Many episodes of TG feature older cars being bought and then put onto diagnostic equipment to test how much BHP they've lost over the years. I've often pondered what factors determine a cars engine losing power.
Is it purely loss of compression caused by worn piston rings or are other parts of the engine susceptible to wear and ultimately loss of power?
Happy new year to all, by the way.
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Valves and/or valve seats worn? Camshaft wear altering valve timing! Wear and tear in carbs of older cars.
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>> Valves and/or valve seats worn? Camshaft wear altering valve timing! Wear and tear in carbs of older cars.
Semi-blocked injectors, fuel lines.............+ everything else that wears
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How is the figure even mentioned? E.g no engine can be made 100% identical, my car is supposed to be 54bhp but its more powerful now at almost 7000 miles than it was when it was brand new.
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Tolerances on engines these days is much better than years gone by. Therefore engines ought to be similar - although it would be impossible to be 'identical'. After loosening up a bit, all engines probably feel more powerful.
I would imagine all sorts of items on older cars could effect performance, including exhausts and even the fuel used.
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I guess on smaller engines you notice it loosening up more, if you have 150bhp from new, then I doubt any loosening up is that noticeable unless you're tearing down the tracks.
There is a Nissan which has a hand built engine, its one of the GTRs and Nissan say there could be as much as 30bhp difference from one engine to the next and though they all have around 400bhp.
My dads Fiesta engine still felt very strong, despite only having 59bhp from new it would have been interesting to see how much BHP it produced.
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>> My dads Fiesta engine still felt very strong, despite only having 59bhp from new it
>> would have been interesting to see how much BHP it produced.
Could that strength be more to do with producing a (relatively) reasonable amount of torque at low-ish revs? Modern small non-turbo petrols don't seem so good at that.
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Probably, I can't remember the exact figures, but I know it did produce a lot of low down torque compared to modern cars with a similar engine size. Its amazing really, my dads was 59bhp, 8v push rod, yet a modern Fiesta 1.25 16v produces 60bhp in its basic tune.
Should be towed away tomorrow, so that is the end of that problem :).
I am guessing my engine is at its optimum now, and will stay that way for the next 50,000 miles or so, and then perhaps start to loose some power after that.
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The engine in the Bugatti Veyron is meant to produce 1000PS wherever it is driven, including high altitude locations. They therefore all produce a lot more than 1000PS somewhere like the UK.
They used to say the 130PS diesel in the Mondeo produced more like 147PS when used in the UK. It would be rated at 130PS even on lower quality fuel.
I couldn't say if my car has loosened up now it's close to 3000 miles. It had plenty of go in it from the start.
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>> They used to say the 130PS diesel in the Mondeo produced more like 147PS when
>> used in the UK. It would be rated at 130PS even on lower quality fuel.
Likewise the 1.9 PD 130 VAG engine for which many dyno charts were plastered on the interweb from standard engines showing outputs in the mid-140s. As you say, fuel quality probably plays a significant part. Plus of course dyno accuracy (many are apparently somewhat optimistic, particularly at certain remappers)
Modern engines are fabulous though. Six figure mileages without so much as a tappet adjustment, and generally still producing close enough to their factory power at starship mileages that only a back to back comparison with a brand new example in hard driving would differentiate them.
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I found myself wondering something similar after test-driving a V70 D3 last summer. I was pleasantly surprised that a 2.0 engine with an automatic gearbox in a heavier car could, subjectively at least, feel as lively as my nine-year-old 2.4 manual. This was before I had the intercooler replaced, and I wondered if my car might be down on power for that reason, but I don't think it is; it's just that modern engines really have got that much better.
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>> They used to say the 130PS diesel in the Mondeo produced more like 147PS when used in the UK
I'd read something like that on the owners' club website. Certainly my 130PS example goes well enough, I was surprised at just how well when faced with a deserted dead-straight stretch of motorway one evening over the Christmas holidays.
As for engines loosening up, I swear my diesel Octavia didn't reach its full potential until it had done its first 100,000 miles. The same thing used to be said about petrol Golf GTI engines.
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Oh good - just short of 50,000 in my Octavia and its certainly still seems to be improving
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15000 miles in the Focus.The TDCI just run in about 54.7 to the gallon.
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>> my car is supposed to be 54bhp but its more powerful now at almost 7000 miles
>> than it was when it was brand new.
That's because it's running itself in as new engines are incredibly tight. It will continiue to feel (rev) better up to about 30,000 miles when it should be fully run-in.
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>> That's because it's running itself in as new engines are incredibly tight. It will continiue
>> to feel (rev) better up to about 30,000 miles when it should be fully run-in.
Didn't one of the motoring programmes (eg, TG or 5th gear) conduct a test with 2 Golfs a few years ago? One had done approx 70,000 miles, the other only 5 or 10,000 miles. Both the same spec, but the one with 70,000 miles wiped the floor with the other one during an acceleration test.
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Why does a car lose BHP? - Meldrew
