All right - who's on this, and how have they been tuning it/what kind of improvements have they seen? I've seen a few random threads, but nothing specific going over user adjustments and how they are using it. Specifically thinking of track/road racing.

 

I would also like to know. Anyone even know someone whos run one? I know there are some other brands that make more rally based ACD ecus though Im drawing a blank on the name of them.

 

I have the genuine ralliart tarmac ACD ECU. Honestly i didnt notice much difference but ive never tried doing back to back testing vs my factory ECU. Might be something to try if we can ever get my thing consistant and reliable enough to back to back test haha.

You can tune the stock ones via evoscan. theres lots of info on here specifically from a guy called merlin who seems to be the ACD expert for tuning maps. Theres plenty of maps uploaded here on a mega thread over in one of the other channels. You could always start with plugging in some of the maps people have already made up.

I dont really see the value for money in buying any of the aftermarket diff ECU's. Possibly if your gravel rallying you might get some decent gains but i personally would spend the pennies elsewhere. or buy an evoscan reflash cable and give a reflash a go.

 

If you read through the Evo modding thread, the Ralliart ECU tune is there but its recommended against using it. At least the guys that have used it said its pretty well junk. The downside to stock ECU is understand what is actually going on. Theres too many variables that a quasi defined and with out actually making single changes and trying to log the difference to make sure its doing what we want we're still guessing in a lot of things.

Im going to keep working on stock ECU but if by the end of next year comes and its just fighting me I may end up spending the money. Though it may coincided with an ECU change also so I may ball-out for M130 since it can do both engine and ACD.

 

Yea i mean the only thing id consider doing would be to just take somebody elses map and load it in i wouldnt try tuning it yourself it gave me a headache reading through some of that stuff haha.

Hmm now you mention it maybe i should see if its a market Haltech are interested in. probably not as theres just not enough people who would buy one. unless they can make a generic style one up that will work on multiple cars.

What other cars have active style diffs?

 

Ive read all the threads so I have at least a marginal idea of what we know. At least enough to know we still dont fully understand it. But Im working on it more, will keep learning.

The Motec unit has both the Suby and Evo version so Id imagine the module is the same with different tunes.

 

also re-including this link -

https://www.motec.com.au/filedownloa...pdf?docid=4399

It's a magazine article, not a super scientific test, but using a X RS they experimented with a few different settings to optimize. What's interesting is, the tuned diff is only 7 tenths faster than a fully open one.

 

.7 is a LOT on an already setup car. But from memory Dave Kern who had that red Pikes Peak build had the motec+diff with 5 different hot tunes he'd flip between as he went further up the mountain. On the rally side Rob the Hungarian had the full on GEMS setup on his X and showed us a bunch of 9's over in the EU that used the GEMS gear. Trouble is support, finding a tuner local to you that can actually do all of that. I'm lucky here in ATL that I have both a top MoTec and a rally shop GEMS guy for evo's once ya'll convince me to try it lol.

 

who's the top motec guy? i've seen a lot for rally guys using it, but not as much for road racing/autox. i think the gains probably aren't as significant on grippy surfaces than in rally.

though i do want to try an acd that's just open everywhere except for on power. honestly, i think that will be 95% of what people on track/autox need.

what's .7?

 

Seven tenth's for the ralliart comment lol. If it was a properly setup car with the same pro driver, and they simply swapped controllers, that's pretty significant. I'm still running an original acd-tuning tune on mine that Matt setup for me back in the day. Slicks, R's, Rains between the 3 maps. One of the best mods I've ever done in terms of turn in/track out.

"THE top" is naturally up for debate but DBW does lots of Motec for 911cup/GTR folks.

 

ohh - i think the difference was for the journalist, but yea i guess the mag has a prepped car.

looking back, i didn't see a huge difference between the gruppe-s acd i had and the acd-tuning acd i had. i got a big boost in turn-in ease from the ER ACD, but been discussing with dallas what it's really doing.

 

I had the ACD-tuning tune a long time ago. It only induced understeer in my car. So my perspective is that their is no one right solution. It depends what/how the car is setup, what diffs it already has, how much grip the car makes, how it handles total weight transfer, and a number of other variable. I think going forward if I find something that works for me i'll certainly share it but I wont support it for anyone. Because its what worked for me doesnt mean it'll be right for someone else. Especially if you consider the diffs and approach to balance my car takes.

The reason I want more control over the ACD is I want it to do less. Almost like the Viscous coupler but when I want it to do something (throttle exit) I want it to do more than the viscous can handle. There is probably also something in high yaw moments or inducing yaw the ACD can help, but I dont really grasp it yet until I see what the line pressure is and feel what the car does.

 

i agree re: doing less. i mentioned in the other thread, i think the ideal is to have it open everywhere but on throttle. is that what you've set up on tune you're working with? even on braking, i dont think you need much, especially with a 1.5 way rear. maybe a little bit if you've got a 1-way front. otherwise, if you have it open all the way almost all the time, save for when you're really getting on the gas, i don't see how that hinders anything. if I got the motec that's probably all i'd do with it. painful for the $1,800

i also mentioned in PM, i wonder if how the ER tune sets the preload is how they achieve how easily the car turns in, the more "aggressive" their map, the less preload.

 

You can easily see if your turn in idea works.. just unplug the acd pump.... The turn in will be worse but try it anyhow..

 

you mentioned that before, which seems to be in opposition to most data, including the motec article i posted above; are you sure when you do that it doesn't also interfere with ayc? otherwise, i'm not seeing a physical reason that why that would hold.

the acd on full open per the article made the car very loose