JohnZ

Here's that ratio story:

Railroadman

So teach me something. If I understand correctly, the advantage to a close ration is to keep the engine RPM within a fairly narrow range of peak output within the torque curve.

Why would that not be desirable for even the low HP engines? What are the advantages of a wide ratio for a tamer car?

JackTripper

Great read. Thanks.

tuxnharley

I'm surprised no one else has responded to your question! I'm no expert - didn't even sleep at a Holiday Inn last night - but do have a fair amount of experience and have done a bit of reading, so I'll take a stab at it.

I don't think its dependent solely on the engine. I believe its a combination of 3 factors - the engine, the rear axle ratio, and the intended use of the car.

With lower and even mid range output engines in cars intended for around town and highway driving with taller rear axle ratios the close ratio box is actually more of a hindrance than a help. Those engines usually have a fairly broad torque curve, and can handle the wider transmission gear spacing - which is an advantage especially when starting in first gear in traffic or on a hill.

The close ratio box is not as friendly for street driving/starting on such cars with the highway rear gears, sometimes requiring a lot of clutch slipping to make a clean start.

Where the close ratio box shines is in performance applications such as autocross or track use or on cars with shorter rear axle ratios used for drag racing. On the track or autocross the first gear is sometimes used in tight corners on a downshift when you want to keep a high output engine with a peaky HP curve in the power band. On the strip when youve got 4.11, 4.56, or 4.88 axle the lower 1st gear of the CR box lets you stay in 1st a little longer before you have to shift, and keeps the engine close to its HP peak as you row through the gears.

Cliff Notes:

- a lower output engine with a broad torque curve intended for street/highway use works better with the WR box

- a higher output engine with a peaky HP curve intended for performance/motorsports applications works better with the CR box

- selection of the appropriate rear axle ration is critical in both cases.

Railroadman

Thank you! What you say makes sense. It has been many years since I had my '67, that had the 400hp, 3:36's and the close ratio. I don't honestly remember HOW it felt in normal everyday driving, but I suppose after several years anything can feel "normal".

When I do finally get back into a C-2 it will be for driving and cruising, so I won't be looking for the ultimate output in a narrow torque range. OTOH if I wind up with a smaller engine, I'll probably want something a little stiffer than 3:36 in that.

I appreciate the info!