Why does it say that my 2004 TL 5AT has a 270hp engine on the new car sticker, but all the dynos I've see all say a stock TL is around 210-215? I know there's a difference between the wheel HP and the flywheel HP, but there's not that much of a difference. What's the deal?

 

The short answer is that you need to read a good bit more. This is not at all mis-leading. In contrast, your research is in-adequate. One rating is at the Crank and the other is at the wheels. This is NORMAL for EVERY car, not just the TL. Now, go do a search on 258 and learn why 270 and 258 is the same thing...

 

I could've sworn I worte that I understood the difference in crank HP and wheel HP in my first post, but if I didn't make myself clear, I'll try it a different way. There shouldn't be a 60 HP decrease in HP from the crank HP and the wheel HP. What's up with this?

 

No, you're right.

AWD systems usually suck around 60whp at those levels... FWD should be 30 or 40 at the most... and 40 is a stretch.

I know that the "new" HP ratings that were designed to include engine load not previously tested, such as A/C and power steering, etc... that's why a lot of '07 ratings went down in HP, although it's the same engine. Such as 270, to 258.

But I see your point, because even BEFORE the ratings change, it shouldn't have been a 60hp difference.

ndabunka just seems a little grumpy!

 

BEFORE the ratings change (to an SAE standard) the HP measurements could be "fudged" by the manufacturer. Or, may be better to say, the Manufacturer could set up the test and Dyno the way they wanted.

So, some manufacturer uses a flywheel/crank measurement "standard" that gives 270 HP as "the number". Now some buyer comes along, dynos the car at his favorite speed shop which uses (surprise) SAE correction and gets ~210 WHP. HUGE LOSS. OMG, I've been screwed.

But then, the manufacturer RETESTS the same engine, also SAE corrected, and gets 258 at the crank. Now 258 compared to ~210 is ~18% loss (mostly drivetrain) and "normal".

IOW - the orginal 270 didn't mean anything to you in the 1st place since you have NO IDEA how the test was run. Not so with SAE as the standard.

What's the mystery?

 

That makes sense. I don't know why Acura wouldn't do it right the first time. I guess as long as they got the rest of the car right, I'll be happy.

 

DD,

That's the problem - there was no "right" before. Everybody did the HP measurement their own way. Sure, they were similar test, but enough difference that trying compare numbers was meaningless. And enough that Marketing could say "run it again, but see if you can get a higher number."

That's why the SAE instituted a standard and certifies the result. Now when Acura says "258 HP" and Infinity says "305 HP", you can make a good assesement of the HP difference.

 

Actually, to be more specific, the tests in the 270 hp rating WERE SAE, just not up to the SAE's newer rating standard. They updated some of the terminology to prevent changes by manufacturers, such as quantity of oil, ecu calibration, etc. It's a well known fact that if you drop about a half a quart of oil from a mustang it will pick up about 4 - 5 whp due to reduced windage. All the new standards did was make the testing procedure more stringent as to how its done. All engines have been on SAE NET ratings for years. You have to go back to 76 or 77 for the last of the Gross hp ratings, where they didn't have exhaust, any accessories, or anything. Funny, as the same motor that was rated at 385 hp gross ended up at 180 net, lol.

You also have to realize that a dynojet dyno is all relative. Relative to what? A 1985 VMax, lol. It's an inertia dyno and uses time to accelerate a known mass to calculate hp, and then by using the hp and rpm, calculating torque. A dynojet doesn't measure like an engine dyno does, so you could make your zeropoint score be whatever you want. Don't look at the power as an end all be all, its more of a tool to see increases and points where tuning can be done.

 

Good post.... Dynojet's can be manipulated in many different ways...

But how about those mustang dyno's!

 

Don't forget the torque convertor steals more HP than a manual does.

 

20% loss in HP in the drivetrain, there's no certain number (not 30 or 40, or whatever).