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Coilover Conversion Top Hat - Help.

Posted: Wed Oct 27, 2010 10:09 pm
by oldroydsr4
Hi All,

I've ordered all of the coilover conversion parts from rally design. The coversion is about finished and all the welding is complete, however I have a question regarding the top hat.


Adjustable Spring Top cap (Pilot hole, 10mm)
Image

As indicated it comes with a 10mm pilot hole, do I machine it to fit on the upper part of the damper where the top mount sits (14mm) or do I bore it to 22mm+ for the damper shaft where it can move with the spring?

Re: Coilover Conversion Top Hat - Help.

Posted: Wed Oct 27, 2010 11:05 pm
by BadDave
Dave
It fits on the upper part of the damper, so 14mm hole required.

You may require non standard topmounts though,as the top hat is usually thicker that a std upper spring platform.


HTH

Re: Coilover Conversion Top Hat - Help.

Posted: Wed Oct 27, 2010 11:38 pm
by thebigfella
22mm you do not want it to govern you top mount just locate the spring

Re: Coilover Conversion Top Hat - Help.

Posted: Thu Oct 28, 2010 8:33 am
by Brian28
Interesting question, never gave it any thought before and always drilled them out at 14mm so they are in a static position at the top of the strut assuming that's how they were supposed to be. Will have a look at factory (ie non DIY) coilovers at the weekend and see how they are set up.

Re: Coilover Conversion Top Hat - Help.

Posted: Thu Oct 28, 2010 8:55 am
by oldroydsr4
Morning guys,

I've got adjustible topmounts so shouldn't be a big issue.

2 options and 2 answer, which one is it?

I bored it out to 14mm but don't want to take it to 22mm until I'm sure which is correct.

Re: Coilover Conversion Top Hat - Help.

Posted: Thu Oct 28, 2010 9:50 am
by rob0r
I've done it both ways. I did it to accomodate the shock diameter as the top hat was too thick and I couldn't get a nut on the thread, this was an E28 rear shock. I'm not sure if it's related but I'm getting very crashy noises and knocking from movement between the top mount and hat (it's not knackered top mounts). I was going to fab some thinner top hats and mount them the conventional way.

I would do it to 14mm unless you had too.

Re: Coilover Conversion Top Hat - Help.

Posted: Thu Oct 28, 2010 11:17 am
by Raj_p
I think it would be 14mm to sit where the top mount is. It woukd need to be static, but doing it tgat way, can you get the nut on?

Re: Coilover Conversion Top Hat - Help.

Posted: Thu Oct 28, 2010 12:23 pm
by oldroydsr4
I should be able to, i have adjustible top mounts so they are not as thick, also If necessary I can counter bore the top hat so it fits.

Re: Coilover Conversion Top Hat - Help.

Posted: Thu Oct 28, 2010 9:29 pm
by speedsnake74
Pics when it's done if you can please......
I had my RD tubes delivered today... What height do you weld them on at ?

Re: Coilover Conversion Top Hat - Help.

Posted: Thu Oct 28, 2010 9:32 pm
by Rav335uk
As above and also springs being used too.
Faulkners???

Re: Coilover Conversion Top Hat - Help.

Posted: Thu Oct 28, 2010 9:35 pm
by BadDave
Rav335uk wrote:As above and also springs being used too.
Faulkners???
Faulkners or if your feeling flush, you could opt for Eibach's

Re: Coilover Conversion Top Hat - Help.

Posted: Thu Oct 28, 2010 9:46 pm
by Rav335uk
Dave, what rating should the srings be??? 500lb's front and 450lbs rear??

Re: Coilover Conversion Top Hat - Help.

Posted: Thu Oct 28, 2010 9:55 pm
by BadDave
Personall preferance Rav.
Testing is the only way to find YOUR ideal setup

With the M20 I use 6" 550lb fronts with helpers and 10 1/2" 275lb on the rear with some preload.
With a 4 pot, I found 350lb fronts too soft and went up to 450lb.
Rears are coilovers, so I can get away with softer springs.

Re: Coilover Conversion Top Hat - Help.

Posted: Thu Oct 28, 2010 9:59 pm
by mattyb
they done it in this month ppc and the drilled out to 20mm :?

Re: Coilover Conversion Top Hat - Help.

Posted: Thu Oct 28, 2010 10:01 pm
by Rav335uk
I've had my RD coilover pack for about 18mths, still in boxes :mad: , think it's about time to start on something now. :D

Re: Coilover Conversion Top Hat - Help.

Posted: Thu Oct 28, 2010 11:09 pm
by gareth
Rav, I'm running 500lb front and 450lb rear iirc. My touring is extra lardy in the boot because of the LPG tank though. I suspect spring rates like that would not work as well on yours as it's all wibbly wobbly! :P

Re: Coilover Conversion Top Hat - Help.

Posted: Fri Oct 29, 2010 7:37 am
by oldroydsr4
Hi rav,
as bad dave said testing is really required but as my car is for road only I didn't want too hard suspension.

I went for 375 Ib x6inch front springs

and

575Ib x5.5 rear springs ,

The fronts may be a little soft but I can always change them.

I welded the treaded collar so it was resting on the abs sensor bracket.

Remember you also need front bumpstops.

I'll post pics when I'm done.

Re: Coilover Conversion Top Hat - Help.

Posted: Fri Oct 29, 2010 9:17 am
by Rav335uk
oldroydsr4 wrote:Hi rav,
as bad dave said testing is really required but as my car is for road only I didn't want too hard suspension.

I went for 375 Ib x6inch front springs

and

575Ib x5.5 rear springs ,

The fronts may be a little soft but I can always change them.

I welded the treaded collar so it was resting on the abs sensor bracket.

Remember you also need front bumpstops.

I'll post pics when I'm done.
Cheers for that.

@Ginge, it ani't that "Wobbly" :mad:

Re: Coilover Conversion Top Hat - Help.

Posted: Sat Oct 30, 2010 10:48 am
by gareth
Put 500lb springs on it and you'll feel how stiff the shell really is...

Re: Coilover Conversion Top Hat - Help.

Posted: Sat Oct 30, 2010 11:27 am
by Rav335uk
Turning the GAZ SHOCKS onto the 3/4 mark is quite stiff enough on the cab Gareth.

Re: Coilover Conversion Top Hat - Help.

Posted: Sat Oct 30, 2010 11:29 am
by gareth
With my coilovers set to around halfway, i can feel the shell flexing in relation to the doors 8O

Re: Coilover Conversion Top Hat - Help.

Posted: Sat Oct 30, 2010 11:57 am
by Rav335uk
That is one of the main reasons I haven't done anything with my kit, i think Gaz adjustable shocks and Eiback springs are enough