Dyno results.. - Page 3

trularin · #41 (**permalink**) 07-29-2009, 10:38 AM

What? Me imply such a thing...never.

Isn't that part of the fun? You never really know where you are going to land.

ItBites · #42 (**permalink**) 07-29-2009, 12:10 PM

Mine dyno'd 540 rwhp on a fluid (not inertia) chassis dynamometer. The build on my pump-gas, street 540 cid engine should have produced about 675hp at the crank. I have IRS and an automatic transmission.

Assuming 20%loss in the trans and IRS, 675 crank hp equates exactly to 540rwhp. I think 20% loss is a pretty good number for Cobras.

BTW, I custom built equal length (34" primaries) headers with merge collectors. I think a good exhaust is crucial.

Also, good tires really help the traction issue. The cheapest way to improving your car's ACTUAL performance is to shoe it with the best rubber you can buy. I run Toyo R888s, and lower the pressure.

greg schroeder · #43 (**permalink**) 07-29-2009, 12:14 PM

Just take the car to the drag strip and get a trap speed.

MPH doesn't change much regardless of your time. Time is more related to how well you start rather than power.

Use the weight of your car and mph to calculate your power. Correct the numbers to sea level and you have a reasonable comparison to others or your own car on diffrent days or after changes.

http://www.prosystemsracing.com/calculate.html

http://www.modulardepot.com/density.php

olddog · #44 (**permalink**) 07-30-2009, 08:37 PM

It would seem to me that side pipes robbing Hp is like the government taxing income. The more you have the bigger percentage they will take.

I doubt 200 Hp measured on an engine dyno would suffer much loss with relatively open side pipes, but a 600 Hp engine through the same pipes would get killed.

Not that I am trying to argue less power is more. Just that the amount of losses most likely increases exponentially, as you build more power. Certainly there is a point of diminishing returns, not that I am smart enough to tell anyone where that is at.

patrickt · #45 (**permalink**) 07-30-2009, 08:46 PM

Quote:

Originally Posted by olddog

It would seem to me that side pipes robbing Hp is like the government taxing income. The more you have the bigger percentage they will take.

I think you're right. Plus, on my pipes, I had Stainless Specialties make them a little "more quiet." That most assuredly robs more horsepower, but it makes the car a little more pleasant to drive. Maybe it's my imagination but I'd swear that my car has gotten a little quieter over the last couple of years. Either that or I just don't notice it as much or I'm losing my hearing.