ghoonk

See http://www.japraceparts.com/store/pr...68764ac1908d61

Changes the final gear ratio to 4.875 (stock is 4.583). I wouldn't mind losing some top speed for better acceleration throughout the powerband.

Has anyone tried this yet? I'm guessing that the Evo VIII MR RS's 5-speed gearbox is the same as the one used in the Evo IX (note that http://toprally.5230.com.tw/06ralliart/ralliart_04.php does not mention that this is for the Evo IX only), and am quite keen to get this done.

Also, does anyone have an Excel spreadsheet that calculates the theoretical top speed of the Evo based on different final gear ratio?

jimmyv65

iTrader: (8)

Bump for a good question. I haven't heard of anyone lowering rations, but it makes sense.

Plenty of good speed/gearing calculators out on the net. Search around and there are more than a few.

FYI, your first link isn't to the product you mention.

ghoonk

I used to own an S2000 and it was one of the easiest ways to improve acceleration -- by trading off top speed. We use 0 to 120 mph more often then we use 0 to 155 mph, and the added engine response would make a significant different in how soon we get boost as well as compensating for the weaker pre-boost zone.

I'm quite surprised no one here has tried high gear ratios. This is also quite common in WRC where the cars top out at 150 km/h, but look at how fast they get there. Of course, other parts come into play as well, but gearing does make a difference

Yogi_B

In other parts of the world the RS 5speed comes with a close ratio gearbox including this final gear, my RS has this close ratio gearbox.

For racing its great, the car feels lively no matter what gear you are in. However my top speed is approximately around 210km/h (130mphish) so the car runs out of legs on high speed tracks and its useless in drag racing as im changing into 5th quite early and high speed cruising is a little annoying (approx 100km/h (62mph) @ 3400rpm).

But if you don't mind throwing away a little speed then you get a really lively car.

Probably the best way to describe what i'm talking about is to go and drive a 6speed evo but only use the first 5 gears. However the 4.829 final in a 6speed box will probably feel even closer than my 5speed.

ghoonk

So, technically, it's possible to use the final drive in the 6-speed in the 5-speed W5MAA tranny?

See http://www.japanvehicles.com/newcars.../Evo9/main.htm. The final gear ratio for the 5-speed tranny is 4.529 and 4.583 for the 6-speed tranny.

Looks like there's payback in fuel consumption though....

Ang Wen Yan

Strange people.....Stock gear is already very short for turbo car but seriously make it shorter???

ries

iTrader: (36)

thats what Im wondering!!!

If anything Id want the gears to be longer so Im not going through the traps at 8000 rpm in 4th or trying to shift to 5th right before the line and actually hurting my et/mph.... + highway driving would be improved too

maybe for short tracks and autocross this would be good though

Ev0ikon

iTrader: (18)

I am not sure what else is needed but you can not just slap another tranny in the stock evo since the Final Gear ratios are different.
But I have ridden in an USDM Evo8 with the JDM Evo7 GSR 5 SPD direct swap tranny (same Final ratio) and it's amazingly different. Going from 4th to 5th gear no longer fall flat on its face. In fact, boost response feels just like going from 3rd to 4th - like a hammer! :P

94AWDcoupe

iTrader: (125)

People who think dropping the final will make you car trap quicker , failed basic math. Raising the final to 4.875 will definately help your car turn a quicker trap. Your top speed will not be lowered that much. Instead of stock 165, it will be lowered to 155. Having to shift to 5th at the quarter is also not an issue. The shift from 4th to 5th will cost about .04 on your ET. Your ET will drop .2-.3 by using the 4.875. The first car to hit a 10 sec 1/4 using stock block had this higher final drive.