Thread: Anything you ever wanted to know about tuning and electrical systems...

in regards to TP scale

all motor application
WOT run and datalog highest TP of say 80

what's the advantage of setting your TP scale to 80 opposed to setting it at say 64? from what i've seen you have better resolution with a scale of 64, and it seems kind of pointless to set the TP scale to the highest TP you recorded (80) because it only utilizes the very top of that column anyhow. hopefully that makes sense..

Peak power can be on either side of the maximum advance before detonation. Ideally we would all have insane octane gas and reach the best timing for torque, in boost you generally reach knock threshold before best timing for power.

You don't want to have too much timing down low. If you advance after best torque you will loose power. If you are on a dyno things are easy to tune, you just start real low in timing. Easiest to do is static number across RPM. Then hit the cell using the loading features of the dyno and adjust timing until torque maxes out or you start to hear detonation.

You will generally have a timing dip at torque peak, after which you should start adding timing as a function of torque. AKA if your torque starts dropping fast, your timing should increase pretty fast. I have found that a lot of times after torque peak, so much timing can be added that you will begin to loose power before you actually start knocking.

What I do is add a few degrees until it levels off, then subtract a few off.

You need to set the max TP scale to the max TP value you reach. You loose some break point data, but you can actually tune the car properly. If you ever request a TP above your max TP the engine will only give you the maximum TP value you set.

This is problem if you have a max TP of say 80, but your Max scale is 64. If you tune this 64 TP line at WOT your WOT will be fine, but you will loose everything else underneath it. What if your accelerator tip is is actually 63. You will flood the engine.

I remember Ben saying add timing gradually until you stop gaining power, if you start to knock then back off until you stop, then you might want to back off more in case a really hot day rolls around.

So basically, start with very low, stock like numbers. Do a dyno run, and up per cell bases, do a run, compare the two graphs and see if you gained power in that RPM range or if you lost power, update accordingly and then go to the next cell?


Say if I can do 25* at 6,800 rpm anything higher will knock. I can I add more fuel to be able to add more timing? Or there comes a point where the engine will drown in fuel and will still knock?



The best example I can think of for this is. When you run so much boost you have to quickly pull back timing, otherwise it might knock. Look at Dan's map to see how he pulls back timing with more pressure/RPM.

Alright so lets put this into TP turns, since Dan's map is Boost/Vacuum based (runs away jealous).

Hypothetically lets say you are at 64TP at 7psi, and you will be at 85TP at 10psi. You will be running a constant 10psi.

At 64TP(7 psi) you can safely run 25* at 6800rpm. At 85TP(10psi) you can only run 20* safely. So since your map is at 64 tops, when you hit the 10 psi you start knocking, so you retard your timing to 20*. Less timing means less power unless your about to knock.

Now if you update your TP scales to have 64 and 90 TP. You can now set your timing to be at 25* at 64TP column, and then at 90TP column you set your timing to be 20*. Now you have the benefit of running more timing, thus more power leading up to the MAX RPM.

Now keep in mind on how the ECU reads the maps. From Map tracing I was able to get a good idea of how it does it. If your TP scales are set to be lets say 60 70 90. Then when you are at 61 you will be using the 70 Column. If you are at 75 you will be using mainly the 90 column. If I recall correctly the ECU does try to calculate an in between number if the scales are far apart.

DSM guys play the timing vs fuel game all the time. I'm not a fan. On boost you run I like around 12.5 AFR. And advance timing until you knock then back off. And that was not a tuned map by any means. It was just something I put in that would get me by. Never got around to a full power tune.

Vadim, thanks for reminding me to stay away from Calum and the likes

You and Ben need to come and tune my car for me!!!!!!!

You need to drive down here on a weekend. =]
Hell, this weekend is a long one. I get Monday off.

=D

Vadim also keep in mind that TP value don't correlate to PSI. Flow correlates to TP.

I was thinking the same thing.