Talk Morgan Forums Morgan Sports Cars Morgan Aero 8, 2012< Plus 8, SuperSports, Coupe & Aeromax aero8 and bad roads...

Brian,

very interesting; do you know if MMC has CFD Program data for the Plus 8? The steeply sloping rear panel might, I guess, perform as the sloping back of the Aeromax. The way it gets dirty on a wet road supports this idea.

MMC quote 155mph as the maximum speed. Given the shape of the front and the plank screen I do wonder.

Peter

thanks ! so far ... i will let dealer have a look at the setting and tire pressure...

It does sound like you've got a bit too much air in them. Your handbook should give you the info you need, but I'd try dropping to 1.7 bar and report back.

I don't know if they have CFD data for the Plus 8, but I will find out. Obviously the aerodynamics of the car must be far from ideal, so like you I very much doubt that 155 mph figure. Have you had your car on a rolling road, do you know the BHP? In my experience the BMW V8's can vary quite a bit in their power outputs, and side pipes definitely increase the HP over the rear exit exhausts.

I have an invite to V-Max in September, but we're taking the Ultima so a lost opportunity really. We'll be at Dunsfold with it on Saurday and they say we'll get some runs down the runway, but doubt whether they will have timing equipment set up.

Next time I'm at the Works I'll see if there is any CFD data on the Plus 8, it would be interesting to see how it performs at top speed.

I doubt whether you hit the brakes as hard as I did Ken, at Bruntingthorpe they install the timing gear what seems like fairly near to the end of the runway, and they have installed a big bank at the end of the runway so the first time through the timer in a different car you tend to brake really hard to ensure you pull up in time. Under these conditions trust me the SS is verY unstable, subsequent runs I braked softer at high speeds and waited until lower speeds for some urgently hard braking.

At least the Mog's are pretty light, when doing it in the Bentley GTC it feels very lardy and at circa 185 mph you wonder whether it will ever stop in time - it does as the brakes are up to the task - luckily!

Has your SS got the twisted bits of aerodynamic metal under the front wings that MMC developed to improve the aero performance of the Series IV onwards, as it does stop some of the air flowing under the car and improves the aero performance. They are not fitted as standard, but are an aftermarket fit by your Dealer.

Incidentally Peter, I've never asked if these work with the Plus 8 too? Another query that I'll follow up on.

Brian,

thanks, I'm very interested in this topic.

The Plus 8 has a relatively unusual combination of a steeply sloping flat rear deck panel, which seems to develop a vortex as air is blown up into the downward facing louvres, and a flat underside that slopes slightly up from the rear axle line. Where they join is essentially a straight line.

Your car has the number plate below the car, which will serve to disturb air flow under the car, others have it above which will disturb the flow over the rear deck.

So, does the rear of the car produce lift or downforce? Both are possible! If there is lift then I do wonder if an F1 style rear diffuser would help. This is an interesting article...

Diffueser

So, yes if they have any data it would be interesting, as would the "under wing bits"....

I've done 130 mph in my healthy S3 Aero with the roof on at Le Mans and 125 mph at Goodwood on a parade lap by hanging well back. Both times it felt great and stable at these speeds, but I wouldn't want to go much faster for lots of reasons. It was very wet at Le Mans and there were too many cars around to go any faster, but otherwise there would have been plenty of room to get to a much sillier speed.

I prefer to simply tell fibs when asked how fast it will go and usually say 170mph. I'm sure that's possible over the side of a cliff or down a steep hill. One thing is for sure - Morgan does not invest too heavily in aerodynamic efficiency or lift and the cars are not tested at high speeds like some other expensive cars. Best to treat them accordingly and enjoy the noise and the scenery. Or get a GT3 - now that's what I really want - only it needs to be properly developed.

How about this as an idea - get Richard Thorne or someone similar to do a £20K GT3 conversion for up to 20 Aero 8s. ECU, winglets, rear spoiler, splitter, diffuser, hard-top, better cooling, better lsd, anti-roll bars or whatever they did to the GT3s, and replacement lighter seats plus a small re-trim inside to add a bit more . I'd be in.

Oh, and I definitely find the 18" wheels better in most cases than the 19" and you don't want to go too high on the pressures. It does impact the ride and traction except on very good tarmac. I find 25 psi is about right all round...

Do you have a picture of what I should be looking for?

My GTN was set up by Richard Thorne at 24psi (~1.7bar). Still running on Yokohamas.
Had it on your wonderful Belgian roads last year - could certainly feel the thumps/bumps but no impact on handling except for the odd, brief lift-off. My sensitively calibrated meter (wife) actually commented on how comfortable it was!

I do find the handling very sensitive to unbalanced pressures (e.g. 1 tyre out +/-) even by small amounts.

The Series 2 has a habit of jumping when a decent bump is hit mid corner. It almost picks up a little into the air - slips sideways and then lands and grips hard on the same line but slightly to the side.

At first it is a bit disconcerting but once you get used to it the smaller size of the car reduces worry. You have room to move a little.