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Geabox Conversion Help

drifter

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I'm driving an S15 with the Nismo Cross Mission 6 speed rated to 420HP
Probably Shawnhalu's best bet to be honest if he can stomach the price :) What's the gearing like, they have different ratios like the OS Giken set don't they?
 
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What's the gearing like, they have different ratios like the OS Giken set don't they?
The gearing is great, ratios are closer together so gear changes are smoother and less impact on your input shaft..These are the comparison specs


SPECIFICATIONS:
Transmission Gear Ratio
1st:
- Nismo Reinforced Cross: 2.9071
- OEM 6-speed (FS6R92A): 3.6264
- OEM 5-speed (FS5W71C): 3.3214

2nd
- Nismo Reinforced Cross: 1.9888
- OEM 6-speed (FS6R92A): 2.2000
- OEM 5-speed (FS5W71C): 1.9023

3rd
- Nismo Reinforced Cross: 1.5373
- OEM 6-speed (FS6R92A): 1.5412
- OEM 5-speed (FS5W71C): 1.3084

4th
- Nismo Reinforced Cross: 1.2179
- OEM 6-speed (FS6R92A): 1.2132
- OEM 5-speed (FS5W71C): 1.0000

5th
- Nismo Reinforced Cross: 1.0000
- OEM 6-speed (FS6R92A): 1.0000
- OEM 5-speed (FS5W71C): 0.8378

6th
- Nismo Reinforced Cross: 0.8624
- OEM 6-speed (FS6R92A): 0.7674
- OEM 5-speed (FS5W71C): -
 

drifter

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Sorry but a noob question :)

the ratio is lesser the better?
Not so much, what the Nismo box does as well a few others is make the ratios closer together from 2nd gear onwards. That way when you change gear the revs don't drop as far and you stay well into the power band. The thing that put me off is the long 1st, from memory the OS Giken 1st is good for nearly 70mph. But I've never driven with one so can't comment.

To keep mine in the power band with the Z32 box I upped the revs to 8k. You wouldn't really have the problem with a small turbo that spools quickly :)
 
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When you have power mods the taller first gear is great because you can get up better road speed and the shift into second is smoother as you don't have to hit the limiter..

I like the changes, smooth with a easy gate between gears..Drifter have you done head work to your SR to hit 8K ?
 

drifter

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When you have power mods the taller first gear is great because you can get up better road speed and the shift into second is smoother as you don't have to hit the limiter..

I like the changes, smooth with a easy gate between gears..Drifter have you done head work to your SR to hit 8K ?
Yeah, it's been ported and polished. It's still on standard valves and rockers, but uses the full Ferrea double valve spring kit and a set of rocker arm stoppers. Cams are Tomei Procam 270's with the adjustable pulleys :)
 
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Ok, be careful of those stock rockers...they are the weakest part of the SR head they are not happy at high RPM...Had a mate pop his even with rocker stoppers...The SR20VE head is becoming a more popular head to use here with big power and E85 tunes
 

drifter

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Yeah it's doing okay though. Apt built the engine 10 years ago and its still going strong. The ve head has interested me for a while, but it's a load of hassle I can't really be arsed with. Maybe if the engine ****s itself :D


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