MSD Dashhawk "Instantaneous Power" readout

[JamesCH]

The instant power readout seems to be pretty sophistocated in terms of how it calculates the power your car is putting down, but apparently my car with only a few intake mods is good for ~370 crank HP, which seems unreasonably high to me. Before anyone asks I wasn't spinning out or seeing wheel hop, and I am just as skeptical of this readout as...well... some guy who is pretty skeptical about it.

I was hoping to see if anyone out there in Mazda Land has a DH and has a dyno chart to see how the two compare so I can get a *rough* idea about how accurate the DH is and an even rougher idea of how much power my car is putting down. There aren't any dyno shops within 100 miles or more of where I live, unfortunately.

 

[b00bs for n00bs]

not accurate by any means. don't know why. don't have a chart to compare it to. but it's not accurate.
just like the 0-60 and 1/4 mile times aren't accurate either.

 

[BillTheCat]

Well, the engine is rated by Mazda at 263hp, and that'd be crank hp, not wheel hp. So, if you figure in the usual variances in testing methods, plus manufacturing tolerances, etc., you'd still think most of our engines should be in the 250-275 crank hp range.

370 is just pure insanity without appreciable mods.

 

[JamesCH]

Read mods in my sig, not an amazing amount, but enough to put down some respectable power. Also consider that it's pretty cold out where I live right now so the intake charge temperature is generally nice and cool. (shrug)

 

[BillTheCat]

Yep, I read your mods previously. I stand by my statement. 370 is pure insanity.

This may seem like a stupid question, but did you set the weight, frontal area, and coefficient of drag in the DH settings?

Curb weight for the 2007-2009 is listed at about 3,150 lbs., but you need to add you & your usual possessions to that.

Coefficient of drag should be .32 unless you have made exterior mods that would alter it.

Frontal area should be 25.5 sq. ft.

 

[JamesCH]

That's precisely what I have. I set the weight at 3350 lbs for car+myself+50lbs of stuff. I carefully read the MSD documentation that said it estimates CRANK hp, so if it's estimating for a RWD configuration instead of a FWD configuration you'd have to subtract 10-12% off the total figure, which would mean ~330crank HP which is slightly less than total insanity (I agree that 370 was WAY too high).

My basic thought with this thread is to get enough information to set the weight in the MSD DH artificially low so that it will give a saner power number, and I was hoping to find someone with the MSD readout and a dyno chart so I can have at least one data point to work out the adjustment.

 

[b00bs for n00bs]

it would probably be different for any two people who would compare dynos and dh readings.
each dyno is different and everyone drives differently. i think you said there was no wheel spin when you measured, but if someone else is testing this, maybe their wheels did spin causing the reading to be even more inaccurate.
you want to know how much power your car has? go to a dyno and don't use the dh

 

[JamesCH]

Well yeah, if I wanted more exact numbers I'd go to a dyno, goes without saying. I just want a slightly-less-ludicrous-than-370hp readout, that's all.