• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Factory Rated HP

Share this page

M

Matthew E. Herd

Jedi Warrior
Offline
I don't suppose anyone can tell me what rear wheel horsepower a '76 Midget (Federal version w/ flat topped 9:1 CR pistons) was rated at? I'm curious as to what it was. I understand the 7.5:1 versions (every year but '76 in the Federal version) were along the lines of 69 hp wheel? Is that correct?

Thanks,
Matt
 
Thanks, Much lower than i thought ...
smile.gif
 
1976 has 9:1 compression but no offically different hp rating. My Spitfire makes 61hp at the flywheel and I think Midget were down from that very slightly due to difference exhaust.
 
I'd guess 65 hp, if you figure about 10% gain for each of the two ... depends on a whole heck of a lot of variables. I'd have to do a little reading, and in the end, its only a WAG. To really find out, need to spin it up on the dyno. The other variable is the compression ratio change despite the officially identical horsepower. Who knows? -- but 61 hp for a spitfire means your hp will be similar ... slightly more given the carburetion, if its set up right.
 
Axles are definitely a weak spot in these cars. I always bring a few extra to the races.

Anyway, I decided to try the calculator-link above, plugging in the standard weight number for a RB Midget (from the Moss Motors car spec page) and a 1/4 mile time from a (stock) '77 Midget road test.
Car is listed as 1849 lbs. Quarter-mile time is 20.7 . I assumed 175 lb driver.

Horsepower figures at 45 to the rear wheel and 53 at the crank.
 
It's so funny to hear about different types of car collectors/enthusiasts discuss horsepower. When I'm at shows with my TR3, people ask how much horsepower the car has, and I'll say "about 100 gross flywheel horsepower." Then if they are muscle car fans, they'll have a reaction such as "oh, it looks like a sports car, but I guess it isn't fast." Then I usually explain the TR2 at 95hp could out drag any stock American car until 1955.

When I have my '69 Corvette out, I'll tell them the car actually has more HP in its current engine than the original 427ci 435hp engine, and enthusiasts usually say something like "wow, it must be like a rocket!"

Then I explain that a 435hp rating in 1969 actually translates: 85% of 435 to get SAE Net, then roughly 80% transmission/rear axle losses (it's an automatic, but even the Muncie 4-speeds are power-sappers) or 295hp, which is exactly what a modern 350hp Vette pumps at the rear wheels.

And then you always need to throw in: power-to-weight. Anyone who has ever been in an old Lotus (or a new one, for that matter) understands power comes from increasing hp, or decreasing weight.

But at the end of the day....

IT'S HOW FAST IT FEELS!

And LBC's give a sensation that can't be matched.
 
For the ultimate speed/power test, take your car to a drag strip. Your 1/4 mile elapsed time and end speed are great benchmarks to which stats from hundreds of cars may be compared. Road & Track magazine and many other sports car mags often post compilations of quarter mile test results from practically every sports car imaginable, going back to the early sixties.

Waiting for those staging lights to change with the engine revved up is tons of fun and a real adrenaline rush. And, the tabulated results (speed & ET) offer an excellent indicator of how your car performs compared to the original model or similar cars.
 
Once mine is properly sorted, I expect to beat a pal of mine's time (from two years ago, I don't know what it is now ... ) in an Olds 442, at 14.9 ... heh! /ubbthreads/images/graemlins/devilgrin.gif Not bad for a car with under a liter and a half of displacement!
 
1/4 mile can be VERY humbling. I don't think you'll be beating 14.9...that's pretty fast as old cars go. The problem is that the faster the cars go, the harder it is to launch. My '69 Corvette should be able to hit 12.5 (which is hauling tushy for a car without drag slicks) but I've never been able to hit a good launch and shifts.

My TR-3? Haven't tried it, but my guess is about 18 or 19 seconds at 90mph.

Here's a good compilation of 0-60 and 1/4mile times:
https://www.eurotuned.com/0-60.htm
 
Back
Top