Stock HP @ Wheels

[Equinox]

I've gotten a lot of figures on the stock hp AT THE WHEELS from people, and none of them match up, but here we go trying to find the truth.

Okay, 2002 Protege5:

At crank: 130hp, 135tq
Source: Mazda

At wheels: 123.9whp, 126.6wtq
Source: Turbo Magazine, Aug. 2002 - Vol. 18 No. 8

At wheels: 110whp, 107wtq
Source: Thread posts

 

[Woody]

EQUINOX,

That figure from Turbo Mag seems way off the mark - someone screwed up there.

I dynoed my P5 locally (its posted here by the way) with less than 2,000 miles on the car, and got 105 peak at the wheels before mods.

I have more experience dynoing sport bikes, and I know from this that dynos can very a few hp from one to another. I don't know why this is true, but it is.

The other thing is that my dyno shop (Elite Motorsports - Mpls, MN) told me is that although dyno equipment is supposed to compensate for outside heat, and humidity, weather can still account for a few hp difference. This is why I am waiting for cooler weather to re-dyno my car again after mods. My benchmark was about 60 degrees F, and low humidity - I am waiting until our weather gets close to this again before I re-dyno.

I hope this helps.

- Woody

 

[sundevilMP5]

yeah...as much as i'd like to believe that figure from turbo magazine i'm very suspicious about it...however it does make me feel good that a lot of people now believe that our cars are very competent and strong in the engine area...lol

 

[nramsey]

The 105-110 number sounds about right. Typical drivetrain losses for most cars are usually in the 20-30 HP range.

 

[redwagon02]

I think its 20-30 percent, not HP.

 

[redwagon02]

Well, probably lower percentage figures. 30% seems quite high.

 

[Traveler]

Most figures I've seen are around 98-101HP at the wheels. I've got a 2001 ES that dynoed at 101 with the J-spec intake cam in it. The dyno place I go to uses a dynojet but it may just compensate a bit low. I've had it on there 3 times now and am up to 113.4 HP and 119.1 TQ with all the mods I've done.

 

[nramsey]

I think its 20-30 percent, not HP.

Actually not really. If you add 30 more horsepower, it's not going to take 9 more horsepower to turn the turn the drivetrain.

Several folks have done engine and chassis dynos on Miata engines and found a consistant ~26 HP loss whether the engine was putting out 100 or 200 horsepower.

 

[redwagon02]

It's still a percantage though. Saying 20-30 hp loss for most cars is misleading.

 

[twa]

Drivetrain Loss

123 at the wheels would be great and only a 5% drivetrain loss. But.....110 is probably right on the money for most cars off of our assembly line. 15% isn't a bad amount of drivetrain loss. 20-30% would be ridiculous though. To me that would be an unacceptable amount of drivetrain loss.

 

[nramsey]

It's still a percantage though. Saying 20-30 hp loss for most cars is misleading.

But the percentage isn't consistant either. If you have a stock P5 with 130 at the crank, you will have around 20% loss. But if you have a P5 with a turbo and over 200 at the flywheel you won't still have 20% loss, will be more like 10-15%. You won't all of a sudden be loosing 20 more horsepower through the driveline

 

[redwagon02]

No Doubt! Big cars, small cars, FWD, RWD, AWD..... all play a contributing factor on the percentage loss.

 

[Equinox]

Thanks for the constructive criticism guys, I really appreciate it. So pretty much we have the same horsepower at the wheels as a Honda del sol has at the crank