Exhaust Systems - Tutorial?
07-26-2007, 02:06 PM
#16
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Thread Starter
It was Greg and David's chip GB that has me on this topic. Thanks guys. I'm trying to decide if I stay stock (current set up) or order a chip that assumes a modified exhaust.
07-26-2007, 02:54 PM
#17
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Originally Posted by TR6
I've been thinking about doing some exhaust experimenting using a dyno to determine where the most bang for the buck is.
07-26-2007, 05:35 PM
#18
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Originally Posted by Ritter
when describing sound levels to the 993 forum of my exhaust set-up, I used a sound pressure meter from Radio Shack (= cheap) to give absolute and relative values. You might consider the same
Originally Posted by Ritter
What was the cost of the dyno btw? Is it by time or pull? Do they give time and space to make the changes you want?
07-26-2007, 05:43 PM
#19
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Originally Posted by JasonAndreas
If you do go through with this try not to use a dynojet or any other inertia chassis dynamometer. ...
Originally Posted by JasonAndreas
Also bring along a Bosch Hammer so that you can match the initial cylinder head, intake air and oil temperature between runs. ...
Originally Posted by JasonAndreas
Otherwise the results will be so skewed as to almost be meaningless. ...
Originally Posted by JasonAndreas
And if you are going for ultimate accuracy you might want to get copies of the results averaged (the results dyno operators usually provide) and raw so that you can calculate an error percentage. The averaged results are more accurate but if there is a +- 15HP error rate...
07-26-2007, 06:53 PM
#20
Here are the flow rates of the 964 exhaust components
Catalytic Converter 442
Primary Muffler 396
Secondary Muffler 462
All are CFM
Best to consider them in comparison to each other. As You can see the most restrictive component is the Primary muffler
Catalytic Converter 442
Primary Muffler 396
Secondary Muffler 462
All are CFM
Best to consider them in comparison to each other. As You can see the most restrictive component is the Primary muffler
07-26-2007, 07:26 PM
#21
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Originally Posted by TR6
I've been thinking about doing some exhaust experimenting using a dyno to determine where the most bang for the buck is. Right now, I'm running Cat Bypass, OEM primary muffler, and secondary bypass. The sound is great, but I'd rather have the horsepower and torque if there is more to be made. I've thought about trying two different alternate configurations to what I have now:
1) cat bypass, primary bypass (cup pipe), and OEM secondary
2) cat bypass, primary custom built 'sport free flow muffler', and secondary bypass.
Of the two options above, #2 should offer the most weight savings because I'd lose probably at least half the weight of the primary muffler and still lose the secondary weight too. I've thought about taking an OEM primary up to my local exhaust shop and having them cut both end pipes off and mate them to a straight through free flow muffler (like a glass pack). The whole custom muffler assembly would fit in the same spot as the OEM muffler and mate up on both ends using the orignal connecting pipes. My concern is that it may be too loud for street.
1) cat bypass, primary bypass (cup pipe), and OEM secondary
2) cat bypass, primary custom built 'sport free flow muffler', and secondary bypass.
Of the two options above, #2 should offer the most weight savings because I'd lose probably at least half the weight of the primary muffler and still lose the secondary weight too. I've thought about taking an OEM primary up to my local exhaust shop and having them cut both end pipes off and mate them to a straight through free flow muffler (like a glass pack). The whole custom muffler assembly would fit in the same spot as the OEM muffler and mate up on both ends using the orignal connecting pipes. My concern is that it may be too loud for street.
I had the same on my RSA, using the Fabspeed cat bypass(dual wall, lightly muffled). Nice weight reduction, not objectionable in cruise.
Noah
07-26-2007, 11:32 PM
#22
Technical Guru
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Originally Posted by TR6
Fine, but where can I get a Bosch Hammer? Is it a tool that mere mortals can afford?
Originally Posted by TR6
Wouldn't the relative difference in horsepower/torque offer any meaningful insight into the positive or negative effect of the mods when you compare runs?
Originally Posted by TR6
I need to do some reading on the subject.
