nitz

iTrader: (3)

Hey All,
I need some advice regarding a transmission upgrade to get the best out of my EvoGreen setup. Relevant mods are as follows.
Mitsubishi Evolution VI RS
Revolver Cams (set straight up with cam gears, degree wheel and dial guage.
They were anything but correct at 0,0. Actual setting to achieve published specs were -11,0!!)
Ported stock intake manifold, exhaust manifold and throttle body
Tubular 02 housing and 3" exhaust
Greddy Spec M Intercooler (47C @ 7500rpm with 23C Ambient)
EvoGreen ported, 18psi Actuator
2.2Bar @ 3900RPM - 6800RPM then tapering to 1.8Bar by 7500rpm
JDM RS Transmission
1st 2.785
2nd 1.950
3rd 1.444
4th 1.096
5th 0.825
Final Drive 4.875

Unfortunately, I don't have access to a dyno in order to figure out my optimal shift points from the torque curve. However, best guess by feel and looking at the rate of tacometer movement would be.

1st - 7300 - 40mph
2nd - 7100 - 56mph
3rd - 6900 - 73mph
4th - 6800 - 95mph
5th - 116mph@6200rpm

On my only 1/4 run this netted me 11.6@116 with a 1.9 60'. I know most people hold fourth, but with this ratio and cams, you are going to have to shift 5th anyway so you might as well make more use of the power band. On this run I didn't do a very good job of meeting my shift points.

Well on to my question. Would it be best to put a 4.11 final drive in my current transmission or replace it entirely with a Evo VIII 5-speed? Below are some of the rpm/mph to expect with both. I have to say though that my current ratio is a blast on a tight track.

Evo VI RS with 4.11 Final Drive

rpm 1 2 3 4

6800 45 64 86 114
6900 45 65 88 115
7000 46 66 89 117
7100 47 67 90 119
7200 47 68 91 120
7300 48 69 93 122
7400 49 70 94 124
7500 49 70 95 125
7600 50 71 96 127
7700 51 72 98 129
7800 51 73 99 130


Evo VIII with 4.529 Final Drive

rpm 1 2 3 4

6800 39 58 80 110
6900 39 59 82 111
7000 40 60 83 113
7100 40 61 84 115
7200 41 61 85 116
7300 41 62 86 118
7400 42 63 87 119
7500 43 64 89 121
7600 43 65 90 123
7700 44 66 91 124
7800 44 67 92 126


Thanks for the help.

sparky

iTrader: (1)

I guess it depends on your intended use. I have the JDM RS close-ratio 5-spd., as well. I love it for the twisties. But, do you want the best setup for drag racing?

On the Drag Racing Forum the guys will tell you the best setup. I think they like the USDM 5-spd. but swap in different 4th gear(or is it 4th & 5th?) from a 6-spd. tranny. But, ask them. As for the final drive ratio I just dunno.

sparky

iTrader: (1)

I thought about your questions with regard to the close ratio JDM RS 5-spd vis-a-vis the Green turbo. Since I´ve got the same tranny and the Green, I´ll give you my take: I´m not real happy with the combo. At least, as fitted with the 10.5 turbine housing the Green spools way too slow for the short gears of the close ratio JDM RS gearbox, w/4.87 final dive ratio.

I went and ordered the faster spooling 9.0 cm housing for my Green and although I haven´t installed it yet, I am hoping that the tighter housing will do the trick as I miss the spool characteristics of my old JDM TiAl RS VIII turbo w/9.8 hsg. If you´re expecting the 10.5 housed Green to spoolup quickly enough for the JDM C.R. RS gearbox, then you may be as disappointed as I was.

nitz

iTrader: (3)

i'm actually quite pleased with the spool characteristics of my setup. even though it's a few hundred rpm slower than standard, it's really not perceivable in every day driving. one of the advantages of a longer ratio box, is that you are in the powerband longer especially on a stock framed turbo. i'm looking for a compromise between street and strip. i'll give the drag forum a try. thanks for you input.

mrdevo

iTrader: (4)

If you wanted different gearing for drag racing, I would go with the 4.529. For more highway performance, I'd get the 4.11. I've always wanted a longer gear setup in my car because I don't really launch the car. Never could justify the cost though.