Dyno Tune Tomorrow

[jermstyle]

I’m renting a few hours on the dyno tomorrow to tune my car. First I wanted to run my plan by you all.

I’ve attached my new tune if you care to see.

I have my AFR set at 12.8 and timing at 26* to start.

As for now, I plan to do the AutoVE on the dyno so I can do whatever necessary to hit more cells and get more time in the cells.

Once that is done I’m planning to start messing with the timing. I thought I’d bump it to 28 and see if I get any KR. If not, then I’ll try 29 and see what happens. Whatever degree gets KR or starts to lose performance I’ll just back off 2 degrees.

Once that’s set, I was going to see if the car likes to be leaner or richer. Is the goal to settle on the AFR that makes no more or less power? Top of the bell curve? Or should I just go with a safe number like 12.8?


Next I plan to tune my 150 wet shot. I have A0016 (COS5) set to pull 6* of timing and I was going to modify A0015 on the dyno to achieve about 11.5 AFR on spray.


Any info is appreciated!

Thanks!

[5.7ute]

I am no expert on the operation of a dyno as I have only had a few hours on one myself. However I have learned a couple of things that may come in handy.
Setting the load cells to hold a set rpm(eg 2400rpm) & using the throttle position to set your map(eg 55kpa) you can hold a steady state, wait for the bens to stabilise & then use this as your correction. This will prevent transients from messing with your data. Then change throttle position for the next cell etc. Make sure you keep an eye on engine & intake temps and if they increase stop & wait for them to normalise.
Spark can be done the same by setting the rpm with the dyno & using your throttle position to set the airmass. Bidi controls can be used here to increase/ decrease timing while watching the dynos torque output. A sharp eye should also be kept on knock & if possible listen for knock with knockphones, as you can generally hear it before the pcm reacts. Also the AFR can be adjusted in the same way to find the best power for all load points.
If you find peak power for a cell at say 25deg but knock is evident at 28deg you should be fine, however if peak was at 27 deg & knock was at 28deg you would want to pull a few degrees timing out or try richen that cell to see if that will give a better knock threshold.
Do not tune in the high load cells in this manner as engine temps climb too quickly & you can damage your engine. Run a wot sweep while carefully mapping your logs & add/remove timing or fuel where necessary. Then you can blend in the rest of the timing afr tables.
Hopefully someone with a bit more dyno experiance can chime in with more info.

[jermstyle]

Sounds good.

When using BiDi to get max torque - Would this need to be done at all MAP's or just in a few?

[5.7ute]

As many of the low/part load cells without overly stressing or overheating the engine (or dyno) is what I would aim for. Max torque for each cell will let you know where the best timing is, and will not only help power but will also improve economy. You should start to see a trend in the timing map as you go & be able to dial it in quite quickly.
Once you have dialled your timing etc in dont forget to set your spark correction tables to prevent damage from high intake or engine temps. Here again you want to try & keep a couple of degrees away from the knock threshold.
Hope it all goes well.
Mick

[TAQuickness]

How'd it go Jermstyle?

[jermstyle]

Lots-o-learning left to go.

For one - AutoVE doesn't work very well on the dyno. The engine gets hot and screws up the data.

I did most of the AutoVE on the road though, I just wanted to hit some of the higher load cells while sitting still.


I still have some AutoVE left to get a solid 1.0 BEN, but I was running out of time so I started playing with the timing. I was running 26* and made one x amount of hp - When I went to 28* I lost 5hp all over. I thought LS1's liked MORE advance?

Is there any reason why N/A it should want such a low degree of advance?

I didn't have time to play with different AFR values either, so I'll go back after I work on my tune some.

I need to do more AutoVE and then I need to learn how to smooth out my tables.

Currently B0101 looks like a bed of nails. Any ideas? I want to fill in the gaps without messing up my recorded data.

[joecar]

Did you apply the BEN filter...?

[jermstyle]

I used the filters from the AutoVE documentation.

I found one prob though - My map reset some how and wasn't hiding cells with > 50 hits - I changed that but I still need to find a way to smooth it because it really isn't possible to hit all cells 50 plus times (and is un needed really).. But in the event that I jump into one of those cells I don't want a huge spike.

[JezzaB]

It lost power because there is a thing called MBT - Mean Best Torque/Timing

More timing does not equal more power. You have to find the sweet spot.

If you do an auto VE on the dyno it should only take about 10 mins to do the main areas (not top end). Like was said, lock a speed or a load and use the throttle to increase your kpa etc. And slightly decrease the load or increase the speed and keep going. You will get quicker at it and not overheat the engine etc.

Then start working on your top end stuff. Its a good idea to put the timing below where you want to be because if its too lean etc it wont detonate.

Once the AFRs and BENs are looking pretty good start putting in a little bit of timing in bit by bit. Each run that you are changing the timing apply the BEN for the last run so you are following it for the spark changes as when you change timing you change the AFRs.

Go up until the power drops or you are making very little increase in power. No use ringing its neck and putting it into danger for gaining 3rwhp etc.

This method will make you get the most out of your limited dyno time and still get a good result.
Good luck and have fun.

Jez

[jermstyle]

Would it skew the AutoVE if I included data logged when the ECT was at 181? (3* more than the AutoVE doc)