Good morning All,

I have looked at the gear speed calculator but I am afraid I just dont get how to use it! Duh...

Am in the process of having my Fireblade engine replaced with a 1999 Hayabusa engine, should be ready in 2 weeks

Can anyone tell me what my in gear speeds will be if running my current 3.62 diff? I have read various things about Freelander diffs being better suited to the Hayabusa engine but frankly am unsure of what that change would mean to in gear speeds!

Any help greatly appreciated....
Many thanks
Jason

quote:

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Originally posted by z3mjasonCan anyone tell me what my in gear speeds will be if running my current 3.62 diff? I have read various things about Freelander diffs being better suited to the Hayabusa engine but frankly am unsure of what that change would mean to in gear speeds!

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Bob,

Thanks very much indeed for that information. It sounds like I may need to find a slightly longer diff then!

Obvious question, does anyone have a 3.36 diff they may sell or swap for a 3.62??
I am not to stressed about top speed but guess a 3.36 or whatever the next step down/up is?

Cheers for help!
Jason

A 3.09 is available for the ford diggs, these work well with busa engine and makes it much better on the motorways. I'm running a 3.44 with my gsxr 1000 engine which is not perfect but ok for now.

Okay so it sounds like a 3.36 is the very least I need to go to. My car will only see fast road and occasional track use so not to concerned with motorway cruising ability. Guess its a compromise without sapping to much of the acceleration away in favour of lazy high speed cruising.

Further investigation/searching for diffs needed then!!

Ti be honest I found that although I dropped from a 3.89 to a 3.44 I didn't loose much acceleration as the gearing with the 3.44 gives much longer gears meaning you can make the most of the fact that bike engines love to rev.

You won't notice a drop in acceleration as it's such a close ration box, the only exception being getting away in first gear but even with my 3.14 I was still fairly spritely off the line.

A 3.36 should give you about 129 in top. I have a spare 3.36 with LSD, someone else said they wanted it but haven't heard back from them.

You could even go 3:14 if you can find one. Try Classic Conversions.

Cheers, Nick

Thanks all!

Bob, you have a mail...
Nick, I will try them thank you

For clarity my diff is a 3.62 Sierra diff, I take it these things are swap in swap out with the same mountings etc?



[Edited on 27/7/11 by z3mjason]

What size are your wheels and tyres and what is your required top speed, I would work out what you need and not guess a 3.14 is the most expensive and differcult sierra diff to get hold off

Cheers
David

FYI-
I noted you're using a 1999 Hayabusa engine.
I strongly suggest you update the starting system to the factory 03 or later.

The pre 03 starting system will break the starter and possibly the cases if you spin the car.

Chet

David,
I am running 195/50/15's on 15 TD's. Top speed would be 130 - 140 to allow for occasional comfortable 80mph ish cruising.

Chet,
Yes I am aware of this "issue" will look to upgrade it before any trackdays. Any idea of cost for this mod?

Cheers this has been very helpful people! Thank you
Jason

Putting those figures into the bike ratios.xls spreadsheet, assuming a 11000 redline which needs to be confirmed, gives

3.64 120mph
3.38 130mph
3.14 140mph

Worth getting a second view on the calculations to confirm them

Cheers
David

David,
Thats brilliant thank you. Looks like its a 3.36/8 then or the gold dust 3.14. I'll probably get the 3.36 first and see. Thinking that my Toyo T1's might be the first change for something more sticky....
Cheers
Jason

3.36 is a 7.5" granada style diff
3.38 is a 7" Sierra diff

You need to look at what's in your car now and buy the appropiate diff, so it's a straight forward swap out

Cheers
David

David, great stuff thank you! On the hunt for a sierra diff with 3.36 then....

Anyone know what the ratio is for a Freelander diff and what speeds that gives on 13 inch wheels for a 1999 standard Hyabusa

Ta

John

I'm pretty sure a Freelander is 3.21