Thoughts on diff ratios

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Re: Thoughts on diff ratios

Post by SiJackson » Tue Apr 23, 2019 3:13 pm

simonjrwinter wrote:
Mon Apr 22, 2019 6:39 pm
My Hawk has a removable panel at the back of the cockpit. This enabled me to bleed the rear brakes while sitting in the drivers seat, pumping the brakes with a spanner on the bleed nipple.
Funny enoughI was thinking about doing this to mine the other day. Do you have a photo of the panel and how much of the heel board you chopped out by any chance?


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Re: Thoughts on diff ratios

Post by frats289 » Thu Apr 25, 2019 8:23 pm


Don't turn on that often but just read your note.

It all depends on what you want the car for. If you want effortless motorway cruising then you've got the wrong car.

The original car had a 3.54:1 diff giving 21.3 mph/1000. I've got a 3.307 diff giving 24 mph/1000. I'm doing the 289 Scotland tour in September and I know that it will be an absolute pain in the arse driving the 320 odd miles to get there but when I get there... Don't forget why you've got a 289.


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Re: Thoughts on diff ratios

Post by clive » Thu Apr 25, 2019 10:24 pm

Frank, it depends on what route you choose. When I drive down to Silverstone each summer I avoid the motorways as much as possible and enjoy the quiet meandering A roads through the borders.
Cheers, Clive.

(If I'm not here I'm in my workshop or on the golf course!)

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Re: Thoughts on diff ratios

Post by John H » Tue May 28, 2019 10:03 pm

Hi Dave, I'm a bit late to the Jag diff is 3.51 and I have Tremec T5- 251 with final drive ratio of 0.63. So in 5th 70 is a steady 2000 rpm!
Here is the full breakdown....I would love to think she would hit 4k in 5th if I was brave enough next time at Le Mans! Hope this helps....also with the hard top I was getting 25mpg on the motorway back from France!
Also for bleeding the internal rear brakes I fed a line to inside the rear wheel arch so no need to get in and under... Cheers John
Axle 1st 2nd 3rd 4th 5th
3.51 2.95 1.94 1.34 1 0.63
Revs Speed
1000 8 12 17 22 36
2000 15 23 34 45 71
3000 23 35 50 67 107
4000 30 46 67 90 143
5000 38 58 84 112 178
5500 42 64 92 124 196
6000 46 69 101 135 214
6500 50 75 109 146 232
Built St Piran Hawk289FIA in Scotland!

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Re: Thoughts on diff ratios

Post by allan horsfall » Wed May 29, 2019 11:11 am

Hells teeth John, 232 mph!!!! How do you keep your clothes on?

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