Rear Diff Options - Power Oversteer Found Here
#34
Evolved Member
iTrader: (32)
My simplified answer is... It's perfect in slaloms... you will be faster through them with this diff!
To the person asking about the core prices.
Jon did not have any cores in stock at the moment. You have to send yours in currently. Like I said... its 1-2 days legit! Well worth the down time. Its 450 for the service and 50 for shipping. I asked Jon to replace the bearings in the diff because I had previously abused the crap out of it.... that was another 60 bucks...and then I really wanted the sight glass upgrade which cost me another 63 bucks or so because my rear diff cover (aluminum) wasn't thick enough for him to do the CNC ops on.
To the person waiting for more reviews...
If you turn with your Evo... you NEED this. Not maybe...not kinda... not after you do Ohlins or a huge rear bar... YOU NEED IT RIGHT FREAKIN' NOW.
I fought the understeer from day one.
Started with this setup going around a tight auto-x like course called PGP. (go kart track actually)
RE01R's, works springs, and 25mm rear bar full stiff.
Result: the car understeered on corner entrance, understeered steady state mid corner... and REALLY understeered on corner exit. The front tires were overworked soo badly they cried (aloud). The car would not turn!
My first attempt at fixing it.
Skunk2 pro-c coilovers 12k rear springs, 10k fronts
Hoosier 285/30/18's
TONS more camber up front, WAY less camber in the rear, MORE air pressure, + toe out in the rear. (adding grip in the front and removing it in the rear...decreasing grip in the rear)
Gruppe-S ACD reflash
Result: Turn in was better, mid corner I was able to trail brake and lift throttle oversteer. I had to REALLY brake late and I had to lift VERY hard to get the car to rotate even the smallest amount. Rotation still sucked. CORNER EXIT: SUCK SUCK SUCK SUCK. The ACD just made the car do burnouts with the inside rear tire... the car felt SLOWER on corner exit and wouldn't put power down. SUCKED!
Next attempt at fixing it.
12k springs in the front 16k in the rear (motion ratio kills the rear rate)
dropped the 25mm rear bar and put back on the stock one. (more rear grip)
Total rear spring rate (ARB + spring rate) was a little less than before (more rear grip!)
Added camber in the rear. (more rear grip)
Set F&R tire pressures the same (more rear grip)
***TRE 1.5WAY MAX LOCK REAR DIFFERENTIAL***
Result: OH MY ****ING GOD. Seriously people...
Turn In: better than before
Mid corner/steady state: I could use the throttle to rotate the car OR lift on throttle and pitch it. both worked VERY well and VERY predicatable!
Corner Exit: RIDICULOUSLY GOOD. I felt the car would rotate on my throttle command and was consistent and REAL ****ING FAST. I dropped 2.5 seconds off my lap times! I attribute EVERYTHING to the DIFF. I made the rear end more grippy instead of reducing grip. I can get on throttle and not worry about pushing off the track. I can get on throttle and now worry about the front tires screaming. The front tires work SOOO MUCH LESS. The front tires DON'T overheat anymore.
When you bought an Evo...and you thought about what AWD should be like... THIS IS JUST LIKE THAT. No more push bull****. You'll have a REAL CAR.
Do not wait. Do not question. Box your diff up and mail it out first thing Monday. Don't wait.
This should be the FIRST handling modification done to Evo's. No joke. You'll waste money on reducing rear grip to try to get the car to turn... don't waste your time. PUT THE DIFF IN!
The following users liked this post:
RWD4G63 (Oct 10, 2018)
#35
i should probably note that i also have the gruppe-s acd flash, which locks the front and rear wheels together more aggressively - more lock to the rear, and then that torque is routed with the rear diff. so it probably makes the set up more aggressive overall in terms of power oversteer
#37
Evolved Member
iTrader: (9)
http://www.teamrip.com/EVOLUTION%20R...20SERVICE.html
Ask for the MAX LOCK 1.5 way Rear differential rebuild.
He recommends Heavy Weight shock proof for drag racing and Redline 75/140 NS (non slip) for road racing. I run the latter.
