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Come on then STW Mechanical Minded People - Does a car lose horsepower as it gets older?
This is the subject of a long running argument with a friend. He asserts that his car will have [i]more[/i] power as it gets older as everything will run smoother or something. I assert that this is a load of loblocks.
So, what's the truth?
he's wrong
I reckon many gain a bit as they run in properly (older VWs are known for this) then once they hit say 80k miles, the power tails off again.
An old knackered car will NOT have more power than it's supposed to have.
Scooby Turbos are known for losing a lot of bhp once they get tired.
There have been numerous classic vs modern car tests and the old cars are almost always well under what they should be bhp wise.
Depends...
On many things, and also how its looked after.
Old cars don't lose horsepower but everybody else's newer cars have more horsepower.
It's a bit like policemen getting younger.
I recall on top gear they re tested an exotic sportscar and Clarkson was adamant it had "leaked" loads of Horses!
After an initial period of running in to it's optimum performance, an engine will start to wear and lose power and efficiency with age.
You win.
My BMW 523i was smoother after 150,000 miles, but no way was it as powerful. Piston rings and cylinders wear, valves and guides wear so the compression tends to drop which results in a loss of power. Well, that's my theory.
As fadda says.
Engines are "tight" when first supplied and as they wear a little friction reduces and horsepower increases.
Top Gear showed this years ago with a drag race of a new and 60K mile MK2 golf gti 16v. The 60K miler was a fair bit faster. I'm sure it's on you tube.
It was up to a point when part wear, injectors wear, sensors work less efficienctly, but for a well maintained modern car, not very high perfoermance car, it's only a small percentage.
if your friend is right, he should get in touch with some of the F1 teams, he could save them loads and improve their results...
My VW transporter 80K 174ps blew the turbo in Germany .
got a new one fitted out there and it was like a different van
goes up local hills loaded one gear above what it used to and does more mpg so quite happy with that
In my experience, cars are at their best between 10 and 30k. Whether that relates to bhp, you would need a dyno to be sure. I'm pretty certain a car that's done 100k miles is unlikely to have all it's horses left.
what fadda said.
Depending on manufacturing techniques you might find initial high levels of friction which take away power. As the components wear in it'll peak and run at it's most efficient. After that it's all downhill as far as increased bearing friction and continued wear goes I'm afraid. 🙁
i saw a top gear once where they got a load of old supercars and tested how much horsepower they had. They had all dropped well, well below what they had when they were new. And these were well loved cars owned by enthusiasts
[i]Engines are "tight" when first supplied and as they wear a little friction reduces and horsepower increases.[/i]
This is less so now, and the reason why its really not too important to bother running engines in.
Yep br. Less so as manfacturing gets better at tolerances and/or low friction higher efficiency engines are introduced.
tonyg - That test between the old and new Golf's was more to demonstrate how much weight the new one had put one
With Nitro RC cars, the engine runs best/fastest just before it blows up!
I like that fact!
DrP
Not sure about cars flashy, but I've heard from the ladies around the West End that you've been losing quite a bit of horsepower these last few years. In fact, they've been using additives in your fuel...could be a rumour, but it's only fair to let you know 🙂
think it's partly true
new
run in loosened up - slightly more
downhill all the way with wear/tear
There's stuff that causes genuine major losses of power but mainly it's just that stuff starts to get shagged out, injectors gum up, etc etc. But at the same time most engines do start out a little "tight" then get better with age before fading in later life, since that's a very effective way of controlling lifespans without unreasonable tolerances. So there's all sorts of things going on but on average I reckon if you took a 50000 mile old engine that'd been well cared for, and got all the ancillaries working as well as they did on day one, it'll probably make more power than a 0 mile old engine.
