Meathooker

iTrader: (2)

In preparing for this upcoming season I (like all of us) started looking for the most efficient use of my limited racing funds. My car was pretty well sorted already but I knew that it had more potential.

Evo ix
Ohlins Flag 10k/12k
RSB
17x9.5
255 Hankooks RS3’s
TBE
E85
Rearranged Diff

Since I was still on street tires I knew that Rcomps would be the obvious choice, but I had back surgery in December so the thought of packing around tires/jacks, bending over to change them out etc… did not sound enticing (or feasible for that matter). I stumbled across and ACD-Tuning thread so I decided to contact Matthew and pick his brain on how it could help bring my times down. After a few conversations I was sold on it so I send my ACD ECU in. He turned it around in one day and express shipped it back to me so I could use it at the first 2 events. For the first day I did my first 3 runs on the existing set-up – no ACD tuning. Runs were:

37.806
37.592
37.325 +1
37.634

Then I put the ACD in on my middle tune
36.9

Immediately taking .7 sec off on a sub 40 sec course!!!!!

36.7+1
Then I tried a very aggressive Rcomp tune:
44.2 +3 (it was like driving a corvette on skinnies, fun)
Then I softened the rear comp 3 clicks and used my mild tune (still much more aggressive over stock):
36.7 clean
Last run I knew the car had more in it (low 36) but I botched it over a parking lot transition bump so I went off course.

This was enough for 1st in class, 1st in Pax, and 9th RAW. Fastest car on street tires by far, and the cars ahead of me were all heavy hitters.

After the event I was reflecting on how to set my car up to utilize the new found oversteer. Like most evo owners I had the RSB full stiff, a few clicks on my rear compression, and front compression full soft. Decided to go full soft on RSB, full soft rear compression, full stiff front compression.

Day 2 our course was very fast with an open start, AWD advantage. It was COLD and windy.

Run 1 – ACD Mid tune. Get a decent launch, pull second and am touching the rev limiter before I felt like I need to lift. Hit the first off camber transition around 60-65 mph and go into a slid. Saved it but run was botched:
61.3
ACD Mid Tune remove 10 clicks front compression. 2 passengers
59.8+1
ACD Mild tune remove 2 psi, no passengers
58.9 clean. This put me 1st class, 1st Pax and would have held for the day
Come back from lunch. 1 passenger, ACD Mid tune
59.0 clean
Remove passenger ACD Mild tune
58.0 clean
Feeling like the car is doing well, learning the tuned ACD so I try the Mid tune as I like it better on the tighter turns and im hoping I can control the car in the fast sections (65+)
58.2 with a HUGE slide almost coming to a stop
Last run ACD Mid Tune I decide to pull 3rd on the front straight to carry more speed, go into another huge slide, almost stop, have to shift into 1st to get going again.
59.5+1

They set up a radar gun at the finish (2 or 3rd gear with 1 gate) and the fastest out of run group was 68 MPH (3rd gen RX7 with built ls6, full areo on r comps). Most cars were low-mid 60’s. 125 shifter kart was 68-69. My first run was 70, then 72, then 75 … I was trapping 7 mph faster than the next closest competitor. The ACD allowed zero throttle lift in that area where most of my competitors sounded like they were lifting.

Ended up 1st in PAX by 1.9 seconds and second in RAW only to a pesky 125 shifter kart, so FTD for cars on STREET tires!

http://srrscca.com/SCCAEventResults/...il%201_raw.htm

All in all I would say it was a good initial weekend, and I am excited for the season because im sure once the nut behind the wheels relearns to drive the car it will show that there is more potential in it. When driving the car it behaves in a much more natural way. When entering a high speed corner the back end, in a very controllable way, acts as if you are slightly trail braking and it really helps the car behave like it should. Before my car would only behave neutrally when i was on the throttle but off the throttle setting up for the corner i could tell i was giving a lot of time up due to front end push. It was also a great feeling to throw the gas can and folding chair in the back of my car and drive off while everyone still messing with their tires

I would like to say thanks to Matthew from ACD-Tuning, so far he has save me HUNDREDS of dollars on Rcomps while still being able to play with the big boys.




photo from daeity

Butt Dyno

iTrader: (10)

That's pretty cool. What class does your car fall in? (XC?)

