I think Moss sold around 200 of these units over a 4 year period. For the T-Series, I chose to use an older design “Magnacharger” M60 as it had the right flow characteristics and a vintage look and these units sold well until the manufacturer decided to discontinue the unit. I was working for Moss Motors at the time developing Mazda and Honda superchargers for their Jackson Racing division. It was bound to happen, and it eventually did the two crossed and a new XPAG supercharger system was born. I was supercharging new cars during the day and old ones (MGs) at night. The problem is that the original units that crop up for sale on Ebay and at the autojumble, are 50+ years old, expensive, often need rebuilding and lord help you if you need replacement parts!Īfter years of supercharging MGs, I became involved in supercharging current production vehicles as a vocation. The German word for supercharger is “Kompressor” and Mercedes proudly emblazes the sides of their product with it, though in reality, they actually use a “Roots pump” type supercharger!įor years I have fooled with superchargers on MG T-Types this initially involved rebuilding old units and in many cases, making new parts for them as well. The concentric superchargers trap a volume of air and then internally compress it before releasing it into the inlet tract. The Roots design is an air pump it makes no pressure internally in the supercharger, but pumps the manifold with fuel and air faster than the engine can ordinarily consume it, creating pressure in the intake tract. These two different type superchargers achieve the same result of pressurizing the intake system of the engine, but go about in two different manners. The superchargers originally offered for the XPAG engines fell into two basic categories: “Roots” pump type superchargers such as Marshall- Nordec, Wade and SCoT and concentric compressors, such as the Shorrock, Arnott and Judson. Still a 45% increase is wonderful improvement remember that when you are pulling on to the motorway next time with your stock spec motor.Īn Arnott installed on a TC. The reality with our XPAGs is we really only see about a 40-45% increase due to the inherent inefficiencies of the engine. So a supercharger adding an additional 7.5 psi pressure or “Boost” to the intake system, should now give you 75 horsepower. into the same volumes yielding a corresponding increase in power. Now if the pressure filling the cylinder were raised by 50%, you would now stuff 468cc’s. The net result of all this is around 50 horsepower produced at the crankshaft. How does it all work? In a perfect world (with our XPAGs being 100% efficient) when the intake valve of a XPAG engine opens, air and fuel fills the 312.5cc volume of each cylinder with the pressure of the atmosphere at around 14.7 psi. Also the power impulses on the crank tend to be more equal in strength as the intake charge is under pressure. How? A supercharged engine is able to make more power at a lower RPM than an atmospheric induced one due to better intake charge distribution. The truth is a properly set up supercharged engine is every bit as reliable as a normally aspirated one, maybe even more so.
In these stories the teller usually has forgotten to mention that when the alleged engine failure occurred, he was p*s*ed out of his mind, running 7,000+ RPM and fitted it to a worn-out old lump with millions of miles flogged on it. Most MG T owners nowadays tremble at the thought of supercharging their cars as they all have heard the dark tales of destroyed engines, broken crankshafts and mushroom clouds of lost money. English companies such as Shorrock, Marshal-Nordec, Arnott and Wade made superchargers, as well as the Italians with SCoT and Itel-Meccancia.Įven we colonials got into the act with our American home-grown effort from Judson. The enthusiast driven aftermarket quickly saw the limits of the mighty XPAG and jumped on the opportunity to add some sorely missing “grunt” to Abingdon’s meagre effort. Supercharging a MG T-Series today is nothing new in fact when our cars were in current production there were over half a dozen different manufacturers that were making kits.
What captivated me about the article was not the supercharger system, but rather his opinion of it, as I am the guy who designed and built it. I read with great interest the recent article by Colin Hooper in TTT2 # 7 on his experience of installing a supercharger on his 52 MG TD.
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