question for the horsepower Gods
Thread Starter
Lexus Test Driver
Joined: Apr 2002
Posts: 1,323
Likes: 0
From: Ft. Lauderdale, FL
question for the horsepower Gods
So i've been wondering, with the old way of calculating hp, it seemed that horsepower to the wheels was about 15-20% lower than crank hp if the car had an auto tranny Now my question is, that with the new SAE corrected numbers... for example the IS350 having 305ish SAE hp, would its real world wheel hp still be about 15% less, or is the SAE number going to be closer to the wheel hp number??
Pole Position
Joined: Oct 2005
Posts: 303
Likes: 0
From: CA
It seems like the ratings are fairly close to the wheel hp ratings. The new Honda Civic Si for example has been shown to put down something like over 210+ hp at the wheels even though it's advertised as 197hp at the crank. It's probably mostly Honda underating the car but I think for the most part, new SAE hp ratings on manual cars will probably put down at the wheels around the same amount that is rated at the crank. Maybe a 5% drivetrain loss on manuals and 10% on auto's. We'll just have to wait and see until people start putting more new Honda and Toyota cars on the dyno. Apparently Nissan decided they are to cool to update their numbers so we can't use them. 
Driver
Joined: Dec 2003
Posts: 160
Likes: 0
From: Michigan
Originally Posted by DrUnBiased
It seems like the ratings are fairly close to the wheel hp ratings. The new Honda Civic Si for example has been shown to put down something like over 210+ hp at the wheels even though it's advertised as 197hp at the crank. It's probably mostly Honda underating the car but I think for the most part, new SAE hp ratings on manual cars will probably put down at the wheels around the same amount that is rated at the crank. Maybe a 5% drivetrain loss on manuals and 10% on auto's. We'll just have to wait and see until people start putting more new Honda and Toyota cars on the dyno. Apparently Nissan decided they are to cool to update their numbers so we can't use them.
Pole Position
Joined: Oct 2005
Posts: 303
Likes: 0
From: CA
Originally Posted by AgentWD-40
I know the new SAE ratings won't let you over rate, I also thought you couldn't under rate either. I thought it was pretty much reported it as is. Perhaps that is incorrect though.
Thread Starter
Lexus Test Driver
Joined: Apr 2002
Posts: 1,323
Likes: 0
From: Ft. Lauderdale, FL
Yea I think its playing a very dirty game if a good amount of the world has recalculated to SAE, but certain manufacturers haven't. Majority of the public has no clue between the difference of SAE or the old method crank hp or wheel horsepower.
Guest
Posts: n/a
Originally Posted by DrUnBiased
Yeah you know thats a good point. I wish ALL manufacturers would update their numbers so it wouldn't be so confusing.
Trending Topics
ClubLexus Stories
Celebrating Lexus & Toyota from Around the Globe
8 Tips for Improving Your Hybrid or Plug-in Hybrid's Efficiency!
Michael S. Palmer
10 Best Lexus Models No One Remembers
Joe Kucinski
TRD Off-Road Premium: Best 2026 4Runner, Except This One Thing
Michael S. Palmer
Top 10 Lexus & Toyotas to Drive Before You Die!
Joe Kucinski
Top 10 Lexus/Toyotas With The LEAST 5-Year Depreciation
Joe Kucinski
Lexus LC500 Convertible Auction: A Preview of Rising Values?
Brett Foote
GX 550 vs TX 550: Best 3-Row Luxury Lexus Family Hauler
Michael S. Palmer
9 Best Lexus Models You Can Buy for Half Price (And 1 You Shouldn't!)
Joe Kucinski
2026 Lexus NX Buyer's Guide: Models, Features, Prices & More!
Brett Foote
Thread
Thread Starter
Forum
Replies
Last Post
