Holy crap, my car is down by 50hp

"Jake - Has Bad Luck So You Don't Have To" (murdersofa) 08/01/2014 at 17:22 • Filed to: None

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I ran some maths to calculate a car's 0-60 time based on its weight and horsepower rating.

From the factory, my car has 205hp (wheel or crank, doesn't say), weighs 3591-ish pounds, and hits 60 in about 8.2 seconds according to reviews I've read of the car when it came out.

The math backs this up, confirming the 205hp is a wheel number, since the calculation says it should do 0-60 in 8.32 seconds. Cool, so that's what my car *should* do.

I've done multiple 0-60 runs in my car in varying conditions, both before and after chopping off half my exhaust to get a better sound and higher flow. I wasn't expecting much increase in speed, but what I got was *no increase in speed*

In both cases my 0-60 time was around 10.3 seconds. I plug those numbers into the horsepower equations and...

150hp. My car is now making 150 horsepower. Holy *SHIT*. I know the car has 220,000 miles, but it's been run on synthetic and had parts replaced at regular intervals, and it still gets the same fuel economy it was supposed to, it's just really down on power. I'll be chopping out the 14 year old cat which is probably clogged to hell, especially after getting a TON of unburnt gas thrown at it when I had to drive to an adjacent town on 5 cylinders (oops) to get a coil replaced, so I'll see what that does.

I know 14 years and 220,000 miles is a lot, but for an engine to be suddenly missing 25% of its power seems like a HUGE problem would have to be present. When I get my PCM back and the car is moving under its own power again I'll take the cat off and replace it with a straight pipe until I can get a high-flow cat, and see if that helps but... damn. 50hp. That's sobering.

For Sweden > Jake - Has Bad Luck So You Don't Have To 08/01/2014 at 17:24

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Time to get cherry bombs

Flavien Vidal > Jake - Has Bad Luck So You Don't Have To 08/01/2014 at 17:25

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a 220000miles car with 205hp according to manufacturer and making 150hp at the wheel is perfectly normal...

These calculations are impossible as it does not take into account the gearing of the car...

HammerheadFistpunch > Jake - Has Bad Luck So You Don't Have To 08/01/2014 at 17:27

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that's 205 crank...for sure. Also, don't forget that is blank without drive accessories.

sm70- why not Duesenberg? > Jake - Has Bad Luck So You Don't Have To 08/01/2014 at 17:28

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That sounds like a normal power loss. Remember the Top Gear episodes with the cheap super cars?

camaroboy68ss > HammerheadFistpunch 08/01/2014 at 17:32

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No current hp testing has all the hp robbing accessories on then when on the dyno, been that way since 72.

Nibbles > camaroboy68ss 08/01/2014 at 17:33

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Yup, all but the transmission lol

camaroboy68ss > Jake - Has Bad Luck So You Don't Have To 08/01/2014 at 17:34

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I bet if you ran a compression test you would see its not as high as the factory. Rings and bearings are worn so power could literally be getting pass piston buy would probably be causing smoke. Old spark plugs, wires, coil could also be a cause for power loss because of a weaker spark

jariten1781 > Jake - Has Bad Luck So You Don't Have To 08/01/2014 at 17:35

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Well, those original numbers were gotten with factory fresh tires and probably brake stand launches. You'd have a better comparison if you looked at the 5-60 roll on times.

JGrabowMSt > Jake - Has Bad Luck So You Don't Have To 08/01/2014 at 17:35

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Sloppy valves. Didn't someone post about this a few weeks ago?

Basically, the internals of the engine become more tolerant than they were originally. The cam lobes can change shape which affects the valve movement, which can in turn affect compression and combustion, too much air, not enough air, timing is slightly out due to the tolerances, etc. Not only that, but as piston rings wear you can see more compression losses and slight increase in oil consumption.

And that's just the internal aspect. Older spark coils that can't ignite the chamber with the same bang as when it was new, plug wires with too much resistance, crappy plugs (not everything runs better on platinum, iridium or any other magic). Then you have to worry about whether the throttle body is clean, and if the throttle plate is clean, or inside the intake manifold, because those areas being dirty can affect airflow into the motor, which can make a huge difference.

And then the transmission gets old and not only the metal gets weaker, but the seals start to go....then the differential gets old......

It's all a big chain reaction of shit that goes wrong, starting from the day you drive it home, ending on the day the car either gets a totally new drivetrain, or crushed.

PS9 > Jake - Has Bad Luck So You Don't Have To 08/01/2014 at 17:37

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V8 swap.

lonestranger > Jake - Has Bad Luck So You Don't Have To 08/01/2014 at 17:39

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From the '70s until at least 2005*, rated HP on U.S.-sold cars is in SAE net. That's at the crankshaft, and with all of the production emissions, exhaust, and driven accessories. 205HP SAE net is more like 175 HP at the wheels. After 220,000 miles, a further loss of 15% at the wheels isn't out of the ordinary. Calm your tits.

