Dyno tuning tips?

[allen22]

Hello,
I've now got a dyno 5 minutes from my house which I think is gonna make my tuning a lot more accurate. It's a Mustang brand dyno and can hold the car at any RPM I like and at any load point too. I'm new to tuning (just got the car running on the MSII recently) and I've never been on a dyno either.

Just looking for a general description of what you do to get a good tune on a chassis dyno. I'm thinking I'd want to hold it at a particular throttle position and have the dyno operator hold the car at different RPM's while I tune the VE and ignition maps, sound about right?

thank
allen

[kg6dxn]

First, turn off accel enrichment by setting the v/s value high. If the Dyno has a WB sensor use it! I assume you have a NB sensor at least. Have the dyno operator start you at a light load. Work on your VE table while watching the sensor output. Remember, the MS averages the VE table so you will have to adjust all the bins surrounding the one the engine is running in. The 3D map is best for this. Slowly increase dyno load while adjusting the VE at various RPM's (1000-4000) this will tune the "cruise" portion of the ve table. Your engine will spend most of its life in this range. If tuned properly you will need very little accel enrich when done. DO NOT run your car on full dyno load until the VE table is tuned! you can melt your engine if you are too over zealous. It took me 3 hours and 8 spark plugs to get mine right. I still have minor tuning to finish, but now it is very close. I have not made a "full pull" yet so I'm not sure the max hp, but that can wait. Good luck, be careful.

[allen22]

First, turn off accel enrichment by setting the v/s value high. If the Dyno has a WB sensor use it! I assume you have a NB sensor at least.

I've actually got an in car wideband courtesy of DIYAutotune so that should help.

Have the dyno operator start you at a light load.

Forgive my ignorance on this but does this mean basically low wheel speed? Like 20-30 MPH?

Slowly increase dyno load while adjusting the VE at various RPM's (1000-4000) this will tune the "cruise" portion of the ve table.

That somehow confuses me, shouldn't I keep the dyno load the same while adding throttle to raise the RPM slowly in stages until redline. Then, go to a higher dyno load and do the same thing from say 1000 RPM to redline and so on until I'm doing a full throttle tune from the 1000 (I guess) RPM spot on up to redline?


Thanks for the help!
Fred

[kg6dxn]

The load placed on the wheels by the dyno is adjustable. If you only want a max hp run the load is put to maximum; the highest resistance. When I say light load, I mean light resistance. Wheel speed will be from 0-80+ mph. When you cruise down the road you are not at WOT. Your vehicle will use 50% or less throttle. Turn the accel enrich off so not to confuse or hamper the VE tuning process. A high setting v/s (volts per second) will enshure your accel does not kick in any extra fuel while tuning. Have the dyno operator turn up the load like this: start at 2-3 (load setting), dial in the VE. Turn load up to 4-5, dail in VE. Turn load up to 6-7, dail in VE... AT each load setting slowly increase wheel speed while watching AFR. Tune the VE table as you go (3D map is easyest). Hold rpm where needed to acheive correct AFR at load setting. Work your way up to you maximum cruising speed. You will be able to "feel" the load on your car. You do not have to tune cruise at maximum load, You will never cruise at maximum load. You will be able to see a pattern on your 3D table, you can estimate the table above where you left off. Once you have achieved VE tuning (AFR 13.9-15) you can then turn up the load, reduce the v/s and play with the accel settings. Don't worry too much about getting it exactly at 14.7 AFR, get it close move on and come back and check it again. Bogging usually means too much fuel, popping means too little. Take your time, go slowly, don't get anxious. You will have good results. Remember NO max throttle/load until VE is tuned.

[allen22]

The load placed on the wheels by the dyno is adjustable. If you only want a max hp run the load is put to maximum; the highest resistance. When I say light load, I mean light resistance. Wheel speed will be from 0-80+ mph. When you cruise down the road you are not at WOT. Your vehicle will use 50% or less throttle. Turn the accel enrich off so not to confuse or hamper the VE tuning process. A high setting v/s (volts per second) will enshure your accel does not kick in any extra fuel while tuning. Have the dyno operator turn up the load like this: start at 2-3 (load setting), dial in the VE. Turn load up to 4-5, dail in VE. Turn load up to 6-7, dail in VE... AT each load setting slowly increase wheel speed while watching AFR. Tune the VE table as you go (3D map is easyest). Hold rpm where needed to acheive correct AFR at load setting. Work your way up to you maximum cruising speed. You will be able to "feel" the load on your car. You do not have to tune cruise at maximum load, You will never cruise at maximum load. You will be able to see a pattern on your 3D table, you can estimate the table above where you left off. Once you have achieved VE tuning (AFR 13.9-15) you can then turn up the load, reduce the v/s and play with the accel settings. Don't worry too much about getting it exactly at 14.7 AFR, get it close move on and come back and check it again. Bogging usually means too much fuel, popping means too little. Take your time, go slowly, don't get anxious. You will have good results. Remember NO max throttle/load until VE is tuned.

Thanks for the detailed description! It's still a little confusing at a couple points but I have a feeling it will all make sense when I get there and am actually doing it.

I'm gonna attemp to tune it on the street with my wideband and the autotune feature of MegaTune. Then go to the dyno to get it dialed in more precisely.

Fred