E92 stock exhaust pipes diamater?

ontopofm · 05-13-2009, 12:37 AM

Are they 2.25" or 2.36"? I've searched and found those numbers in different threads. I have the 2.5" high flow cats but if the pipes are 2.25" I will need to return them and reorder the right ones before I have the pipes cut. Thanks

Zeph · 05-13-2009, 09:36 AM

good question. I always assumed they were 60mm which I believe is 2.36 inches. Last time I checked Germany was using the metric system

scalbert · 05-13-2009, 12:48 PM

60 mm is correct.

JoeyFiasco · 05-13-2009, 01:02 PM

but 60mm is 2.4" haha or is that the overall diameter and 2.36" would be the internal?

scalbert · 05-13-2009, 01:05 PM

60mm is the ID. So a 2.5 inch ID pipe will slide right over it (some pipe may be loose while others require some assistance).

Zeph · 05-13-2009, 01:06 PM

which is why most aftermarket stuff in the US is 2.5" so it is slightly bigger (good) and I believe the HKS exhaust is actually 65mm to accomodate all of these 2.5" downpipes.

60 millimeters = 2.36220472 inches

65 millimeters = 2.55905512 inches

ontopofm · 05-13-2009, 10:08 PM

thanks guys, so 2.5" high flow cats are perfect

scalbert · 05-14-2009, 08:03 AM

Yes; however, you will need to get a shop to weld them up as 2.5 inch cats are meant to slip onto 2.5 inch ID pipe. In other words, do not expect to use clamps. But I doubt that was the plan anyway.

ontopofm · 05-14-2009, 09:55 AM

Quote:

Originally Posted by scalbert

Yes; however, you will need to get a shop to weld them up as 2.5 inch cats are meant to slip onto 2.5 inch ID pipe. In other words, do not expect to use clamps. But I doubt that was the plan anyway.

Exactly, I will have it weld up

ontopofm · 05-14-2009, 08:37 PM

the high flow 300 cell count cats are welded on but the oem pipes are actually 2.25". Throttle response is better and a lil bit louder. Is it a good idea to run stage 3 even though it's not completely catless? Has anyone tried yet? Anyway, Im gonna try and see how it drives

scalbert · 05-14-2009, 08:44 PM

They are 60mm as that is 2.36. The tenth on an inch difference can be accounted for by variances in wall thicknesses.

On 91 octane, I would leave it at stage 2 IMO.

ontopofm · 05-14-2009, 09:08 PM

Quote:

Originally Posted by scalbert

They are 60mm as that is 2.36. The tenth on an inch difference can be accounted for by variances in wall thicknesses.

On 91 octane, I would leave it at stage 2 IMO.

we compared the oem pipe end to the 2.25" end and they are exactly the same size. Anyways, I'll try stage 2 as well. Thanks Steve

05-13-2009, 12:37 AM	#1
ontopofm Lieutenant Colonel 76 Rep 1,548 Posts Drives: stock Join Date: Jun 2007 Location: CA iTrader: (4)	E92 stock exhaust pipes diamater? Are they 2.25" or 2.36"? I've searched and found those numbers in different threads. I have the 2.5" high flow cats but if the pipes are 2.25" I will need to return them and reorder the right ones before I have the pipes cut. Thanks
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05-13-2009, 09:36 AM	#2
Zeph Major 27 Rep 1,410 Posts Drives: 2008 E92 335i 6MT SGM CR/BD Join Date: Jul 2008 Location: Southeast USA iTrader: (0)	good question. I always assumed they were 60mm which I believe is 2.36 inches. Last time I checked Germany was using the metric system
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05-13-2009, 12:48 PM	#3
scalbert Major General 153 Rep 5,780 Posts Drives: '13 S4, '15 Q7 Join Date: Feb 2007 Location: Woodstock, GA iTrader: (8)	60 mm is correct.
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05-13-2009, 01:02 PM	#4
JoeyFiasco Major 22 Rep 1,211 Posts Drives: '09 Coupe Join Date: Aug 2008 Location: P'boro, UK iTrader: (0)	but 60mm is 2.4" haha or is that the overall diameter and 2.36" would be the internal?
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05-13-2009, 01:05 PM	#5
scalbert Major General 153 Rep 5,780 Posts Drives: '13 S4, '15 Q7 Join Date: Feb 2007 Location: Woodstock, GA iTrader: (8)	60mm is the ID. So a 2.5 inch ID pipe will slide right over it (some pipe may be loose while others require some assistance).
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05-13-2009, 01:06 PM	#6
Zeph Major 27 Rep 1,410 Posts Drives: 2008 E92 335i 6MT SGM CR/BD Join Date: Jul 2008 Location: Southeast USA iTrader: (0)	which is why most aftermarket stuff in the US is 2.5" so it is slightly bigger (good) and I believe the HKS exhaust is actually 65mm to accomodate all of these 2.5" downpipes. 60 millimeters = 2.36220472 inches 65 millimeters = 2.55905512 inches
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05-13-2009, 10:08 PM	#7
ontopofm Lieutenant Colonel 76 Rep 1,548 Posts Drives: stock Join Date: Jun 2007 Location: CA iTrader: (4)	thanks guys, so 2.5" high flow cats are perfect
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05-14-2009, 08:03 AM	#8
scalbert Major General 153 Rep 5,780 Posts Drives: '13 S4, '15 Q7 Join Date: Feb 2007 Location: Woodstock, GA iTrader: (8)	Yes; however, you will need to get a shop to weld them up as 2.5 inch cats are meant to slip onto 2.5 inch ID pipe. In other words, do not expect to use clamps. But I doubt that was the plan anyway.
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05-14-2009, 08:37 PM	#10
ontopofm Lieutenant Colonel 76 Rep 1,548 Posts Drives: stock Join Date: Jun 2007 Location: CA iTrader: (4)	the high flow 300 cell count cats are welded on but the oem pipes are actually 2.25". Throttle response is better and a lil bit louder. Is it a good idea to run stage 3 even though it's not completely catless? Has anyone tried yet? Anyway, Im gonna try and see how it drives
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05-14-2009, 08:44 PM	#11
scalbert Major General 153 Rep 5,780 Posts Drives: '13 S4, '15 Q7 Join Date: Feb 2007 Location: Woodstock, GA iTrader: (8)	They are 60mm as that is 2.36. The tenth on an inch difference can be accounted for by variances in wall thicknesses. On 91 octane, I would leave it at stage 2 IMO.
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