Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Urgent warning Empire kit

Empire risers removed and the original track rod ends reinstated, as promised. I am once again the proud owner of a car with downward-slanting steering arms, but this time with a properly sized top wishbone that as we know, puts its pivot point in the same plain as that in the rack. So will I have regained some of that sharpness to turn-in? Maybe, but as I've not run this combo before, I am quite excited to find out.... which will have to wait till Friday when I can hopefully get to the tyre bay up the road for the tracking to be checked.

No outward signs of any corrosion nor fatigue marks on the removed Empire risers, so suspect I would have been OK to leave them on regardless.

I am not sure that is going to do much for the bump steer. I think the arc described by the outboard steering joint as the upright/stub axle carrier rises in bump is not going to be same as the arc described by the steering arm, as it rises in bump. You need to have the steering arm at close to the same static angle as the top wishbone. To get it perfect it needs to be parallel to and of the same radius as the theoretical middle wishbone. As the wheel rises in bump, the top of the upright is going to move inwards. Whereas the end of your steering arm is going to move outwards. It is very difficult to totally eliminate bump steer unless you have parallel wishbones, like you see on most single seat cars.

The easiest way to visualise this is to cut out bits of cardboard the length of the wishbones, upright/stub axle carrier and steering arm, tack them to a large sheet of plywood, using brass two tail press through fasteners to represent the joints. You can them move the upright up and down to see the effects of bump steer. Before CAD, this is how suspension used to be designed. I doubt Morgan used anything as sophisticated as this :-)

You are of course right, it won't help at all and before removing the Empire risers and rose-joints, the steering arms were indeed parallel, as expected.

However, in the old bump-steer days, as well as having tendency to jump a full 6ft across the road following a big pothole or compression on one side, then cars used to turn-in really sharply, making the steering feel almost Caterham-like in its responses. For whatever reason, the simple act of lifting the steering arm (a la MMC Comfort Kit) changed this completely and made that initial turn-in MUCH more gentle, to the point of giving the impression of increased understeer.

Of course the Empire kit removes the geometric incorrectness that caused the bumpsteer in the first place, but also removed that sharp turn-in, in the same way as the Comfort Kit did for non-Empire owners.

So my (perhaps optimistic) hope here is that my 'hybrid' solution that corrects wishbone geometry (via Empire) yet reintroduces droopy steering arms (MMC pre-Comfort rack rod ends), might turn out to be rather good mix of the two! Maybe....

I also am in two minds. I much prefer the almost single seater feel of the Mk1 steering but the Mk.2 which has similar geometry to that resulting from the comfort kit, is definitely lazy feeling in comparison. My thinking was to go for the comfort kit but Blockley tyres to sharpen it up again. My original Avons are near end of life anyway, as my house is at the top of a 6km road with around 15 hairpin bends on it and lots of other bends as well. Heavy on front tyres. It is nice to be wearing out cheap 4.50 x 19's rather than 235/35 x 19's on the front of my other car.

Tyre prices have come down amazingly over the last few years. I have just bought a new pair of rears for my normal car, which are 305/30 x 19. When I first got it in 2007, the rears were £350 each. They are now down to £190 each.

Wilson

What the heck are you driving that takes 305's in the rear?
I have 275's, and that is considered very wide...

A 911?

I'm no suspension engineer, but thinking about the original geometry it looks to me like body roll in a corner will cause the outer wheel to toe-in a bit and the inner wheel to toe-out a bit, hence increasing the effective steering angle and producing the feeling of improved turn-in.

That is on my 997 Turbo S with engine upgrade. My older 1977 rally 3.3L 911 RSR now has to fit either Michelin TB15 23/62 x 15" or Pirelli P Zero Corsa Classico 285/40 x 15" on the back, as nobody now makes ordinary road tires in the correct 275/45 x 15" size. These road legal race tyres arrive with only around 4.5mm of tread on them (pre-worn). I did the Scottish Malts trial last year and even though we trailered up and down, we still wore a set of the Michelins out in 5 days/1200 miles.

That sounds undeniably feasible and might explain the significant difference in the feel between original 'non-Comfort' and the revised setup. But, I have news from taking my 'Hybrid' setup to the tyre shop to get the tracking set back to parallel.....

Wow - WHAT a difference! I can authoritatively announce a return to that Caterham-esque feel to turn-in and quickness of the initial change of direction. Perhaps it is indeed down to the effect on steering angle due to roll, but it sure feels like it used to before I fitted the Empire Risers with the rest of the kit.

Maybe just a little of the bumpsteer has returned, but this time it's just to make the wheel feel a little lively to the hand, instead of being a complete liability to both car and passengers. I came back over my usual bumpy, undulating test route and all that fizz and excitement that I felt originally in the steering response is back, but without the life-threatening bumpsteer I had before.

So to recap - I have Empire Top Wishbones and once again the original MMC track rod ends that point downhill once more. I am unable to lower the suspension any further as my shocks hit the headers over bigger bumps.

So if you have Empire and are worried about the resilience of the kit risers, try what I've done and see what you think. It takes 15 mins to change them and a simple £10 trip to the geometry chap.

One VERY happy camper

I might give that a go in the new year.

Hi Laurens,


Have you heard anything back from Paul re replacement of risers from Empire?
Rgds

JJ


This question I got from Nadvys a few days ago and need to all let you know that I didn't hear anything from Empire.
Due to this lack of responsibility by Empire I have replaced my risers with the Comfort Kit upgrade.
I don't want to take the risk to get a broken riser with all serious consequences.