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Discussion Starter #1
Does anyone know where the extra 5 hp for the 6 sp model comes from?

Thanks
 

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Where are you seeing this?

Granted the 6-speed uses a slightly different motor (well, same motor -- just without MDS) I don't see why there would be a HP difference.
 

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Page 6 of the new Dodge Challenger Brochure indicates a 5 hp increase for the 6 sp over the automatic for the R/T. Increase in torque as well.

It may be the exhaust but I'm not sure.

Thanks.
 

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Hmm. Yea, exhaust could be it. 6-speed exhaust (both R/T and SRT8) have the mufflers removed and two resonators in its place. Perhaps that is responsible? *shrug*
 

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Could be because of the new VVT in addition to the absence of MDS on 6-speeds, or maybe the added inertia from the heavier flywheel? Whatever the reason, I'll take it!:)

Jack
 

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Not sure how they measure horsepower these days.. But Pretty sure it takes more horsepower to run an automatic. (less horsepower to the ground) maybe thats the 5 hp gain in the 6 speed...
 

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Well I'm not 100% but I think you lose about 2% more power with an automatic transmission. It takes a bit more power to change gears itself and with the manual your doing all the clutch work and the tranny is a bit more simple.

Its not that the manual has +5 hp... Its actually the automatic that has -5 hp.
 

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Per the link on Allpar I'm guessing the hp difference comes from the cumulative changes of the muffler-free exhaust and the special power steering pump. On a chassis dyno maybe one would expect the difference to be even greater than 5 hp, since manual cars regularly put down more than comparable auto cars due to the parasitic losses. We'll find out soon enuf I'm sure.
 

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Oh wait... Ignore me heh.. I'm thinking whp but I guess these ratings are at the crank so the tranny wont really come into play... Ok well I'm at a loss then...

My explanation would be one that would apply to a whp rating..
 

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Oh wait... Ignore me heh.. I'm thinking whp but I guess these ratings are at the crank so the tranny wont really come into play... Ok well I'm at a loss then...

My explanation would be one that would apply to a whp rating..
This is true. The OEM's don't rate at the rear wheels. It's most likely the as mentioned earlier the diffent exhaust. I also was told that the exhaust was the only thing different between the Ram's 390 hp 5.7 and the Challengers 370/375 hp engine. Don't know how true it is though.
 

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This is true. The OEM's don't rate at the rear wheels. It's most likely the as mentioned earlier the diffent exhaust. I also was told that the exhaust was the only thing different between the Ram's 390 hp 5.7 and the Challengers 370/375 hp engine. Don't know how true it is though.
Actually from what I've heard about this the trucks supposedly have a different tune.. So maybe its an exhaust and tune that separate the two?
 

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The 5.7L 6sp is a Premium Fuel Only package while the 5.7L Atx MDS are Premium Fuel Recommended. Therefore the manual rating is done on Premium while the auto is mid grade which explains the torque difference.

Unique exhaust tuning for the manual with reduced back pressure is responsible for the power difference.

The 5.7L RAM has an active short/long runner intake manifold and unique cam grind relative to the Challenger/Charger/300C.
 
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