Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Suspension upgrade

Most things work better if they are fitted properly. What, specifically, is critical when fitting the suplex conversion?

I'm not that fast!
Guess I'd better go and have a long chat with Richard Wragg just down the road at Omex

Brake reaction bars I've had on all three of my Morgans, not that I brake hard very often, but they do steady the front end up a little. The rear springs on RTA were a little soft - used to get a fair bit of sideways step, but never enough to bother me. 'Q' is much taughter at the rear and I don't, yet, feel the need for panhard rod, or anti-tramp bar...

I have the Suplex kit, hard chrome king pins and brake reaction bars. This makes a Morgan front suspension as good as it can be and eliminates any need for power steering. I also drive my wife's 2011 Mercedes AMG E350 CDI Coupe and at low and high speed the Morgan steering is no heavier than the powered Merc set up. But there is a load more feel and feedback, but no kickback. It is tyre pressure sensitive, I run my Roadster at 22 psi.

If I understood the lecture correctly the pre-loading of the upper springs has to be set individually for each car,so that the rebound springs are just free to turn under the lower bushes when the car is sitting on the ground. The rebound springs only function under re-bound, normally the upper 2 springs do all the work. Yes, there are 2 upper springs mounted concentrically to give the required amount of progressive action without the risk of coil lock.

Different engines and cars have different weights and so it isn't the same for every car. It takes 20 min or so to do and this need to set up the car is the main reason Morgan doesn't use the setup.

Done correctly as well as the published advantages this make the steering light to turn as the bush at the bottom of the stub axle doesn't drag on the top of the spring. Getting it right is a knack. As Williams fit a lot of these kits they know what is right.

I'm waiting to see what Suplex come up with for the rear: one option mentioned may be a single piece glass fiber spring!

The Suplex kit can be adjusted with the C spanners that are provided with the kit. You can set the ride height to suit your car with these. It is all explained in the booklet that comes with the kit.

I read this conversation the other day you might find it interesting.



So what were the criteria for the SUPLEX RS, well here are some words:- To significantly improve ride, increase roll stiffness at the limit and have no detrimental effect on handling for average/experienced drivers for normal to fast road driving. It was not set up for race or such like competition work although a race set up has been proven this year in the UK by setting Morgan class lap records, with new spring and damper rates.



As we all now know Morgans were and still are set up with a very stiff initial spring rate that then goes soft in bump and at high lateral acceleration (high speed and/or tight corners). This suits some drivers who want a very rapid instant response to steering inputs, maybe more suited to the race track/competition but also favoured by experienced 'hard' drivers who want that, even if it detracts from good ride. (Both handling and ride are significantly subjective, although they can be measured but we will not go there today). Our pal Colin is a case in point. Although his driving style is not unique it is quite rare, shows a lot of skill/experience; it is very precise and very much demands rapid response to steering inputs. The SUPLEX RS is not aimed at him as he needs what the std set up gives - fine! He might well like the SUPLEX 'race' setup...........?



Now we all know the compressed rebound spring gives the high initial spring rate which is also why the standard Morgan system will then crash though that and 'bang' over potholes and little steps, tough, that's what it does, that's also what Colin's car does. Its normal.



So over a few years I worked with SUPLEX UK Ltd to develop a rising spring rate in bump and a rising spring rate in rebound. This we did over many 1,000's of miles on various cars. We needed a good ride yet a significant rising spring rate to minimise full bump crashes and to give high increasing roll stiffness once the initial soft bump travel is gone. (Yes the roll stiffness increases the harder one corners, rather than reduces as standard)



My driving style and many others is a quite smooth technique with few rapid steering inputs, to maintain high speed but also to achieve comfort. So to maintain say 60 to 90 mph on typically British winding 'A' roads that can have broken tarmac patches and bumps/potholes.



So we then set up some highly gas pressurised Bilstein monotube dampers to match the springs. We worked with an ex 'Touring Car' race driver to set initial rates for "oh my god we won't make that corner" type of driving. But the ride was hard. So we reduced the low speed bump and rebound damping to give good ride without dramatic loss in handling from his set-up, OK the rapid turn-in was a little reduced but the ride was now very good.



Adjustable dampers were not supplied as they can easily be maladjusted in bump to destroy the benefits of the spring design and are mostly (not all) very low tech, unlike the very sophisticated Bilsteins.



When I drove Colin at up to around 70 mph on an undulating 'B' road I had not driven before (except once in Colin's lovely +4 and once in mine at sensible speeds), the SUPLEX RS front end performed well absorbing the undulations, potholes and bumps. Now without being judgemental, Colin is significantly heavier and taller than average and certainly more than my 'other half' and my typical passengers; the rear dampers (GAZ adjustables) were set too soft for this test as they were set for my typical use, so I accept that they did not cope well with our combined mass. Compare his assessment with that from another mutual friend Andy Garlick with the same settings, but Andy is a lot lighter than Colin but also has lots of experience driving Morgans and performance cars.



