Afterhours automotive just put on their new mufflers on my car and also dyno'd the car for me.
I was wondering if anyone could interpret the results.
I am pretty sure there wasnt much gain because i already have other mods, flash headers and cold air intake.
but was wondering if it looks like there is any other loss due to these mods?
if anyone is wondering, the afterhours muffler is just awesome, if you are thinking about a more tame bypass pipes sound, with the benefits of a sport muffler this has to be the best and only option.

 

I can't really help with the dyno result but I'm wondering what are the mods you got in your car?

 

hp 328 tq283

 

Overall it looks like a small gain, but not enough to think about, overall I would say the mod left you about even on power, on another day on another dyno you might see losses you might see a gain.

 

yeah, but how bout the dyno itself. not worried about the mufflers

 

Your car had somewhere around 308hp stock... if that helps with what you're looking for.

 

yeah, kinda.
so do you think the K&N intake might be causing me to lose power.
doesnt the 997s have 350 hp or something?

 

oh, i understand now, the 308 is what my car should be stock on the dyno, and then you multiply that by 1.165 to get the hp to the wheels?
so it looks like i am still above stock. i know these dynos are never perfect but i just wanted to make sure it wasnt showing a loss of power.
thanks

 

B-morebroker got 352.4HP for his, that multiplied by 1.165 = 410.5 HP
yours shows 327.9HP, by 1.165= 382 HP

382 - 355 = 27HP gain

 

yeah, but he also had large differences with the same mods on different runs...
i dont believe these dynos are the best way to measure power, i just wanted to make sure at least it showed more power than stock.
i only have flash, cold air intake, headers and mufflers, so 382 compared to stock 355 is pretty good. dunno which mods gave the most power, or if anything at all since i dont have a dyno with everything oem.

 

I don't know either but I think high flow cats will get you the most gain

 

Guys... First of all, I'm not trying to be a know it all here. But I want to suggest a different way of computation, that I think is actually the right way. Guesses at driveline loss, etc, are much more ambiguous and vague. I will post this on B-More's thread too.

Givens:
You have to have a given as to what a car made at the wheels STOCK. Most come in around 308, as I said. That's what I'll use for my computation.
Also, we will assume that 355 was the ACTUAL HP at the crank. In other words, we'll assume Porsche to be 100% correct.
We'll assume that there's nothing lost in the dyno from stock measurement to modded measurement, including environment. This is unimportant since we are using my stock number here. Just wanted to note it.

Here's how you set up the math.

In prose layout, it goes:
"Stock rear wheel horsepower is to stock engine horsepower as modded rear wheel horsepower is to modded engine horsepower." Simple enough. This assumes a steady rate driveline loss.

So it is set up like this:

308/355 = 328/X

Work this out and you get that you now have 378 crank hp. A gain of 22hp.

This equation takes out an assumed multiplier and makes it all based on your car's actual performance numbers (again, assuming Porsche was spot on with the 355).