Downpipe Fabrication Question

jdub

Official SM Expert: Motor Oil, Lubricants & Fil
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Feb 10, 2006
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Valley of the Sun
If you could find one, a 90 deg 3" to 3.5" expander elbow would be sweet!


(for those of us without the baller 3.5" V-Band...lol)
 

IJ.

Grumpy Old Man
Mar 30, 2005
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Mild Steel you'd probably get away with swaging the end of a 3" elbow no probs at all John!

Truck exhaust shop would have the dies in house.
(then again most shops would have these days)
 

Blackfin

Beach Bum
Jun 16, 2005
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John's Pass, Florida
Jdub, now I understand. Thanks for the thorough description. I got my bungs in order now.

The plan is starting to come together. I will locate the expander as close as possible to the 90 degree elbow from the turbine. The elbows I have seen have either a 4" or 6" leg so that should give me plenty of fall to clear the firewall. At this location, I will need to use a shorter (greater angle) expander because there is very little room for lengthy tangents.

What is the verdict on a bellows. Should I include and where. A 3" in to 3-1/2" out bellows would be useful for this application.
 

jdub

Official SM Expert: Motor Oil, Lubricants & Fil
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Feb 10, 2006
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I assume you're talking about a flex section...I'm a believer in them...other folks will disagree. If you hit the downpipe on a speed bump, it dampens the shock to the turbo/manifold. I prefer to fit one further down the pipe though, but that's just me.
 

Blackfin

Beach Bum
Jun 16, 2005
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John's Pass, Florida
jdub;964128 said:
I assume you're talking about a flex section...I'm a believer in them...other folks will disagree. If you hit the downpipe on a speed bump, it dampens the shock to the turbo/manifold. I prefer to fit one further down the pipe though, but that's just me.

Yes, I meant flex section. The car is intended to be a daily driver. Your advice makes good sense.