this is due to the air intake temperature. Do you advise I keep it as is - or should I modify the IAT timing retard table to be less conservative?

Shifting point for a cammed engine - I tried to get it to 6,000 rpm. Should I be at about 6,200 rpm?

Thanks!

gagliano7

If you look at your spark tables .72 and .76 air mass from 5600-6800 is less then the surrounding areas and those 2 rows are off compared to there surrounding areas.

Chevy406

iTrader: (12)

Take a look at the attached tune file with some changes that I would suggest. Your VE table was very choppy. You should always work on smoothing the VE table as you work down the fuel trims. I threw in a timing table that should help make a lot more power. Your IAT timing table was pulling a ton of advance when the intake air got anywhere near 100° or hotter. Where is your air filter pulling from?

Hope this helps a little.

Clyde