CaptainJosh
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| posted on 12/7/06 at 07:51 PM |
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Light Rear End
Hey guys
I am hoping to build a 1.3 Suzuki GTi powered locost with the emphasis on making the car light. The engine puts out 100bhp standard, which is amazing
for a 1.3 car engine, very torque'y and revy.
Anyway, I have sourced parts for pretty much everything which are light and within budget, except from a rear end.
I wanted to use a ford sierra backend due too the independent suspension, but they are pretty heavy, although they have good ratios.
I had a look into mazda backends, but I couldn't find much.
Any suggestions would be great
cheers
-Josh
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Mansfield
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| posted on 12/7/06 at 08:29 PM |
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I read in PPC about a guy called Chris Snell who used a Subaru Justy 4x4 diff. PPC wrote "3.67:1 ratio, are small, light and with a very light
output flange. They are also cheap - Chris bought five for just £100".
That is all I know, although I do seem to remember him posting on here shortly after the article (Nov 2005). There are also some contact details in
PPC if you are interested.
Edit - username 'ChrisS' on here.
[Edited on 12/7/06 by Mansfield]
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peterriley2
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| posted on 12/7/06 at 08:45 PM |
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just in case you didnt know, the sierra lsd's weight around 8kg's (i think) more than the open diffs.
just out of interest, what parts have you sourced for it so far, and where from? im making mine as light as possible, for handling and to make the
ponies stretch a little further... so would like to know where you get lighter components from, without breaking the bank!
Joel
If you dont respect yourself, dont expect respect from anyone else
Live your dreams, dont dream your life
Women only want you for one thing- everything!
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andyharding
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| posted on 12/7/06 at 09:01 PM |
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Sierra diff, half shafts and hubs with a custom DeDion is pretty light.
Are you a Mac user or a retard?
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MikeRJ
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| posted on 12/7/06 at 10:01 PM |
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If you want overall light weight, you have to try quite hard to beat the Ford English (live) axle, though unsprung weight isn't as good as IRS.
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CaptainJosh
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| posted on 13/7/06 at 09:48 AM |
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peterriley2-
All the parts that can be machined myself I will be doing so, things like wishbones and alike- I can shave weight off in my designs.
There is also alot of weight in things like cortina uprights, so I will be getting cast aluminum ones, not off the shelf because that means paying the
middle man, but I know a few places where I can get them cast pretty cheaply. Its just things like that really.
The suzuki engine and the suzuki 4x4 gearbox weight in at about 80kg together, that is not alot at all, especially when against something like a ford
type 9 attached to a crossflow or pinto.
Cheers for the help so far guys, I'll have a look at the subaru diffs and get back to you.
By the way - I don't really want to use a liveaxle because I really need a proper camber change on the rear wheels as the car corners. Although
I have to agree, the old school is hard to beat when it comes to weight.
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MikeRJ
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| posted on 13/7/06 at 01:30 PM |
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quote:
Originally posted by CaptainJosh
By the way - I don't really want to use a liveaxle because I really need a proper camber change on the rear wheels as the car corners. Although
I have to agree, the old school is hard to beat when it comes to weight.
The beauty of a live axle car is that you don't get any camber change when the car rolls, or under acceleration/braking etc. The only time that
camber is adversely affected is when one wheel is in bump/droop.
Traditional double wishbone IRS systems are inferior in this respect as it's a compromise between camber change in squat and in roll, i.e. get
it perfect for one case and it will be poor for the other.
The only advantage an IRS system gives you is lower unsprung weight which will give a better ride on rough surfaces. On a track it's advantages
are negligible, and a de-dion setup gives you the best of both worlds.
Initialy I wanted an IRS system, but after seeing the performance of live and de-dion axled cars on both road and track I changed my mind.
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CaptainJosh
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| posted on 13/7/06 at 02:37 PM |
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After reading through the forums it seems that kind of arguement routes down to opinion - so I don't really want to spark anything off. But
whatever works for you is fine.
Does anyone know the weight of the ford seirra diff?
[Edited on 13/7/06 by CaptainJosh]
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Bob C
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| posted on 13/7/06 at 03:19 PM |
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18.5kgs springs to mind.
I wouldn't trust this figure unless no others are forthcoming.......
Bob
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JoelP
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| posted on 13/7/06 at 05:24 PM |
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closer to 20kgs i thought, but thats the ballpark. 
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procomp
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| posted on 14/7/06 at 07:44 AM |
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Hi the lightest irs setup using a sierra diff is 32 kg heavier than a live axle setup usng the ford english axle. Plus no relevent antisquat with the
irs.
cheers matt
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coozer
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| posted on 14/7/06 at 03:09 PM |
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Just had my diff that was lying on the floor on the scales. 20Kg with NO oil in it.
Thinking back I remember the Escort diff in the live axle being heavy as well. The advantage of the Sierra set up is the diff being attached to the
chassis = less sprung weight.
Canber can surely be dialed out with the correct length wishbones and the right amount of, if a bit stiff, spring rate??
Steve
1972 V8 Jago
1980 Z750
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