You mean, all I have to do is use words like "tracking" and mention auto-x, and I'm automatically an experienced driver? The five years I spent discussing automotive dynamics on this forum are erased in an instant, when a word like "tracking" enters the picture. It's bad enough when genuine motorsports' efforts are demeaned by many individuals coming to this board for advice, implicitly equating themselves with those who make tremendous personal and financial sacrifices to race by discussing the "tracking" they never actually do. Now we have a new metric - "tracking" as a sign of driver competence. Just mention the word and you're an ace.

"99% street." This means that for every 1000 street miles there are 10 non-street miles. I'm not about to post my entire automotive history on this board just so that every newb could feel better about his suggestion. That's not who's being addressed here. EvoM is a community. Folks know each other. I've been here for years as have many of those responding to this thread. We know were we stand. When you walk into a thread started by a long-time forum participant please consider that his comments may be based on a little more than the words you initially see on a screen. There's quite a bit of history here. If I don't know you, or if you have not impressed this forum with your expertise and withstood the subsequent questioning over an extended period, I don't want to hear from you. Not trying to be rude. This is a big decision for me and I won't be basing it on the comments made by a totally anonymous entity on the 'net.

All this being said, do you drive an Evo with a locking diff?

 

So, I have to be an expert or "impress" the people on this forum to post a comment? I have to be popular and have over 4,600 posts to be heard?
I'm not trying to attack you here..I'm only giving you my personal opinion?
And why would I comment if I didn't drive an evo with a locking diff?

 

I think my comments were very clear.

 

jdmdc2r01, I think it's safe to say that the rest of us are happy to have you here and enjoy your participation. FJF is out of line here and doesn't represent the attitude of the rest of the forum by any means.

 

You have a total of 13 posts in the Suspension board, half engaging Smike and the other half trying to troll me. We typically require a minimum of 25 ridiculous moves before allowing someone to speak for the forum.

 

Im happy with the way my stock mismatched diff drives. However, if i could take the next logical step to improve the handling on the 1-5 autocross events I do each year it will be the rearrangement mod. I think that this would make sense because A) cost:benefit extremely high if you can do it yourself B) gradually will introduce you to the feeling of more lock.

my thoughts.

I have autcrossed my evo a couple times with 320 whp @ stm (self tune), and the rear was very lively. The only thing I have is MR bilstein, swifts. granted I had Z1's .. I will be doing the free mod, because afterall, I want to feel the natural progression, and going from nothing to a lot in 1 step can be too much in many circumstances.

 

I'm trying to understand this thread. Modifying the rear diff is to increase lock up and create more traction on acceleration out of the turn? If so how does this increase oversteer or rotation on an Auto-x course. I thought less lock up or an open rear diff allows much more throttle oversteer.

 

https://www.evolutionm.net/forums/ev...ound-here.html

 

In a nutshell, open diff = waste a lot of torque spinning the inside wheel (since its easier to spin, it will automatically get more of the torque split from the diff). That in turn wastes a lot of energy you send to the rear diff. Locked diff = split torque evenly between the rear wheels. Less energy wasted means more available to light up both wheels and kick the tail out.

The 8 plate mod moves you further from open diff and closer to a locked diff. The 12 plate even more so. Hence the 12 plate is more likely to give you oversteer.

EDIT: A diff with more lock up doesn't give you more mechanical traction. What it does is make more efficient use of the energy you send to it in the context of powering you through a turn.

 

A more locked rear diff will increase corner lift-off understeer, eg stabilize car under braking and it will increase corner exit power-on oversteer.

In some cases a very locked rear diff can be quite awkward on a street car when you cannot use your throttle at will or do not have enough bottom-end torque. From the responses here this does not seem to be the case with a 12-plate on an Evo.

Still itching to do this mod on mine ... not that I am complaining about the handling on mine, but I think a will enjoy less FWD dynamics and a little bit more of a rear wheel drive effect.

And yes, ultimately this is what I'd personally like to get out of this thread: Does the 12-plate have any negative effects for street driving other than the dent in your wallet? Track and Auto-X benefits are without doubt ...

 

Thanks for the links and explanations. To the OP's request for advice on a street driven Evo it seems from what I have read it may be better and cheaper to experiment with Redline gear oils and friction modifiers. I would do this mod myself to save money but it's not a trivial task since one has to remove the diff first than perform surgery on it. I have rebuilt automatic transmissions in the past so I feel comfortable taking the diff apart. My issue is not being able to live with the clunking on a semi daily driven car. All I'm interested in is getting my IX to rotate a little easier like an old school BMW E30.
Perhaps I need to also look into tires and ACD reFlash options as well.

 

agreed. TRE will be your best bet

 

Most people who run diaqueen find there's no clunking or noise at all.

 

FWIW I've definitely noticed the increase in lift of understeer in long sweepers autocrossing before. LFB may need to be applied rather than lifting off the decrease speed in those scenarios.

No negative effects in street driving, except some clicking noises from the rear in low speed turns.

 

A little bit of info because someone asked some posts ago. You're going to have to service your rear diff fluid more frequently because the plates are now shedding material.

In 3k miles, my fluid was silvery. I have 10k on mine now and no signs of giving up the ghost. From drift experience with clutch LSD's, they last sometime. Most drifters rebuild their's every year if they compete a lot. Some every other year.

I can't see the Evo needing that frequent of a rebuild because we're not spinning our tires through every turn.

Your tires will also wear a lot faster in the rear with this mod.