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Discussion Starter #1
Guys over at HGMotorsports put a CLA Edition 1 on the Dyno completely stock and compared with Mercedes numbers.

Mercedes rating at the crank:

208 HP
258 ft/lbs

HGM rating:

181 HP
249 ft/lbs

 

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Interesting.. this mean that Mercedes numbers are fibbing??
 

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Booker,
This brings up a question that I'm curious about Merc says 208 hp, but I have also seen mention of a short term overboost available. Can anyone give details about this overboost? Did HP find it, or even look for it?
 

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Nashville brings up a good point. While the generally accepted loss is 15%, it varies by lubricant, engineering, fwd vs. rwd, auto vs. manual (don't forget this car does not have an automatic, it has a 'dual clutch', and "could" be as efficient as a manual), and finally the dyno itself.
Even though most dyno operators try to adjust for standard conditions, it is rare to find two dynos that produce the same numbers, even machines from the same manufacturers. Take all these numbers with two grains of salt. Tuner A's dyno will show 200 whp while Tuner B will have 215. Is B better? The answer is only, maybe.
 

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Sounds about right.
 

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This is my first time buying a German (or foreign) car. Maybe MBUSA took the German BHP number and didn't bother with noting that it is BHP? I know in general I can't recall any US car's power listed as BHP. That would explain the ~12% difference in the dyno and the crank, like Nashville and vracer.

Doh! I didn't make the connection of "at the crank." Boy am I tired. Yeah, so the 208 is probably BHP.
 

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Discussion Starter #9
Nashville brings up a good point. While the generally accepted loss is 15%, it varies by lubricant, engineering, fwd vs. rwd, auto vs. manual (don't forget this car does not have an automatic, it has a 'dual clutch', and "could" be as efficient as a manual), and finally the dyno itself.
Even though most dyno operators try to adjust for standard conditions, it is rare to find two dynos that produce the same numbers, even machines from the same manufacturers. Take all these numbers with two grains of salt. Tuner A's dyno will show 200 whp while Tuner B will have 215. Is B better? The answer is only, maybe.
hey vracer CLA does have overboost just not advertised. Same as BMW's 'button'. Mate the CLA's pedal with its floorboard and you'll see an extra 13hp and 15 lb-ft in breif bursts. 2014 Mercedes-Benz CLA 250 Sport First Drive - Autoblog

Also about HGM's dyno if you click through to the Youtube link they claim their dyno is called the heartbreaker because it gives typically lower numbers...

TBH it wouldn't be right to include the kickdown in the dyno tests becasue its not sustainable performance IMO.
 

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Mercedes rating at the crank:

208 HP
258 ft/lbs

HGM rating:

181 HP
249 ft/lbs
These numbers seem right, you do lose some power going from the crank to wheels, it's expected in every car.

BTW the CLA sounds great!
 

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a drop of 27 horsepower is not terrible but it is significant. I bet you that Mercedes published the best possible scenario for the CLA. But when you test it in the real world there is variation.
 

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Discussion Starter #12
a drop of 27 horsepower is not terrible but it is significant. I bet you that Mercedes published the best possible scenario for the CLA. But when you test it in the real world there is variation.
its mechanical drag. When you measure power at the crank like most published stats are you bypass the mechanical drag that comes from gearbox and driveline components, the CLA difference between dyno and crank measurements is ~12% pretty average IMO
 

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I can't believe that there are still people that don't know how a dyno works? I mean, don't we all have one in our garages now days? I do..
 

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Dynos will always read lower than what manufactures rate them at. Wheel Horse Power is different than Crank hp which is how all manufactures typically rate their engines using engine dynos. Ive heard Renntech is in the works of a plug and play tuner which should be released in the next 6-8 weeks.
 

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Dynos will always read lower than what manufactures rate them at. Wheel Horse Power is different than Crank hp which is how all manufactures typically rate their engines using engine dynos. Ive heard Renntech is in the works of a plug and play tuner which should be released in the next 6-8 weeks.
Might be time for car makers to start giving us numbers at the crank and to the wheels. I would like to know both, so would many others.
 

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that would be hard to do though, sadly. sometimes there are "factory freaks". what i mean by that is you could have two identical cars and one would have 20 more HP than the other. happend on my brothers integra TYPE R
 
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