This service includes:
* magnaflux inspection of differential carrier housing
* magnaflux inspection of ring & pinion and spider gearset
* bearing replacement (as necessary)
* all new friction plates
* modified side sheaves
* shot peening of ring & pinion
* shot peening of spider gearset
* correct adjustment of the spider gearset backlash
* shim kit for preload of both pinion shaft and carrier housing
* adjustment of ring & pinion for high torque applications
* pinion shaft and axles shaft oil seals
* a heavy coat of satin black paint so it looks like new again
* new carrier cap bolts
* new rear cover bolts
* oil sight glass upgrade FREE till August 1st.
If any bearings need replacement I'll let you know when I contact you. It is my advice that you replace both pinion bearings if the EVO is to be road raced or drag raced.
Ask for the MAX LOCK 1.5 way Rear differential rebuild.
He recommends Heavy Weight shock proof for drag racing and Redline 75/140 NS (non slip) for road racing. I run the latter.
This service includes:
* magnaflux inspection of differential carrier housing
* magnaflux inspection of ring & pinion and spider gearset
* bearing replacement (as necessary)
* all new friction plates
* modified side sheaves
* shot peening of ring & pinion
* shot peening of spider gearset
* correct adjustment of the spider gearset backlash
* shim kit for preload of both pinion shaft and carrier housing
* adjustment of ring & pinion for high torque applications
* pinion shaft and axles shaft oil seals
* a heavy coat of satin black paint so it looks like new again
* new carrier cap bolts
* new rear cover bolts
* oil sight glass upgrade FREE till August 1st.
If any bearings need replacement I'll let you know when I contact you. It is my advice that you replace both pinion bearings if the EVO is to be road raced or drag raced.
#38
i think i asked about this when i was interested long ago - i believe the response was that it really depends on how you drive it. i *think* jon said that for people who road race their cars competitively all the time it'll be like 3 years before it even needs to be checked again or something like that
#39
Evolved Member
iTrader: (32)
Jon stated that one of his road race customers (guy who ordered the stg2.5 gear box with 4.11FD) has used the diff racing NASA TT and other series and sent it back in to be checked after a full season of racing...John said it didn't need anything, spec'd out, and looked just fine.
If you're competitively racing I would say have it checked after 2 years. If you're DD'ing it with some aggressive driving...closer to 4 years. I have no idea... that's my educated guess.
If you're competitively racing I would say have it checked after 2 years. If you're DD'ing it with some aggressive driving...closer to 4 years. I have no idea... that's my educated guess.
#44
Evolved Member
iTrader: (9)
Jon stated that one of his road race customers (guy who ordered the stg2.5 gear box with 4.11FD) has used the diff racing NASA TT and other series and sent it back in to be checked after a full season of racing...John said it didn't need anything, spec'd out, and looked just fine.
If you're competitively racing I would say have it checked after 2 years. If you're DD'ing it with some aggressive driving...closer to 4 years. I have no idea... that's my educated guess.
If you're competitively racing I would say have it checked after 2 years. If you're DD'ing it with some aggressive driving...closer to 4 years. I have no idea... that's my educated guess.
i think i asked about this when i was interested long ago - i believe the response was that it really depends on how you drive it. i *think* jon said that for people who road race their cars competitively all the time it'll be like 3 years before it even needs to be checked again or something like that
#45
Evolved Member
iTrader: (32)
With the interior in you can barely tell that there is more decel noise on lockup. I didn't notice it with the interior in, but when I took the rear seats out and everything I could tell...and then when I put the interior back in... it could be faintly heard. Lets put it this way. My transfer case and transmission make more noise. Scale of 1-10... 1
To the people who don't like the slow speed clicking...you can add the Redline LSD friction modifier to the diff and reduce the amount of lock up. I currently have NO LSD friction modifier... so mine locks up as much as it can, as frequently as it can. So for the sake of your understanding how loud it is.. with the interior stripped out of the car with no friction modifier the diff is just another sound in the symphony of noises my car produces. Its much quieter than the exhaust, much quieter than the geartrain(tranfer case and trans) howl, much quieter than the turbo, much quieter than the BOV, much quieter than the tires, much quieter than other people's rubber bouncing off my car.
I'll go and take a video to show you guys. I think that will best explain it.