ACD Tuning Options - USDM CT9As, Read!
^ The low speed binding was definitely an issue with the ACD-Tuning flash which just made for understeer. The ER flash goes the otherway though, more lockup at higher throttle and speed. BrianAWD on here got to try the ER heaviest map on his street tired evo and it went from being a pretty neutral car with some throttle rotation to spin-city. He literally could not complete a run without the car nearly spinning and having to skip gates to not kill cones.
He really needed the mid-setting but we were testing things and he didn't have that available. For cold race tires or street tires, the low and mid setting are great. With hot race tires the high setting gives me a ton of mid to exit rotation and definitely keeps me on my toes driving. That said, Its been worth some significant time in my case. Hard to quantify how much because its course dependent but with late corner rotation I can lift for rotation and roll on throttle much earlier so less boost lag, earlier acceleration, and tighter lines in many needed places.
He really needed the mid-setting but we were testing things and he didn't have that available. For cold race tires or street tires, the low and mid setting are great. With hot race tires the high setting gives me a ton of mid to exit rotation and definitely keeps me on my toes driving. That said, Its been worth some significant time in my case. Hard to quantify how much because its course dependent but with late corner rotation I can lift for rotation and roll on throttle much earlier so less boost lag, earlier acceleration, and tighter lines in many needed places.
Thanks guys for your feedback. I've read from multiple folks now that some of these flashes are causing low speed speed binding issues which has been a turn off to me in the past. Given that my drug of choice at least this point in time is auto-x if that is the case its a deal breaker.
So Im glad to hear the the new ER flash does not suffer from this common issue.
Dallas- you noted that on street tires the low and mid settings seemed to work better so that is probably where I will end up. I've got an SM car but run 255 Zii's.
I think my suspension setup is really coming along and my car has never felt better than yesterday. The car is stable through the slaloms and doesnt get upset like it used to although that was partially due to me overdriving the car. Turn in is amazing, it will set and then bite hard like it should.
My biggest issue right now though is mid corner push. I need to be very careful with the throttle mid corner. If I stab the gas I have crazy power oversteer thanks to my TRE rear diff which while fun, certainly isn't the fastest way around the course. If I try to be gentle on the throttle I find that the car starts to push. There is only so much grip in a given corner and as such you can only go so fast.
How does the ACD reflash help mid corner push?
In terms of actually getting the service done, does ER have spares on hand? I cant exactly be down for a week or two to send mine in...
So Im glad to hear the the new ER flash does not suffer from this common issue.
Dallas- you noted that on street tires the low and mid settings seemed to work better so that is probably where I will end up. I've got an SM car but run 255 Zii's.
I think my suspension setup is really coming along and my car has never felt better than yesterday. The car is stable through the slaloms and doesnt get upset like it used to although that was partially due to me overdriving the car. Turn in is amazing, it will set and then bite hard like it should.
My biggest issue right now though is mid corner push. I need to be very careful with the throttle mid corner. If I stab the gas I have crazy power oversteer thanks to my TRE rear diff which while fun, certainly isn't the fastest way around the course. If I try to be gentle on the throttle I find that the car starts to push. There is only so much grip in a given corner and as such you can only go so fast.
How does the ACD reflash help mid corner push?
In terms of actually getting the service done, does ER have spares on hand? I cant exactly be down for a week or two to send mine in...
We have a few cores on hand but not enough as of yet to offer it as a core free exchange. The car will still be drivable without the ACD, it is just an open center diff. I reship the ACD ECU the same day I recieve it and we can expedite shipping if need be as well.
Last edited by JohnBradley; Aug 11, 2014 at 02:28 PM.
^ The low speed binding was definitely an issue with the ACD-Tuning flash which just made for understeer. The ER flash goes the otherway though, more lockup at higher throttle and speed. BrianAWD on here got to try the ER heaviest map on his street tired evo and it went from being a pretty neutral car with some throttle rotation to spin-city. He literally could not complete a run without the car nearly spinning and having to skip gates to not kill cones.
He really needed the mid-setting but we were testing things and he didn't have that available. For cold race tires or street tires, the low and mid setting are great. With hot race tires the high setting gives me a ton of mid to exit rotation and definitely keeps me on my toes driving. That said, Its been worth some significant time in my case. Hard to quantify how much because its course dependent but with late corner rotation I can lift for rotation and roll on throttle much earlier so less boost lag, earlier acceleration, and tighter lines in many needed places.
He really needed the mid-setting but we were testing things and he didn't have that available. For cold race tires or street tires, the low and mid setting are great. With hot race tires the high setting gives me a ton of mid to exit rotation and definitely keeps me on my toes driving. That said, Its been worth some significant time in my case. Hard to quantify how much because its course dependent but with late corner rotation I can lift for rotation and roll on throttle much earlier so less boost lag, earlier acceleration, and tighter lines in many needed places.
