Merged image of a V8 engine, Sherman Tank,  Clementine the Cat, and my MGA in the Alpes

MGB V8 Conversion

Restoration

The previous restoration

V8 engine

Engine lowering

Engine steady bar

Weber 500 carburetor

Twin pipe exhaust

Manifolds

Wheelarch modifications

Twin pipe system

R380 Gearbox

Gearlever remote

Gearbox mountings

Front suspension

Front suspension mods

Drawings

4 link rear suspension

Setting up

4-link rear suspension

Panhard Rod

Coil Over Damper Mounting

Upper Arm Mounting

Rear Axle and Propshaft

Sound proofing

Door window frames

Interior sound proofing

Radio and speaker installation

Interior

Interior trim

Development

V8 engine problems

Ride and ride heights

MGB V8 Ride and Handling Development

www.VORD.net


The front suspension geometry and springs were carried over from the original MGB V8. I added some adjustable dampers. The rear suspension is 4 link plus panhard rod to my own design with coil over damper springs.

Ride heights

Ride Height

The front of my car has ended up too high and the rear too low. The car looks silly. I think the chrome strip along the side of the car should be parallel to the ground.

My ride heights (measured from the centre of the hub to the bottom of the chrome strip on a more level surface than in the photo) are 371mm front and 345mm rear. I'm guessing that 350mm front and rear would make an MGB look more sensible.

   
Mass added to driver's seat

Ride Frequencies

The ride frequency (in Hz) is the number of times the car bounces on the suspension each second. The rear suspension ride frequency should be about 0.2Hz higher than the front suspension frequency. This is so the rear suspension catches up with the front suspension after the car drives over a bump thus avoiding a feeling of pitching.

My test condition was how the car will normally be driven. 75kg in the driver's seat and about 2/3 of a tank of fuel.

   
Rear spring fitted without damper

I removed the front and rear dampers and bounced each end of the car up and down in tune with the natural frequency of the suspension for 1 minute. Removing the front dampers for the test was easy (on my car). For the rear I removed the damper and propped the spring on a block of wood.

The front suspension ride frequency turned out to be 1.8Hz, and the rear suspension 1.7Hz.

1.8Hz for the front suspension is pretty high. A modern sports tourer would be closer to 1.6Hz. I guess this is because the MGB has a relatively small spring travel so the springs have to be stiff. As far as I can tell from the internet, the front springs are currently 370lb/in which translates to a rate of 220lb/in at the front hubs (the front springs are set inboard so there is a lever ratio in the lower wishbone).

This rules out the option of fitting aftermarket "performance" springs to lower the front to chrome bumper ride height. The other downsides of stiff "performance" front springs are that they would increase understeer and make the ride too firm.

I think my best option would be to either modify the rubber bumper crossmember by removing the spacers between the crossmember and the chassis, or to modify a chrome bumper front crossmember. That way I won't screw up the suspension geometry.

If I take this route then I'll need to increase the stiffness of the rear springs from 130lb/in to close to 180lb/in in order to raise the rear ride frequency to around 2Hz. Actually the rear feels too soft at the moment so this shouldn't be too much of a problem, and it will allow me to carry things in the boot. I have plenty of adjustment in the rear spring seats so this won't necessarily increase ride height.

I'll give some more thought to the possible modifications and add more to this page later.


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