Why is an MGB so slow?

[cml]

On paper an MGB GT has 95hp and weighs a whisker under a ton. So it should be reasonably nippy. Only it manages to sprint to 60 in 13 to 14 seconds. It may have felt fast and fun, but it was very slow.

A modern car with figures around 100hp per ton manages under 10 seconds.

Is it all about grip?

[hidetheelephants]

I'd guess it's because the B series is asthmatic and has given its best by 3.5k, which probably equates to about 70-75mph in top; doing 2 gear changes to get to 60 can't be fast.

Edited by hidetheelephants on Monday 26th September 02:01

[pthelazyjourno]

Gearing + gearbox? How many gears did it have?

[cml]

Four with overdrive on 3 and 4, to 60 you can just reach 3rd IIRC

It be fair its much better when you get to in-gear stuff, get up to speed in 3rd switch on the OD and throttle back - then boot it and switch the OD off - almost speedy!

Edited by cml on Monday 26th September 02:16

[ajsphead]

Well the B series engine was basically designed as a small capacity unit for little family cars in the 1950s. Alright, so its internals grew to 1798 in the B but it's still a heavy old iron lump with, by today's standards, short gearing. Judge it by the standards of the time and early Bs were fast enough. They did get slower as they got older for the usual reasons. 0-60 is not the point of a B. It's more to do with how fast can I keep going along a twisty road before my bottle, or the car's ability, gives up first. A lot of fun at relatively low speeds for not a lot of money.

[v8250]

I'm probably biased here as have one of these slow devices. They're slow-ish as have an old engine design, and percentage-wise, have reasonable power-loss though gearbox and differential. Plus, today there are many examples that are simply tired.

However, a correctly tuned and balanced MGB can be a real flyer; particularly if induction & extraction is sorted and the suspension is set-up correctly.

Tony Dron wrote an article for Octane in 2009 confirming...'How can MGB's be that bloody quick now?', 'The answer is simple: they were that bloody quick then...' he went on to explain 'As I discovered 20 years ago, you don't have to do much to an MGB to make it devastatingly quick...'

'What made the car quick was not expensive; it gave just 130bhp at the flywheel, thanks to the Weber and a midly teaked camshaft. The big secret was in the roadholding, handling and traction, which can be perfected largely by adjustment of the standard components...'

[alfa pint]

Plenty grip in an MG B, apart from unmodified rubber bumper Bs. As said above, it's not the best breathing of engines and was considered a heavy car in its day.

Make it breathe better and they're pretty quick for not much cash. The engine is quite torquey, so it's more about conservation of speed and momentum and picking your moments to overtake.

[davepen]

ajsphead said:

Judge it by the standards of the time and early Bs were fast enough.

To put it in some context, the MGB was the first (standard) MG capable of 100mph - and only just. When released in 1963 there was only a short section of the M1 open.

Wikipedia shows the donor A55 Cambridge had a top speed of 77mph and took 25s to reach 60mph.

[saxxeblt]

Drive any of the contemporary vehicles apart from exotica and you’ll find the ‘B was more than fast enough in it’s time, it got overtaken in the last ten years of it’s life through lack of development but even then it could hold it’s own until the hot-hatch came along.
It also had a respectable racing career against more expensive machinery, Abingdon could tune the ‘B to compete in a variety of races.

[davepoth]

The 0-60 times back in the day weren't that hot; cars were geared for an even torque spread rather than getting to 60. As another example, the Dolomite Sprint. 0-60 in 8.4 seconds doesn't tell the whole story as you have to shift up to third at 59mph.

[Skyedriver]

I had a 1972 Roadster between 1977 & 1979. Bought it after a couple of Midgets and it was considerably better than them but slower than my mates TR4A & a TR6. Traded it for a 2.5 litre V6 Ford Consul (poor mans Granada) which was faster and cornered better (honestly).

[restoman]

BL even embarrassed themselves when they brought out the Marina TC - even that was faster than their MGB.

[sparkythecat]

saxxeblt said:

Drive any of the contemporary vehicles apart from exotica and you’ll find the ‘B was more than fast enough in it’s time, it got overtaken in the last ten years of it’s life through lack of development but even then it could hold it’s own until the hot-hatch came along.

My contemporary car isn't exotic, but it will eat the MGB.

[cml]

ajsphead said:

It's more to do with how fast can I keep going along a twisty road before my bottle, or the car's ability, gives up first. A lot of fun at relatively low speeds for not a lot of money.

This is exactly why it is so much fun! (and nearly killed me)

I guess its the gearing and lack of a punchy top end that kills the 0-60, which is a bit of a pointless test anyway.

It asked becasue so many little hatchbacks with pretty much the same power to weight can manages sixty in 10 seconds and under, that quite a gap. Having the back wheels jump around doesn't help mind...

[a8hex]

davepoth said:

The 0-60 times back in the day weren't that hot; cars were geared for an even torque spread rather than getting to 60. As another example, the Dolomite Sprint. 0-60 in 8.4 seconds doesn't tell the whole story as you have to shift up to third at 59mph.

Now that is just bad planning.

[chard]

sparkythecat said:

My contemporary car isn't exotic, but it will eat the MGB.

Your right, but bare in mind the MGB was a 12 year old by 1974. A long time in automotive design.

[mph]

saxxeblt said:

Drive any of the contemporary vehicles apart from exotica and you’ll find the ‘B was more than fast enough in it’s time, it got overtaken in the last ten years of it’s life through lack of development but even then it could hold it’s own until the hot-hatch came along.
It also had a respectable racing career against more expensive machinery, Abingdon could tune the ‘B to compete in a variety of races.

Didn't take a hot hatch to see off a 70's MGB.

I owned 5 in the early/mid seventies and the performance was becoming an embarrasment even then.

They are a great car though. I have fond memories of them and they make an excellent affordable classic. With a bit of tweaking they can be made to go quite well.

[mph]

sparkythecat said:

My contemporary car isn't exotic, but it will eat the MGB.

Well it is a bit exotic by British 1970's standards. Nice car but not without it's problems.

Friend of mine's wife owned a new one. You only have to mention it and she develops a nervous twitch.

[Touring442]

sparkythecat said:

My contemporary car isn't exotic, but it will eat the MGB.

Yes, and they were an absolute disaster.

I once drove an MGB Roadster with a 1900 Oselli engine (SU carburettors) and mildly tweaked suspension - Koni shocks and some different springs. What a lovely car that was to drive - plenty of go and it drove really nicely. Compare that to the hateful BL standard offering on rubber bumpers......what a pity.
When the MGB was current, a 1275 Cooper S could get to 60 in 10 seconds which was pretty lively in 1965.

[davepoth]

a8hex said:

davepoth said:

The 0-60 times back in the day weren't that hot; cars were geared for an even torque spread rather than getting to 60. As another example, the Dolomite Sprint. 0-60 in 8.4 seconds doesn't tell the whole story as you have to shift up to third at 59mph.

Now that is just bad planning.

Not really; it was designed a close ratio 'box, so it's an utter joy to drive; they just didn't have 0-60 in mind when they set the ratios like they do these days.