Sounds like the heavy map would be good for sticky R comps on the road course, or in general for an autox setup.
Im glad ER has taken up to tuning our acd ecus. Seems like its been a slow progress in this dept with evos.
Aaron- I called in and spoke with Myles yesterday. Im getting ready to send mine in to be flashed but am a little unsure what would be best for me.
Today I auto-x on street tires but plan to take the plunge to r comps in a couple years once I start trailering the car. As such the most aggressive setting will probably be too loose for my setup today but could make sense down the road when I switch to stickier rubber.
Am I understanding it correctly that I will receive 3 settings, 2 of which are more aggressive and 1 being the stock setting? I know you guys are working with some locals to really dial it in. If I were to opt for the mild setting and the moderate setting is there any "plan" where down the road I could get it reflashed for the most aggressive setting when I switch tires?
Dallas- Have you testing the different settings running your 255 zii's. I know you got some seat time in the wet but have you tested that setup in the dry?
I have a few weeks off until my next auto-x so I really want to send it in ASAP. I just want to fully understand what I am getting myself into before I pull the trigger. I've been wanting to tune my ACD for about 5 years now but still don't feel confident enough to make an educated decision.
Today I auto-x on street tires but plan to take the plunge to r comps in a couple years once I start trailering the car. As such the most aggressive setting will probably be too loose for my setup today but could make sense down the road when I switch to stickier rubber.
Am I understanding it correctly that I will receive 3 settings, 2 of which are more aggressive and 1 being the stock setting? I know you guys are working with some locals to really dial it in. If I were to opt for the mild setting and the moderate setting is there any "plan" where down the road I could get it reflashed for the most aggressive setting when I switch tires?
Dallas- Have you testing the different settings running your 255 zii's. I know you got some seat time in the wet but have you tested that setup in the dry?
I have a few weeks off until my next auto-x so I really want to send it in ASAP. I just want to fully understand what I am getting myself into before I pull the trigger. I've been wanting to tune my ACD for about 5 years now but still don't feel confident enough to make an educated decision.
i'm actually a little worried i'll have too much on-power oversteer on street tires with the ACD tune - autox-ed my evo 9 with stock acd and cusco 1.5 way and it was power oversteering once in boost (note: cold & wet + worn rs3s). i'll be able to test out everything in the dry soon. if ER's ACD tune does what people are suggesting, I may set the rear diff a little less aggressively. maybe also get a rear bar after that to do more in the way of turn in.
my wants from the ACD reflash is more along the lines of better entry/turn in, and more grip on power rather than more power oversteer, which i've already got. we'll see how it turns out very very soon here
my wants from the ACD reflash is more along the lines of better entry/turn in, and more grip on power rather than more power oversteer, which i've already got. we'll see how it turns out very very soon here
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I have a TRE diff and a custom ACD flash. Front LCA with PSRS, RCK and sphericals. Robispec springs and Bilsteins. No understeer on turn in and car could be steered on the throttle without being tail happy. But the mid corner push continued until I changed the rear trailing arm bushings for sphericals and the toe arm bushings for offset Whiteline bumpsteer bushings. That took care of it - likely dynamic toe change issue. Did FSB at the same time which feels nice - stock rear bar.
My biggest issue right now though is mid corner push. I need to be very careful with the throttle mid corner. If I stab the gas I have crazy power oversteer thanks to my TRE rear diff which while fun, certainly isn't the fastest way around the course. If I try to be gentle on the throttle I find that the car starts to push. There is only so much grip in a given corner and as such you can only go so fast.
How does the ACD reflash help mid corner push?
My biggest issue right now though is mid corner push. I need to be very careful with the throttle mid corner. If I stab the gas I have crazy power oversteer thanks to my TRE rear diff which while fun, certainly isn't the fastest way around the course. If I try to be gentle on the throttle I find that the car starts to push. There is only so much grip in a given corner and as such you can only go so fast.
How does the ACD reflash help mid corner push?
I have a TRE diff and a custom ACD flash. Front LCA with PSRS, RCK and sphericals. Robispec springs and Bilsteins. No understeer on turn in and car could be steered on the throttle without being tail happy. But the mid corner push continued until I changed the rear trailing arm bushings for sphericals and the toe arm bushings for offset Whiteline bumpsteer bushings. That took care of it - likely dynamic toe change issue. Did FSB at the same time which feels nice - stock rear bar.
Kyoo, On street tires the highest ER setting would be way to much for you but the ACD doesn't give you necessarily throttle oversteer. Its more of a part throttle mid corner rotation it adds.
