Gearboxes ??

[zentac]

Ive currently got a Mitsubishi FTO with a VR4 engine in, 287bhp at the hubs and 314lb-ft torque. However Im running
an FTO, LSD gearbox and the gear ratios mean that my max speed is 135mph (ish) which will be crap for 10 of the best
next year ;) Also I will be in 4th/5th on a 1/4 mile run, So I need to get it sorted. The only problem is I know
nowt about gearboxes. Engines I can play with all day long, gearboxes not a clue! My current gear ratios are

1st 3.583 31.670 MPH
2nd 1.947 58.282 MPH
3rd 1.379 82.288 MPH
4th 1.030 110.170 MPH
5th 0.820 138.384 MPH
Final Gear Ratio 4.312


Not sure how I would go about this but if I can lower the Final Gear Ratio to approx 3 then that would be ideal
for both santapod and 10 of the best

Top Speed in 1 gear = 45.521 MPH
Top Speed in 2 gear = 83.771 MPH
Top Speed in 3 gear = 118.275 MPH
Top Speed in 4 gear = 158.351 MPH
Top Speed in 5 gear = 198.904 MPH


Is this possible?

[Nick Mann]

That looks a tad long. Not that I know much myself!

The VR4 hits 130-135 in 4th and theoretically about 180 in 5th. Do you think you will need higher gearing than that?

[Polabear]

That looks a tad long. Not that I know much myself!

The VR4 hits 130-135 in 4th and theoretically about 180 in 5th. Do you think you will need higher gearing than that?


I have always felt that I need a 6th gear Nick, I think most manual owners would agree..

[zentac]

To stand a chance at 10 of the best I need to be running 500bhp and have a top speed of above 180. I dont need to win every event but it would be nice to :)

[Nick Mann]

To stand a chance at 10 of the best I need to be running 500bhp and have a top speed of above 180. I dont need to win every event but it would be nice to :)


Please ignore everything I said. Your plan sounds like a good one. I don't need to see you win every event, but I agree it would be nice to!! :-D

[Wodjno]

You may need a top speed of 180mph .. But that dont mean you need it geared for 180mph .. Watching previous meets at the POD , max speed over the line has been between 150 and 160 mph for the quickest down the strip .. Road legal cars that is .. These crossing the line in the 10 sec area .. So i reckon for you to be getting up there you need gearing for no more that 170mph otherwise it's gonna be o long nd granted you will probably get to 190mph by te end of the runway . :rolleyes5.. But then you gonna have to find some room to stop :laugh: :D :p We could all park our VR4's at the end as a crash mat .. :laugh: :Eyecrazy: :arse: :uhoh:Oh yes .. Forgot to mention .. YUP YOUR GONNE NEED IN EXCESS OF 500 bhp .. ;)

[Wodjno]

Plus about maybe 200 more :D :-b

[zentac]

yeah but one of the competitions at ten of the best is a top speed shootout on the main runway, and the fastest FWD cars run 180+

[zentac]

any one know the gear ratio`s for the VR4 ?

[zentac]

hmmm just been playing and if I can find a final gear ratio of about 3.6 I should be pulling 135+ at the top end of 4th and over 170 flat out in 5th which would be ideal. Just need to a few diesel gearboxes apart to find a low final diff that will fit :)

[Roadrunner]

any one know the gear ratio`s for the VR4 ?
5-sp manual:
1st: 3.333
2nd: 2.105
3rd: 1.407
4th: 1.031
5th: 0.761
Rev: 3.416
Final: 4.111

5-sp INVECS II:
1st: 3.789
2nd: 2.057
3rd: 1.421
4th: 1.000
5th: 0.731
Rev: 3.865
Final: 3.684

[zentac]

Thats interesting that give a rough top speed for a manual of

1st 40mph
2nd 60mph
3rd 90mph
4th 120mph
5th 165mph

[FTOLTD]

I would use a combination of two differant ways to get there richard. One would be to change your rev limiter, i have my rev limiter set too 8500 and I regularly bounced of the rev limiter at full boost, which for me is 18Lb, eventually i melted a piston but i got 6 months out of the first engine and 12 months out of the second engine. You just need to get it tuned up there by a good tuner.

Currently having problems with 3rd engine but it will be getting replaced with another engine next week.

Also change your gearing in your LSD, there should be engineering shops around that can manufacter the gears at the nessecarry ratio, lot cheaper than building a dog box.

[zentac]

Ive got a gearing shop at the moment looking for a better final gear ratio. The recon the cheapest way to do it is find a diesel that is compatable as they should have a ratio around 3.6 which will give me

1st = 42
2nd = 75
3rd = 105
4th = 140
5th = 180

which would be ideal if we can find one.

[FTOLTD]

if they are succesfull could you find out what model the diff comes out of and what was involved or if they can send one to Australia.

I have the Diff ratios on my to do list, would love to get a bit longer out of 1st and 2nd, i spend more time changing gears than accelerating between 1st and 3rd