What HP level requires transmission upgrades?, I have 200 HP to the wheels, what do I need? Options

[FourBlades]

I realize it is probably torque that kills a transmission, but I don't know the torque output of my engine.

I am building a 901 transmission for my IMSA 914 and wonder what upgrades it will need. I have some possible upgrades I could do now.

First, I have a set of 930 stub axles, CVs and the corresponding sway-away axles for a 914. They are stronger and the CVs are available for $80 from pelican. Downside is I have to destroy the existing rear bearings in my axles to use them, which were rebuilt by PMB.

If I have 200 HP to the wheels are the 930 CVs a necessary or worthwhile upgrade?

Second, should I upgrade to the billet intermediate plate at this HP level?

If I do, will I have to reset the pinion depth? That is something I can't do myself and would need to find a shop here in Florida that can do it. I know this is overkill for a typical 914, but with 12 inch rear tires and a 2.5L six, is this when the upgrade is worth while?

I am not adverse to starting with the 914 axles and upgrading down the road. Pulling the engine and transmission is not that time consuming. I would hate to break the smaller axles or CVs the first time at the track though.

I have a stock gearset and know there are probably better gear choices for Sebring, Daytona, etc. No idea where to start with those.

I will be running a transmission cooler to start and may move to gear set spray bar over time. I have read that the mesh point of the gears is where to aim the cool oil sprays, not sure this is correct.

I appreciate any advice people have.

John

[slivel]

For gear ratio selection, You want to be at redline in top gear at the braking point at the end of the longest straight. Obviously this applies to only one track, so unless you are going to have multiple gearboxes or are going to change gearsets for each track , you may have to compromise. I had two boxes a long and a short gear box (AFNSY and AFMSX) but always kept the long box installed and kept the short box in the trailer as a spare. I could hit redine in 5th on the front straight at Miller Motorsports (now UMC) which was 145-150 but was not at redline on most other tracks.

You have to know the tire diameter that you will be using, your redline, and the track with the longest straight to plan your gearset. I have an interactive excell file that lets you change the tire diameter and or gear ratios but I cannot attach an excell file so I've saved it as a JPG.