[Steveng93]

ford advertises it as 300 hp.. im hearing 275 ish.. is that true? and if so.. wtf how is that possible to drop 25 horsepower, or what is ford doing so that they can advertise at 300 hp.. or was it never 300 and they are lieing.. can someone just explain it all to me please? (:

[travelers]

300 HP is at the flywheel. The 275 is at the wheels.

[Steveng93]

what does that mean lol ^.^

[travelers]

The 300 hp is what it's ratted at on an engine dyno. The 275 rear wheel hp is read on a chaise dyno.

[jep23]

Yeah Ford rates it at the flywheel. There is a certain percentage that gets lost through the drivetrain. So there is only 275-ish at the wheels.

[UofASouthpaw]

Flywheel = last piece of the engine before the power is transferred to the transmission. So the power going INTO the transmission from the engine is 300.

But every vehicle has power losses in the transmission, u-joints, differential, wheel bearings, etc. So the power coming out of the axle and going INTO the wheels is closer to 275.

[AvroAero]

Originally Posted by Steveng93

ford advertises it as 300 hp.. im hearing 275 ish.. is that true? and if so.. wtf how is that possible to drop 25 horsepower, or what is ford doing so that they can advertise at 300 hp.. or was it never 300 and they are lieing.. can someone just explain it all to me please? (:

Every company advertises flywheel numbers, except maybe exotics. Subaru might also do bhp too. Flywheel is always higher.

[rltrahan]

Originally Posted by Steveng93

ford advertises it as 300 hp.. im hearing 275 ish.. is that true? and if so.. wtf how is that possible to drop 25 horsepower, or what is ford doing so that they can advertise at 300 hp.. or was it never 300 and they are lieing.. can someone just explain it all to me please? (:

Understand that the steel bearings in the differential, the extremely over weighted 2 piece stock drive shaft and stock windage tray that puddles the oil on to the crank causing uneccasary resistance can be replaced with an aluminum drive shaft, ceramic coated bearings and an efficient windage tray to let loose about 15 of those horses. But thats if you feel that route would be a good choice given the cost of aluminum drive shafts and the durability of ceramic coated bearing. Beleive it or not and Ive tested this theory but a larger oil pan with a good draining windage pan can relieve allot of that HP loss with properly draining the oil away from the crank as to not constantly slop it back on to the crank leaving more oil and resistance to drag down the performance. Even though its not behind the flywheel once that energy is dispersed all the way through to the crank shaft it has a cause and affect starting from the pulley all the way back. Weve played with this Idea at the shop and tested it with an actual gain of over 300 on a stock motor with a stock tune. But again thats Aluminum crank pulley to the larger capacity oil pan with a good windage tray, to a aluminum groung flywheel to a aluminum drive shaft to a differential with ceramic coated bearings, all in all about $1600 for the total. Is it worth it, sure if you have money to blow but that $1600 is a good chunk for saving towards a supercharger, hands down the best possible mod dollar per HP you can get.

[ski]

Also, the rear wheel hp(rwhp) will vary all over the place due to the following factors:
1- Auto trannys chew up more hp than manuals.
2- Some S197 GT's come straight from the factory with more power than others simply due to manufacturing and assembly differences in the engines.
3- Different dynos(devices that indicate rwhp) give different results, e.g., a Mustang dyno will show less rwhp than a Dynojet dyno.
4- Some dyno numbers are uncorrected for temperature, humidity, and atmospheric pressure(higher hp), while other numbers are SAE corrected(lower hp).
5- Some dyno runs are performed on cars with cooled down engines(higher hp), while other runs are done on cars with heatsoaked engines(lower hp).

[GAP]

Even at 275rwhp STD, that would be 323hp assuming 15% drivetrain loss.

[stlwagon]

Originally Posted by AvroAero

Every company advertises flywheel numbers, except maybe exotics. Subaru might also do bhp too. Flywheel is always higher.

BHP and flywheel horsepower are the same thing.

[pwmustang06]

I've never seen an auto company that rated at the rear wheels. As everyone has said all cars are rated at the flywheel.

For example, here's a blog entry for the Corvette ZR-1. It's rated at 638 hp at the flywheel and the dyno measured 535 rwhp. That's a 16% drive train loss. Pretty much what you'd expect.

Corvette ZR1 dyno'd at 535 rwhp

Not to be confused with net hp vs. gross hp. Prior to '72 most auto manufacturers used gross hp ratings, that is a test engine running on a stand with no losses at all. Totally unrealistic. Today's ratings are net hp, so an engine measured with everything, except drivetrain loss. It's much more accurate.

For example, a 1971 Corvette with a 454 big block was rated at 365 hp. That sounds impressive doesn't it!

The 1972 Corvette basically the same engine, rated with the now common SAE net standard was 270 hp. I'm guessing with a 15% drive train loss it would have dynoed in at 230 rwhp.

[dtuna42]

and the bottom line is..... it's all just numbers.... just go drive the car and have fun, and if it's not fast enough, open up the wallet and start modifying!!

[apex8199]

a stock gt on the dyno puts out around 250-260 at the wheels

[stlwagon]

Originally Posted by apex8199

a stock gt on the dyno puts out around 250-260 at the wheels

And as low as 235 and as high as 285.