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Phoenix R1 diff ratio
sdenne - 21/10/20 at 09:58 AM

Hello,
my recently bought Phoenix R1 has an english axle with 3.54:1 diff ratio - this is the longest available ratio.
Is this okay and why?
sdenne

Edwardo - 21/10/20 at 12:50 PM

Hi - 3.54 is the lowest 'generally available' and most commonly used for English Axle'd BEC's it seems.

But you can get a 3.31 from Retro Ford :-

https://www.retroford.co.uk/product/3-31-english-crown-wheel-and-pinion-cwp-3-3/

Cheers
Tony

[Edited on 21/10/20 by Edwardo]

adithorp - 21/10/20 at 02:12 PM

Ideally you'd want higher ratio than that (depending on which version R1) but difficult with English axle unless you go for the custom options. Even 3.36 Sierra diffs are considered too short by some, though probably fine for most uses.

I use a 3.22 Freelander diff'. It's a bit tall at times setting off. Gives me72mph at the rev limit in first and will top 140 flat out but a bearable 7k rpm at 70mph on the motorway.

Have you tried the gear calculator in this section to see what you'll get?

TimC - 21/10/20 at 08:54 PM

Depends which R1 and what tyres you have. My 2007/8 engine with a 3.54 Diff and 205/60/13 tyres is geared for c.136mph.

sdenne - 22/10/20 at 06:34 AM

Thank you for your replies - it is a 1999 carburetor R1 with 185/60/14 tires.
I will try the gear ratio calculator.

adithorp - 22/10/20 at 07:22 AM

quote:
Originally posted by sdenne
Thank you for your replies - it is a 1999 carburetor R1 with 185/60/14 tires.
I will try the gear ratio calculator.


In which case the 3.54 will be pretty good. You'll be fast enough off the line and unlikely to have the power to rev' out at the top end.