Transmission Options

[gordonliu]

first of all, I know that this is by no means a comprehensive list. There are a multitude of options. Indeed, if you start to consider high prices, you can realistically have one custom fitted to the SR20DET Bell housing, output shaft, etc.


but these appear to be some of the more common options or vendors:

Z32 transmission with adapter, custom DS, mounts, etc.
z33 transmission with the same
S15 transmission (which has essentially been completely superseded by the Cross 6 speed by Nismo and/or HPI)

Gearsets made by OS Giken or HKS

Standalone aftermarket transmissions made by HKS and the like...


from what I have been able to deduce...


you basically cannot spend less than $5,000 to get a transmission with internals rated for power >500 ft lbs of torque


the standalone transmissions from HKS, the HPI s15 cross transmission, and the OS giken gearsets all cost more than $5000. The gearsets cost about $10,000, and the HKS transmissions similarly cost around $10,000.





basically, I would like to build a transmission that can handle 500 ft lbs of torque. I am wondering if there is a tradeoff at some point, or if I ABSOLUTELY MUST use a specialized transmission with hardened internals...


or perhaps: is there any other option besides OS giken? they are exorbitantly expensive, so I am wondering if I can find a gearset for $5000 or less.


also any other offerings for SMG transmissions? I know HKS and OS giken offer them, but I was wondering if anyone had any other suggestions...

I assume Getrag, Quaife, hewland, etc might have offerings, but I havent found any prices on them.

[PyR0NiAk]

The 6 Speed SR transmission is weaker than the 5 speed transmission, so I have no idea why this is in your list. Honestly, the stock KA/SR transmission does just fine. There are several large turbo setups running 500+ on stock KA/SR trannies. Just make sure you preload before launching.

[Seishuku]

A W71C will still break sooner or later, mine recently cracked 3rd gear and I'm still under 300WTQ! Of course mine is 25 years old too, with a lot of hard mines on it.
I think the Z32 TT trans is the way to go, cheapest option.

[cobhc]

the ka 5 speeds are fine to use and cheap!

[ke70 sr20det]

z32 and rb25 trannies are quite strong for your goals ...

[gordonliu]

The 6 Speed SR transmission is weaker than the 5 speed transmission, so I have no idea why this is in your list. Honestly, the stock KA/SR transmission does just fine. There are several large turbo setups running 500+ on stock KA/SR trannies. Just make sure you preload before launching.

since they started selling the 6 speed "cross" transmission, at least 2 companies sell "reinforced" versions of what was originally just a modified rear housing for the stock s15 transmission.

the Nismo and HPI transmissions genuinely have non-standard (standard to the s15 production line) internals (indeed, they have different GEAR RATIOS from the stock s15 transmission)


this is not the "6-speed SR transmission."

this is a completely different, OEM "aftermarket" product designed specifically for people who want to modify their S13 or S14 for performance purposes.

different internals and a different housing fit the standard s13/s14 speed sensor red-plastic gear thingy so that your stock gauge cluster works fine, without the necessity of modifying the Differential, as was previously the case in the aftermarket scene.



I am not trying to claim that these transmission offerings are signficantly "stronger" or are even "strong" at all...


I am simply calling into question the claim that these (the ones I have been talking about FROM THE FIRST POST, not the stock s15 transmissions pulled out of Japanese junkyards) transmissions are "weaker" than the stock s13/s14 transmission.