37 replies to this topic

[miniOwnerGetMeOutaHere]

there are many ways of calculating horsepower (you can't measure power, only torque and you have to arrive at power by calculation)

The relationship between torque and power is fixed

I assume that what you are referring to is the fact that a rolling road will measure power at the whhels and this has to be approximated back to the power at the flywheel, which is what manufacturers will be quoting

[pikey7]

The first thing I've done on all my BMC/Triumph engines is put an elctronic dizzy kit on them. It saves setting the thing up every 10 minutes as the point wear and is a damned sight more reliable.

The other thing I've *heard* on a mini, is to dump the waterpunp driven fan, and fit an electric one (pacet or kenlowe). They are simple to put on, and if you get the right seller at an autojumble (or ebay), you can pick'em up for a tenner! I'm not sure how much it's worth HP wise, but I can't imagine either of those adding anything onto your insurance.

As for the rest, I totally agree with what Dan says! It'll probably cost less than a stage 1 kit too.

[Dan]

You must not remove the engine driven fan from a Mini, the unusual placement of the radiator means the fan is required to re-direct the air coming in through the grille through the rad. You can fit an extra electric fan but you must leave the engine driven one there. It's normal to remove it on all other classic cars, but not Minis.

I think you are agreeing with Dave aren't you (whom I also agree with!)?

[Turbo Nick]

i know quite a few people who have removed the mechanical fan on their minis and replaced it with an electric one on the inner wing. it doesn't cause any problems at all. above 30mph and you dont need the fan anyway from all the air coming in through the grille.

[TURBO HEARSE]

Brakes and suspension! Make the car handle and stop better and youll be able to embarass alot of modern cars round the twisty bits :grin:
But more power never hurt anyone :wink:

[Jammy]

But more power never hurt anyone :wink:

What about that guy who went for the land speed record in that immensely powerful car that crashed and killed him? :tongue:

[Clubby1275GT]

point!! u never hear of people in 2CV's having high speed crashes, although they are made of polystyrene, wood chippings and bostik wood glue, so not the safest places to be!

[eddyg]

sorry to kinda hyjack but has anyone had their engine refurbished by any companies. i.e. whole thing taken out, taken apart cleaned checked bad bits replaced etc. What did it cost. Cause i would love to do that before i start adding bits to it. as you said make sure what u got is working first!

[Dan]

I assume that what you are referring to is the fact that a rolling road will measure power at the whhels and this has to be approximated back to the power at the flywheel, which is what manufacturers will be quoting

No what I'm refering to is the fact that it isn't possible to measure power, as I said.

All rolling roads and dyno's measure torque and apply a calculation to arrive at a figure for BHP (a dyno is also called a brake, hence BHP). And the relationship between torque and power is in no way fixed. There are several different calculations that are commonly used to determine BHP from Torque, all of which rely on a different constant (or fudge factor) and a different multiplyer. There's the American method (by far the most optimistic), the British method, the German method and I think there's a French and an Italian method as well. In Europe (meaning the EC) manufacturers have to quote the German method (which is why the rating is quoted as PS, a literal translation of this in to English is Horse Strength) which you will notice is always different to the quoted figure in HP which they also sometimes quote. It is not simply a metric to imperial conversion. And then there's HP being different to BHP as well.

There is no rule that says which system each dyno has to use, and so all dyno's are very different. Some dyno's even try to allow for gearbox losses and quote a flywheel BHP which is normally wildly inaccurate.

And manufacturers don't quote approximations, they aren't allowed to. If they want to quote flywheel power they have to use a proper brake connected directly to the flywheel to measure it. They can play with the way they do the calculations though. A little difference in the significant figures here or there makes a world of difference to the outcome. Fiat did that once with the engine size of a car. They sold it in some countries as one size to get under a tax band, but in other countries they represented it as a lot larger so it would sell better. Same engine, different maths.

Edited by Dan, 09 January 2006 - 02:58 PM.

[Clubby1275GT]

wow, learn something new every day, thats well cool, where the H8ll did "brake horse power" come form anyway?? is it derived from the fact that horses used to pull stuff

[eddyg]

http://auto.howstuff.../horsepower.htm

good link try it!

[Jammy]

And then there's HP being different to BHP as well.

I've known they were different for a while but never known why? Is it just how they are calculated, or the equipment used, or do they essentially measure different things?

[Dan]

They measure different things in different ways. I seem to remember that a BHP can only be measured at the crank not the wheels but it's been a while since I read anything about it. I'll have to check.



Ok, I went away and had a look. I looked at that page listed above about horsepower and I'm afraid to say that it's largely dingo's kidneys.

This page contains a lot more information about horsepower and all the ways of defining the term and shows why it's such a rubbish unit of power.

Edited by Dan, 09 January 2006 - 05:34 PM.

[TimS]

Hp= (2Pi x Torque x RPM)/33000
or more commonly seen as


HP= (Torque x RPM)/5252

So calculating HP figures is fairly one way. But when it comes to reading and calculating power figures including transmission losses things get a little lost. A way roudn this is to use an engine dynomometer rather than a chasis dynomometer but then you still have different readings from each dyno due to calibration issues. 10% differneces from one dyno do another are not uncommon. This can be increased even buy the dyno owners fiddling to get higher outputs from their dynos and so more custom!

There is also differnt standards as said before. DIN, SAE grossand SAE net figures. So really BHP and power figures are relied on far too much... what you should really worry about is how well the engine runs and how it goes. Leave the dynos for setting the car up!


Now for insurance. If HIC have BHP barries then you could probably get away with around 15-20 percent less power than a rolling road gave out to you! And this would be very difficult for the insurance company to prove against you.

[Sprocket]

Now for insurance. If HIC have BHP barries then you could probably get away with around 15-20 percent less power than a rolling road gave out to you! And this would be very difficult for the insurance company to prove against you.

That is unless your car is featured in a magazine on a RR shoot out or similar. It would then be documented whether it is wright or wrong. What would also rub salt in the wound is if the oposite page had an advert for the insurance company you use :nugget: