Dyno tuning comments, observations, setup ideas - collection of thoughts

[Chevy406]

After a long dyno session last night I decided (after 3.5 hours of sleep) to create a thread to both help me remember settings and experiences; create a collection of things I've found that might help others; and no doubt learn from the diverse experiences of members on this forum.

** Number one problem I've found with dyno tuning is lack of fuel delivery. Go ahead and upgrade that fuel stock fuel pump if you have hopes of moving beyond say 600 rwhp (especially in an automatic). For the dyno operator - make sure you have a fuel pressure gauge handy with some way to record.

For Automatic Cars (got to love the manual transmission cars for simplicity while dyno testing):
1. Transmission >General > Cmd Gear Control Limits: Set the Max RPM to your rev limit and Max Speed higher than what you will reach in 1:1 gear ratio. I had a very repeatable power dip at 5,600 rpm last night in a 2017 Chevy SS. Once I correlated the power dip was at 93 MPH which matched the Max Speed setting in the stock calibration, I simply bumped the value to 130 mph and finally a smooth curve. (Note this car has 3.91 gears)
2. For an unknown car I like to start making pulls in a lower gear for less time at WOT, less MPH, etc. Once the AFR and ignition timing look good make a pull in a 1:1 ratio transmission gear for the hero power/torque numbers.
3. Lock up torque converters using the Scanner for a little more power/torque - but typically only do this for that final hero power/torque graph.

Engine:
1. Engine>Fuel>General>Injector Control>Desoot Mode: DISABLE make this a standard practice to Disable. If you see a lean spike at 2.1 seconds following PE then go back and disable it like you should have done in the first place.


I plan to keep this thread updated with things that I run across, and I welcome all additions that are meaningful for the forum members.

[Chevy406]

Disable Traction Control / Active Handling:

• On Fords and Dodge you can change the engine size to anything but stock in order to disable traction control while on the dyno. Dodge in particular will apply ABS during a pull if you don't fully disable.

Fuel Delivery:
If you ever see injector duty cycle start to drop under WOT it's time to order up a larger fuel pump. This graph shows a fuel pressure drop from 58 psi to ~30psi
dropping fuel press.JPG

[GHuggins]

Did not know that one the engine size - So question here and a serious question even though it may not seem as such - can I change cylinder volume by something miniscule such as .00001 or something like that and this work? I've always held the traction button down - wait for the traction and active handling disabled light to come on then immediately get up to speed and get in and out of throttle at progressions waiting on the ABS light to finally come on before doing any pulls - even then on "certain" fords it can activate ABS or go through fits until it finally 100% shuts itself down...

Don't forget using vehicle loads for tuning where available

[Oleblu]

Correct me if I'm wrong but for ford doesn't one usually hold the brake pedal and traction control button for 8 seconds until the advance Trac and traction control is disabled. Does this not effectively disable the abs while on the dyno.

[GHuggins]

^^^^ Sometimes, but A LOT of the newer ones throw fits and may even require an entire power down and reset before it will deactivate correctly - on the one's that have thrown fits on me like this they'll even try to activate the brakes at really high speeds - 100mph+... I know there's some sort of shorting you can do around the airbox to kill it - just haven't tried that yet either...

[Oleblu]

Thanks for the clarification. I've never heard of this shorting technique.

[Area47]

trucks with stock drive shafts. dyno in second. it's not pretty when it explodes. {3rd for 6 spd trucks}
set the trans shift speed on the 2-1 to 20mph, set the 3-2 to 30 mph to keep it locked in gear and not downshift on you. gear command in the scanner does not trump this.

Dropping IDC is not always a fuel pump issue. Typically the ecm will command more IDC to get closer to the target. Look at air flow for a more telling tail. This will tell you if you have a restriction somewhere that needs to be addressed. {btr stg 4 cammed ls3's with stock intake/tb will show up about 5700 rpms and flatline to 7.}

To bypass the stabilitrak on 08+ silverado's. pull the number 9 abs fuse. If you don't you run the risk of smoking the rear brakes.

[Chevy406]

Great input Area47. Thank you so much for sharing your experience.

I've had 3 driveshaft failures on the dyno (2 in the same 67 Chevelle with the transmission tunnel cut-out to fit a 6L80). I'm pretty nervous with the high MPH 1:1 ratio pulls.