Uprated torsion bars vs coil overs

[IslipMinor]

Front:

Marina van torsion bars (+25% stiffer approx), Koni's (+25% increased bump valving and full hard rebound setting), OB anti-roll bar (mounting is a solid welded and drilled/tapped pad either side, not the bolt-through as OB supplied), poly bushes throughout, reduced length bump stops (-1") and lowered about 2". All standard mounting points, except anti-roll bar.

Camber set to 0°/-0.5° at normal ride height and castor increased by approx 1°.

Rear:

7-leaf springs, with bottom leaf inverted and placed on the top of the remaining 6 - gives slightly softer rate and approx 2" lowering (been like it for nearly 40 years!), reshaped and reduced height bumpstops (-1"). Koni's (full soft setting), Ital rear anti-roll bar, anti-tramp bars and poly bushes everywhere. All standard mounting points except anti-roll and anti-tramp bars.

The result is a firm, well damped but not harsh ride. The front is still a little soft on rate, but has coped with the worst of Irish and mainland European roads for about 10,000 miles with no problems at all. Minimal roll, unless really provoked.

My intent during the rebuild 10 years ago was to 'develop' the suspension as much as possible using the technology that was available in the late 1960's (poly bushes excepted).

I would be very interested to try some sort of 'back-to-back' comparison with coilovers on a track, but how?

[jonathon]

We are often invited to participate in charity track days, but unfortunately my trav is not jet finished so cannot offer an immediate chance of a comparison. If its finished this summer I'll try to arrange for several minors to attend a trackday either at Snetterton,Oulton Park or Goodwood. Should be interesting !

[pauln]

Paul, are you keeping the torsion bars with the OB kit. If you do not then you will find that the car will sink onto the stops or worse the wheel.
We have been working with Koni to develop a new coil over unit with a bit more flexability and increased damping, to help bring down the spring rate. Were not far off now, just need to fit a new set onto a drone.

Don't know much yet i have'nt seen them (don't forget it's not my car anymore).I thought you HAD to keep the torsion bar with the ob kit. If the springs are 120lb the first thing we will do is try the 160s i bought for my Cortina (it's using 2.25 springs as well). We are having lots of fun with springs at the moment as my neighbour has 1.9 springed coil overs on his mini (another car in development)I'll keep you posted (about the Minor).

[jonathon]

You are correct ,you should keep the torsion bars with the OB kit as they are really only usefull as assisters. You will not be able to fit the 2.25 springs to the coil overs as the diameter is too large and will contact the top trunnion and possibly the actual king pin. You will find that you will need at least a 350lbs 1.9 id spring just to support the car. Don't attempt to drive the car on the coil overs without the torsion bars, there is not enough strength in the two bottom arms and tie bar plus the location points for this kit are inadequate for this application. Good luck with both projects.

[IslipMinor]

I'll try to arrange for several minors to attend a trackday

Would be very interested to take part if that's possible? Especially if it is at Goodwood, as that was popular haunt in the 60's!

[pauln]

Fitted (tempory fit found trunnion wear) the ob coil over kit today to my neighbours car. A bit of extra work was required such as making the holes in the brackets match the hole in the lever arm damper mounts. We will have to weld on the strengthening plate when we refit (the instructions suggest welding or riveting !!). Anyway all trial fitted 5 clicks of damping on the lowest spring position and away on a test drive. Despite the rotten look and feel of the kit it has made a great reduction in roll and stopped the suspension crashing into the stops. Still more fine tuning to do. We will now spend time getting the uprights back to top condition and sorting the strengthening panels. I personally would not use this kit having seen and fitted one but at least it does provide a reasonable result for the price charged.

[jonathon]

Yes, but you can do the same or better by just fitting a good damper kit, as the coil overs are doing nothing due to their low spring rating.

[pauln]

Prior to fitting this kit we removed a set of spax adjustables so as the coil overs were virtually a coil over version of the same damper and mounted on the same points we have a good comparison. I appreciate the fact that they are merely "Helper" springs and they seem to have done just that. I was too late to advise against buying this kit but we are stuck with it and the early test showed promise in terms of improved handling and suspension complience.