better or worse???
04-17-2012, 02:18 AM
#5
Burning Brakes
I don't think the compressor bypass valve should be open at the same time as the wastegate?
I like the extra performance of an open wastegate, but IMHO the noise does not match the character of a Porsche. I'm considering adding a Supertrapp muffler to the wastegate outlet,
like this one:
http://www.ebay.com/itm/SuperTrapp-D...ht_1344wt_1037
I like the extra performance of an open wastegate, but IMHO the noise does not match the character of a Porsche. I'm considering adding a Supertrapp muffler to the wastegate outlet,
like this one:
http://www.ebay.com/itm/SuperTrapp-D...ht_1344wt_1037
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04-18-2012, 02:18 AM
#8
Burning Brakes
04-18-2012, 02:31 AM
#9
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I don't think the compressor bypass valve should be open at the same time as the wastegate?
I like the extra performance of an open wastegate, but IMHO the noise does not match the character of a Porsche. I'm considering adding a Supertrapp muffler to the wastegate outlet,
like this one:
http://www.ebay.com/itm/SuperTrapp-D...ht_1344wt_1037
I like the extra performance of an open wastegate, but IMHO the noise does not match the character of a Porsche. I'm considering adding a Supertrapp muffler to the wastegate outlet,
like this one:
http://www.ebay.com/itm/SuperTrapp-D...ht_1344wt_1037
04-30-2012, 12:08 AM
#10
Burning Brakes
Guess what I did today?
I got tired of the noise from an open wastegate, so I took my own advice and bought a Supertrapp 12 disc muffler like the one I linked above. I was pleased to see that it's USFS approved for use on off road motorcycles as a spark arrester. Install was easy since I can weld my own stuff. The muffler fits 2" pipes, but my wastegate outlet pipe was 1.75". No problem, the muffler inlet pipe tapers down. I just cut an inch off the end until the pipe size matched, then welded them together. I gave it a quick shot of ceramic high temp paint for a stealth look, and to prevent rust since the body is made of mild steel. Here's a coupled pics;
Results are good/not so good. It's definitely quieter. I was driving and boosting with the windows down and the noise was very tolerable. Not the least bit embarrassing at all. The tone was unchanged, still raspy and edgy. With the windows up the noise was even quieter. The bad news is that it's a noticeable restriction. (did I just hear someone say, 'I told you so.' ?)
The only way I was able to know it was a restriction is because I'm running Speed/Density on my car, so any change in VE will show up in the wideband A/F ratio. It was richer at peak torque, around 3800 to 4500 rpm. I pulled out roughly 3% in that area.
* I have a feeling that the wastegate dump is a larger benefit on my car since it still has the stock cat pipe and cat. It just has a 3" cat back right now, so any exhaust removed through the wastegate will relieve a good amount of backpressure. After seeing the results of todays mod I'm very motivated to finish building the rest of the exhaust system.
HTH and BTW I'm keeping it.
I got tired of the noise from an open wastegate, so I took my own advice and bought a Supertrapp 12 disc muffler like the one I linked above. I was pleased to see that it's USFS approved for use on off road motorcycles as a spark arrester. Install was easy since I can weld my own stuff. The muffler fits 2" pipes, but my wastegate outlet pipe was 1.75". No problem, the muffler inlet pipe tapers down. I just cut an inch off the end until the pipe size matched, then welded them together. I gave it a quick shot of ceramic high temp paint for a stealth look, and to prevent rust since the body is made of mild steel. Here's a coupled pics;
Results are good/not so good. It's definitely quieter. I was driving and boosting with the windows down and the noise was very tolerable. Not the least bit embarrassing at all. The tone was unchanged, still raspy and edgy. With the windows up the noise was even quieter. The bad news is that it's a noticeable restriction. (did I just hear someone say, 'I told you so.' ?)
The only way I was able to know it was a restriction is because I'm running Speed/Density on my car, so any change in VE will show up in the wideband A/F ratio. It was richer at peak torque, around 3800 to 4500 rpm. I pulled out roughly 3% in that area.
* I have a feeling that the wastegate dump is a larger benefit on my car since it still has the stock cat pipe and cat. It just has a 3" cat back right now, so any exhaust removed through the wastegate will relieve a good amount of backpressure. After seeing the results of todays mod I'm very motivated to finish building the rest of the exhaust system.
HTH and BTW I'm keeping it.