It really is amazing how little modern engine internals actually wear over time, I had a couple of motorbike engines in bits last year swapping bits from a new-ish, blown up motor into an older one, and you couldn't tell the difference between the 10000 mile old engine's bores and the 120000 mile old one. The older one had a few minor issues but really very little to show for its age. The rest of the bike was shagged though 
iDave: "if your friend is right, he should get in touch with some of the F1 teams, he could save them loads and improve their results..."
Meaningless comparison, race engines are highly strung and short lived, built to give best results almost immediately without any thought to long term lifespan.
Pieface it was a comparison years ago of two identical mk11 golf 16v one with ~60k miles on and one new. Otherwise a comment between different models (heavier vs lighter) would be a pointless posting 😉
Yes. And some cars are more and some are less powerful than they're claimed to be, depending on whether the variations caused by manufacturing tolerances work in your favour or not. Much more consistent than older cars though. Cars always seem to get more efficient over the first few thousand miles and presumably gain some power through reduced frictional losees too.
fadda - Member
After an initial period of running in to it's optimum performance, an engine will start to wear and lose power and efficiency with age.You win.
Nothing further to add.
Top Gear showed this years ago with a drag race of a new and 60K mile MK2 golf gti 16v. The 60K miler was a fair bit faster. I'm sure it's on you tube.
It was a Mk1 Golf btw and the owner later admitted that the car wasn`t as standard as he claimed,reworked head iirc,the same car has done the rounds of every car programme and has the dullest geekiest owner of any car that I have had the displeasure of meeting.
My opinion is that a car will gain slightly after a period but will start to lose as wear overtakes.Blueprint engines are a good example of a looser engine in some cases.
Lol @ dd
Horses lose horsepower with age.
One day they wake up and its all gone.
easy test this.
I have a 1999 mondeo estate. Have had it since 2005. Did a high speed run in it when I bought it, it got up to 120 on the GPS. Repeated the test on my way home from Oktoberfest 2 weeks ago, struggled to get over 105 (on the flat)
its either got a lot less aerodynamic, or its lost a load of power (around 30% for 15mph by some calcs)
Do you remember the top gear where they tried to make some people carrier as fast as an Evo? They did a dyno test on it, it was meant to have 230bhp or something and ended up having 170 I think.. then they got it back up to 200 or something with a thorough service.
But as above.
Incidentally my Prius gained efficiency over the first 60k miles, by about 3-5% or so, and ,most other people reported this. The engine was continuing to loosen up until that point.
its either got a lot less aerodynamic, or its lost a load of power (around 30% for 15mph by some calcs)
My guess would be weather conditions, tyres, road or most likely the quality of the fuel causing a large part of that - 30% is a pretty big difference.
There are a couple of really good reasons why classic cars and bikes never make the origianl claimed power:
Original claimed power figures were often pure fiction - read any books about the industy and it's clear that the procedure 'often' followed the 'look at your closest competitor and add 10% to their claims' method. Good for sales and bragging down the pub, but that's about it 🙂
Press demonstators were often specially fettled or tuned to provide much more power than the machine available to Joe Public. Suzuki and Ford (I'm thinking of the RG500 stroker and the some of the hot Capris) were particularly good at this, as were Ducati and Guzzi.
Also, until camparitively recently, hardly anyone outside the industry had access to a dyno - Bike Magazine did, but it was an ancient Heenan and Froude water brake that constantly overread by up to 20%.
Also, each dyno gave a different reading: If manufacturers did test, they would make sure it was on the dyno that gave the highest reading. Dyno's are great at comparing engine power curves, but unless calibrated properly, useless at giving accurate max power readings.
You can however build a modern replica of an old engine with modern manufacturing materials, techniques and tolerances that will produce way more power than an original - some companies (Works Replica for one) now make Manx Nortons that pump out nearly 75hp, way, way more than an original, built using worn out pre WWI tooling could ever hope to achieve.
Anyway, everyone knows it's not about power, it's about how you use it.