*SAE "Certified Power" began voluntary use in 2005, but it is not mandatory and not all vehicles made since then quote HP using the new standard.

Jake - Has Bad Luck So You Don't Have To > camaroboy68ss 08/01/2014 at 17:41

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Compression is fine and it's not burning *any* oil. The engine seems tight as a drum.

Jake - Has Bad Luck So You Don't Have To > JGrabowMSt 08/01/2014 at 17:43

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Wouldn't valves result in it burning oil? Because the thing's oil level is steady as a rock

Jake - Has Bad Luck So You Don't Have To > lonestranger 08/01/2014 at 17:44

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My tits shall not be contained.

It's still 3 or 4 seconds slower than reviewers noted the car as being when new. Just seems like a really significant reduction.

lonestranger > HammerheadFistpunch 08/01/2014 at 17:44

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SAE net is measured at the crank, but it is with driven accessories (and air cleaner, exhaust, emissions controls, etc.) I'm assuming by the 205HP figure that it's a Buick 3.8 Series II V6, which has introduced in 1995. SAE net replaced SAE gross in the early '70s.

Jake - Has Bad Luck So You Don't Have To > PS9 08/01/2014 at 17:45

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Northstar? Northstar.

HammerheadFistpunch > lonestranger 08/01/2014 at 17:46

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not ALL driven accessories though, (AC, waterpump, etc) that change happened in the early 2000's i beleive, lots of car makers ratings took a dive, especially the Japanese brands.

JGrabowMSt > Jake - Has Bad Luck So You Don't Have To 08/01/2014 at 17:55

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No, because it needs to get past the valve stem seals first. Oil floats around up there, but would need to pass through a seal in order to get to the combustion chamber. Otherwise oil would have to go upwards through the piston rings. Those are the only two ways oil gets up in there.

If you're not burning oil, then you're just seeing mechanical resistance build up, in my opinion. The bearings aren't quite what they used to be, all the metal parts have expanded and contracted enough to seemingly change the whole inner workings of the engine, to the point where maybe it requires more energy to get the whole thing moving at 25mph than it did before. That extra energy required to keep the engine running is what lowers the HP rating later on.

Even if you kept a car to concourse standards from the moment you drove it off the lot, after a number of years, you'll see a loss in HP.

pfftballer > JGrabowMSt 08/01/2014 at 17:59

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+1 on worn out cam. I pulled one out of an 85 K5 blazer I once bought and was astounded at the amount the cam lobes had been worn away by the hydraulic lifters. The valves were hardly opening at all. I new cam and lifters and a carb rebuild and that Blazer was a beast again.

pfftballer > Jake - Has Bad Luck So You Don't Have To 08/01/2014 at 17:59

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You need to replace cam and lifters.

lonestranger > Jake - Has Bad Luck So You Don't Have To 08/01/2014 at 18:02

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Three or four seconds is significant.

However, how are you measuring your times? Any one thing might not seem like it means much, but together they may account for much of the discrepancy. For example:

Are you using a stopwatch, and are possibly slow to click the stop button?

What are you using to measure your speed? The dashboard speedometer is likely not 100% accurate, especially if the tires aren't original size.

What conditions are you measuring in? Temperature, humidity, wind, and especially altitude will affect the results. Published 0-60 times are measured in ideal conditions.

Are you achieving WOT? Don't laugh. A floor mat under the gas pedal isn't uncommon. Ensuring that the pedal actually travels as far as it should is the easiest, cheapest HP gain one can find.

Jake - Has Bad Luck So You Don't Have To > pfftballer 08/01/2014 at 18:09

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Hmm, then the decision is if to get performance cams or cheap out and get stock ones.

Jake - Has Bad Luck So You Don't Have To > lonestranger 08/01/2014 at 18:13

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Filming the dashboard while doing the test. Then I go back and cycle through the video, mark the point where I drop the hammer, and then go frame-by-frame 'till I get to when the speedo says 60, and I get the delta of the two times. Probably accurate to a hundreth of a second depending on how audible it is when I put the hammer down, but I've done the test two or three times and gotten the same numbers.

I've done it at night and at day, so wildly different temperatures and other conditions, didn't appear to make a significant difference. Totally flat ground as well.

No floor mats here. The pedal is going down to its mechanical limit.

lonestranger > Jake - Has Bad Luck So You Don't Have To 08/01/2014 at 18:52

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So, we've ruled out everything that I can think of, with the exception of the speedometer accuracy. If you have GPS device, you can check the GPS speed report vs. what your speedo indicates. Better yet, if you have a smartphone:

https://itunes.apple.com/us/app/dynolic…

https://play.google.com/store/apps/det…

Jake - Has Bad Luck So You Don't Have To > lonestranger 08/01/2014 at 19:01

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The speedo is 2mph fast. I've already checked it with GPS