MGE December 200924 Subscriptions 01959 541444 December 2009 MGE 25Subscriptions 01959 541444

Fuel-injected MGB

he car you see on these pages is the most refined, most civilised road going MGB GT that I have experienced. Part of that is due to it being the first MGB to receive Webcon’s excellent new fuel injection system, although that is only the latest twist in a very long story. You see, owner Geoff Bradshaw has toiled over this car and spent a small fortune developing it, yet it was only supposed to

be a temporary relationship when he bought it eight years ago. ‘I had a Triumph Stag and was in the process of replacing the

Triumph engine with a 3.9-litre Rover V8,’ he explained. ‘My wife Jane and I had planned to go on a motoring tour to Vienna, but the Stag wouldn’t be ready in time and so I decided to buy an MGB GT. It was supposed to be a short term measure and I was going to sell it when the Stag was back up and running.

‘The car I found was advertised as an up together car, which is what we wanted as we didn’t have much time to play with. It didn’t have overdrive, which is essential for continental touring, so I had that fitted and also a Webasto sliding sunshine roof. Then we set off to Vienna with a smile on our faces and it got us round. We loved it and decided to keep it. We subsequently did a number of tours including a trip to New England in the USA. Three years ago on a trip to France, someone ran up the back of us. Nothing too serious, but when we got home I decided to sort out the MG. That’s where it all started, really.’

Geoff stripped down the car and sent it off to a local body shop at Selsey in West Sussex for a bare metal respray, opting for Tartan in lieu of the original Flame red. Back home, snug in his garage, instead of refitting the standard engine, Geoff bought an Oselli 1950cc stage two engine with a fast road cam, fitted with an aluminium backplate. He also ditched the MG gearbox and overdrive in favour of a Ford Sierra five speed gearbox and modified prop shaft from Hi Gear Engineering.

‘The gearbox is very neat and quite a bit lighter,’ he said. ‘It really is a vast improvement and I would recommend to any MGB owner that it’s the first thing they should do to improve their car. It went straight in with no cutting or messing about. I also fitted coilover front suspension from Hoyle Engineering in Epsom, power steering from the MG Owners Club and a smaller 14in Moto Lita wood rimmed steering wheel, stainless steel exhaust and Kenlowe electric fan. The interior was completely renewed with comfy black leather seats, also from the MGOC, a wood veneer dash from Classical Dash and magnolia faced Smith’s instruments from Holdens.

‘It went quite well,’ Geoff recalled, ‘but I did have a bit of a problem with flooding carbs and it was never that good on cold starts. On the other hand, my Stag had fuel injection and it is so trouble free – you just switch it on and away it goes. So I began to wonder if it was possible to fuel inject the MG and bring it up to date. I phoned a few people who do this sort of thing and got mixed messages. Some of them said you could, some of them said you couldn’t and one firm who supply kits for other models just didn’t want to get involved. I then phoned Webcon at Sunbury. They were very positive and said: ‘Funny you should phone because we are thinking about doing a kit for MGBs. Can you bring the car up and we can have a talk about it?’ So I did, last September.’

Webcon’s development engineers, Alan Collins and Peter White, both with over 20 years of service with the company, enthusiastically embraced the project. Indeed Alan, an ex-Isle of Man TT sidecar racer, is currently in the process of building an MGB GT track day car which will be used as a working test bed for the company’s products. They explained to Geoff that the main problem with fuel injecting an MGB was the standard cylinder head’s siamesed (or shared) ports. As a result of this design, one cylinder can rob another of fuel leading to uneven running, and possibly even the complete cutting out of some cylinders on idle. The solution lay in the fitting of an aluminium crossflow cylinder head with four inlet ports, one for each injector. These heads have been available for some time made to Webcon’s specification, but previously they’d been mated up to a traditional twin carb set-up.

