The Triumph Dolomite Club - Discussion Forum
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Racing suspension
http://forum.triumphdolomite.co.uk/viewtopic.php?f=3&t=35418
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Author:  DollyMolly [ Tue Nov 19, 2019 11:29 am ]
Post subject:  Racing suspension

Hi all,

I’m new on here but currently have a sprint doing a bit of circuit racing. I thought it about time I popped into say hello and, well, no time like the present given the current problem I have.

The problem - The suspension is woeful. I’ve no idea what it is as it was on the car when I bought it. It is, however, well past it’s sell buy date - basically, it’s uneven at the back.... it’s good going left... :lol:

Anyhow, I’m looking for any ideas as to where to go next with a wholesale replacement.

The car had been, err, “troublesome” so I’d love something proven to work.

I’ve had a couple of ideas sent my way - as with everything, there is a budget which may end up dictating what to buy but any ideas would be very gratefully received. TIA. :bluewave:

Author:  gmsclassics [ Sat Nov 23, 2019 10:58 am ]
Post subject:  Re: Racing suspension

Based on what I was using over the 17 years I raced the maple sprint in the avatar:

Springs: 200/225lb variable rate on the rear, I started with 350lb on the front but changed to 500lb when I only trailered it to events.

Shocks: I used professionally re-valved Bilseins that lasted over 400 races.

Anti-roll bars: Remove the rear and have a thicker one (approx. double cross sectional area) on the front. I used the mounting position on the subframe and then adjustable links to the outer part of the upper suspension link.

Lowered only 25-28mm all round.

LSD is a must, otherwise the inside rear spins exiting corners and you lose time (and places). 4.11:1 diff head (ex 2000 manual saloon) so you can use max revs in 4th on the fastest straight.

Front suspension set up: Toe as straight as possible, no toe in. Caster 4-4.5ᵒ, camber – 3.2ᵒ (helps turn into corners but loses the self straightening on the road making the car feel twitchy). Adjustable front tie bars essential to achieve this.

Better front brakes of course as well as pads. I did use race linings on rears too. Dual circuit brakes of course plus use something like Motul 660 brake fluid, highest boiling point you can find.

In a lot of places rubber bushes will be okay, but where you change to poly, such as tie rod ends, go for a harder compound.

Anything else, just ask.

Geoff

Author:  80Sprint [ Mon Nov 25, 2019 6:11 pm ]
Post subject:  Re: Racing suspension

When you get a chance Geoff. Could you post some pictures of the front ARB
Thanks

Author:  DollyMolly [ Mon Nov 25, 2019 8:33 pm ]
Post subject:  Re: Racing suspension

Geoff, thank you so much. That’s great and really helpful. I love your car collection too! :wave:

Author:  gmsclassics [ Thu Nov 28, 2019 6:18 am ]
Post subject:  Pics as requested for front ARB

First shot shows the overall installation - same both sides. Note the modified plate for the top mount and adjustable tie bar. Adjustment to the ARB is made using 3 holes in the end of the ARB and by adjusting the length of the adjustable connector. Must admit when I got it handing right, I just left alone. The final shot explains the construction and installation of the ARB to the subframe.
First shot also gives you an idea of the brakes, Willwood calipers, vented rotors (BMW E21 323) and Ferodo DS3000 pads (Nissan Skyline MC).
Important note - these are old photos - make sure brake hoses are braided, not standard as in these shots
Geoff

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Author:  new to this [ Thu Nov 28, 2019 3:05 pm ]
Post subject:  Re: Racing suspension

Geoff

Looks like you have a lot off adjustment on that set up,whats the brakes like with the wilwood calipers ?

Dave

Author:  gmsclassics [ Sat Nov 30, 2019 12:02 am ]
Post subject:  Re: Racing suspension

Very good indeed, but don't forget this setup is on a racecar that was difficult to drive on the road. Tyres were 195/60R14 Dunlop DZ03G Tarmac race tyres and even these would lock under heavy braking until after a warm up lap. Then the combination of brake and tyre was astonishing, a world away from standard Sprint tyre size, brakes and pads. See YouTube, search for Dolomite Sprint No 20.
Geoff

Author:  RichardHyde [ Sat Nov 30, 2019 8:38 am ]
Post subject:  Re: Racing suspension

Hi Geoff,
What car did your ARB come off or is it a custom job ?
Thanks, Richard

Author:  gmsclassics [ Sun Dec 01, 2019 8:57 am ]
Post subject:  Re: Racing suspension

Custom, but secondhand. I bought the remains of a crashed race car back in 2002.

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