Blanket for downpipe?
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This is a discussion on Blanket for downpipe? within the Engine Modifications forums, part of the Tech & Modifying & General Repairs category; I'd like to go stage 2 soon, and I was looking into getting a blanket for the downpipe. I've heard ...

  1. #1
    Registered User pizzazombie's Avatar
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    Blanket for downpipe?

    I'd like to go stage 2 soon, and I was looking into getting a blanket for the downpipe. I've heard mixed reviews about wrapping the downpipe, yet I see it all the time. Is a blanket/wrap something that I can do as long as I don't cover the cat? I'm confused about what not to do and why. I'm planning on getting a Cobb, if that matters.

    Thanks for the help.

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    Master Baiter EJ257's Avatar
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    If you're planning on a Cobb downpipe, there's no issue of wrapping the cat, since you gain little/no benefit wrapping past where the piping bends back under the firewall. Wrapping a downpipe isn't really about maintaining higher EGTs, but reducing heat soak. Since once the exhaust goes under the firewall, it won't be affecting the TMIC, I view further wrap as a waste of $$.

    Wrapping pre-turbo is where EGTs come into play a bit, as well as heat soak. The only thing you have to worry about there (since removing any pre-turbo cats should be a top priority if you have a 2.0L WRX), is that you don't want to wrap any flex sections, as that can cause premature failure.
    Last edited by EJ257; 02-27-2013 at 04:12 PM.
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    Registered User Axex's Avatar
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    Quote Originally Posted by EJ257 View Post
    If you're planning on a Cobb downpipe, there's no issue of wrapping the cat, since you gain little/no benefit wrapping past where the piping bends back under the firewall. Wrapping a downpipe isn't really about maintaining higher EGTs, but reducing heat soak. Since once the exhaust goes under the firewall, it won't be affecting the TMIC, I view further wrap as a waste of $$.

    Wrapping pre-turbo is where EGTs come into play a bit, as well as heat soak. The only thing you have to worry about there (since removing any pre-turbo cats should be a top priority if you have a 2.0L WRX), is that you don't want to wrap any flex sections, as that can cause premature failure.
    Thanks for explaining this. Lately I have been thinking a lot about wrapping downpipes and turbos for when I inevitably go stage 2. If the wrap doesn't significantly raise EGTs then how useful is it even for heat soak? Once you start moving won't air cool everything off pretty quickly anyways? I could see this stuff being useful for someone who drag races and wants all the power possible immediately off the line, but for everyone else I'm not sure how beneficial it would be. I understand why people wrap the turbo compressor to ward off heat soak of the TMIC, but even then I wonder how useful that really is or how long it would take to "unsoak" it if you will. Just looking for some discussion as I would like to know if it is money wasted or money well spent

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    Master Baiter EJ257's Avatar
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    Quote Originally Posted by Axex
    Thanks for explaining this. Lately I have been thinking a lot about wrapping downpipes and turbos for when I inevitably go stage 2. If the wrap doesn't significantly raise EGTs then how useful is it even for heat soak? Once you start moving won't air cool everything off pretty quickly anyways? I could see this stuff being useful for someone who drag races and wants all the power possible immediately off the line, but for everyone else I'm not sure how beneficial it would be. I understand why people wrap the turbo compressor to ward off heat soak of the TMIC, but even then I wonder how useful that really is or how long it would take to "unsoak" it if you will. Just looking for some discussion as I would like to know if it is money wasted or money well spent
    Once air starts flowing over the TMIC through the hood scoop at speed, heat soak isn't really an issue; even after sitting at a light for a few minutes, after a relatively short period of time, it will cool back down and not be that big of a problem. Some turbo blankets come with a certain amount of heat wrap. Since the downpipe is so easily accessible, I'd say use the wrap there, and wrap as much as you can. In the real world for a DD, heat soak isn't that big of an issue with a proper heat shield if you're not looking to drive like an asshat from every light. Once in a while, though, you may come across a light with a long stretch of open road and you'll want to open the car up a bit, and you want the TMIC to cool the air as best as possible.

    With the IAT sensor in the MAF housing, the worst thing you can do is have an open filter element in the engine bay, since that will cause your car to pull timing unless you tweak the compensation tables. Honestly, unless you relocate the IAT sensor, heat soak isn't that much of an issue because IAT compensations aren't affected by how hot the TMIC is; it will just potentially register knock, but if you always take off from a long-term stop reasonably, it shouldn't be a problem. As a general rule, you want the coolest intake charge possible, but like I said, IAT compensations (without relocating the sensor) have nothing to do with the TMIC outlet temps.
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    Registered User pizzazombie's Avatar
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    Thanks, EJ257. I replaced the uppipe with a solid catless one right after I got it, so no worries there. Would you recommend wrapping rather than using blankets for the up/down pipes? Is wrapping just better for heat soak and keeping high egts?

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    Master Baiter EJ257's Avatar
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    Quote Originally Posted by pizzazombie View Post
    Thanks, EJ257. I replaced the uppipe with a solid catless one right after I got it, so no worries there. Would you recommend wrapping rather than using blankets for the up/down pipes? Is wrapping just better for heat soak and keeping high egts?
    You've already installed the uppipe, so it's not worth considering anything for that. It's a PITA install, so it's not worth pulling it for wrap, IMO. Next time it's in your hands, wrapping wouldn't be a bad idea.

    I don't see the point of an "exhaust blanket". I'd just either ceramic coat with something quality (e.g., JetHot) or wrap with some of the newer Lava Rock wrap (e.g., DEI).
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    Registered User pizzazombie's Avatar
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    Yeah, if I put anything on the uppipe it would be something like Perrin's lace-up blanket so I could leave it on.

    Alright, I'll look into that stuff when the time comes.

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    Master Baiter EJ257's Avatar
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    Quote Originally Posted by pizzazombie
    Yeah, if I put anything on the uppipe it would be something like Perrin's lace-up blanket so I could leave it on.
    You can leave wrap on, too, and it's a lot cheaper. There's a reason I mentioned wrap over a blanket when it comes to exhaust components...
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  10. #9
    Registered User pizzazombie's Avatar
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    I meant that I would be able to cover the pipe without removing it. Not removing the wrap. But this is all speculation anyway. I'm not going to just throw money at it for minimal gains.

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