How to calculate TC slip.

4x4dually

4x4dually

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So what's the calculation to see how much, if any, the converter slips? It is as simple as using the RPMs, gear ratios, and axle ratio or are there conversion factors and more complex crap? Anyone care to share how to calculate it before I try to do it myself and screw it all up? LOL
 
I'm assuming this works?

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So if it were to be calculated and displayed real-time, the processor would just have to substitute the gear ratio in for what ever gear the tranny is in at the time?
 

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You would use abs sensor.
Then compare engine rpm to trans ratio/ gear ratio. So it will change in every gear.
 
I guess I don't get what the ABS sensor does. The display already knows what gear it is in.
 
I get my wheel speed from the ECM....which prolly gets it there. LOL

I'm assuming at over #26,000 GVW, there's a substantial amount of slippage while getting going. I'm just curious as to how much. Gonna load up to about that weight tonight when I get home. I might play with it and see what it tells me. Just curious if that is the acceptable equation that everyone agrees with or if there is a better way.


I think the stock TC hates my guts. LOL
 
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Pasteing this here for my safe keeping. :D These are correct, right?

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Gonna be a whopper of an equation for it to use if/else statements to use the correct gear ratio for each gear. Simple to PITA in 3...2...1... LOL
 
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I would look at the output speed sensor on the trans if you have access to it. Pretty sure there is an input and output speed sensor on the transmission.
 
You can do total loss but not TC without an input shaft speed.

From My Not-So-Smart Phone
 
Alright, so I now have the calculation event in my display. My questions now is, if you were going to do a meter, say a circular bar graph, with green being good, yellow being fair, and red being bad, what levels are acceptable for slippage?

Since the actual data will be a combination of any TC slip and tranny slip, it will be just a general "slippage" between crank and tires. What levels would be acceptable in everyone's opinion? Running in 6th and locked down the highway...should there be any slippage at all? Is 0% the goal or is there a acceptable 1-5% or something?

Edukate me.
 
Mine seems to flash to 1500 then barley slip at all until boost is over 15psi then it just blows through it. Truck doesnt feel like it goes anywhere until I flip lockup and thats only if it hooks up.
 
What? I'm confused. LOL

Lemme rephrase....if I display slip in 0-100%, what should be the breaks be for "acceptable", "fair", and "bad"?
 
madmikeismad said:
I would think zero if locked.

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Click to expand...

0 would be close cruising but you will need a mild debounce for drivetrain deflection when the truck hits bumps. This it speculation on my part.

Monkey Fist Rage
 
I would log the data, and you could get fancy and use a calculation to factor in engine load.
Since at low engine loads your slip should be less.
 
biggy238 said:
0 would be close cruising but you will need a mild debounce for drivetrain deflection when the truck hits bumps. This it speculation on my part.

Monkey Fist Rage
Click to expand...

I tend to agree.... 0% for TC locked (lord I hope so), and then I would gander with the converter unlocked you would experience greater slip in each successive gear. (loading is much less in 1st than in 6th)
 
zstroken said:
I would log the data, and you could get fancy and use a calculation to factor in engine load.
Since at low engine loads your slip should be less.
Click to expand...

The ecm already has a load calculation available. I'm not sure how realistic it is.

Monkey Fist Rage
 
biggy238 said:
The ecm already has a load calculation available. I'm not sure how realistic it is.

Monkey Fist Rage
Click to expand...

Yes, I was saying to use the load to help determine the acceptable range on the slip meter. LOL
 
I set up the log...just haven't hit the go button yet. ;)

I did an equation with an IF statement to assign the gear ratio for each gear. I used 1, 2, 3.... When it didn't work, I remembered it is in Hex. :bang I'll fix it and update ya on how it works.
 
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