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Discussion Starter #1
I recently put my 300 SRT8 on a Mustang Dyno, and put down 447/446. Any other 392 owners dyno, and what numbers did you see?
 

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I will be the first to admit Dyno's are not my strong suit.
When I had my 07 model on the Dyno he gave me both figures and always wondered how they know the flywheel HP but never bothered trying to find out.

Those numbers are showing only about 4% loss to the wheels which seems incredible, hence why I was just checking.
 

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Discussion Starter #5
I will be the first to admit Dyno's are not my strong suit.
When I had my 07 model on the Dyno he gave me both figures and always wondered how they know the flywheel HP but never bothered trying to find out.

Those numbers are showing only about 4% loss to the wheels which seems incredible, hence why I was just checking.
I was just messing with you a bit. They usually use a calculation which is normally 15% drivetrain losses to estimate what your flyhweel horsepower is. Today's cars are a bit more efficient, and some have losses as low as 10% if not a bit lower. I have seen 3 dyno in person , and my bosses 392 6 speed put down 446, my 300 SRT with an auto put down 447, and another friends 392 6 speed put down 429. I would imagine that the true output of this engine is actually 500-510 flywheel horsepower.
 

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SRT has a history of underrating their motors. The SRT-4 was rated with a heat-soaked intercooler, which is why most of them dyno around 230hp at the wheels but are rated 230 at the crank. The motor was actually putting out about 270-280 at the crank.
 

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Discussion Starter #9
I was expecting closer to 410 rwhp, and I asked quite a few people what they dyno'd elsewhere. The dyno was in line with their previous numbers.
 

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Dynos are tools for tuning...and you can make a car on a dyno make more HP or less by load factor...so to me that's a high number...maybe not 100% what it really is I think its a little high...The best way to know what your car is really putting down take it to a track run and see what mph and 1/4 mile times are and weigh it and that will get you close to what it is really putting down...
 

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Dynos are tools for tuning...and you can make a car on a dyno make more HP or less by load factor...so to me that's a high number...maybe not 100% what it really is I think its a little high...The best way to know what your car is really putting down take it to a track run and see what mph and 1/4 mile times are and weigh it and that will get you close to what it is really putting down...
Agreed! Lots of factors play into dyno numbers and while the ones your seeing are impressive, they are not inline with the ones I have seen on the 392's... I can see the 420ish one on the high side but on the tune day I stopped at the two I watched were both around 400-415... Which seems about right for drivetrain loss... Good way to tell is at the track... You know the weight, get the times and you will know what it takes to get the job done once calculated... With that kinda power you should be much quicker than most SRT's... Some cars are stronger then others... My stock baseline was almost 20hp more than 2 other C's dynod same day day same conditions, it happens, and SRT is known to under rate. Those numbers are solid, even if a little off (who knows!) be proud of them and enjoy the ride! Good for you!

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Discussion Starter #12
It is a bit cooler here than some parts of the country, and the dyno seemed to be dead on with most other people that had been to a dyno elsewhere. I will be taking it to the track this upcoming spring.
 

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I put down 434hp/414tq on a stock 2012 with only 18k on it.. thought that was pretty good power.. Thursday I'm putting on longtubes, midpipe, and tune.. so I'm wondering how much power I'll gain from that
 
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