Does anyone know if the American 7.5" diff is the same as the one in this country used on the 2wd Cosworth.
The problem I'm having is I'm finding it difficult to obtain the ratio I want (4.57:1) but http://www.richmondgear.com/01ford.html to a 7.5" 4.56:1 CWP and I was wounding if it would fit.

This is to go with the S2k lump? Is the original diff really that high? Or do you feel the acceleration isn't enough as it is?


James

My understanding is that they are not compatable as I have been told by the american turboford group.
Dale

Yes its for the S2K lump. The original diff ratio is 4.1:1 but I want better acceleration and lower top end. Car's mainly going to be used for track and hill climbs so I was going to go with 4.44:1 but then I read this...

In the quest for improved performance and drivability, most S2000 enthusiasts would agree that new rear gear set with a higher ratio over stock provides one of the greatest performance values available for the S2000.

Through an exclusive arrangement with Richmond Gear, the leading US manufacturer of professional quality, high performance ring and pinion gear sets, we are pleased to announce that we now have in production a never-before available rear gear set for the S2000: a 4.57 ratio. Rick's new Richmond 4.57 gear sets are a far superior product to the 4.3, 4.44, and 4.77 gear sets previously available. They are stronger, better made, and are delivered with special treatments for hardness and improved lubrication (the latter uses a process developed by NASA for the treatment of critical engine parts in the Space Shuttle). But the price will remain the same: $590.

Richmond Gear is the leading US manufacturer of professional quality, high performance ring and pinion sets, and its gears are the highest quality in the racing industry The superior quality of Richmond gears is the result of continual research and development, outstanding design, and state-of-the-art manufacturing. For example, the teeth of Rick's 4.57 gear sets are 20 percent stronger than those in the stock Honda gear set or the 4.3 and 4.77 gear sets, which are made by Mazda.

On the advice of Richmond engineers, who have unmatched experience in ring and pinion gear design, we concluded that the 4.57 gear ratio would be ideal for the S2000, falling in the “sweet spot” between the 4.44 and 4.77 ratios made by Mazda (which makes the stock 4.1 rear gears and diff), and ideal for both improved acceleration and highway cruising. Since the 4.44 and 4.77 ratios are relatively old designs made originally by Mazda for use in other cars, both involve trade-offs on the S2000. While it provides brisk acceleration and performance, the 4.77 compromises highway cruising, forcing drivers to run much higher RPM at cruising speeds in 5 th and 6 th gear. The 4.44, although better for highway operation, lacked the performance kick of the 4.77. The 4.57 provides the best of both worlds.

All the gear sets previously available, since they were made my Mazda for cars with far less power than the S2000, were subject to breakage and damage when used in S2000s with forced induction, or by drivers who routinely use clutch drops for quick starts or drive very aggressively.

Until about six months ago, the 4.44, and 4.77 rear gear sets for the S2000 were routinely priced close to $1,000 and occasionally fell just under $900 in group buys. Through special arrangements with suppliers around the world, Rick's was able to reduce the price to only $590 + shipping. The new Richmond 4.57 rear gear set, which offer much improved quality and strength, represents an exceptional value at the same $590 price.

With the debut of the Rick's 4.57 Richmond gear set, we will no longer carry the 4.44 ratio, a moot point perhaps, since the world supply is nearly exhausted. However, the 4.77 ratio is still being manufactured and will remain in our inventory for performance enthusiasts who want its extra kick and are willing to give up some comfort on the highway.


http://www.ricks2k.com/products/reargears.php

I am going to try getting in touch with Richmond to see if they can supply as CWP to fir the Cossie diff.

[Edited on 2/11/04 by atomic]