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YOUR RESEARCHBHP loss over time?
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lack of consistency between dynos makes it very tough
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The problem is the lack of consistency between dynos makes it very tough to give an answer.
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Suggestion
Poorly maintained cars, especially carbureted engines that need occasional adjustment, lose power; engines that have seen thousands of operating hours also tend to lose power as tolerances change due to wear.
Leading evidence: 'lack of consistency between dynos makes it very tough' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'lack of consistency between dynos makes it very tough' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Replace due' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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I have used my dyno dyno to compare new factory engines, low mileage factory engines, and hundreds of my own engines.
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Suggestion
Poorly maintained cars, especially carbureted engines that need occasional adjustment, lose power; engines that have seen thousands of operating hours also tend to lose power as tolerances change due to wear.
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Suggestion
Because I change the oil every 3,000 miles and stay up on maintenance...
Test testers found different gasolines produced hp ranges
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Suggestion
In an EVO mag fuel test the testers found different gasolines produced HP ranges from 204hp to 212hp and torque ranges from 234 ft lbs to 252 ft lbs.
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Suggestion
Poorly maintained cars, especially carbureted engines that need occasional adjustment, lose power; engines that have seen thousands of operating hours also tend to lose power as tolerances change due to wear.
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No, there is no rule of thumb. My 5.7-liter Corvette is making more power than it was rated when it left the factory in 1996; I have not dynoed my 996, but it makes the pull from 100 to 150MPH the way a car making ~300HP should.
Maintenance and mileage, not time, are the two factors. Poorly maintained cars, especially carbureted engines that need occasional adjustment, lose power; engines that have seen thousands of operating hours also tend to lose power as tolerances change due to wear. Timing gets off as belts stretch and cams wear; valve springs lose tension and valves start to float...things just get sloppy.
My backup answer is also 7.
No rule of thumb I'm aware of.
No way to really know and I have no info on which to make a guess.
I can offer only my own experience (with no dyno runs though) and that is after over 305K miles my Boxster feels as good as it ever did. I suspect it has lost some power but I don't notice it except when I switch from driving my 996 Turbo then the Boxster feels a bit (just a bit...) down on power. But after a few minutes behind the Boxster wheel all is right with the world.
If you are that interested, dyno the car/engine now and get a base line established then at some point in the distant future dyno the car/engine again and compare results.
Good read
kcattorney
The question may have sounded a tad daft for most of you, but I'm quite blank when it comes to these kind of things. We had a quick talk about this at work (a work mate of mine has a M3 from 1996) and the question popped up one morning when we talked about aging cars :-)
Anyway, Thanks all for your replies...
The problem is the lack of consistency between dynos makes it very tough to give an answer. The best comparative numbers you can get are on the same dyno on the same day. After that it starts getting fuzzy. But as long as the engine is functioning properly you shouldn't see a drop in power.
The last dyno I had was a '99 with 85k miles it dyno'd at 245 RWHP. Of course there was a 10 hp difference between the 3 pulls so take it with a grain of salt.
Also, remember that everyone talks about peak HP when they talk dynos. And this can be an extremely misleading number. What is really important is what does the HP look like across the power band. Any tuner can program a spike in to get a high peak that has nothing to do with useable power. But I digress.
My 2003 still pulls extremley hard...l so I'm going to say none. Because I change the oil every 3,000 miles and stay up on maintenance... Also on stock RMS/IMS still
These engines typically don't lose power with miles. Thanks to low tension rings and light valve spring pressures, you'd need to have a mechanical issue to reduce power.
I have used my dyno dyno to compare new factory engines, low mileage factory engines, and hundreds of my own engines. The same goes for extreme high mileage engines, the results are negligible.
If an M96 doesn't fail, it'll stay strong for its whole life.
274.5hp showing at the rear wheels. The '99 engine developed 296hp. Factoring in a 10% loss to the drivetrain the reading should be in the 266hp range.
Additionally who knows what tune that engine is in? What gasoline the owner is using? A fuel test published in Evo magazine a few years ago found a considerable difference in gasolines with a low HP reading (on a dyno) of 234hp vs. a high of 242hp for an 8hp gain just from buying the better gasoline.
Unrelated to any videos here - just an observation: If the dyno operator doesn't know what he's doing, the readings are worthless. I have been to more than one dyno day where the operator was obviously clueless (unless every crappy SRT4 Neon with a catback and underglow in San Diego County actually DOES make ~400WHP...).
In the above video, after the pull the dyno operator turned off the engine and then turned off the fan. At least the engine compartment lid was left closed during the pull.
That represents an approx. 17.8% drivetain loss. That's a few percent points about the 15% I've seen bandied about for these cars.
So, nothing I've seen/read so far gives me any confidence the results are accurate. Just the opposite in fact.
Even if one accepts the numbers 274 "at the crank" represents an approx. 7% drop from the 296hp when new. While 7% is 7% it is not that much for a 16 year old car with I don't recall seeing the mileage and with who knows what kind of usage/servicing it has received, what quality of gas is in the tank. In an EVO mag fuel test the testers found different gasolines produced HP ranges from 204hp to 212hp and torque ranges from 234 ft lbs to 252 ft lbs.
I dyno my car twice daily and have noticed an increase in power of 1/2 HP at the wheels per day. I'm currently at 2,875 WHP. My 0-60 time is 1 second and my 1/4 mile time is 4 seconds. Unfortunately I have noticed a drop in miles per gallon, down to about 18 mpg, but I suppose that's due to age.
