BUGA Community
Technical => Driveline => Topic started by: mezzmo on August 04, 2013, 04:45:43 PM
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So last week i was looking at a 5 speed celica box, this week i want know if anyone has a highway diff (3.5) matched up to a 4 speed aussie box on a 173. any info? how does it rev? whats it sit at around 100k's etc etc
Thanks guys
Mezz
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Yes have owned this set up too.
Well 186 and 4spd 3.5 rear end, didn't rev in top end, so good there, but I think it was a little under powered on take off, but this was a loooooooooooong time ago so could be wrong.
Think the 3.7 ratio would be better
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The original diff in mine was 3.70 at 100ks it was reving at 3800 put the 3.08 in & now revs at 2800 @ 100ks big difference crueses nice now
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so how do reckon it would go with the original 3 speed?
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The original diff in mine was 3.70 at 100ks it was reving at 3800 put the 3.08 in & now revs at 2800 @ 100ks big difference crueses nice now
But it must be slow on take off..? as I said it was a long time ago, so might have it wrong...
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I'm still using the original 3 speed manual gearbox with a 3.5 diff. The ratio seems fine.
It's good on take off and sits at 100 - 110 kms okay, without excessive revs.
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Yes, from what I can recall mine went well with the 4spd and 3.5 Cresta rear..
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Thanks for the comments guy's, looks like i've bitten the bullet - got myself a fully reco'd 4 speed today - if it sits well on a 3 speed Hobbit, i can only assume she'll go a little better with a 4 speed - i'll let you know when she's on the road - whenever that is!!! ::)
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Your trouble Messmo will be that the top gear is the same ratio: that is 1:1..... the sillycar 5 speed has an overdrive top, same as the v6 auto's, so @ 100k, your engine will be reving just as hard with the 4 speed. What will happen is you get an extra gear to get there, making it easier on the engine. Realise that @ 100 k, the difference between a 4.7 and 3.5 diff is nearly 25% (3700 rpm vrs 2700 rpm, depending on tyres.) I would be changing the diff as well... I even thought about getting 15 or 16" tyres as a solution to drop the revs. Have a look in the old posts as there is a lot of experience there and you don't have to re-inventing the wheel.
Cheers & good luck
Russell
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Thanks Rumax, i am getting the diff checked this week to make sure it's ok - hopefully i wont be doing anything to it at this stage other than a clean up. What i thought was that i will get it set up with 3.5 and 4 speed and just see how she goes. if i'm unhappy then i'll get the centre changed - i'd rather do it that way than change the centre first (at a cost) be unhappy and then have change it again - also at a cost.
Thanks for the advice though - i will be keeping everything in mind.
cheers
Mezz
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Mez
As Rumax said (and we discussed) the 4 speed won't change your top speed as the 4 speed is not an "overdrive", only a diff center change or 5 speed with overdrive will do that.
By the way, let me know if you need some one to drink your beer while you swap the box over, as I've done it before and can supervise quiet well :)
Warren McThirsty :)
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hey mr mcthirsty - i may take you up on that offer, always a beer or 3 in the fridge!!!! i'll keep you posted.
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Have Beer....
Will travel ;)
Wozza McHickup
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I'm in Melbourne and free Monday/Tuesday night ;D
Mike
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This could get ugly ;D