If your rear diff is giving you too much rotation then you need to add toe-in or soften the rear diff with fluid/friction modifier. My guess is you have a car that understeers early in the corner and oversteers on exit and you want less of both? Need less rear diff action and more front grip.
If your rear diff is giving you too much rotation then you need to add toe-in or soften the rear diff with fluid/friction modifier. My guess is you have a car that understeers early in the corner and oversteers on exit and you want less of both? Need less rear diff action and more front grip.
I have a TRE diff and a custom ACD flash. Front LCA with PSRS, RCK and sphericals. Robispec springs and Bilsteins. No understeer on turn in and car could be steered on the throttle without being tail happy. But the mid corner push continued until I changed the rear trailing arm bushings for sphericals and the toe arm bushings for offset Whiteline bumpsteer bushings. That took care of it - likely dynamic toe change issue. Did FSB at the same time which feels nice - stock rear bar.
Kyoo, On street tires the highest ER setting would be way to much for you but the ACD doesn't give you necessarily throttle oversteer. Its more of a part throttle mid corner rotation it adds.
If your rear diff is giving you too much rotation then you need to add toe-in or soften the rear diff with fluid/friction modifier. My guess is you have a car that understeers early in the corner and oversteers on exit and you want less of both? Need less rear diff action and more front grip.
If your rear diff is giving you too much rotation then you need to add toe-in or soften the rear diff with fluid/friction modifier. My guess is you have a car that understeers early in the corner and oversteers on exit and you want less of both? Need less rear diff action and more front grip.
Kyoo, On street tires the highest ER setting would be way to much for you but the ACD doesn't give you necessarily throttle oversteer. Its more of a part throttle mid corner rotation it adds.
If your rear diff is giving you too much rotation then you need to add toe-in or soften the rear diff with fluid/friction modifier. My guess is you have a car that understeers early in the corner and oversteers on exit and you want less of both? Need less rear diff action and more front grip.
If your rear diff is giving you too much rotation then you need to add toe-in or soften the rear diff with fluid/friction modifier. My guess is you have a car that understeers early in the corner and oversteers on exit and you want less of both? Need less rear diff action and more front grip.
part throttle mid corner rotation sounds perfect for sweepers. in theory depending on how they set up the acd it should be able to assist (or at least not hinder) corner turn in as well.
i was getting a lot of power on oversteer on a wet cold morning with 3yr old rs3v1s at the wear bars - on asphalt. with concrete and fresh current gen tires, i don't think i'll be getting too much rotation.
more or less just want the car to understeer less early in the corner & through sweepers. on power rotation is fine, and if it's not, i'd rather adjust the rear diff first. it's got a lot of preload as it is set up now (it BANGS at parking lot speed tight turning - a little less with oem diaqueen now), i think a little less wouldn't hurt for turn in purposes also, if the acd is "too aggressive"
Well sounds like you're on pretty worn out and dead tires. Usually when overall grip increases understeer increases, and vise versa. So with tired tires, it may be a cause of increased oversteer. Itd get back to a good baseline with fresh tires before making any balance or handling changes.
Kyoo, On street tires the highest ER setting would be way to much for you but the ACD doesn't give you necessarily throttle oversteer. Its more of a part throttle mid corner rotation it adds.
If your rear diff is giving you too much rotation then you need to add toe-in or soften the rear diff with fluid/friction modifier. My guess is you have a car that understeers early in the corner and oversteers on exit and you want less of both? Need less rear diff action and more front grip.
If your rear diff is giving you too much rotation then you need to add toe-in or soften the rear diff with fluid/friction modifier. My guess is you have a car that understeers early in the corner and oversteers on exit and you want less of both? Need less rear diff action and more front grip.
Thats exactly where Im at right now. I think that I may need more toe in to fine tune it, but while reducing mid corner, and corner exit oversteer, wouldnt more toe in increase turn in understeer, speaking for a road course setup that is? So ideally just a bit of toe in and then focus on front grip?
My setup currently feels pretty well balanced, but two things I just felt I could improve on, increase initial turn in response and initial turn in grip, and reducing the overall body roll Im still seeing on turns.
Heres on example, maybe not the best to show the roll because of how that turn is banked, but you get the idea. Short of coilovers the only option I can think of, apart from other mods already done to reduce this, is more weight reduction.
^ what suspension are you on right now?
PS, it IS safe to drive without the ACD ECU right? actually all I really need to do is to reverse the car into the garage. the brakes are kinda rusted so I can't just roll it or I would
PS, it IS safe to drive without the ACD ECU right? actually all I really need to do is to reverse the car into the garage. the brakes are kinda rusted so I can't just roll it or I would