I quote here what Andy experienced (slightly edited by removing nonvital stuff): "Peter Ballard's 2.0 Zetec engined 4/4. Within a few hundred yards/metres it is obvious that the car rides so much better over potholes and surface changes that it is almost uncanny. After a bit more time , the lack of roll becomes evident, and that makes the corners feel easier, it almost corners like it was on rails. The rear end just seems to float over the rough stuff as well and the whole effect is to make the car very comfortable in ride, a big improvement on my +8 that is for sure. However the big plus for me was the confidence it inspires to tackle corners quickly even when the approach is rough or pot-holed. After lunch Peter drove it back with me as passenger and we were keeping up some pretty high speeds over Wiltshire lanes. On one crest on a left hand bend, the car went light over the top, and then a transverse rut appeared , the car just touched back down on the tarmac, squirmed a fraction , but settled immediately and I am sure that Peter didn't even lift from the throttle. Pretty impressive. ".



Colin did comment that we had achieved something that is just one of the aims of ride work, that is the ability or tendency of a car to seem to 'float' so that the tyres are following the road surface with the springs and dampers doing what they are supposed to do to tend towards, but not completely, isolating the car from the road, but without losing essential 'feel'. Some drivers at Williams Morgan also found this and liked it. BUT knowing (I think) some of Colin's driving style he would find this quite disconcerting as he would prefer to be in firm hard contact with the road surface at all times, whereas many others like the suspension to be quite compliant, like other small/sports cars out there.



So there you are Button, that's some background. If you want to maintain quite high speeds say up to say 100 mph on normal bumpy/undulating winding roads to feed into corners smoothly then that is what the SUPLEX RS is aimed at. If you want a quite hard ride, rapid turn in with very little initial roll then run with a compressed rebound spring with the standard set up and buy double adjustable dampers and twiddle the knobs to suit.



Most of the initial concerns of a very few owners with the SUPLEX RS have been due to wornout/damaged pins/bushes (eg yours Button), poorly adjusted main spring seat (Hub must be kissing the rebound spring) or poorly set rear dampers.



SUPLEX have had great feedback from their customers and reports back from UK dealers relating to their own assessment on cars from the '4/4 Sport' up to the '3.7 Roadster' , including John MacDonald (Beamish - used to race), Mike and Ben Duncan, Rob Wells (used to race), Terry Foxen GEE - used to race), Melvyn Rutter, Williams Autmobiles, and others.



But as Colin quite rightly says, it is not for everyone, like the standard system is not for everyone either. Cheers Peter.


Jim.

Jim,

Your report describes my impression to perfection. I've now completed about 1000 miles with the Suplex kit installed.

I should point out that my Morgan experience is limited. We road tested the Roadster: very heavy steering and all the usual Morgan suspension foibles. Prior to that we had driven a 4/4 and a +4 together in total about 700 miles.
I really didn't like the 4/4 suspension, it crashed and banged into every pothole and ridge between Aldermarston, Salisbury and Dorchester. The +4 seemed a bit better but it was only over about 50 miles and the Roadster was much like the +4.

It was the crew at Williams who convinced me that the Suplex kit would be a big, bug improvement: I took it on trust as they didn't have a Suplex fitted car to road test.

Jim's article makes one important point:

Most of the initial concerns of a very few owners with the SUPLEX RS have been due to wornout/damaged pins/bushes (eg yours Button), poorly adjusted main spring seat (Hub must be kissing the rebound spring) or poorly set rear

It is the main spring seat adjustment that is critical, get it wrong and most of the advantages seem to dissapear. Which is why I advise a professional fit. It is also why it is worth fitting new king pins, preferably hard chrome. Again reaming the bushes to fit the pins is a skilled job.

Last, although Suplex don't mention the brake reaction struts linking the top of the shock to the chassis rail they make a signigicant difference once the Suplex kit has been fitted. For the modest price well worth adding to the job. I had them fitted about 6 weks adter the Suplex kit: the difference is noticable especially when applying the brakes on a rough or broken surfact as you steer.

Jim's 'article' is actually a post by Peter Ballard (yes, you met him at the Williams open day) in response to comments by one of our American Mogtalk (and NBC) posters, one Bill Button - a well known Morganeer

As Peter says, it's important the rest of the suspension is working correctly before converting to a Suplex kit...

My enthusiasm for the system as fitted to our Plus 4 is well noted in other threads on the same topic.

Other than the correct adjustment of the system it is also important to get the existing rear supension working as well as possible as, when the front is sorted out, you really notice any faults at the rear. I have the adjustable GAZ dampers on the rear (same a mentioned by Peter Ballard) and during our recent trip, when heavily loaded, I realised that I need to increase the damping to compensate.

I say go for it. Not only will you enjoy the improved handling, but you back, and your co-pilot, will thank you.

I also have the Gaz adjustables on the rear and ran with them turned down to zero for a while this seemed to work quite well at first. A bit to soft for me so decided to adjust them up a step at a time and finally settled on setting no 6.

Jim

Also waiting to see what Dan at Suplex comes up with for the rear suspension.

Hi ,once again thanks for the info ,it is a fantastic help.
Geordie

Some great comments for me as one who has not yet seen a Suplex Kit 'in the flesh' as it were. Thanks for sharing.

Out of interest, Will any of you be fitting both Upper & Lower 'Gaiters' to keep your new Springs in pristine 'Grit Free' condition from 'New'?





Frank