boomn29

iTrader: (47)

One of the hardest things to get rid of in an Evo is understeer - or push. Like most cars from the factory, the car is front heavy and is setup to understeer once you turn up the wick. You have to drive the car pretty hard to find this barrier, but once you do it will drive you crazy!

I started tracking my 2006 Evo in... 2006! After ahile I had upgraded the tires to wider & stickier 255 RA1's and was having a lot of fun and getting faster. But the car was starting to push in a few turns. I implemented some of the well-known 'tricks' like increasing my camber and adding a bigger & stiffer rear swaybar. This helped some, but all the RSB was doing was reducing the rear grip instead of fixing the issue.

I continued to gain speed and by 2009 I was running Hoosier R6's. By this time I had a full set of coilovers on the car, ligtened it some (3300 lbs w/ driver), and upgraded the brakes. The car pushed now more than ever. Because of class regulations with NASA, I chose not to upgrade and stay in the class I wanted - thus I was forced to adapt my driving style to the push. This meant either throwing the car in a turn hot and sliding it until the traction caught and power out, or over-braking early to reduce corner entry speed and late-apexing everything. Neither option was ideal.

In mid 2010 I was so fed up I decided to jump classes and upgrade the rear diff. I chose Shep's version which is a 1.5 way 12-plate. Oh my god; the car freakin rotated now! I was now able to better control the car, and hold a 4-wheel slip angle. Instead forcing the rear to come around with tricks, I could get rotation with just the gas pedal.
Especially in the wet, the car was so much more fun and controllable. At my first event, I could carry a small drift ~80mph for over 100ft w/o drama! The car now rotated through the turns and I could pick up the gas soooo much quicker. Times dropped and no side-affects. I did a lot of refining the car and really liked where I had it sitting at this point.

After awhile though, as I put on wider and stickier tires, my speeds continued to increase and some of the push came back. I had heard about ACD updates a few years ago but never really believed anything about them. This was one of the reasons I got the Shep unit originally and not some fancy software that did not have a lot of feedback out there, at least not from many people I knew.
But I heard something about a newer company - ACD-Tuning - and I started researching them in late 2011. I talked awhile over email with Matthew and I explained how the car has progressed and what would make it better. We decided to team up and I quickly received an updated ACD unit for testing. I have to say it came quickly and was packaged very tightly - A+!

Now I've received a lot of offers to test products in the past. Some are new, some are proven, some have been offered at a discount and some even free. A majority of the time I do my homework and end up going a different direction. Meaning just because it's free, I'm not slapping it on the car. The same goes for stickers/decals. I keep the car pretty clean and prefer it that way. But this ACD-Tuning I really wanted to see if it could help so I pulled the trigger.


Test weekend #1 - Road Atlanta
In March 2012 I made my first trek to Road Atlanta. I ran Day #1 with my normal setup using 245 Hoosier R6's and had a good time of 1:32.8 I think. For day #2 there I swapped in the updated ACD unit and ran it in map #1, which had the smallest change as compared to the factory Tarmac mode. Overall I did not notice much of a difference. I only ran a few sessions that day given the 11hr drive but I did better my time to a low 1:32x. The good news is that the updated ACD unit did not cause me any problems or issues at all. There was no bind-up, no loss of grip, no crazy understeer or oversteer, no wheel spin or wheel hop or anything negative. Now being a new track I only ran about 8/10's so I didn't push the car incredibly hard or drive 'on the edge', so the ultimate decision on the ACD-Tuning software would need more testing.
I talked with Matthew about the event and Map #1 and he assured me it was the smallest change and said everything was good. He recommended to start with Map #2 next time, especially since I'm running Hoosiers and all. So that was the plan!

Test weekend #2 - Autobahn.
Although a small facility, a lot of people know this place as Redline and GTA and One Lap have all been here. It's actually one of my closest tracks and a great facility. The track is pretty wide and mostly smooth with some difficult corners and a few oddly placed bumps - and is known to be hard on brakes. I ran the first day with Map #2 on the same tires and the car rotated well but felt a little 'skaty'. In retrospect, I attribute this to some other factors including the new 6pt cage I had installed, and the fact I was pushing hard on a familiar track with skinnier tires than my last trip (245 vs 255's). The car still rotated well.
With day #2, I switched classes and bolted up my wider 255 A6's from the previous year. In my first hotlap I ran a new personal best of 1:31.9 (vs 1:32.1 in April/2011) in Map #2. The car felt great. It was so much more stable and sure-footed on the wider stickier tires and it again felt like my 2011 setup - the rotation felt good and I even played around with Map#3 which Matthew put on there for insane drifto! Even that map wouldn't turn the car into a drift-machine which is actually good. I didn't want to sacrifice grip in the front in order to gain it in the rear. I wanted the whole system to work together... just better - and it was.