Geoff, being a very competent home mechanic, wanted to work on the car himself, so a collaboration was agreed. Webcon

TGeoff Bradshaw wanted more modern drivability from his MGB, Webcon wanted to develop fuel injection for the model. Put the two together and is it a match made in heaven? Words and pictures: Steve Havelock

Fuel injection for the BGeoff’s BGt has been extensively modified, but with smooth running, comfort and ease of use very much the goals in mind. A brand new fuel injection kit is just the latest of these changes.

MGE December 200926 Subscriptions 01959 541444 December 2009 MGE 27Subscriptions 01959 541444

Fuel-injected MGB

pump are retained, but instead of supplying fuel to the carbs, it’s fed to a separate little tank, or swirl pot, which has a high pressure pump within. This sits within one of the two battery boxes. (Due to the efficiency of modern batteries, most MGBs only have one fitted nowadays.) The fuel is then pumped forward at high pressure to the throttle bodies and injectors, so there is a low pressure circuit and a high pressure circuit.

The brains behind the fuel injection is the ECU, or Engine Control Unit. This is a tiny computer loaded with thousands of predetermined values. It analyses such information as throttle position and engine revs, refers to its tables and issues instructions on how much fuel to squirt into the engine and when to fire the spark. The distributor is removed and a trigger disc is fitted to the front engine pulley. Webcon had no detailed data on MGB engines, so programmed the ECU with a set of approximate values based on engine size, rev limit and power output. This was adequate to get the engine up and running safely. Geoff sited the ECU in the passenger footwell behind a false footboard, an ideal spot away from engine heat, water and dirt. He also fitted an Lambda sensor into the exhaust which is wired back to the ECU. This was mainly for the gathering of information for Webcon, and is not really required for cars without catalytic converters.

‘The fitting was not difficult for me as a home mechanic,’ said Geoff, ‘but an MG specialist could do it easily. My MGB has power steering, so I had to shorten the back of the pump a

would supply the parts they thought he needed based on years of experience in supplying fuel injection and engine management systems for other engines, especially in the kit car sector, while Geoff would fit them and then report back with his findings.

First of all, Webcon put Geoff’s car on the rolling road so that they had a benchmark to work from. The B was producing just over 80bhp at the back wheels and about 100bhp at the crank. Then, armed with a big box of bits that included a new head, inlet manifold, throttle bodies, coil pack and ECU, Geoff returned home and set to work installing them.

He was doing this for fun and didn’t want it to become a chore, so it was a case of an hour or two here and there and the odd weekend. After all, he still had his Stag to play with! As this was effectively a prototype, the occasional tweak was needed. Take the wiring loom, for instance. This was originally from one of Webcon’s Ford kits. Geoff offered it up, made a note of which wires were too long or too short, and sent it back to Webcon who then remade it. This all takes time.

Then a solution had to be found for the high pressure fuel system that is required for fuel injection. A high pressure pump is needed, which has to be kept submerged under the fuel at all times. This is because the fuel lubricates the bearings and any sucking of air would lead to very quick failure. It wouldn’t do much for the running of the engine, either! The initial thought was to fit a petrol tank from a modern fuel injected car, like the MG RV8 which has a swirl pot and high pressure pump built in, but this seemed a rather expensive and laborious option. So the thinking caps went on and the end result is neat, simple and inexpensive. The existing fuel tank and its low pressure fuel

bit on my lathe because it fouled one of the throttle body spindles. That wouldn’t be an issue on standard cars.’

Whilst in the garage, Geoff took the opportunity to fit Hoyle Engineering’s independent rear suspension which incorporates a Ford Sierra differential. As he explains: ‘It’s given the car longer legs and allows me to keep up with fast lane motorway traffic easily. I bought the complete kit with new hubs, disc brakes and coilover shocks, but it meant yet another prop shaft. It’s very well engineered and bolts straight in; there is no welding involved. It’s very substantial and the overall weight is about the same as the components that are removed, but the unsprung weight is considerably less. I had to fit larger 15in wheels to accommodate the brake calipers, though.’

