...Think I found my exhaust leak

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AbeFM
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...Think I found my exhaust leak

Post by AbeFM »

I noticed a gentle overtone of fuel when driving the other day, and after staggering out of my car desperate for fresh air (even funnier in a convertable) I noticed this small gap where apparently some fumes managed to escape:

Image

So, your hero pack the "trunk" of his other car and headed to NSFab for a bit of fix-er-up'ing.
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Fred
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Re: ...Think I found my exhaust leak

Post by Fred »

Love the self portrait :-)

questions :
do you have a flexi post down pipe pre exhaust?
do you have the down pipe braced to the box in some fashion? (I do, but mine is going to cause it to rip)
why was it only welded top and bottom? that would cause it to be able to flex and therefore accelerate the work hardening project

apology :
sorry for going techy in the lounge (bad habit that I can't help)
I staggered back through the underground and the breeeeeeeeeze blew back my hair
your text reminded me of that for some reason :-)
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AbeFM
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Re: ...Think I found my exhaust leak

Post by AbeFM »

Fred wrote:Love the self portrait :-)

questions :
do you have a flexi post down pipe pre exhaust?
do you have the down pipe braced to the box in some fashion? (I do, but mine is going to cause it to rip)
why was it only welded top and bottom? that would cause it to be able to flex and therefore accelerate the work hardening project

apology :
sorry for going techy in the lounge (bad habit that I can't help)
I staggered back through the underground and the breeeeeeeeeze blew back my hair
your text reminded me of that for some reason :-)
Yes, the end in the backpack has a flex section, and there's braid around that. It's a standard FM downpipe (2.5"). The bendy is a few inches from the cat-side flange, and it has my wideband bung in it.

You can see it here, with the old, OEM exhaust.
Image

Braced to "the box"??
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Fred
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Re: ...Think I found my exhaust leak

Post by Fred »

Is it just me, or is that flexi quite far away from the turbo? Taken to the extreme, it does nothing if you weld it on the tail pipe. it's maximally effective at the turbo, and it is best placed immediately after any sharp turn if its like mine. That looks like its about level with the rear end of the box?

Here's my badly done setup, "braced to the box" such that less weight/stress is applied to the turbo/manifold/vband clamp etc. Unfortunately (as pointed out by rob before using it, and obvious when used due to the ting ting ting) heat expansion is going to tear it out of the pipe... i need to brace it from the opposite side of the pipe with a ring that can flex forward and aft, but not up and down.

http://i50.photobucket.com/albums/f323/ ... 0_4227.jpg
http://i50.photobucket.com/albums/f323/ ... 0_4271.jpg
http://i50.photobucket.com/albums/f323/ ... 0_4272.jpg

mine needs a flexi here :

http://i50.photobucket.com/albums/f323/ ... 0_4241.jpg
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Re: ...Think I found my exhaust leak

Post by AbeFM »

Yeah, your flex isn't between the turbo and the rest of teh exhaust. If I kick your tail pipe, I'm directly trying to bend the exhaust manifold, the only "give" is the motor mounts.

It's not really in there (on mine, at least) to save weight, but to let things move in x, y, z. My whole exhaust is on hangars, and can move a few inches relative to the car. Yours is one with the engine. Seems like it would be hard on it.

Nice pipe though, I like it, much jealousy.
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Re: ...Think I found my exhaust leak

Post by Fred »

http://i50.photobucket.com/albums/f323/ ... 0_3939.jpg

Oh no it's not :-)

Yeah, its one with the engine, but its also only about 2.5m long compared to most cars 4m.

I want the flexi for less stress, but the engine is braced and barely moves. It's also hangered the whole way back.

You'd have a hard time kicking the tail pipe, it dumps in front of the diff :-p ;-)

Thanks for the compliments though :-) You should click the "other project" link in my sig ;-)

Fred.
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Re: ...Think I found my exhaust leak

Post by AbeFM »

Nothing like a good, high res pic of any part of the male form to make you greatful you're not gay. Off topic, I know. :-P

It wouldn't surprise me if the brace caused issues. The header is going to change shape a lot as it sems 1000 degrees of temp change every time you step on the gas. The head/block sees no change, and the pipe connects one end of that triangle to the other.

But, reality is weird. I've seen set ups where it helps, set ups where it hurts, and setups where it makes no difference.

How long till VW TDI support is in and working? Diesel Power!
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Re: ...Think I found my exhaust leak

Post by Fred »

have you felt how heavy a holset is? you NEED that brace to the block, the one to the gearbox is a bad plan, but i intend to fix it when i get a chance

i prefer mild steel thin walled tube that has some softness and give to the weldel cast hard business. support the thin wall and it will survive no worries.

i was jumping on that bracket, the motor moved on the mounts, the bracket did not move at all :-) its "brick shit house" solid.
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Re: ...Think I found my exhaust leak

Post by gross polluter »

I learned a good lesson that night about welding on parts that have been plastered with a high temp rattle can.
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Re: ...Think I found my exhaust leak

Post by ababkin »

92GSX wrote:I learned a good lesson that night about welding on parts that have been plastered with a high temp rattle can.
so what did you learn? (cause i was wondering whether i should paint the whole exhaust or just the manifolds)
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