I think the '03s came with different alignment specs from the factory then all the other years. My car has always been tail happy on street tires. I remember test driving an '06 RS from the dealer and was surprised how different it handled compared to my '03. Felt like a completely different car. It had more grip overall, but didn't have the same ***-out attitude of my '03.

Still wish I had traded in my '03 for that '06 RS.

 

I just came back from 2 days at Thunderbolt - as a reminder I have the ACD flash and a freshened Shep rear diff. I was suffering a very odd and annoying binding issue on tight turns that wuld cause me to NOT want to apply throttle until the wheels were nearly straight. The Shep rear diff was my last hope...
... The binding is now 100% gone. Through turns 9 and 10 (Jersey Devil and Octopus Head) I have zero binding and can take the racing line which is unusually tight.
The configuration run included using the second chicane, here's a brief run down of behavior with lap times of 1:35-1:40 depending on lines I was trying...
T1 - neutral
T2 - chicane - car lightened on blind apex and oversteered slightly
T3 - (a/b/c) - Somehow this became a straight line by day 2
T4 - FAST and neutral
T5 - my worst turn (a little early on turn in) and throttle oversteer every time
T6 - FAST and neutral
T7 - slight throttle oversteer
T8 sweeper - neutral to mild throttle oversteer (used to be understeer). I punched it here 2x to try some different lines and had 2 saves, one which yielded corner worker applause as I was about 80 degrees and managed to recover just to go about 30 degrees the other way and recover again
T9 - mild throttle oversteer
T10 - mild throttle oversteer
T11/11A - Straight on the race line and throttle oversteer not on race line
T12 - (non-race line) heavy throttle oversteer on WOT and very stable

Verdict? My VIII now acts much more like a full track setup XMR with the electronic goodies deactivated. Throttle oversteer is present beyond just neutralizing understeer and it may require some people (like me) to relearn the car's behavior. Despite the cost, this is a big change in handling.
This is not for everyone, but those would like to reduce understeer have a viable option.

Because I think my rear diff may have been extremely worn, it's hard to determine the benefits of the ACD flash vs the modded rear diff vs the combined result. Personally, I'm very happy with the combined result!

 

glad to hear the rear diff is working for you too!

 

Awesome review as always - it's great to hear the rear diff fixes the binding issue from the ACD reflash - sounds like the combo is the best way to go.

Hopefully more and more people will see why I'm encouraging this mod so much!

 

Nice feedback. Can you offer up more information on your suspension and settings for the alignment, what tires ect? Have you changed the suspension setup since your installation of everything?

nice

 

Haha awesome, that's what I'm talkin about! I'm 5'8" 163lbs. Short man high five lol

 

I'm going for a 1.5 rear diff and the only one available here is a KAAZ SuperQ. Appreciate feedback on this.

 

Now I don't know what to do anymore.. Voltex rear diffuser or rear diff

03' VIII: Let’s say I buy a shep rear diff and install it. How does the stock front diff feel? Does it understeer? Is this an item that makes a huge benefit for autox\handling as well(the front diff)? I haven’t seen too many posts about the 03's on here. Basically is it worth changing vs the many other parts I could modify on my car?

Also on this rear diff does it make the same huge benefit on the 03 with the stock TC? I read in this thread that the 03 was already tail happy by a previous poster.

The car has coilovers, caster camber plate and 300whp. If this helps.

 

never heard of it - no cusco or carbonetics? i'm sure you could get one shipped. though, it's probable the kaaz will be fine

 

it does make a huge benefit for auto-x, unless you're trying to stay in a particular class. It will definitely make a bigger difference than a voltex rear diffuser. the car will power oversteer.

i mean the parts you "need" to get really depends on what your wants are. everyone who got the diff in this thread got it because they were tired of the corner exit understeer that evos suffer from

 

Thanks kyooch. Shop here giving me a really good deal on the 1.5 KAAZ. Website says no break-in required and SuperQ = quiet.

 

let us know how it goes! i'd still give a few hundred miles before i really lay into it, no matter what they say

 

Will do! Might do the install next week and have a few trackdays planned

 

I'm on JIC FLT A2's/ 0 toe / med-aggressive camber / BFG R1s (265/35/17). I haven't changed my suspension settings since the install.

I'll be at the Nasa event at NJMP in 2 weeks for those that will be in attenedance...

 

Would you say the acd reflash and rear diff is too much oversteer? Did you run in tarmac street or rain?