Ign Tuning without dyno (road tuning)

[tseitz123]

Hello all.  I am in the process of tuning my Evo VIII and have pretty much setup and tuned a hybrid boost comp fuel map, AIT correction, knock control, O2FB, etc.  NOW, the ONLY task which is daunting me is how to effectively go about road tuning my ignition map.  I know that a dyno is really hte way to go, but that is out of the question as of right now.  Any and all suggestions would be greatly appreciated.  THanks

[tseitz123]

Come on ppl!

[shaundrake]

It is extremely difficult because 1) you don't have dyno feedback and 2) it's very difficult to keep the engine at a steady state.

If you can keep the engine at a steady state, log RPM, load, and ignition timing. Keep the load and RPM steady, start at a low ignition timing and increase it in steps with a few second pauses between each increment. Look at the log and if you see the load drop and RPM increase, then you're headed in the right direction. It will continue to drop until eventually it will start to fluctuate up and down (or you'll be knock limited). Back it off and you're all set for that cell.

Unfortunately as I said it's too difficult to keep the load steady enough to get conclusive results.

[TheBoz2]

Same for me, how are peopel doing this.

For me what I have been doing is take the car out and do a 3rd gear pull, check the timing logs, add or remove timing based on knock.  On CA pump gas, I only have about 5 degrees of timing under full load(25psi) and 120 degree intake temps.  I will just move the timing curve up a little bit at a time, until the knock gets to high.  I then try to smooth out any of the spikes if they happen in the same area.

Here is what I log

Engine Speed
Engine Load
Throttle
O2
O2 FB Value
Coolant Temp
Air Temp
Ign Trim Air Temp
Fuel Trim AIT
Ign Timing
Knock Volts
Knock Retard
Knock Fuel

That normally gives me a good idea of what is going on.  If anyone else has some more insight I would love to hear it.

Load
25.74 [-5.05  -4.34  -3.28  -2.23  -1.17  -0.47  0.57  1.63  3.03  3.74  4.44  4.44  4.44  4.79  4.79  4.79  4.79  4.44  4.09  3.74  3.39]
         500rpm --------------------------------------------------------------------------------------------------------- 10500rm

[paulvr4]

Same for me, how are peopel doing this.

For me what I have been doing is take the car out and do a 3rd gear pull, check the timing logs, add or remove timing based on knock.  On CA pump gas, I only have about 5 degrees of timing under full load(25psi) and 120 degree intake temps.  I will just move the timing curve up a little bit at a time, until the knock gets to high.  I then try to smooth out any of the spikes if they happen in the same area.

Here is what I log

Engine Speed
Engine Load
Throttle
O2
O2 FB Value
Coolant Temp
Air Temp
Ign Trim Air Temp
Fuel Trim AIT
Ign Timing
Knock Volts
Knock Retard
Knock Fuel

That normally gives me a good idea of what is going on.  If anyone else has some more insight I would love to hear it.

Load
25.74 [-5.05  -4.34  -3.28  -2.23  -1.17  -0.47  0.57  1.63  3.03  3.74  4.44  4.44  4.44  4.79  4.79  4.79  4.79  4.44  4.09  3.74  3.39]
         500rpm --------------------------------------------------------------------------------------------------------- 10500rm

[Aurélien]

Use 3axle G meter and 2nd Newton law  , thermocouple and detcans .

As you have no knock and you won in acceleration , increase your timming .

Not as good as a dyno , but better than nothing .

And hum , please take an over guy to drive , i don't want you have an accident because you was reading your computeur !

[Joseph Davis]

Log crankcase pressure.  When it elevates detonation, or pressure spiking that happens before detonation, forces extra combustion gasses past the rings since they can't push the piston down fast enough.

At the drag strip with a good driver you can determine correct ignition timing under high load, aka taking "pulls."  You spend a lot longer pouring over the datalogs than when on the dyno as it is a much less controlled environment, but you can also make improvements that can't be manifested on a dyno.

[nutzsrt4]

if you have a knock sensor and know the threshold for "false knock" i would start by
#1 make sure your log (must be internal to get it fast) is set up correctly
#2 make you knock ign feed back very cautious IE: allow it to use a ton of retard (this will just be for protection)
#3 find a big long steep hill to do pulls on, maybe put some sand bags in the trunk for extra load
#4 as soon as your done PULL THE LOG FROM THE EMS
#5 watch the logs to see how the motor reacts to the increase in timing and at the first sign of knock pull 2-3 degrees (this will be a softy margin for street conditions/ fuel)

if you have a good base map use that as a guide, changes in head/ cams will need a much faster ramp up, free flowing exhaust likes a little more too .......


be very careful and take baby steps because if you get over zealous with the advance you will blow the motor