Power Loss- How Much?

[nd 4 holden spd]

OK, so my car isn't new any more and it has never been on a dyno (no point yet), so I was wondering if anyone knew what kind of power loss someone can expect. Is there a rough percentage power loss per distance travelled, or maybe so many kilowatts (or horsepower) loss per time period? Can someone help me out? Every time someone asks me the power my Ute has I gladly say a smidge over 130kw- but deep down I know this probably isn't true, and the car would have lost power since it rolled of the production line 14yrs and 180 000km ago. What do you all know?

 

[Boz Mon]

Theres no way to know how much power loss you have experienced over time. There are rough percentages of how much power you lose through the drivetrain though. I dont know them off the top of my head.

 

[nd 4 holden spd]

Why, does it depend on displacement and engine design?

 

[Thirdeye]

I would say it depends on how much compression your motor has. Try running a compression check in your spark plug cylinders and see what that gives you. I know of a product that's really good at cleaning rings/varnish/sludge, etc. that can restore compression safely too, if they happen to be low.

 

[nd 4 holden spd]

So restore the compression and restore the power? I thought it was permanent power loss. Can you tell me what this product is?

 

[Famine]

There's so many factors it isn't even funny - age, engine size, engine type, gearbox type, gearbox age, gearbox condition, drive type, drive parts condition, hell even down to the make of grease you slop onto the CV joints.

How much should you expect to lose? Well, if it is running spec parts and has been properly maintained, almost nothing.

 

[1X83Z]

Theres no way to know how much power loss you have experienced over time.

You can't measure it? Say, on a dyno?

 

[Famine]

That assumes factory power is correct - the Impreza WR1 (320hp) owners' club went on a dyno day, and of the 21 that turned up only 3 mustered more than 300hp. None of the cars was over 8 months old.

 

[vr6gti72]

That assumes factory power is correct - the Impreza WR1 (320hp) owners' club went on a dyno day, and of the 21 that turned up only 3 mustered more than 300hp. None of the cars was over 8 months old.

Was 320hp claimed at the wheels or the crank?

 

[Famine]

Was 320hp claimed at the wheels or the crank?

Crank.

Only one of the cars managed factory torque too.

 

[JCE]

Loss of compression, cylinder wall wear, excessive carbon deposits, dirty fuel system, and a whole host of other things effect power. Losing compression is a killer because that's a sign of a more serious engine problem usually. At least a top end rebuild will be needed unless it had a huge amount of miles. *points to his Camaro* Then its a complete rebuild.

 

[Boz Mon]

You can't measure it? Say, on a dyno?

No, absolutely not. Thats preposterous, impossible.

 

[niky]

It's hard to figure out Subies on the dyno... turbo heat-soak... AWD drag... adaptive ECUs (20,000 kms of hard driving can give you +10 or +20 hp), break-in (good for another good shot of power...)... as well as which gear you dyno in...

Fun fact... a Ford 2.0 TDCi makes 15 whp more in 3rd gear than 4th gear, due to the godawfully abrupt torque curve.

For wear, there are so many variables, like Famine says, that it's not funny. We've also seen about 5-10 hp differences on the dyno for cars which have either not been broken-in, been broken-in poorly (never thrashed) or have been broken-in properly (the occassional thrash, but no hogging the redline for minutes on end). And that's for 110 hp grocery getters. That's a lot. Same grocery getters can expect to lose about 5 hp or so after a lot of kilometers have passed.

For your rear drive ute, I'd say maybe 15 - 20% drivetrain loss... depending on how much torque you have and how heavy your wheels are.... and where you dyno. Since you're in Australia, you'll likely be doing it at a dyno dynamics machine, which reads a bit lower than the ubiquitous dynojet. As for wear loss, it'll depend what your compression and leakdown numbers are.

 

[Troux]

Impossible to say what to expect. I can tell you this, though, I'm getting 34MPG average on a 23 year-old engine with 203K miles. It all depends on how well you treat the car, but honestly, power loss is a very minute loss among signs of aging. Your car will show more severe signs of wear in the form of burning oil and coolant, poor fuel economy, etc. before it will be noticeably slower than a brand new iteration of the car.

You COULD get a dyno done if you're curious. I know there are some shops around here that offer "dyno days" for meets where they offer a special rate for a very short time on the dyno to try to get multiple people running on it. Next time you see a shop hosting a meet with a dyno day, look into the price. Around here I've seen shops offering $20 (USD) per pull, or I know of another couple shops that have permanent rates of $50/3 pulls.

 

[nd 4 holden spd]

Well my engine runs almost brand new (needs a new tensioner pulley thing- I can't remember the proper name right now ), otherwise there are no known problems with the engine, it runs smooth, gets better mileage than it should and impressed my friend on speed (despite being essentially stock still). The gearbox however it would seem needs a rebuild, past its life expectancy and has a loose bearing (it's always the bearings with cars isn't it). So I'll be fixing that within a week or 2 so I imagine it'd have very little loss then, maybe 5kw or less I guess.
Are there dyno shops that test power at the flywheel? (same as factory quoted power yes?)

 

[Jay]

Honestly, especially with 'only' 180,000km's I doubt it has lost all that much from what it had from new, some older 'loose' run it engines with carbon buildup has even gained small amounts of power, but from my observations at the dynoshop I frequent and tune (and other various observations) of newly rebuilt, low km's, mid km's engines generally are not too far off the mark, though it really does depend from engine to engine (even within the same make and model) car to car even if you disregard km's

 

[nd 4 holden spd]

180 000km isn't too bad for a Commodore this old. Many have over 200 000km on them. So being Australian, how many VR and older V6 Commodores do you see at this shop? Do they generally hold power well? Generally....

 

[Jay]

Yes 180k is not too bad.

Well this shop usually specialises in modified cars, and most Commodores that enter have some kind of forced induction or a built NA engine, but really even if you have lost some power I personally doubt it will be much.

This is coming from a guy whose first car was a 1981 VC commodore with a old 202 I6 with crow cam and extractors which still managed 88rwkw's (roughly 115whp, where roughly 100whp was stock) after being thrashed for years and blowing small traces of blue oil smoke.

 

[Troux]

Are there dyno shops that test power at the flywheel? (same as factory quoted power yes?)

Yeah, there's a bunch. All you have to do is pull your motor out, haul it over in a truck (with the ECU and all engine control circuits), pull out your checkbook and grab your ankles.

 

[nd 4 holden spd]

Oh dear, power at the wheels is fine anyway- do a little maths and find out roughly power at the engine I guess. It's just interesting to know how much you improved on stock and how your car compares to modern cars.