Geoff had his car back up and running in March and the ECU was programmed well enough for him to drive to Webcon’s facility in Sunbury. There, Alan and Peter checked the installation and fine-tuned the ECU. ‘They needed it for a few days,’ said Geoff, ‘because they had to sort out cold starting as well as warm running. There is a diagnostic socket on the ECU – they connected their laptop while the car was running and made the necessary adjustments.’

‘Having an oxygen sensor in the exhaust on Geoff’s car helped us get the calibration right,’ said Peter, ‘but now that we have the data, you don’t need one as it will run on pre-determined fixed values. Nobody in their right mind would put a cat on a car. They are a daft idea which the politicians thought

“Fitting wasn’t difficult for me as a home mechanic; an MG specialist could do it easily”

of and we are all stuck with. But if you do need to fit one or have one already, our ECU is capable of providing the fuelling.’ I asked if the fuel injection has increased power, to which Peter replied: ‘To get more power out of an engine you need more air. The fuel injection isn’t going to do that. The crossflow head is better than the standard one because it overcomes the limitations of the siamese ports, but the objective of what we’ve done is to produce a nicely driveable car.’

Alan then added: ‘The Alpha system has been going for about 20 years now and we sell a lot of ready-calibrated kits to the kit car market. When Geoff approached us, we had already been thinking about a system for MGs. We’d had feedback that a lot of MG owners who wanted to use their cars frequently were disappointed with the drivability compared to their modern cars. We thought we could improve that and make a car that was nice to live with.’

So, has it worked? ‘After this final fettling,’ says Geoff, ‘it ran like a dream. We took the car touring to Austria, Italy and Switzerland and did 1750 miles in nine days. We did 13 Alpine passes in two days including the Stelvio, and it performed amazingly well. It pulled like a train and was really quite extraordinary. Its torque and drivability has improved no end and we averaged 28.8mpg. I’ve now done about 2500 trouble-free miles and even after days of standing, it starts first time.’

To see for myself, Geoff and I went for a spin. Sure enough, from a dead cold start the engine fired on the first turn of the

Below: crossflow cylinder head does away with the B-series’ siamese ports and opens up the way to fuel injection.Bottom: changes to the interior are extensive, but all quite subtle and certainly well in keeping with the character of the B.

Above: Once the fuel injection was fitted and calibrated to suit the B, Geoff embarked on a touring holiday to the Alps to test it out. He was not disappointed.

MGE December 200928 Subscriptions 01959 541444

key and instantly settled into a smooth idle. Pulling away and accelerating through the gears there was no fluffing or hesitation whatsoever. Even when the revs were allowed to drop right down in a high gear, a prod on the throttle resulted in a clean pick-up with bags of torque in evidence. Just like a modern car, in fact. The suspension was also a revelation. It soaked up the bumps admirably without any knocking, crashing and banging and yet didn’t seem at all wallowy, although we didn’t really push that hard. As Geoff reminded me: ‘This is a touring car. I don’t like revving my engines too hard and I don’t like harsh suspension. I’ve got it just as I want it and I’m very pleased.’

The complete system, which will be marketed through Moss, costs £2865.95 (incl.VAT), with the swirl pot an additional £200 or thereabouts. Webcon say that it can all be fitted by a competent home mechanic in a weekend. Those with special or highly modified engines should speak to Webcon because the standard mapping may not be adequate. They did add that recalibration should only be done by one of their authorised Alpha dealers so they could control the standard of the work – mistakes could leave you with a very damaged engine.

Is it worth it? Well, you get a lot of good quality equipment for the money and it does what it says on the tin. But remember, it is smoothness and driveability you are buying, not increased power and performance. At the end of the day, it all depends on what’s important to you.�

Fuel-injected MGB

Right: Full length folding sunroof was one of the first things Geoff had fitted to his BGt – along with an overdrive ’box.Below: 15in wheels were needed to clear new calipers, but overall, the changes have all been very discreet.

cOntActs www.moss-europe.co.uk�or�call�020�8867�2020.�www.hi-gearengineering.co.uk�or�call�01332�514503.�www.hoyle-engineering.co.uk�or�call�0208�393�2555.