1.6 vs 1.8 Downpipe - Miata Turbo Forum - Boost cars, acquire cats.

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DIY Turbo Discussion greddy on a 1.8? homebrew kit?

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Old 01-02-2008, 04:31 PM   #1
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Default 1.6 vs 1.8 Downpipe

All I've seen recently for sale are 1.8 DPs.

How much work is involved in getting a 1.8 DP to fit on a 1.6? Will it hang low? Or have clearance issues?

I haven't purchased an exhaust or cat yet, if that makes a difference.

Thanks.
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Old 01-02-2008, 04:42 PM   #2
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I bet it has to do with the flange thats on the end of it, but I to am curious.
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Old 01-02-2008, 05:09 PM   #3
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what manifold and turbo are you using, thats the most important thing
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Old 01-02-2008, 05:13 PM   #4
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I used a downpipe and exhause that was made for a 1.8. I had to change the hangers, and weld up some pipe to get it to go to the turbo. Lastly, I had to torch the DP/exhaust in some places to bend it a little for it to fit perfect.
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Old 01-02-2008, 05:28 PM   #5
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Quote:
Originally Posted by whaaamx5 View Post
what manifold and turbo are you using, thats the most important thing

I'm using a T25 w/ a BEGI manifold.
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Old 01-02-2008, 05:31 PM   #6
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your best bet in this case would be to ask someone at begi if the 1.8 and 1.6 DP's are interchangeable...my guess would be yes
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Old 01-02-2008, 06:50 PM   #7
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Quote:
Originally Posted by whaaamx5 View Post
your best bet in this case would be to ask someone at begi if the 1.8 and 1.6 DP's are interchangeable...my guess would be yes
my guess would be a no... they sell the 1.6L downpipes in 2.5"... the 1.8L downpipes are 2.75". Unless they just don't think anyone needs the extra flow on a 1.6L, there is probably a fitment issue with the larger piping.
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Old 01-02-2008, 07:21 PM   #8
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ahaaa, makse sense, but i assume you could make it fit if your turbo was in same location and on both engines...just some extra work
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Old 01-02-2008, 07:23 PM   #9
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I'm currently running a downpipe originally made for a prelude... I bet it would be easier to make a 1.8L miata downpipe fit on a 1.6L
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Old 01-02-2008, 07:29 PM   #10
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I have both FM 1.6 and 1.8 downpipes right next to me here in my office. If you ignore the fact that one of them is set up for an external gate and the other is not, they are basically the same. Only big difference I see is the cat flange. Both are 2.5" T25 with flex section.
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Old 04-06-2014, 03:11 AM   #11
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Dead thread is dead..

But, I am currently assembling a turbo kit onto the car, and the downpipe does NOT mate up. Appears to be a couple inches short of the cat, and rotated approx. 1/8 turn or similar.

From what I read, this is probably a 1.8L downpipe. Begi SS divorced, and with the Begi 1.6 manifold and SR20 turbo, it seems to fit properly in the engine bay.

Is a viable solution to put in a 1.8L cat for this? AFAIK, the exhaust applies to both 1.6 and 1.8, so a 1.8 cat could connect everything together.

LMK if you have any advice for this
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