Say it ain't so oh holy tooning gods!

I did a quick and dirty retune of a members car yesterday because both of us didn't feel the cars tune from another tuner was safe. The car was pulling timing every pull.

It is now running less timing and a much smoother and ecu-friendly timing advancement in the meaty low and mid range and a little more timing up top since the other tune had too little.

It is also running slightly richer numbers in the mid to upper revs.

I also detuned the low octane maps to give a safety net incase the owner ends up with a bad tank of gas. The tune before had the low and high octane maps set the same.

Graphs speak for themselves.

 

amazing he still gets business

 

Were those pulls both started at comparable RPM points and both made using the same gear?

I'm trying to figure out if you lost the low-end or if that's just a product of starting the runs at different RPM.

 

Same gear, same road but yes the RPM was slightly off. I was too busy holding onto the laptop and watching the timing and knock voltage plots to see when he was starting the pulls.

I wouldn't look at the graphs for spool differences. Didn't change much.

 

somthin don't jibe with that chart.

 

What doesnt jibe?

 

So before it was pulling timing throughout the pull?

Also, all tq and hp values are on (cross @ 5250) but what caused everything to shift right in RPM from the control - different tire size?

 

The pulls where started at slightly different RPM.

The first graph shows the green line falling off at around 6400. We aborted the pull cause the timing was being pulled and the knock voltage was spiking.

The second graph the ends aren't the same because again we didn't want to rev to high because the car was pulling timing.

You can see the timing pulls on the green plots from the bow in the power curves.

 

It would be interesting to know how rough the actual timing run on the original map was.

I think if the low and high maps were different and smooth, when there was a lot of knock in one area then the whole lot would be pulled nearer to the low maps - this would be smoother. It also makes sense - if the timing is a sensible shape then on pump gas when knock limited you'd expect to be a similar amount from the knock threshold across the range. With the low and high maps different the ECU can learn from this and do better next time. With them the same I think it will be rough every time.

 

jcsbanks,

The high and low octane maps where exactly the same with the previous tune. This also brings up another data point about if the ECU is able to pull timing if both maps are the same. In these pulls and logs we did, yes it certainly can! The only time the car actually hit it's programmed ignition numbers without pulling timing was around 5500 to 6000 but then knocked again and pulled timing. I would love to tell you the actual ignition numbers in the map but I think the tuner would get mad.

The peak torque ignition numbers where also too aggressive and never hit the assigned number in all 3 pulls.

The "retune" has the low octane maps a bit lower than the high octane maps but not as much as stock. I did this incase the owner gets a bad tank of gas.

In all fairness to the previous tuner, this was an off-the-shelf reflash and also for a california car where 91 octane is quite a finicky equation.

 

So you took your ECU+ and put it in his car to get the graph? Awesome results.

 

RAZORLAB doing a great job , now everyone stop hating.

 

Ah.

Scorke

 

Yes I used the ECU+ with harness for logging and graphing. My car is sitting on a lift with no gearbox so I currently don't need it on my car. It's a great tool.

The knock compensation came in quite handy let me tell you.

I am actually thinking about buying another ECU+ and a clamp on wideband sensor to do things like this.

 

So Bryan, it seems that you did at least two things that seem sympathetic to the ECU's knock control. First of all you run a nice smooth knock free high octane map. Secondly, you have a low octane map that is retarded so that if your high map does knock it won't go rough, but the ECU's octane value will pull the whole map smoothly towards the low octane map, relying less on live rough knock control. The previous tuner did neither of these so the car runs rough. This is how I think it is all working, seeing octane values in these situations would confirm. I can't bring myself to do a rubbish enough tune to pull my octane value down