This section is dedicated to discussion of DTA engine control units such as the DTA E48 EXP, P8 Pro, DTA S40, S60, S80, and S100, as well as all things ECU related.
Can anyone give me a simple to understand rundown of how the TC on a S60 works. I know it calculates the difference between the driven wheels and a undriven wheel and cuts engine power if they differ but I can't get my head around the "agression" aspect of it.
If I am using a rotary dash mounted pot to vary the agression what is it actually doing? I think that it alters the agressiveness of the spark cut but I don't understand how that applies to wet and or dry conditions.
When it comes to settings if I am using a rotary pot and I have entered the minimum and maximum agression figures do they overide the % figure in the "Excess Slip to Hard Cut (agression) box.
Also I take it that the Target slip % remains constant whatever I do with the rotary knob - is that correct?
And aggression means just that. Like a really harsh cut, or a smooth progressive cut.
it will depend on traction available, driving style etc.
A car with a lot more power than traction may require a more aggressive cut than a car that is barely able to spin the wheels
But obviosuly mid slide for example, you may not want a very aggressive cut, as it may unsettle the handling. SO it's a balance, and the only way to establish what works for you, is through lots and lots of testing.
Yeah but not too much. A little slip is preferable to a complete cut. 5-10% cut in the dry and 15-20% cut in the wet are good places to start but as Stevie says, it will need a lot of experimenting to get it how you want it.
VR6Turbo wrote:Yeah but not too much. A little slip is preferable to a complete cut. 5-10% cut in the dry and 15-20% cut in the wet are good places to start but as Stevie says, it will need a lot of experimenting to get it how you want it.
Ah, now you see this is where it all gets too much for my tiny brain. It seems to me that on the S60 the amount of slip allowable before the TC takes effect is preset for all conditions. i.e you set the target slip % at 8% (for example) and then it is the way in which the TC is delivered that is varied by the knob. Is that correct?
I know that on other DTA models you can alter the actual amount of slip %allowable for wet and dry conditions but that needs 3 or 4 wheel sensors. I find all that easier to understand than all this agression business!
I think in order for the TCS to work on an S60 you would also need a gear position sensor, either calculated by a shaft speed, or an actual switch or switches on the box or stick.
As it bases "slip" on undriven wheelspeed and rate of change of rpm ? ( I think, never actually used an S60 though )
Unlike the S80 as you say that monitors actual wheel speed for all wheels.
So I imagine it's effectiveness is much reduced because of this. Especially with say a diff that allows one wheel to spin and rpm to rise
VR6Turbo wrote:Yeah but not too much. A little slip is preferable to a complete cut. 5-10% cut in the dry and 15-20% cut in the wet are good places to start but as Stevie says, it will need a lot of experimenting to get it how you want it.
Ah, now you see this is where it all gets too much for my tiny brain. It seems to me that on the S60 the amount of slip allowable before the TC takes effect is preset for all conditions. i.e you set the target slip % at 8% (for example) and then it is the way in which the TC is delivered that is varied by the knob. Is that correct?
I know that on other DTA models you can alter the actual amount of slip %allowable for wet and dry conditions but that needs 3 or 4 wheel sensors. I find all that easier to understand than all this agression business!
You need to read the manual a bit more as there are significant differences between the S60 and S80/S100
Without knowing how the DTA reduces engine power, it's difficult to predict how the aggression will work. On Racelogic's TC system, it's aggression is controlled by how many injectors it cuts. Starts off with 1 (or 2 in a 6 cyl) for soft aggression and then more as the agression increases.
I don't know if the DTA does it by ign retard, then fuel cut, or fuel cut alone, or even spark cut. It doesn't say in the manual.
I will say that I have sampled Racelogic's in a very powerful FWD car and it's absolutely superb. Easy to setup and it just does what it says on the tin.
It is supposed to retard, and then cut cylinders. Not sure if by fuel or spark.
It does work, but it's difficult for me to judge just how well even though I do use it to a degree.
I have rather an excess of traction defying ability on the road, so the amount of power reduction required is massive, so would be tricky for any system to do it nice and smoothly.
"You need to read the manual a bit more as there are significant differences between the S60 and S80/S100
I don't know if the DTA does it by ign retard, then fuel cut, or fuel cut alone, or even spark cut. It doesn't say in the manual."
The section in the manual that relates to TC for the whole S series is all of one page and reading it doesn't take too long. Reading it again won't help. Power cut/TC is most likely the same as for launch control which is by retarding the ignition followed by a soft spark cut then a hard spark cut.
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