Amazon: - Brake System Upgrade - Page 26

Burdekin · Oct 24th, 2013, 11:42

Sorry to be negative Derek with this being your build and I'm not wanting to be the baddy here but putting the spring inboard and offset like that seems like it is a downgrade from the original set-up. When I finally get round to working back on the P1800, attached is what I'm going to put in the rear.

Colonel Froth · Oct 24th, 2013, 12:19

I'm not sure how much the P1800 and 220 rear floors differ, those miata dampers look like they would require turrets in the estate boot. I think reversibility is a fairly key aim of this design so that wouldn't be an option, but as you mentioned the trade-off is a more inboard spring location.

Derek UK · Oct 24th, 2013, 12:19

Certainly can't fault your fabrication skills but would agree with Mitch about the design as it is now. Perhaps OK if you were into drag racing and were going to stuff a pair of 15 x 10's and slicks under there and needed the clearance. As is, if you hit a bump on one side, laws of levers will mean that the coil overs will have much reduced movement/control.
Off the wall but your cross tubes could be ideal as the basis for a torsion bar set-up but you would still want the shocks as far out on the axle as possible and as upright as possible too.

Quarterless · Oct 24th, 2013, 12:21

Quote:

Originally Posted by Khe Sanh

Sorry to be negative Derek with this being your build and I'm not wanting to be the baddy here but putting the spring inboard and offset like that seems like it is a downgrade from the original set-up. When I finally get round to working back on the P1800, attached is what I'm going to put in the rear.

This may be a toss up between wanting to fit larger wheels and tyres. You can't have everything so the springs etc need to go inboard. Only other option is a bell crank system but might be considered overkill.

Burdekin · Oct 24th, 2013, 12:57

Quote:

Originally Posted by Colonel Froth

I'm not sure how much the P1800 and 220 rear floors differ, those miata dampers look like they would require turrets in the estate boot. I think reversibility is a fairly key aim of this design so that wouldn't be an option, but as you mentioned the trade-off is a more inboard spring location.

Hats off to Derek for doing it and giving it a go. I know it annoys me when people are critical of stuff I do so wasn't sure whether it was a good idea to comment or not. I don't have any ideas of how you could do a good coil over conversion without any body mods though, so haven't got anything helpful to add for your build and it's a hard one to nut out that's for sure.

dheming · Oct 25th, 2013, 05:12

Thanks for all the feedback guys. As always these kind of things come down to tradeoffs. Ideally you want a coilover that's as long as possible. I don't want to do a huge amount of cutting on the frame or rear floor so mounting the coilovers in front of the axle is the only way to make that happen. On the stock estate rear setup the spring is located 5-1/8" (13.02cm) behind the center line of the rear axle and my proposed layout moves the new coilover to be 4" (10.16cm) in front of that center line. The biggest drawback to my current design is that it induces a torque motion due to the small lever that is formed by the lower coilover mount.

To eliminate that problem I've been considering building a variation of the stock lower arm for the coilover to mount to instead. I finally taught myself Google Sketchup this past weekend and I'm drawing up the axle, 4-link, coilovers, upper crossmember and wheel/tire. Once that's done I will post so screenshots to show what I'm thinking.

Bartezz · Oct 25th, 2013, 19:27

Quote:

Originally Posted by Khe Sanh

Sorry to be negative Derek with this being your build and I'm not wanting to be the baddy here but putting the spring inboard and offset like that seems like it is a downgrade from the original set-up. When I finally get round to working back on the P1800, attached is what I'm going to put in the rear.

Trying to understand what you are saying. By inboard you mean in between the chassis beams? And by offset forward of the axle position making them sit diagonal.

What would you do if cutting up the chassis wasn't an option, just curious as I'm thinking of doing a coilover onversion too.

Cheers,
Bart

PS. people do all sorts of things

http://www.youtube.com/watch?v=vghvEoqZocY

Colonel Froth · Oct 25th, 2013, 20:24

Quote:

Originally Posted by Bartezz

By inboard you mean in between the chassis beams? And by offset forward of the axle position making them sit diagonal.

The springs have been moved from behind the axle to in front of it, and also towards the centre of the axle a little bit. The difference in damper placement between Derek's coilover position and the stock estate position looks pretty small.

Quote:

Originally Posted by Bartezz

PS. people do all sorts of things

http://www.youtube.com/watch?v=vghvEoqZocY

The problem with adjustable perches on smaller diameter springs like that is that as the suspension moves the perches tend to bind on the spring and it gets quite twangy.

Bartezz · Oct 25th, 2013, 21:17

Quote:

Originally Posted by Colonel Froth

The springs have been moved from behind the axle to in front of it

Don't they sit on top of the axle normally, not behind?

222s · Oct 25th, 2013, 21:19

That's the saloons. The estate rear suspension is completely different, and has the springs behind the axle.

Oct 25th, 2013, 05:12	#256
dheming Member Last Online: Jun 29th, 2022 04:38 Join Date: Mar 2009 Location: Corvallis, Oregon USA	Thanks for all the feedback guys. As always these kind of things come down to tradeoffs. Ideally you want a coilover that's as long as possible. I don't want to do a huge amount of cutting on the frame or rear floor so mounting the coilovers in front of the axle is the only way to make that happen. On the stock estate rear setup the spring is located 5-1/8" (13.02cm) behind the center line of the rear axle and my proposed layout moves the new coilover to be 4" (10.16cm) in front of that center line. The biggest drawback to my current design is that it induces a torque motion due to the small lever that is formed by the lower coilover mount. To eliminate that problem I've been considering building a variation of the stock lower arm for the coilover to mount to instead. I finally taught myself Google Sketchup this past weekend and I'm drawing up the axle, 4-link, coilovers, upper crossmember and wheel/tire. Once that's done I will post so screenshots to show what I'm thinking. __________________ "Why is it that there's never enough time to do it right, but there's always enough time to do it again?"

Oct 25th, 2013, 21:19	#260
222s Amazoniste Last Online: Sep 19th, 2016 21:52 Join Date: Nov 2002 Location: Emsworth View Photos By: 222s	That's the saloons. The estate rear suspension is completely different, and has the springs behind the axle. __________________ Paul - 1967 Amazon 222S B20 o/d Estate & 1961 A-H Sprite Mk2 948cc WANTED - For '67 Amazon estate - offside rear quarter, preferably new old stock.

Oct 24th, 2013, 12:19	#252
Colonel Froth Senior Member Last Online: Mar 3rd, 2022 14:20 Join Date: Oct 2009 Location: Edinburgh	I'm not sure how much the P1800 and 220 rear floors differ, those miata dampers look like they would require turrets in the estate boot. I think reversibility is a fairly key aim of this design so that wouldn't be an option, but as you mentioned the trade-off is a more inboard spring location.

Oct 24th, 2013, 12:19	#253
Derek UK VOC Member Last Online: Yesterday 21:35 Join Date: Jul 2006 Location: Chatham	Certainly can't fault your fabrication skills but would agree with Mitch about the design as it is now. Perhaps OK if you were into drag racing and were going to stuff a pair of 15 x 10's and slicks under there and needed the clearance. As is, if you hit a bump on one side, laws of levers will mean that the coil overs will have much reduced movement/control. Off the wall but your cross tubes could be ideal as the basis for a torsion bar set-up but you would still want the shocks as far out on the axle as possible and as upright as possible too.

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