Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) ARP4 - First impressions.

Should not need to tune tyre pressures for ride quality. Set the tyre pressures for optimum contact patch, speed and stability in fast corners or rapid changes of direction. Then set spring rates and then damping rates for ride and handling. For good ride best to have a significant rising spring rate with a soft initial rate to take out the road surface degradations then stiffen up over bumps and with load. Then tune the dampers so the 'knee point' in bump is such that the low velocity bump damping still controls handling but the valves open to give ride comfort.
Q? So is the ARP4 suspension set up for track or road?
Regards PJB.

I was worried, as I tried but didn't buy the +4SS as it lacked torque/hp in the lower rpm's and the steering was too slow for my liking

now I'm glad you're not in doubt!!

The steering is really very impressive, at least with the electric power assistance. Well weighted, not at all heavy at parking speeds, and not too light when on the move, but the best thing is the way it turns in, like a rabbit down its' hole. Oh yes, and not a trace of bump steer, [early Three Wheeler owners will know what I'm talking about here],

I've just done a nice journey down to Plymouth and back, about 75 miles each way, mostly on dual carriageway, and even with the lower tyre pressures the bumps are ridden really badly. I've slackened the shock absorbers right off too. Shocks and tyre pressures are really just playing around the edges, as Peter says, there should be some sort of duel rate or progressive springing in place, shock absorbers and tyres aren't designed to affect the ride, they are merely supplementary to it. I am quite happy to put a thousand miles or so on before I start getting serious about doing anything about it though. Peter, I may be in touch!

I cruised most of the way at 3500 revs which is an indicated 80mph for those that want to know the gearing, 70 is 3000, which is convenient, given the lack of any appreciable power below that. I can't wait to start to open up a bit, I'm really looking forward to unlocking the potential in the upper rev. range. I was also impressed how easy it is to drive in heavy traffic, in Plymouth. No jerkiness or flat spots, and especially no rev. hang issue!

Talking about revs. reminds me that the rev. counter is inconveniently covered by the left hand in RHD cars. Given how important the rev. counter is going to be with this motor, which red lines at 8000rpm, I intend to buy a set of I-Shift change up lights which show a new light in 1000rpm increments, changing from green to orange at around 5000 and then to red at 7000 and 8000. It is entirely configurable though, so this can easily be changed. I had a set on my last Cosworth engined car, and they were invaluable at higher revs. when you really cannot take your eyes off the road, even for a split second to check the rev counter.

I'm loving the car more and more, and think we are going to get along very well indeed, whether my wife will take the same view, I will have to wait and see though. Noise and harsh ride being the two qualities she may object to, but for the time being she is away in Africa enjoying being close to wildlife, which is definitely not for me, after all what are zoos for?

I wonder if the shocks being too soft is the problem?

set them to the middle?

Maybe, I have had a couple of PMs with ideas too, for which many thanks, they are much appreciated. I will keep you all informed of progress, but other than that, there is just so much potential when I can start using a few more revs.

I don't think I have mentioned fuel economy yet? The readout is showing just over 22mpg, so maybe 'economy' is a bit of a misnomer? Once there are a few miles showing I will do a more accurate test though. I'm so pleased we are in a window of relatively cheap fuel at the moment.

Paul,

it sounds as if you have a true Morgan Sports Car...and a total counterpoint to the Aero Plus 8, which although having a passing resemblance, is really a GT.

As to the ride...I was wondering if the springs/shocks are properly loaded for the weight of driver and fuel and spare wheel?

The development cars will have been driven by the factory guys and without much fuel or a spare wheel. From memory most of them are not very big people... It might be worth turning the pre-load on the shocks up to mid to hard, just to see what difference it makes.

But in the end the car was intended to be biased towards track use than long gentle runs. For mostly road use you may end up needing to optimise the rear springs: Peter Ballard is probably worth talking to.

I came across this old post of mine from spring 2016 when I had recently taken delivery of my new ARP4 and thought an update might be of interest after 3 years and around 9000 miles.

First of all, unlike quite a lot of ARP4 owners, who moved on very quickly, I still own and regularly use the car, although admittedly only during spring, summer and autumn. I am simply not prepared to allow salt to start its' insidious damage, nor for the extra cleaning entailed in winter use, no matter how sublime a winters drive under cold but cloudless blue skies is.

Re-reading my initial post I note that I was quite unhappy about the rock hard suspension, this is now sorted with some new springs from Peter Ballard, who went to an awful lot of trouble for me, even driving down from the Cotswolds to Somerset to strip the original front springs out. He supplied springs better suited to road use, and once the front pillars had bedded in, the suspension is now quite acceptable, without any wallowing in the corners.

I have been busy personalising it, as any good Morgan owner would, I took off the removable steering wheel hub and 14" wheel, replacing it with a nice 13" Momo off my old Caterham CSR, I can now see the rev. counter so had no need of a set of Epitec change up lights. The wheel is now further away from my body allowing a more comfortable driving position and with the electric PAS steering, is well weighted at all speeds and perfect at parking speeds.

I am fairly short in the back, so raised the seat up a little, at the same time giving the squab a little more rake. Whilst on the subject of seats, I have always been a little peturbed by the uselessness of Morgan head restraints. I could not even get my head to make contact when fully bent back, so in the spirit of using as many Caterham parts as possible, I now have a Caterham head restraint, bent forward to be much more useful. The passenger seat has a nice foam roll, in matching velour, bought locally for a few pounds, which my wife finds does it for her.

Talking of wives, as it turns out, she really loves riding in it, though has not yet taken the plunge of driving. Now the suspension is more compliant and I have fitted a side exhaust exiting on the right hand side, from her POV it really works. Another success!

After much research, I have finally taken the plunge and fitted a combined oil pressure/temperature gauge in place of the clock, which I have now move to the left of the centre dash insert, in front of the passenger. Making a hole for it was a bit nerve wracking, but worked OK. Why Morgan see fit not to fit an oil pressure gauge on their modern cars is beyond me, though I expect there is a perfectly good commercial reason.

As far as performance is concerned, I complained about a lack of torque, this has improved marginally as the miles increase, but frankly is still a little disappointing. I am very tempted by Griffos turbo conversion, but if I go down that route I will probably destroy any residual value in having a rather special limited edition model, as half of the the 'specialness' is the Cosworth engine.
As a matter of interest, after a couple of thousand miles I thought it would be interesting to have a power run done to see exactly how many horses I was actually getting and was surprised and pleased that out of the advertised 225 bhp, the run showed I was actually getting 220bhp. Just not much torque, and as anyone who knows about engines will testify, it is torque that makes a car feel accelerative, especially for road used where it is not really practical to rev. the nuts off the engine to make progress.

There are a dozen other little 'improvement' I have made, but these will be familiar to all Morgan owners, so I won't go into them here.

To sum up, after 3 years, I am still in love and looking forward to getting out in her again in the spring.

Paul , the thing I really liked about the ARP4 when I had a passenger ride during the TM visit to the factory when the ARP4 was being built was the fantastic pops and bangs from the two lovely special exhaust system pipes . Presumably you get that in your right ear now from the side pipes ??

Pleased to hear you are still enjoying your ARP4 Paul. With regards to salt, I am totally with you on that one if the car is a long term keeper.

There is one for sale at Krazy Horse. Not my ideal car but I can see why some people would like them.