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)

[shane]

I use auto ve all the time on the dyno, the key is to have a big enough fan to keep the car at a stable temp. i generally use the road runner (gods gift to easy tuning).When doing ls2 etc i just lock in a speed and skip across the load cells then up the rpm and repeat doesn take long. I still prefer to do very light throttle cruise etc on the road as its easier to put the correct light load on. I have yet to see a ls series engine take any more than 26-28 degrees at wot normally less through peak torque 22-24.Especially if its big in compression 11 -1 up.I do the wot by running a very safe timung figure at first then run it up till i get the ve right so that commanded fuel is exactly what im asking. Then sneak up in the timing till it goes backwards then pull a little more as on the road they knock easier(cant accelerate like a dyno run).
The other thing to watch when tuning is to make sure that actual spark and commanded spark are similar and if there not whats taking it(iat, coolant temp, burst knock etc).Can be frustrating especially on e38s where theres 300 different things taking there little piece.Its all good for them to take a bit of spark you just need to know why its dissappearing....
It really is an easy process but unfortunatley it takes a while to learn(and about 40 cars lol).Stick with it youll love the results
:cheers: shane

[Nine-Eight]

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'm going to go out on a limb and guess that you have a fairly decent aftermarket head/cam and boltons car- it is true that a car will usually gain power with timing, up to a point.

a modified, more efficient motor will want less timing to get the job done than say a stocker because the valve timing and cylinder burn events are faster and more complete(results of compression, combustion chamber design, blah, blah blah....)

[joecar]

I use auto ve all the time on the dyno, the key is to have a big enough fan to keep the car at a stable temp. i generally use the road runner (gods gift to easy tuning).When doing ls2 etc i just lock in a speed and skip across the load cells then up the rpm and repeat doesn take long. I still prefer to do very light throttle cruise etc on the road as its easier to put the correct light load on. I have yet to see a ls series engine take any more than 26-28 degrees at wot normally less through peak torque 22-24.Especially if its big in compression 11 -1 up.I do the wot by running a very safe timung figure at first then run it up till i get the ve right so that commanded fuel is exactly what im asking. Then sneak up in the timing till it goes backwards then pull a little more as on the road they knock easier(cant accelerate like a dyno run).
The other thing to watch when tuning is to make sure that actual spark and commanded spark are similar and if there not whats taking it(iat, coolant temp, burst knock etc).Can be frustrating especially on e38s where theres 300 different things taking there little piece.Its all good for them to take a bit of spark you just need to know why its dissappearing....
It really is an easy process but unfortunatley it takes a while to learn(and about 40 cars lol).Stick with it youll love the results
:cheers: shaneShane, good pointer. :cheers:

[The Alchemist]

Hi Shane,
and those timing figures must be on 98 octane.......on 95 octane here in New Plymouth, New Zealand, I run 22 deg up top and 18 deg at peak torq (4800rpm) figures on LS1's standard cam, slightly more with a LS2. You achieve nothing going over this believe me :secret:

Don't tell any one :)

[joecar]

Is that because the LS1/LS6/LS2/LS7 style heads are a "fast burn" design...?

[5.7ute]

Hi Shane,
and those timing figures must be on 98 octane.......on 95 octane here in New Plymouth, New Zealand, I run 22 deg up top and 18 deg at peak torq (4800rpm) figures on LS1's standard cam, slightly more with a LS2. You achieve nothing going over this believe me :secret:

Don't tell any one :)

Before I fitted the 1.8 roller rockers my cam loved timing between 28 & 30 deg. It was still up near 28 deg at peak torque. Now, however with the 1.8's in it doesnt like as much timing, especially at peak torque where it is back around 25 deg. This is on our 98 octane fuel.

[shane]

Sure is on 98 wouldnt use anything but. Bp ultimate 98 always seem to be the choice ,we've back to backed all the 98 fuels on the dyno and the bp 98 is always good on timing (probably the ethanol in it).The shell 100 was even better but they stopped making it:bad:Mind you rumor has it that the private
fuel company united is selling 100 octane and that it comes from shell(whats up with that).I always tell my customers to bring the car in with whatever there most common fuel is and tune from there.
:cheers: Shane