Evolution Drivetrain for Dummies

[Rez90]

neato

[Akeem]

[b][i] How has installed afinal gear HKS Kansai Service 5spd Final Drive Gear ?
HKS Kansai Service 5spd Final Gear Set
Set contents 1. Center ring gear 2. Output shaft

GSR RS: (stock final) 4.529 (after) -> 4.111

RS : (stock final) 4.875 (after) -> 4.111

Vehicle speed was calculated with 235-45-17 size tires at 7000rpm

Final 1st gear 2nd gear 3rd gear 4th gear 5 speeds

Genuine: 66.3 94.6 131.2 179.0 242.5 (km/h)

Kansai: 73.0 104.3 144.5 197.2 267.2 (km/h)

i need advice please
Thank you

[Akeem]

Is the HKS Kansai Service 5spd Final Drive Gear will increase the preformance from 0 to 60 mile/h ?
Thank you

[SuperHatch]

Going to a taller (numerically lower) final drive gear generally decreases performance. This is due to the torque output being multiplied less when it gets to the wheels. However, if the change in gearing allows you to hold a particular gear longer, eliminating a shift, the slight decrease in acceleration may be offset in the loss of a shift.

There is also is also a secondary effect. The final drive gear is just that, a final reduction in gearing. You need to look at the total gear reduction from engine to transmission output. It's hard for me to explain clearly, but I'll do my best...

EXAMPLE:

First gear on stock gearing runs out of steam (depending on gearing) at 30MPH... second at 55MPH... third at 80MPH. You change your gearing by 11% (that is the same change of goign from a 4.56 to a 4.11). You can now hold first to 33.25MPH... second to 61MPH... and third to 88.75MPH. Even though less torque is making it to the wheels, it is only slightly less torque, but it is held in each gear for slightly longer. so from 30-33.25MPH the 4.11 final drive is putting much more torque to the wheels that the stock gearing in second gear. From 55 to 61MPH again, more torque to the wheels than the stock gearing in third gear, and from 80 to 88.75MPH, again more torque at the wheels than the stock gearing in 4th. Do those short period of time make a difference? No necessarily, but in an Evo that's hitting the rev-limiter on the stock gearing in 4th gear before going through the traps, a slight change in gearing to keep the power on longer, could result in a higher trap speed.

Ugh, sorry if this post was unclear, my mind is goign 1000 ways right now with all the crap going on in the world today.

- Steve

[cchan]

Hi SuperHatch,

great cross section. Question: is the 05 TC (or all for that matter) set up with a 1:1 ratio front to rear end, resulting in MAX torque split of 50/50? If so, doesnt this mean the clutch pack (Tarmac,Snow,Gravel) only changes rate of engagement and/or allows rear slip relative to front?

thx frm noob

[SuperHatch]

From the best I can gather looking at the systems mechanical design, and not being in any way affiliated with Mitsu and therefore not knowing the system as intimately as their designers...

The maximum torque split is 50/50, and that occurs when the VCD/ACD is completely locked up. The thing that intrigues me, is that I don't see a physical way of resricting where the power goes, when the VCD/ACD is partially/fully unlocked. IE, there is no limiter telling more power to go to the front or rear. If the VCD/ACD is at 90% lockup, then 5% more torque will go to one end and 5% less to the other, but there is no determinig factor as to which end of the car would get more or less.

Admittedly, I'm having a hard time visualizing this system in action, and that bothers me somewhat I'm going to keep thinking about this and I will have a more definitive answer to you.

My instinct right now is telling me that the center diff acts like a rear diff in a pegleg car, such that there is a normal mechanical tendency for one side to spin than the other. Mitsu may have designed the system with this in mind, and the end of the car they instinctively want to get more power is attached to the side of the center diff that "sees" more torque. If this is the case, at full lockup the car is 50/50, and if the front diff is on the high-torque side of the center diff than when the VCD/ACD is unlocked, the car acts as FWD. So a partial unlocking of the VCD/ACD can result in a 60/40, 70/30, whichever amount desired torque split. However, there can never be more than 50% of the torque going to the rear wheels.

As I said, this is just a theory at this point, I'm going to think about this more...

- Steve

[cchan]

and another thing...

is the six speed an add on cover and gearset to the 5 speed or whole different trans casting? or, can the 6 trans be bolted on to the 5 transfer case and get the 6 that way?

thx

cc

[SuperHatch]

The 6 speed trans is a completely different unit, you can't make a 5-speed gearbox into a 6-speed gearbox. However, a 6-speed transmission can be bolted into a 5-speed car and you can retain your 5-speed OE transfer case. You will also need the shifter assembly and the shifter cables to complete the swap. Jon at TRE (www.teamrip.com) sells a complete package.

[EVO-Lust-VIII]

First of all... great diagram... thanks for the info.

Ok, I'm a noob, and I appologize for this fact. But... I'm going to ask a question, because I'm a new EVO owner and I really want to understand this. Try not to laugh too hard.

This diagram is looking from the top down (with the nose north and the tail south) correct? So if you trace a line out from those two purple front differential spider gears... you will be hitting the FL and FR wheels correct? And the light blue "ring and pinion" is what goes down to the two rear wheels... am I looking at this right?

[SuperHatch]

Yes, you are correct

[sleet]

Good information

[Redcloud]

Originally Posted by Rcebowl

ok i kinda get what's going on.... but my question is... when someone blows their TC... what exactly is blowing up??

I just had to replace my TC. It was due to just a warn out bearing. No abuse or driveline shock from launching. The bad bearing caused the gears to mis-align and whine like crazy. When mitsu drained the TC a nice metalic mud came out! I also replaced the input and output shaft bearings on the tranny while it was appart.

[wbresson]

Thanks

[evo2ner]

Cool Dude

[Makos1610]