This downpipe looks really good
09-03-03 | 07:42 PM
#26
Rotary Enthusiast
Joined: Feb 2001
Posts: 1,025
Likes: 4
From: Huntington Beach, CA, USA
This has been the topic of endless debate. Some people say yes, but others say no. In one camp is the position that the flattened area is to clear the power steering pump on the JDM cars. This makes sense although I thought that JDM cars had a downpipe stock. The other problem with this theory is the US spec precat still maintains this flattened area, and I'm fairly positive the precat only came on LHD cars. Perhaps it still saves some money for Mazda to just use the same flange on the precat as well. The other camp maintains the flattened area is to reduce turbulence coming out of the turbo, because the full 3" downpipes mate a round hole to a square hole, which isn't very ideal either. If you buy into both of these theories, the ideal downpipe would have a cast flange that flattens to match the turbo outlet, but without the abrupt bend necessitated by the JDM power steering pump. The flat area would also quickly open up to the normal round 3" diameter pipe used for most downpipes. The bottom line is no one has proven one way or the other, so its really all speculation.
09-03-03 | 10:19 PM
#27
Senior Member
Joined: Dec 2001
Posts: 468
Likes: 0
From: Somewhere in California
Originally posted by Nathan Kwok
This has been the topic of endless debate. Some people say yes, but others say no. In one camp is the position that the flattened area is to clear the power steering pump on the JDM cars. This makes sense although I thought that JDM cars had a downpipe stock.
This has been the topic of endless debate. Some people say yes, but others say no. In one camp is the position that the flattened area is to clear the power steering pump on the JDM cars. This makes sense although I thought that JDM cars had a downpipe stock.
Originally posted by Nathan Kwok
The other problem with this theory is the US spec precat still maintains this flattened area, and I'm fairly positive the precat only came on LHD cars. Perhaps it still saves some money for Mazda to just use the same flange on the precat as well.
The other problem with this theory is the US spec precat still maintains this flattened area, and I'm fairly positive the precat only came on LHD cars. Perhaps it still saves some money for Mazda to just use the same flange on the precat as well.
Originally posted by Nathan Kwok
The other camp maintains the flattened area is to reduce turbulence coming out of the turbo, because the full 3" downpipes mate a round hole to a square hole, which isn't very ideal either. If you buy into both of these theories, the ideal downpipe would have a cast flange that flattens to match the turbo outlet, but without the abrupt bend necessitated by the JDM power steering pump. The flat area would also quickly open up to the normal round 3" diameter pipe used for most downpipes. The bottom line is no one has proven one way or the other, so its really all speculation.
The other camp maintains the flattened area is to reduce turbulence coming out of the turbo, because the full 3" downpipes mate a round hole to a square hole, which isn't very ideal either. If you buy into both of these theories, the ideal downpipe would have a cast flange that flattens to match the turbo outlet, but without the abrupt bend necessitated by the JDM power steering pump. The flat area would also quickly open up to the normal round 3" diameter pipe used for most downpipes. The bottom line is no one has proven one way or the other, so its really all speculation.
One reason for so many full 3" DPs in the US could be ease of construction. The flat upper piping looks like it would require a little bit of extra work to make (casting) and integrate into a completed DP system. Whereas with a full 3" DP all you need is some 3" piping with Mandrel bends.
09-08-03 | 06:41 AM
#30
Call me gramps!
Joined: Jul 2003
Posts: 2,334
Likes: 0
From: Temecula, CA
Originally posted by LAracer
This looks alot like the dp I have, I had problems getting the bolt heads to clear the weld material. Some other people had this problem too, but we worked around it using some spacers.
This looks alot like the dp I have, I had problems getting the bolt heads to clear the weld material. Some other people had this problem too, but we worked around it using some spacers.
