Convert from 18 splines to 25

[AnAx]

I'm about to add some hp to my car (-91 VR4 US-model) and since I have the 18-splines was I thinking about getting the 300M output shaft from supercar-engineering.com. I did then read something about it beeing possible to upgrade from 18-splines to 25-splines and then get the 300M 25-splines version.

What is required to upgrade from 18-splines to 25-splines if I have the TC with the large bearing?
Output shaft, transfer Case Sleeve and VCU?

And would it actually be a point in upgrading to 25-splines when going for the 300M shaft (300M 18-splines shaft Vs. 300M 25-splines shaft)?

[defgh1]

If you want to convert from 18 to 25 spline you will need a 25 spline Bell housing and output shaft for your transmission since the 25 spline output shaft is larger. You will also need to modify the input spline of the transfer case from 18 to 25 spline. The 300M shaft is pretty stout even in the 18 spline version and will handle a fair amount of HP. However, the stock transfer case (TC) will always be the weak link. Regardless of what you do, I would seriously consider upgrading your TC to the SS or Billet Aluminum case. In my experience, the stock cast aluminum TC housing will not take much abuse even with a housing bracket.

Doug H

[91vr4n00maxima]

what are your goals. more likely than not the 300m 18 spline will be enough for you.

if youre set on upgrading....OS, VCU, bellhousing, input spool for the t-case (or if its the small bearing case..the entire t-case) and associated seals