I noticed at least in the 2.8 version of EvoScan that I have that the temperature was wrong for the MR Transmission entry. Turns out that the Imperial Units field was just using the Metric formula. Also the Intake, Manifold and Engine Coolant temps don't have the metric field filled out either. Just go to the Logging menu and choose Edit Data Item List which will let you edit these to give you the proper values:

MR/SST Transmission Temp

Eval: ((x-50)*9)/5+32
Unit: Deg F
MetricEval: x-50
MetricUnit: Deg C

Intake Air Temp, Manifold Air Temp, Engine Coolant Temp

Eval: 1.8*x-50
Unit: Deg F
MetricEval: (((1.8*x-50)-32)*5)/9
MetricUnit: Deg C

 

When it comes to SST temps. is colder always better or is there a certain optimum temperature range to target? What temp reported from the ECU does it start to give you the slow down messages?

 

Temps in the SST don't work the way you think they do.

The stock table looks like this:
Limp mode on 293
Limp mode off 275

 

Actually I thought they had trigger temp and then forced a recovery period before turning off again. I had no idea the values were that high though, seems like very high temps. Having it read in celcius when it indicated *F was misleading for sure though. :P

 

I consistently got Temp Slowdown at 135 C using CAN 28-0 and "x-50"
which is ~275 F

I have logged this extensively and the results were very repeatable.
I know the tables say slowdown should happen at 145 C , but that's not the case with my car. Nor with another friend's car i tested.

So maybe the ecu draws Temp from another sensor, or there's another table involved...
I'll cook the SST again once the new motor is in and see what the Clutch Temps are compared to the SST Temp. Maybe they are 10 degrees hotter?



And to answer your question, IMO colder isn't always better.
Ideally around 70-100 C , or 160-210ish in your speak, seems to be the sweet spot. I guess it affects the way the clutch material and the fluid works.

 

If you are seeing 135C with the CAN address then it can very well be 145c+

 

Bryan, can we (or at least YOU) log the address that causes the Temp Slowdown? Or do we think it's internal and not broadcast to the ECU?

I only have the 3 temp addresses already mentioned but I'm guessing none of them is the one responsible.

 

Funny you say that, we are actually looking into it now (well, Richard is finding them and I am helping him).

It has to be broadcast to the ECU since the ECU has the limp mode condition.

 

^good luck lads

On this off-topic topic... The ONSET/OFFSET table for Temp Slowdown - does altering that actually work? I'm assuming the one Golden referred to is in the ECU rom...
I would have thought Temp Slowdown is initiated by the TCU and we can't mod it (yet)?

 

Hi Beeble.

Yeah, that onset/off table thing is exactly what I'm tracking back from. The code seems to have the following mechanism...

Raw Sensor Value -> Temp Scaling Table -> Scaled Temp Value -> Onset/Off Table Check


However, while logging around town, the "Raw Sensor Value" scrapes along the floor at its apparent "coldest" reading... and the "Temp Scaling Table" does this weird wraparound thing with its values. So it's all very much a work in progress right now.

So far, I haven't had the opportunity to get my SST CAN-bus measured temp over 60C - the address-based temp just shows all zeroes.


If you want to help test, be my guest! For your 53050009 ROM, log these two things...

Raw Sensor Value: 0x80873a (2-byte).
Scaled Temp Value: 0x80873d (1-byte).


On my few street drives so far, the "Raw" value has stayed around 997. It should reduce as temperatures rise.

The scaling table just looks like a way to get a non-linear sensor reading over to Celsius. Below a certain temperature, it doesn't look like it works properly - perhaps that's why I'm getting zeroes.


For completeness, Bryan's ROM (55590007) has these addresses as:

Raw Sensor Value: 0x808756 (2-byte).
Scaled Temp Value: 0x808759 (1-byte).

My 2009 RA (53610010) uses:

Raw Sensor Value: 0x808742 (2-byte).
Scaled Temp Value: 0x808745 (1-byte).


Now, this could all turn out to be bogus. The "sensor" reading could be non-functional... but I have hope. It jitters between 996 and 997, so to me that looks at least half-alive. Perhaps it doesn't wake up until temps get high.

So go get that SST toasty, and see!

If this works, it'll be great for standalone logging, as that doesn't do CAN style. Fingers crossed.


Rich

 

Hey Rich, thanks for the info.
Yep always happy to test out stuff for the SST
Unfortunately my car is in pieces right now, but will be back on the road hopefully within a month or so with a 2.2 to get that tranny warmed up extra fast
Will get in touch with you again and see if there's anything new to try..

FWIW the higest i ever got my CAN temp on the road was 104 C after a serious twisties run for 20+ minutes, changing gears ridiculously often.
However, on the track you can cook it after 10mins if you try with the cooler not switched on.

PS where are you located mate? I'm down in Melbs.

 

Yeah, the track temps get hot fast!

I'm gradually improving the RA's cooling... like, an Evo X intercooler. Which, as it turns out, used to be yours!

Rich

 

^^ i thought your name sounded familiar

 

When I said temps don't work like you think they do, I mean physically in the SST / Hardware.

That's about all I can say, but you can really chase your tail on it from the software side and get nowhere.

 

Chris,
now I'm confused!

for IAT and Coolant temp, Evoscan 2.8 uses x-40 for temp in C (in the imperial section)
and the formula listed above for temp in C also (for metric)

so - is the correct value for temp in C the "x-40" or the other formula
as they give values that are 5-6 C apart
eg if x=140,
temp = 100 , or temp = 94 , depending which method you choose.
94 i can live with on the track. 100 means i need to back off