Running with open downpipe for a day or two - Miata Turbo Forum - Boost cars, acquire cats.

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Old 09-12-2009, 04:57 PM   #1
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Default Running with open downpipe for a day or two

Just as a hypothetical, if I wanted to do a few shake down runs and had access to a closed course to keep things legit. Would their be a negative to running my with nothing after the downpipe for a day or two. I'll have exhaust fabbed up sometime next week, with a cat, but for now I'd like to make a few runs to check for leaks while idle, and after boost.
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Old 09-12-2009, 05:24 PM   #2
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free flowing is good for a turbo
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Old 09-12-2009, 06:07 PM   #3
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Just make sure you're tuned for it - I run a straight-through exhaust on the race car (no mufflers/cats)
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Old 09-12-2009, 06:38 PM   #4
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I'll have the laptop in the car while running, I'm super excited, the car actually has more low end. I didn't expect that, and I hope it doesn't go away once I get and exhaust system on it.
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Old 09-12-2009, 07:20 PM   #5
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+1 on tuned for it. I took off my exhaust (stock) for a few hours a while ago and it started leaning out like crazy from all the extra flow. Watch those afr's.
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Old 09-12-2009, 08:01 PM   #6
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Also you might notice your boost decrease after you install an exhaust system if it's too restrictive.
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Old 09-12-2009, 09:45 PM   #7
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where does your dp end? I ran my car with just a flying miata elbow and ended up melting my speedo cable. Also there will be less back pressure and depending on your tune it will run differently after the exhaust is on.
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Old 09-12-2009, 09:56 PM   #8
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I didn't think about that.

The downpipe ends near the shifter I believe.

Quote:
Originally Posted by LagunabluMX5 View Post
where does your dp end? I ran my car with just a flying miata elbow and ended up melting my speedo cable. Also there will be less back pressure and depending on your tune it will run differently after the exhaust is on.
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Old 09-13-2009, 07:37 AM   #9
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don't forget your earplugs either
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Old 09-13-2009, 12:23 PM   #10
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Its loud, like, really loud. You will get pulled over. I may drive my green car home from Wylie to Lewisville today if you want to show me how loud it is, lol.
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Old 09-13-2009, 12:51 PM   #11
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Driving your car home from Wiley in this weather has to be a challenge, I hate driving my miata when its wet. The addition of boost has to make that much more intresting, and not in a good way.

I drove the car last night, and its really loud, my neighbor told me he could hear it two blocks away. Considering the weather and the noise it will probably stay in the garage until I can take it to get exhaust put on, hopefully this tuesday. When do you expect to get back to lewisville?
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Old 09-13-2009, 01:08 PM   #12
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Quote:
Originally Posted by apariah View Post
Driving your car home from Wiley in this weather has to be a challenge, I hate driving my miata when its wet. The addition of boost has to make that much more intresting, and not in a good way.

I drove the car last night, and its really loud, my neighbor told me he could hear it two blocks away. Considering the weather and the noise it will probably stay in the garage until I can take it to get exhaust put on, hopefully this tuesday. When do you expect to get back to lewisville?
the brand-new sticker rubber should help, but its going to be pretty scary on the drive home. I still have to get it road tuned, 3.63 swap, to the dyno on sunday night, then Hallett Friday morning.
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Old 09-13-2009, 01:10 PM   #13
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Are you going to a dyno in Lewisville?
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Old 09-13-2009, 01:14 PM   #14
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Quote:
Originally Posted by apariah View Post
Are you going to a dyno in Lewisville?
Exatorq in Garland.
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