Sorry to disappoint - but theres
no way that MPH and weight = 500HP. PERIOD
113 mph at 3600lbs = a flat 12, and appx 400 FWHP.
Rule 1 - gears don't effect the trap speed that much, so it doesn't matter if he was running 4.11s or 3.23s- the MPH/weight tells the story -
I don't know if thats what RYan told you, or you got the MPH and used one of these on-line calculators, MOST of which are wrong.
Big statement I know, but read on..........
Rule 2 - Most of the on line calculators are based on the Moroso slide rule -
(Without getting too antsy - A lot of guys out there like to think its RWHP because they can then say that their engines are making X+ more HP than they actually are).
But here's the reasons why its not RW hp:
Rule 3 -
The reality is the Moroso (and therefore the Mopar charts in the books) deal in FWHP -
How do we know? Well,
1st / Mainly and most obviously because to deal in RWHP, there are far too many losses and variables to be sure and arrive at a constant formula. (losses through converters, tyre size, etc) make it impossible to arrive at a predictable Rear Wheel output....
In summary - the Moroso does not take into account "20% drivetrain losses" for one car, and "25%" for another. How can it ?- Its a simple tool based on a set of known constants and trialled data.
So - the Moroso has to be FWHP - and therefore the Tech charts also.
To prove this case further - Lets take an example:
The chart says for a 3600lb car - its making 400 "RW" HP :bootysha: to run 113mph.
Why do we know this is false?
Well, if we reverse the situation, that means that it takes 500 FWHP to run the same flat 12 sec qtr. (assuming 20% losses)
I'm sure most experienced racers will agree with me that a 500FWHP car which is well set up will be in the flat 11s and running appx 121 mph..... NOT the 12s at 113.
- In fact Im sure there's plenty on here who've dynoed their engines and fit this equation almost perfectly.
Id even go so far as to say take any KNOWN engine thats been on an engine dyno and see what times the car subsequently runs - 99% of the time the Moroso will agree with the engine Dyno and reveal that the "RWHP" assumption is incorrect.
Moving on - the purpose of this post is not to "can" what Ryan has said - I dont know how the quoted 113/500HP figure was arrived at - But there's a lot of folks out there who still don't realise the HP calculators are not RWHP.
Most of the time, when the car runs a full second slower than the "HP" they THINK the engine should be making (Cos its never dynoed) , they look at other areas - without understanding how the Moroso calculator was invented.
Another example - The car in the vid is a full weight appx 500 FWHP 360, No big arm, NO gas, 3600lbs, sorted over a period of 7 years , no traction issues, J heads (yep Js....) that flow appx 280 CFM, rear leaf sprung etc.
Basically its as "sorted" as you'll ever see for the fairly straight fwd engine combo it is.
Its best was 10.89 at 123 mph through the Magnaflos- Yep - thats 500HP for a consistent 123 mph.
This was an earlier run in its build as far as I recall......476 FWHP - 118@3600lbs = 11.18
No way no how is 113mph making 500FWHP. :-D
http://www.youtube.com/watch?v=YLt-YmaJuJk
