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OS Giken 5 Speed Close ratio information

Hi,

I'm sure I read that someone on here had or has an OS Giken close ratio transmission. Product specs below.

My question is there are 2 different gear kits, the 3 speed and the 5 speed which also changes the input shaft. From the pictures I have seen it looks like either option comes with a new counter / lay shaft.

My question is whether or not the 5 speed option changes the input shaft and the input shaft counter gear on the counter shaft. I ask this because if they changed either of those gears then that would effect 5th gear as well.

I say that because I notice the 5 speed close ratio comes with a 0.821 5th gear.

My car currently has a 0.762 5th gear, and if I was to go to the bother of installing the close ratio I would really like the tallest 1st gear, with the closest gears 1-4 and then a nice tall highway cruising 5th gear.

If I put the 0.762 or 0.719 5th gear in, what do you actually end up with if you use the 5 gear option. It seems OS Giken changed the tooth count on the input shaft and input shaft counter gears that would effect the final drive.

Code:

Product Specs

Brand: OS Giken

Product: Close Gear Kit 5-Speed + Main Shaft Mazda FC3S FD3S



SPECIFICATIONS:

Gears Ratio:

- 1st: 2.578 (3.483 OEM)

- 2nd: 1.772 (2.015 OEM)

- 3rd: 1.289 (1.391 OEM)

- 4th: 1.000 (1.000 OEM)

- 5th: 0.821 (0.806 OEM)

Code:

Product Specs

Brand: OS Giken

Product: Close Gear Kit 3-Speed Mazda FC3S FD3S



SPECIFICATIONS:

Gears Ratio:

- 1st: 2.714 (3.483 OEM)

- 2nd: 1.742 (2.015 OEM)

- 3rd: 1.267 (1.391 OEM)

A bump for you, same question here too~

don't we normally want closer ratio transmission for the FD? in order to keep it more in the power band?

Its pretty much being said by Jobro, I love the long first gear and close gear ratio until 4th, but i also want a low cruising rpm for the 5th

I once had this gear set but never installed... I wrote down all the gear teeth figures at the time to verify ratios.

OS Giken 5 Speed

Input shaft:
18 teeth for input gear

Main shaft:
20 teeth for 3rd
22 teeth for 2nd
24 teeth for 1st
?? for reverse (didn't have it, maybe kit reused stock gear)
?? teeth for 5th (didn't have it maybe used stock; should be 27 to achieve 0.821 ratio)

Counter shaft:
29 teeth for input
25 teeth for 3rd
20 teeth for 2nd
15 teeth for 1st
13 teeth for reverse
53 teeth for 5th

For future searches, here's a good calculator for figuring gear ratios if anyone doesn't want to do the math...

Standard Gear Ratios

Quote:

Originally Posted by PandazRx-7 (Post 11650537)

Thanks for that post.

I will buy one, one day. 5th gear does run through from the input shaft into the counter shaft doesn't it.

I think you have provided enough info for me to work out what ratio 5th would actually work out to if it is effected.

Quote:

Originally Posted by Jobro (Post 11651965)

With the current exchange rate, this gear set is about $2,200 shipped. That's a steal! I remember when I sold my used set for around $1700 the new sets were more than $3500.