Dynoing the ‘Six
Written by Brian McCullough
On a cold morning, I pulled our 1980 MGB V6 from its winter nap. The car sat through the winter with about a half tank of low grade 87 octane fuel. This rust free car has never seen any salt in its life, and with only a few minutes to warm up, was now making its way through slippery roads to HiTech Motorsport in Elk River to be strapped down to strut its stuff. The drive was fun, especially since I was having serious LBC withdrawal from the past six months of non-use. While all the back roads had no other cars to tangle with, it did gave me a trip with a bit of twists and something more to look at than a boring, straight freeway run would have produced.
Now, Hitech Motorsport certainly sees their share of high powered American modern and classic muscle, but from my gathering British is a ‘bit’ less common. Up front, they have a large parts store for aftermarket bits for your Modular Fords (namely 4.6L V8 Mustang) and GM LSx series (Corvette) and more. In the shop, you have your Corvette powered Porsche's, your Higher than Hi Powered Mustangs, your Diesel Ford pickups that will blow by most hot hatches and leave ‘em crying- and even your Corvette powered Corvettes- only faster! I should mention that they also work on daily drivers, but as most shops (such as our own!!) tend to get a reputation for one type of vehicle, and people may not realize they can do so much more. Ask BMC to tune your Corvette and we will be referring you to Hitech Motorsport; we’ll stick to the Rolls Royce, Lotus and MG. :-)
So, back to Dyno Day at Hitech... My reason for running on the dyno was less for finding out how much my 1980 MGB had, but more for tuning Dad’s (Dwight’s) MGB. As long as we’re there, the basic 3.4L V6 with nothing done to it was the perfect comparison for a well built MGB with about the same amount of money put in it.
The results speak for themselves- the V6 powered car has more torque, just off idle than the hot MGB I4 has anywhere. The V6 has a wide power band, not requiring it to rev to kingdom come. And because of this, the V6 does not have to work hard, producing far more power reliably. The passing power on the freeway at 80 MPH with the V6 is better than most MGBs have at 40 MPH. Is the V6 better? Yes and no- depending on what your searching for. The options between a standard B series, high-output B series, supercharged B series, various V6 and V8 conversions all have their place. Am I convinced that the GM V6 is one of the top choices? Yes, and that is the reason we starting producing MGB V6 conversion parts nearly 10 years ago.
When reading the dyno graph, keep in mind these numbers are rear wheel horsepower and torque figures, not the flywheel horsepower and torque figures posted by car manufacturers. By adding a certain percentage to the rear wheel figures you can calculate the flywheel horsepower and torque. Our v6 is completely stock and still produces more horsepower and torque at the rear wheels then an MGB GT V8 does at the flywheel! Of course, just like any engine, there is room for improvement; but we'll focus on that in another article.
* The red labeled car is an MG B V6 conversion with modifications and specs we will list out in a different article.
| Car | 1977 MGB | 1980 MGB |
| Colour | White w/black “MGB” lower side stripes and MGB black rubber baby buggy bumpers | White w/MGB black rubber baby buggy bumpers |
| Motor | 1972 MGB block, crank and head | 1995 Camaro L32 3.4L V6 |
| Induction | APT manifold, mostly stock HS4 S.U. Carb set | Stock manifold, stock throttle body driven by stock and unaltered PCM/ECU (computer for those uncertain) |
| Exhaust | 3 into 1 long branch headers and large exhaust | 3 into 1 CCE type headers with BMC Y pipe and exhaust |
| Ignition | Electromotive adjustable DIS | Standard GM DIS. New spark plug wires about a year ago |
| Motor Notes |
TOO MUCH TO LIST HERE! For full list, please review the article (it can't fit in the space provided) |
Sat for many years, about half that time outside. Mileage unknown but it was a cheap motor in very poor looking condition. Frankly, it looked like a pile of garbage covered in leaves, water and all things showing the bonnet of that particular K-marrow had probably been pulled a year or two previous. The first time it was started, the injectors were stuck and the motor had a horrid smell. In order to ‘unstick’ the injectors, think: side of the road, SU fuel pump, car died... The correlation between SU pumps and Bosche injectors? The cure for the SU Fuel pump on the side of the road and a set of stuck injectors happens to be the same! As I have mentioned in other locations, this engine was dirty, grimy, old when installed and installed- stockity-stockity-stock-stock-STOCK! |
| Gearbox | Standard MGB Overdrive 4 speed (sort of a MGB 6 speed for those of you who do not understand how an MGB O/D works) | Camaro V8 T5 using BMC HTOB, clutch kit and Alloy flywheel (the only alteration on this motor that is not stock) |
| Rear Axle | Standard MGB | Standard MGB |
| Main Tires | Autocross type. Good for 5,000 miles on the street but stick like glue | Street use |
| Suspension | lowering blocks rear, Drop A frame Front, BMC U bolts, Stock shocks, upgrade anti-sway bar | Moss Drop springs Front, Doug Jackson’s British Automotive lowering pads, BMC U bolts, Stock shocks, upgrade anti-sway bar |
| Body Alterations | Old type removable soft top | Old type removable soft top |
| Wheel Horsepower (peak) | 84 whp | 140 whp |
| Wheel Torque (peak) | 94 ft/lbs of torque | 186 ft/lbs of torque |
Now that you have seen our video (above) of the B V6 on the dyno you'll see that the car sounds healthy, beautiful and with nothing other then a cold air intake is completely stock. It's the ideal car to go on a Saturday morning drive to get breakfast, and in the same breath go confidently on a road trip to a modified British Sports Car Club meet! If you have never driven a converted car, give it a try. Most find loads of excitement and really puts a smile on their face, and everyone loves the reliability of the newer technology in these engines. Whatever you discover, we know it will be a great experience, making your British sports car reliable for years to come!