Meathooker

iTrader: (2)

We run grouped classes. XC is for the street prepared classes, XB for mod classes

Butt Dyno

iTrader: (10)

Ah okay. I didn't realize this was legal in SP. That's interesting.

lan_evo_mr9

iTrader: (10)

Here's the line from the SCCA SP rules....

14.10N---Limited slip differentials are permitted. This permits locked differentials, either by design, welding, or mechanical means. Differential cases, internal differential parts, and axle stubs may be machined as required for clearance and installation to the extent that material may only be removed, not added, and the exterior of the case may not be altered in any way. This machining may serve no other purpose.

14.1D--- Alternate computer control modules may be used whenever an equivalent change to the conventional system is allowed. For example, alternate computer module control of ignition settings or fuel injection is allowed. Direct turbocharger boost control by alternate computer control is not, since there is no equivalent mechanical allowance.


I don't see anything in there that mentions alteration of ACD electronics. I may be missing something, but that's what I gather from those sets of rules. It seems that this mod is legal because there is no pyhsical alteration of mechanical components and no alternate computer is being used.

Dallas J

iTrader: (1)

From a discussion I started last year some time,

https://www.evolutionm.net/forums/mo...r-than-xp.html

The ACD computer is considered a traction control system and can not be modified in SP. SM allows what ever the eff you want though

lan_evo_mr9

iTrader: (10)

Poop. When I think of traction control (this coming from working on Audis for the last 12 years), I think of ABS and ESP or some sort of control that cuts power to a slipping wheel or cuts power from the engine. That's not how our specific system works, but oh well.

Meathooker

iTrader: (2)

It's debatable

Read that and after talking to Matthew my take is this:

Traction control senses wheel slip and cuts/transfers power. A tune Acd distributes power based on a many variables, but not wheel slip. It is a modified differential (IMO)

Let's save further scca interpretation for your thread and leave this as a review.

Dallas J

iTrader: (1)

Sure, as long as you don't go around saying it is legal... cause its not .

Good review though, Ive been curious if it'll actually do much for me though since I don't have rotation on demand problems. Actually I have to run the stock rear bar to reduce the rotation.

So for your set up, Tarmac is stock but gravel and snow are more agressive?

kyoo

iTrader: (29)

im curious, because intuitively, if you have more rotation/torque going to the rear, you can keep adding more grip to the rear and having an overall higher limit, no?

Dallas J

iTrader: (1)

In a month Ill have my car out on the big course in Packwood Wa instead of the gokart sized crap lot here in portland so I should be able to find out whats holding me back. The car is amazing in transitions and accelerating through weird stuff, but it was the sweepers my car just flat out sucked at in comparison to different cars.

I swear the STR miatas have more sweeper grip than I do with their RS3s, although I was still running 245 kumhos to their 275s and 600lbs less weight.

Has anyone with big springs and tires (285 hoosiers) and an upgraded rear diff tried the ACD flash yet?

Meathooker

iTrader: (2)

Deal!

i have 3 tunes + a stock controller so i can switch back and fourth

that's my thought. most things we do to make the evo rotate (big bar, higher PSI, less camber than the front) REDUCE rear end grip. So far its looking like i can dial some of those things back because of the acd.


we're planning on putting my ACD in a local guys evo that is running 275 hoosiers and/or i might try a set of rcomps ... i'll keep this thread up to date as we journey down that road

i drove a local guys well sorted out civic hatch on 225 rs3's and it felt like the cornering of that little car was as good or better than my evo's when i was on 245's last season!

lan_evo_mr9

iTrader: (10)

Yes, here ya go...

https://www.evolutionm.net/forums/mo...ng-review.html

Meathooker

iTrader: (2)

Attended a test and tune today with the Evo. Got 12+ runs in and had more time to get used to the car. Beginning of course had. 5 cone slalom and the car really seemed to like that. The back end rotates at each apex beautifully. Still learning how to fully utilize the added turn in on decreasing radius turns but it is faster as is and should only get better. Still trying to get my head around how/why the acd helps so much with turn in.

lan_evo_mr9

iTrader: (10)

Don't question it, just embrace it

There are some questions or techniques that I can't answer