opinions on Cobb DP and Test pipe
May 14, 2014, 02:27 PM
#6
I've had great experience with Cobb products. I have the Cobb High Flow Cat installed and it works great however I can't recommend Cobb's Downpipe.
The Cobb downpipe only replaces the lower portion of the downpipe which isn't addressing the real problem with the stock downpipe which is the small diameter and sharp curves of the bell housing (top portion). It also does not include a flex section.
You will be much better served by going with one that replaces the upper bell portion of the DP and includes a proper flex section to isolate engine vibration/movement from the rest of the exhaust.
Here are a couple examples:
AMS Downpipe - Widely considered to be the best flowing pipe and has great build quality though it is pretty heavy.
MAP o2 eliminator Downpipe - good design, quality build fairly light weight. Available in recirc or external dump variations. Recirc (like shown in the picture) will put the discharge from the wastegate back into the exhaust system. This gives minimal performance impact and keeps sound levels in check. The external dump will dump wastegate discharge out the bottom of the car without putting it back into the exhaust. The result is less turbulence in the exhaust and will result in a very loud exhaust note when the wastegate is discharging (normally only under full throttle but it depends on your setup)
Several other brands are available but these are the 2 basic designs that you are likely to see which will replace the entire downpipe and not just the bottom half.
Here is a video that shows the effect of an external dump:
The Cobb downpipe only replaces the lower portion of the downpipe which isn't addressing the real problem with the stock downpipe which is the small diameter and sharp curves of the bell housing (top portion). It also does not include a flex section.
You will be much better served by going with one that replaces the upper bell portion of the DP and includes a proper flex section to isolate engine vibration/movement from the rest of the exhaust.
Here are a couple examples:
AMS Downpipe - Widely considered to be the best flowing pipe and has great build quality though it is pretty heavy.
MAP o2 eliminator Downpipe - good design, quality build fairly light weight. Available in recirc or external dump variations. Recirc (like shown in the picture) will put the discharge from the wastegate back into the exhaust system. This gives minimal performance impact and keeps sound levels in check. The external dump will dump wastegate discharge out the bottom of the car without putting it back into the exhaust. The result is less turbulence in the exhaust and will result in a very loud exhaust note when the wastegate is discharging (normally only under full throttle but it depends on your setup)
Several other brands are available but these are the 2 basic designs that you are likely to see which will replace the entire downpipe and not just the bottom half.
Here is a video that shows the effect of an external dump:
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