That's why Mini Coopers and Saab's kicked the ruled World Rallying for over a decade 😀
5lab - Member
easy test this.I have a 1999 mondeo estate. Have had it since 2005. Did a high speed run in it when I bought it, it got up to 120 on the GPS. Repeated the test on my way home from Oktoberfest 2 weeks ago, struggled to get over 105 (on the flat)
its either got a lot less aerodynamic, or its lost a load of power (around 30% for 15mph by some calcs)
Or you had a headwind that wasn't there the last time you tested it? Or you had a tailwind the first time you tested it? Or both?
Or the car was loaded differently. Or it had different tyres on. Or it wasn't clean. Or you had windows open. Or the flat wasn't truly flat. Or...
Similar to Rusty Spanner's post but of no interest whatsoever to you car people: Lawnmower and snowblower manufacturers in the US recently got done for their hp claims for their machines. Someone bought a 7hp snow blower and had it dyno'ed and discovered it had only 3hp. So now they all talk about cc instead of hp.
Some manufacturers have got in trouble for over claiming.
The E36 M3 was often at least 40bhp under it's claimed figure.
The B7 RS4 Audi has been regularly dynod at under 380bhp - it's meant to be 414.
Luckily some are better than claimed - mk3 GTi 16v was usually 160+bhp (meant to be 150) when run it, the BMW 335i is usually 20-30bhp over and so it the 335d (meant to be 286bhp, most are well over 300) 😉
No idea what the mower and strimmer chuck out bhp wise - enough to do the job!
You'll be amazed at what a good service does for a car, I had my 944 on a rolling road producing 178bhp, after new plugs filters and an oil change, the bhp had rocketed back up to 210bhp
of course an engine will loose power as it gets older and starts to wear out. It will also use more fuel as it becomes less efficient due to worn parts, it'll begin to rattle, the oil will blacken quicker and it'll start to belch smoke out the exhaust.
How can that have more power than a younger counterpart ?
Kev
of course an engine will loose power as it gets older and starts to wear out. It will also use more fuel as it becomes less efficient due to worn parts, it'll begin to rattle, the oil will blacken quicker and it'll start to belch smoke out the exhaust.
my 170,000 miler mk3 golf hasn't dropped efficiency in the slightest and I'm now leaving it 20,000 miles between services.
engine is running perfectly, its just everything else is falling off.
Jam - my mk3 GTi 16v was similar - absolutely bulletproof engine. Dad still has one - like yours the car is falling to bits but the engine is still sweet on a very high mileage.
i should be at 200,000 in about 18 months time. gearbox is a bit noisy but alright as long as I don't have to reverse.
will do 38mpg on a run, 40+ if I granddad it. not bad for a worn out, 13yr old, 2 ltr petrol engine.
You can get cars 'compression tested' where each individual cylinder is checked by the garage to see how much power goes to the engine and how much blows back down the sides of the cylinder (sorry if someone has already said this above, not read it all).
They will have a table that says what mark you car should hit.
Mine got a 'very good rating for its age' at around 200,000 miles. Its age at the time being around 16 years. Its loosing power now at 220,000 but not sure if thats the cylinders or some other issue messing stuff up a bit.
Remember, some BHP claims are "at the fly", whilst generally cars are tested "at the wheels", which can drop by about 15%.
DrP
Yes - as posted above, loss of compression
Most leave the factory down on the spec sheet BHP
IMHO, and FYI:
HP: mathematically calculated engine output using such variables as coefficients of friction, calorific value of fuel, etc etc.
BHP: engine crankshaft output measured on engine Brake (Dynamometer)
Then of course there is the output measured by rolling roads (Chassis Dynamometers), more accurate than a guess, but only just. Don't believe it? take a car to as many rolling roads as you want, test in all different gears, wonder why no two results are the same? QED.
I guess the answer to the OPs question depends on many variables: quality of original engine (design and materials), expected service life, servicing, usage, etc.
Another FYI, compression can increase with engine age due to better cylinder ring sealing (after break in) but more importantly due to carbon build up on the cylinder head combustion chamber.