MGB GT ?

Keith wrote: I've driven a Rover-engined MGB GT. It's the car that started me thinking about V8-powered ones. But I don't care much for the engine. The car I drove made a stupendous noise but I think a stock 1.6 Miata could have taken it in a straight line. Then the Miata would have slaughtered it under braking and cornering, and run off into the distance laughing. In the UK where the engines are more common and the SBC is only a legend, it makes sense. Over in North America, it's a difficult one to justify.

Don't know why, as the Rover V8 weighs less than teh stock MGB 4 cyl, at 318 lbs. Which means it's BARELY heavier than the Miata motor.

I've been contemplating this for my B, as well. The V8 woudl be fun, but an injected Miata engine would start and drive like a modern engine, and it'd have a nicer transmission. But weight and handling woudn't enter in my decision either way, as that part would be near identical.

Why? Because the Miata has a braking and suspension system that was designed less than 50 years ago Sorry, I'm not a big believer in drum brakes and lever arm shocks. In the case of the GT I was driving, both the braking and handling were less than exemplary. Weight is always a factor, but it's not the only factor.

Matt B wrote: My curiosity is piqued, but I'm not convinced yet. Expected hp is quite different from real world numbers, no offense intended. I would love to see a dyno and build sheet when it is done if you get the chance.

dyno - this is still short of peak. Ignition numbers were only fair, and fuel numbers were almost as bad. Tuning has progressed significantly since this plot.

Oregon Emissions

http://forums.club4ag.com/zerothread?id=26593 - build info

Well, my GT is running now but no hot dyno action as of yet. I think I'll be able to double those numbers though

Not a bad looking chart, it's fairly close to what I get out of my worked Miata 1.6 (dyno chart) other than that bump of extra torque you have between 3500 and 4000.

Keith wrote: Not a bad looking chart, it's fairly close to what I get out of my worked Miata 1.6 (dyno chart) other than that bump of extra torque you have between 3500 and 4000.

Your #s measured @ the wheels??

Yes, of course.

Thanks for the update oldskewltoy - now I'm going to waste more of my workday reading your build thread.

I have built three Miata powered MGs and they all turned out to be nice balanced and reliable cars. Lots of power and as a side-benefit, excellent fuel economy. '72 MGBGT, '59 MGA roadster and a 1980 MGB roadster. Lots of work incorporating the modern Japanese wiring harness into the MGs and having them look stock inside and out, but worth the effort.

A Rover V8 would be a more logical swap than a Miata. Lots of info and parts available for this conversion.

What about a zetec? I bolted up a pinto 4 speed up to one and with some work a 5 speed from a XR4ti would work with stock parts. It seems that with a good header and ITBs with a fancy ECU, the zetec will pump out about 170hp. At least that hp number seems like what people expect to find with the zetec in Sevenesque car.

As far as MGB GTs go my 2.3T one was a lot of fun. I would love to prepare one with a 3.8L/T5 from a 1997-2004 Ford Mustang and a Miata suspension. OBDII, efficient, cheap, plentiful, easy to work on and dead nuts reliable. Oh yeah, fast as hell.

Funny, I've found that a 180 whp Zetec has about as much power as my 148 rwhp Miata engine based on chasing a Caterham R on the track. And a 300 crank hp Ecotec isn't really any faster. There are some pretty wonky numbers out there :)

But the Zetec would be a good option for a B. So would an S2000 engine, although it's possible it would be too tall to fit happily. The Miata's an easy choice because it's plentiful, inexpensive, comes attached to a great transmission and even looks right in the engine bay thanks to the design of the valve cover. The wiring isn't a big deal unless you pick up a 2001-05 engine with the immobilizer.