I'd like to know what parts it takes to convert a non ACD (03-04) Evo to having the ACD. I've done a bunch of searching and I've yet to see a list of what it actually takes to make this happen, just people saying its a pain. While I can respect that as an answer for a street car, I'd still like to know whats involved.

I'm going to be building a car for the Pikes Peak International Hillclimb, so the car is going to get stripped down to the shell, seam welded, FIA roll cage welded in, painted, then reassembled.

I'm still trying to decide between building a WRX or an Evo, and cost of the salvage starter vehicle are one important deciding factor. I've done the research on the Subaru side of things, so I have an understanding of what it takes to get the ACD into that car. With the Subaru, I can start with a base model shell, then find a wadded up STi and just start swapping parts over. The center diff has its own wiring harness, so its easy enough to get it working in a non ACD shell. So now, on to the Evo questions:

Can I just source the ACD transfer case, ACD wiring harness, get a RalliArt Diff Controller, and connect up a few wires?
Or does the ACD need inputs from all over the car? (e-brake, steering column, ABS, etc.) making this nearly impossible?

If the partial retro-fit isn't reasonable what about a full transplant?
Are all the mounting points there on an 03 or 04 shell so I can take everything from an 06 and bolt it right up?
Will all the parts from an 06 swap into an 03 shell?

Thanks for any insight!

Dave

 

buy an 05 or 06...
problem solved

 

He said he is buying a shell so what year he buys doesnt matter , What you need is a 05 and up Tranny , that allows the ACD to bolt up . ACD computer and wiring harness , any others members care to chime in

 

there's one hydraulic line that goes to the transfer case. how hard could it be if you're going to be building the car anyway?

i'm not intimidated by evo's anymore. i just did the clutch in my 05. it was tough but not significantly difficult in any area. i've installed AWD transaxle's in my Expo LRV twice. its the same drivetrain as the evo 2. and i've had a lot of experience saving my 67 camaro from the junk yard.

anyway, I think you can do it. there will be differences but you'll just use the 05 parts and ecu and wiring and brackets and stuff. you'll get help from evolutionm.net for sure. and common sense says its just not going to be really really really different. see ya. good luck.

- Max

 

Lucky for you man , I did a clutch on my 2005 Evo and it ook me and some freinds almost 1 whole week . Very difficult to get that tranny off and unbolting everything is very time consuming , considering you have to unbolt almost the whole engine . Anyway im not saying it cant be done , you just need alot of time and patientce and know how to wrench of course

 

If you know what you are doing then its not that complicated of a task. 1 Week is funny, me and a buddy of mine do manual conversions in 4-5 hours from start to finish. So before you attemt to install an acd into a shell or anything else, make sure you pickup the evo factory service manual and read up on everything there is about tranny and acd.

 

I'm not sure about the mechanicals, but the electrically you would need at least the engine harness dash harness (the acd does not have a seperate wire harness it's all integrated together with the engine/interior), ecu, and acd controller(or aftermarket). As you said it does use sensors from all over the car. You can look in the service manual at the electrical diagrams and see what's going on. It would probably be in your best interest to get a donor car to save cost. Although at that point you might as well just use the donor car as the base for your project.

 

Perfect, that's the info I was looking for. Sounds like this is why adding ACD really isn't practical for a street car.

I found a beachballed 2006 that I'm thinking about trying to buy, then I'll just have to keep my eyes out for a theft recovery shell. I'd love to just buy the right car at the outset, but the $$ isn't there for a used model with ACD. Prepping the shell with the rally related hardware runs in the $30k range, and that doesn't count any $$ towards making the engine more powerful.

Thanks guys!

Dave

 

I'm still confused about the performance advantages of ACD. Sure on paper it looks good, but I've yet to see ACD show an obvious advantage over non ACD equipped evos.

 

for racing I would think you wouldn't want ACD really as it's one more thing to break and doesn't really offer a true race driver much of any advantage.

 

i am fairly certain that former WRC and Group N evos run AYC/ACD...

 

From what I've heard from seasoned rally folks, there is no comparison. The ACD or DCDD equipped car is going to be faster, all other things being equal. For top level teams, the benefit is on the order of a couple seconds per stage mile. While not huge, over the course of Pikes Peak you're looking at probably 20-25 seconds. For stage rallies the difference could be much greater.

On the subaru side of things (most rally guys run WRXs), having the stock DCDD isn't really any better than a mechanical center. Where you really find the benefit is after you buy the racing maps for these differential. RocketRally sells such a thing for the Subarus, and RalliArt does have racing programs for the ACD. From what I've been told (again, on subaru stuff), if you're a left foot braker, you can order a set of maps that are dialed for that driving style. You'll end up with a 'race' mode, 'drive it like you stole it' mode, and 'I really need to make up some time - drive it like you hate it' mode.

Sure these different settings can be achieved with conventional mechanical diffs, but it would require a fluid change or a clutch pack change, neither of which are reasonable things to attempt while out on stage.

Dave

 

The VCD equipped cars by design have low center diff locking force. You can change to some form of mechanical center diff and increase the locking ablity but you run in to compromise situations where increased locking may slow the car down in some parts of the track and speed the car up in others. ACD, being programmable, is less effected by those types of compromises. For rally there is the added benefit of being able to use the e-brake in a "traditional" way with ACD. Weather you're a good enough driver or not to actually tell the difference is a different matter (I'm certainly not).

 

then you shouldnt be driving an evo...and truly you need to read up on the history of these cars...