Test weekend #3 - Putnam.
Back to another track I know well - running those same 245 R6's which was nearing the end of their useful life! I ran the car in my favorite Map #2 and tossed down some low 1:17's. Despite a gearing change from 2011 the altered my shiftpoints for the worse, everything felt great. Putnam has 2 long L-hand sweepers that can be torture to run - especially T4. They used to be torture with understeer frankly, and I've seen many a RWD car have trouble getting the power down here consistently.
Leaving the car in Map #2 all weekend - as the grip from the tires got worse, the car dynamically changed in T4. Keep in mind, that because of the reduced grip I was pushing really hard, close to 10/10's and the car was a handful with lots of steering inputs and corrections needed to keep it literally on-course. As the weekend progressed, the rear was beginning to rotate more and more in T4 specifically and it was great! I never adjusted my line, I just kept my foot down and adjusted the steering angle by opening up the wheel earlier as the rear rotated more and more. If you want the full writeup on the weekend go here: https://www.evolutionm.net/forums/10168766-post197.html There you'll find the same 2 video's I'm going to post below. And you can read all about the 2012 changes to the car in that parent thread - including my cliff's notes about the ACD-Tuning.

Synopsis:
Now I wouldn't really call my car overly developed or refined. It's running a ton of factory OEM parts still and some off-the-shelf items. There's no trickery and nothing really custom on it. I'm saying this so anyone reading this can put themselves in my shoes with regards to how the ACD-Tuning has helped further refine and aid the rotation in my car. My full setup can be found here: http://boomn29.blogspot.com/p/2012-car-setup.html
Now what I can't tell you, is how much the ACD-Tuning will help a car on the stock rear diff. I can only guess, and that guess would be enormously! With my car already having an upgraded rear-diff, coilovers, an aggressive alignment and setup to rotate well - it only made it better, more controllable and more predictable.

Customer Service:
Matthew has been very easy to work with. We exchange a lot of emails as I send him my thoughts on the car along with turn specific information and video. He takes all that in, and I believe they are continually refining their tuning solutions to help the entire market get an even better product. They even offer an exhange program, but no worries as our Evo's work w/o the ACD unit in them anyways if you're in a pinch for time.



Sunday S1 (rubber & drifting vid):
http://youtu.be/NoJ-7ZV5I-M

Sunday S2 - backwards:
http://youtu.be/67Mjlo1c62A

Loser

iTrader: (9)

Nate,

Good write-up. I was browsing through the ACD-Tuning website trying to get more info and came across this link. Figured I'd start the discussion here first (after all isn't that what forums are meant for) before emailing Matthew.

My understanding of the stock tarmac map is that it completely unlocks the diff when there's any steering input and keeps it locked otherwise. If that's accurate, do you know how the maps you got differ from the stock tarmac map? How does that result in better mid-corner rotation?

I'm still running the factory sway bars on my car and I'm looking for more rotation but for similar reasons you mentioned I don't want to just throw a RSB and remove rear traction. That being said, I just ordered one, but would love to try this out first.


- Char

kyoo

iTrader: (29)

boomn29

iTrader: (47)

fwiw, I'm still on the stock swaybars. I did run a RSB for a bit from 2006-2007 but I removed it shortly after I joined NASA so save pts.

I'm honestly not sure how it works. You can have multiple maps put in the car from ACD-Tuning if you're skeptical - like I was. You can even have them leave the stock Tarmac map alone so you can always fall back to that or use it for a comparo in the same session!

kyoo

iTrader: (29)

it takes into account more than just steering input - throttle position, braking, whatever else, and varies the lockup based on the map and condition. however, since it is the stock map for regular driving there is a lot left on the table in terms of the aggressiveness of the lockup and how quickly things react - my very basic understanding is that the lockup will be quicker and greater based on conditions allowing for more aggressive exit without sacrificing, or maybe even improving (based on the map programming) corner turn in. an open area in tuning for the evo. i have some info in the sig

Loser

iTrader: (9)

kyoo - Just read through some of that ACD discussion thread you have in your sig. Pretty good feedback there as well.

kyoo

iTrader: (29)

thanks -

a belated bump for this