RV8 suspension damper adjustment

Peter Tothill (Woodcote Green 1636) from Oxfordshire has been working on his front suspension set up for some time and has produced a useful note with his views on settings for the shock absorbers. (Jul 04)

My low mileage Japanese specification RV8 appeared to me be under-damped particularly at the front, leaving the ride and handling something of a disappointment; indeed the Autocar road test in 1993 indicated "it's handling leaves rather a lot to be desired". Some owners may not be aware that the Koni dampers are adjustable as there is no visible external sign that they are adjustable and the Factory workshop manual only mentions adjustment after 48,000 miles! The good news is they are adjustable but the bad news is that, unlike Spax shock absorbers, you have to remove these Konis to make adjustments. This makes trial and error setting tedious in the extreme.
Front suspension set up - item 11 is the Koni damper. (Source: RV8 Repair Manual)

During the development of any car, much effort is put into spring and damper tuning to get the ride and handling right for UK driving conditions. For example Ford spends vast sums on every new model and came up with a different set up for the UK as opposed to Germany where the car was designed. The fact that the design engineers specified adjustable dampers on the RV8 may have been a farsighted decision to allow owners to adjust them to suit. However it is surprising that the subject is not covered adequately in the workshop manual and that the cars left the factory on the minimum damper settings. Wishful thinking or did they just not have the development budget to cover it?

For owners with a copy of the factory workshop manual (RV8 Repair Manual AKM7153) the relevant sections are:

Removal & refitting front dampers
Service Repair Ref: 60.30.02

Removal & refitting rear dampers
Service Repair Ref: 64.30.02

Adjustment is described in Maintenance Section pages 15, 16 & 17. For owners without the manual the relevant procedures are reproduced below. Copies of the RV8 Repair Manual AKM7153 are available from Ames and Brown & Gammons on an RV8 Technical Information CD, or as a printed manual from Clive Wheatley.

My trial and error adjustment and tests have reached the following conclusions for RV8 shock absorber settings for a Japan spec RV8, assuming the dampers are in good condition and have been on the car for less than 48,000 miles:
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Front: 1.75 turns clockwise from the minimum setting.
Rear: 0.75 turns clockwise from the minimum setting.

These settings provide a firm, well controlled ride that one would expect in a roadster on English roads. Some points to note when setting your dampers:

General. Do measure the turns accurately when adjusting the damper settings.

Front damper. The wooden blocks to support the front suspension upper arms can be made from 6in x 3in x 3in softwood and must be inserted before jacking up the car,; put the steering on full lock and then insert the block from the rear. Do not forget to remove the blocks at the end of the process! Although the procedure for refitting the front dampers described in the workshop manual is accurate, the 1.75 turns setting makes it difficult to extend the damper in situ. Extend it fully off the car, insert the damper into the crossmember and secure the stem in situ using a large o/d washer under one of the locknuts as a temporary measure. Secure the damper to the spring pan as described in the manual; grip the flats at the end of the stem with molegrips and extend the damper so that the top mounting can be fitted, discarding the temporary washer.
Wooden block is item 1 in the diagram above. (Source: RV8 Repair Manual)

Rear damper. There is no need to remove the upper mounting from the righthand rear damper. The rear dampers act as a rebound check so on refitting you need to put a jack under the spring to allow the bolts to engage in the holes in the upper mounting.

Rear shock absorber set up. (Source: RV8 Repair Manual)

John Barnes in New Zealand commented "Peter Tothill's findings on Konis shocks are interesting and are generally in line with my earlier note (RV8NOTE174). I think it is important that all owners of Japan spec RV8s should have the shock absorbers checked and adjusted as I suspect that most are probably not doing much damping. Whatever adjustment is made, the rear should be softer than the front. I would recommend that the settings suggested by Peter are good starting point. They could also consider lowering the rear end as described in my earlier note (RV8NOTE194)".

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