Do you loose HP over time? - The Unofficial BMW M5 Messageboard (m5board.com)

540i6 · 19th May 2003, 05:14

Guys, does anyone have any idea how much HP you loose over time and miles? I was going to buy a use M5 and what to know at what point do you start to wear the engine suce that HP starts to disappear. Anyone have any data on this subject?

Need4Spd · 19th May 2003, 05:45

I don't think any such data exist, but my sense of my own car is that it's gotten stronger with age rather than weaker. It was quite tight until about 10k miles, when it seemed to rev more freely and is stronger than when new (now has about 40k miles). If you take care of the car, I don't think you'll see any appreciable decrease in HP due to wear until well over 100k miles (so long as you do spark plug changes at around 50k miles and I don't care what they say about plugs going 100k miles), but that's just a guess based on other cars I've had.

MEnthusiast · 19th May 2003, 07:12

every BMW Ive had has felt stronger with the passage of time. I dont have a dyno so I cant say for sure the hp has gone up, but I can tell you that fuel economy generally has gone up over time.

M5XTRM · 19th May 2003, 07:28

I believe BMW produces a fantastic array of cars with incredile longevity if taken care of.

I still have my first BMW 1987 325, it has 378,453 miles. One clutch, timing belt, air compressor and evaporator change. No other major changes. It still runs as good and feels as strong as when I first bought it 16 years ago.

My E39 2001 M5 has 61,000 miles and it seems to get stronger with time. Logic of machinery will indicate deterioration = lose of power, but for BMW it seems that the engines are like muscles, the more you use them and exercise them properly, the stronger and healthier they get.

Just my opinion.

M5XTRM

KirklandM5 · 19th May 2003, 11:14

The engine will improve after it is broken in, but after time it will begin to lose power as the piston rings begin to leak and/or the valves no longer shut tight. In addition, the fuel system if not maintained will have issues...but that's a tune-up issue rather than engine wear issue.

Fortunately, BMW engines IF maintained correctly (that means staying on top of the cooling system). Can put down GOOD power for a long time. There are guys club racing witn 140K mile engines. I've seen E28 M5s (256hp, quoted from the factory), still lay down 215-220 hp to the rear wheels.

Darn good.

MIB · 19th May 2003, 12:58

I once had a BMW Tech guy tell me in General conversation that it takes at least 50,000 Km before a BMW motor is fully loosened up.

Therefor the responses you are getting as to the vehicles getting stronger with age.

I also concour with Need, that they should be fine right upto 100,000 Miles.

NEED, 20,000 is all I'll ever expect from a Plug, and 5,000Km is far enough for Oil. I have to have something to play with on a regular basis.

I have had my 540 for 3 years and the Oil still is not Black, and its never used a single drop. Zero Top Ups.

ELEVENS · 19th May 2003, 14:46

Don't know if it's true w/ BMW, but valve springs, then piston rings are the major source of HP loss w/ miles on small block chevy motors.

Need4Spd · 19th May 2003, 17:27

MIB, I'm obviously lazier than you since I'll let my plugs go 50k miles. But certainly not 100k. Even though I'll bet there's still life in them, they might seize in there pretty good if left in there that long.

Elevens, you and I are on the same wavelength. I was a Chevy small block ('70 Z28) hot rodder in my youth, too. The M5 engine is built much differently, but the age/wear items are still the rings and valves.

Having been shamed, I think I'll go down to the garage tonight and change my oil and plugs....

540i6 · 20th May 2003, 02:56

It is clear that opinion states that HP wanes, but not for a while. I guess I should not have any reservation of HP decreasing at 40k miles - but you have to admit it is hard for us humans to determine if we lost 20hp or not.

In all cases, thanks for your feedback