scootz
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| posted on 20/6/07 at 08:26 PM |
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IRS
I have a Caterham chassis (narrow bodied) that I wish to try out an IRS with.
Before I start bracing the rear chassis to take the wishbones, etc, I thought I'd better firm up on my Sierra Diff / Driveshaft knowledge...
I'm using a 7" 3.62 LSD. It has Lobro's so the Caterham driveshafts are a no-go. I thought I'd keep it (relatively) simple
and use Sierra shafts. This should extend the original rear track width by about 10cm - hopefully this will not uspet things too much.
So...
I know b*gger all about Sierra shafts. Are there any differences that I should know about? I'm looking for the lightest suitable shaft with
disc capability.
Cheers
Scootz
[Edited on 20/6/07 by scootz]
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3GEComponents
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| posted on 20/6/07 at 09:03 PM |
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The lightest possible would be the push in type that caterham use, theses are obviously shorter than Sierra parts, thus lighter. Use these with a set
of disc adaptors from any of the Locost suppliers.
HTH
John
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scootz
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| posted on 20/6/07 at 09:10 PM |
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Hi John.
I already have Caterham push-in shafts - the problem is that the Sierra LSD doesn't take a push-in shaft.
[Edited on 20/6/07 by scootz]
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britishtrident
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| posted on 21/6/07 at 07:14 AM |
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If it is the earlier type of Caterham chassis ie the same as the Lotus Seven S3 you will have to do major structural work in the cockpit area to take
the loads from the IRS. The modifications to recent Caterham chassis are so extensive that little is left of the original Chapman designed frame.
see
http://www.mycaterham.com/mediac/400_0/media/DIR_39305/DIR_121116/22.jpg
http://www.mycaterham.com/117516/117447.html
Going de Dion with a Caterham style A frame lower link is a better option as is retaining the Escort or Marina rear axle.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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britishtrident
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| posted on 21/6/07 at 07:30 AM |
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In contrast a late Lotus Seven S2 chassis (almost identical to the early Lotus S3)
http://www.georgecushing.net/Lotus7.html
Not a lot of it !!!!!
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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scootz
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| posted on 21/6/07 at 08:51 AM |
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Hi BT.
It's a De-Dion chassis I have - I just fancy trying something a bit different.
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JonBowden
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| posted on 21/6/07 at 10:56 AM |
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A while ago I found some pictures of what was referred to as a Lotus 37. This was a Lotus seven with IRS using trailing arms as used to locate a live
axle to feed the loads into the chassis sides. This was combined with lower wishbones for lateral support. The arrangement is similar to that used on
many old formula 1 cars like the Lotus 25
This would seem to be a better approach for a S3 style Caterham
[Edited on 21/6/07 by JonBowden]
 
Rescued attachment l737ag9.jpg
Jon
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JonBowden
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| posted on 21/6/07 at 10:59 AM |
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Another pic of the same car
 
Rescued attachment l737ag3.jpg
Jon
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britishtrident
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| posted on 21/6/07 at 04:48 PM |
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It would be easy to do, only fault is a small ammount of roll steer.
Len Terry used an alternative version with two parrallel lower links in place of the reversed wishbone.
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scootz
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| posted on 21/6/07 at 07:02 PM |
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Just been looking at the De-Dion set-up. Sure the tube is a substantial b*gger, but there's not a great deal of engineering connecting it (and
therefore the wheels, etc.) to the chassis...
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