Talk Morgan Forums Morgan Sports Cars Morgan Photo Gallery Tweaking Henry's rear end (5 link Suplex)

OK, as I reported previously having driven Henry's car for 90 miles I found it a bit harsh on the rear, not quite what I expected, although it did handle and corner very well. So I looked at the Quantum shock absorber settings this morning. The coil over springs are set to what looks about half way, I could not adjust these as I do not have the right tool, the top shock adjustment was set to 11 out of 24 (being hardest). So pushed up and down on the rear and as I expected it was very firm with a lot of resistance. I took the top shock adjustment back down to position 6 making the shocks softer, and bounced the rear, still reasonable resistance but easier to get it to move up and down.

So out I went in the car and took to some well known roads and open lanes where I live, a mix of fast A road sweeping bends, bumpy lane with bends that can be taken at 60 if clear and feeling brave. Conditions were not great due to mist and slightly damp roads.

So I am pleased to say the change was obvious, more compliant rear and a pretty comfortable ride, still no under or oversteer. In fact very responsive steering not dissimilar to the feel from my old MR2 hit climb car. I think once confidence grew you could really be quite adventurous with it. On the bumpy parts the rear soaked them up and did not feel the usual transfer of the bumps to the chassis upsetting stability. So a good result.

One think I still do not like is the way the front Suplex reacts on turn in to corner when driving hard. Initially there is what can only be described as an immediate lean in on the outside wheel, this does not in any way seem to unbalance the car and it continues to go round the corner as you would expect. Maybe this trait can be dialled out to an extent but suspect it may be that the front Suplex may have been set up more for comfort, and maybe sightly higher lbs springs would improve this, but I am sure PJB can give light to this.

I did do some wibbly wobbly steering when no one was around to see if the car remained balanced when provoked and it just turned when the wheel moved with no dramas. So very stable, some might be surprised how reactive it is compared to a standard setup.

So to sum up.

1. Is it an improvement?
Yes
2. Does it give an improved ride?
After I tweaked the shockers yes, with minimal change, I suspect that most types of handing requirements could be catered for by dialing in the right settings i.e. from general touring to track day use. How it is set nows gives a very comfortable ride, slightly sporty feel.
3. Is handling improved?
Yes, better turn in, very responsive to steering adjustment during turns and no dramas
4.Would I buy it?
Well this is the big question. If I had the dosh, and I was not considering joining Speedmog in the near future, then probably yes. I would be likely to wait for leaf spring replacement, and shock absorbers, unless money did not matter.

So there you have it, I think the Suplex 5 link is a success, it delivers what it is supposed to a controlled rear axle which helps the Morgan handling and steering. It is probably a big investment for most but probably worth it if you use you Morgan regular. If you are an occasional user (get the Morgan out a couple of times a month and do a few long drives resulting in a couple of thousand miles a year) then I would question the value add against cost. It depends on the depth of your pockets and what you want at the end of the day.

I have no relationship with Suplex, or Quantum so my views expressed hear are independent and as honest as I can be.

By the way Henry's car is a really fun drive, with the induction kit and exhaust system it zipped along, great fun, and pulls up really well with the Williams 4 Pots on it. It would be a great car to buy if it goes on the market. (this setup might suit you Jays, colour to match the Porka )

Personally I think comparing a rigid Ali chassis tube with a flexi ladder chassis with quite different characteristics and suspension design is a waste of time. They will by definition have different traits good or bad.

With respect to the missing inner wings I suspect these have been removed to fit the frame and assembly and have been left out for now until all has been checked out and ok, then will be refitted to finish off the job. Makes sense to me anyway.

Me too

What missing woodwork?

I agree, looks like the standard cutout for axle access to me.

Pretty much as I suspected Adrian. I can well imagine that Chunky and Henry, being used to the setup on the race car, had set the dampers for a more solid ride.

The cross frame actually has a join in the middle to aid fitting.

Regarding the front end: I have never had the pleasure of driving a well setup competition car sor I have no basis for comparison. I have tried very hard to feel the soft initial turn in that some people have mentioned but I really can not distinguish it. I wonder if the toe-in and camber on my car are such that this sensation is all but eliminated.

Hi Peter, an interesting thought of yours, how much camber is yours set up with? I would have expected 1/16" total toe in?

That is my one criticism of the Suplex front kit, I spent ages getting the front rebound springs to just turn but not be under load. Wheels off , adjust until just free , wheels on , torque up correctly, road test, inspect; only to find that it had changed. All through the same procedure again, and again , until I finally gave up and just accepted that my rebound springs are not quite free, but not under much tension, as they seem to be able to stay constant at this setting. Even now I occasionally look at the front from the ground and see one rebound spring totally free , and the other in contact , but after the next drive it reverts again. I wonder if we just have too much friction in the pins and bushes to be able to hold a constant setting. Has yours changed since the original set up work David?

You are probably correct that it does make a difference , because when I drove Peter's (PJB) 4/4 , the improved ride and lack of roll was immediately apparent. On my +8 , the ride improved, but perhaps not by as much as I would have expected after driving the test 4/4. I am sure his settings were pretty much spot on.

Just for clarification whilst fitting the kit I went for new hard chrome king pins and grooved p/b bushes and these were precisely set up by Colin (Spanner Juggler) so I know they are as perfect as anything can be on a Mog.

I have two possible explanations, firstly the main springs take time to bed in and settle down and also the king pins will take at least several thousand mile to settle down, it is even worse with the standard ones. As you suggest if there is any binding for whatever reason, newness, lack of grease and so on then you can set it up perfect and then a few hundred miles later it can go out, and one side may remain ok and the other go out and visa versa.

You might want to try Lucas Red N Tacky grease, I switch to it recently and am convinced that it gives better lubrucation to the king pin and seems to remain so for longer. I still top up the bottom every 500 miles and do both nipples every 1K.
This might give you a more consistent set up.

So I drove the Blue Meany of Henry's back to Williams today, I took the twisty windy route and have to say that my last report holds up. Good road holding, turn in and pretty comfortable. Still not sure about the front Suplex, but I suspect it may need twerking as was fitted quite a few thousand miles ago.

Anyway I drove my Roadster home on the same roads so was able to immediately get a direct comparison.

Basically the only way I can describe it is that in Henry's car on the rough roads it feels less bobbly (if that makes sense). My car corners pretty much the same, but can bobble about if the road is bumpy during a bend (I mean pretty bumpy). That is not to say you don't feel the big bumps with the 5 link, they are still there but it has less impact on the chassis, so ultimately it improves ride and must improve road holding. I suspect that if I was brave enough to push Henry's car through a known bend which was bumpy until it broke away and then attempted the same in the another Plus 4 2l Duratec with standard suspension on the rear that it would not do it and would break away at a lower speed.

Maybe someone should try it and see.

So in conclusion the 5 link is an improvement, is it worth it, probably if you drive your Morgan a lot and like going fast round corners, and can afford it.