PUR NRG

For those (like me) who haven't tuned a turbo on a dyno before here are the basic steps as described by Scott:

1. All runs should be done in 3rd gear, which is long enough to give you meaningful graphs. (Yes you can do 5th but it isn't necessary.)
2. For the first run set the boost controller off to establish a baseline. During the run verify the BOV isn't leaking boost and adjust if necessary.
3. Adjust screen 1's AFR to desired levels (target 11.5 AFR)
4. Turn boost controller on, set for 8 psi. Make another run, adjusting AFRs again.
5. Continue increasing PSI in increments of 2, making a run and adjusting AFRs as you go. Scott recommends this incremental approach to make sure nothing untoward happens along the way. It's safer than setting desired boost right off the bat.
6. If detonation occurs during a run, pull timing to compensate.
7. Once AFR ratios are set for final desired boost, then adjust timing for fine tune.
8. Slight RPM fuel enrichment (instead of boost based) may be desired.

Moostafa29

Thanks Robin. I'm sure this will be extremely helpful on Sat!

dmp

I'd contend dyno'ing at a 1:1 gear ratio (5th in our cars) IS highly 'better' I'd bet there's a decent chance of making more power, too - My previous car made about 20 more HP in 4th than it did in 3rd, after being boosted...something about engine load?

Brice-RX8

From what I have heard the stock ECU has different setting for the first 3 gears compared to the last 3 gears, if this is true, wouldn't it interfer with what is going happening on the dyno when running in 3rd compared to 5th?

PUR NRG

Better for what? If all you're looking for is a peak HP graph (which 5th gear will give you with its lower drivetrain loss) then yes. But if you're looking to tune an ECU for the proper fuel and timing then 5th puts more stress and heat on the engine.

MazsportScott

Let me clarify, I meant to say I prefer to do my initial A/F adjustments in third gear. There is less load on the equipment yet the pull will last long enough to provide a accurate chart to make corrections. Once the A/F are set I usually do a Fifth gear pull to "load the turbo" and eliminate the gearing correction factor. Sorry for the confusion,Scott

Xyntax

I think 4th Gear is a better compromise. It's closer to 1:1, without the stress of the 5th gear. After two dyno runs on 5th gear, your temps will have gone up really high that you would need to cool off before you could make another run. 4th gear will give you a finer resolution of readings compared to 3rd gear, a closer to 1:1 ratio, and lesser stress on the engine compared to 5th gear.

Brice-RX8

Ok, I just thought I remember reading that the ECU is much different settings for 1-3 compared to 4-6 and thought it might play an effect on tuning that is all.

epitrochoid

that shouldn't matter since the interceptor controls all the injection/timing. it doesn't know what gear you're in