Author Topic: Exhaust heat shields on a Diesel? (possibly a stupid question).  (Read 1995 times)

March 29, 2012, 11:33:19 am

DarkwingDork

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I have a feeling this is a no-brainer, but I'd like to get a few opinions before I do anything:

I'm converting an 84 Wolfsburg Rabbit from gas to Diesel, said car has a massive heat shield that runs the entire length of the exhaust (which is now loose and rattling like a mother). My other Rabbit (Diesel from the factory) had no traces of such a shield. Did the Diesels have the heat shield, or was that unique to the gassers? I have a feeling, as rusty as the old Rabbit was, that the shield had long ago liberated itself from the car and was removed...does anyone know if the diesels had such shields?

Common sense tells me I should weld the darn thing back up there, it's in good shape, but is it worth the effort to do so? I know cats run pretty darn hot (and I obviously won't have one) but the truck bed lining under the old car was never affected by the heat. Wouldn't the shield be one more place for salt spray to collect and eat away the floor?

Thoughts?


1984 Rabbit Wolfsburg 1.6/5-speed
My Mk1 FAQ/DIY site:
http://mk1ultra.com
My build thread:
vwdiesel.net/forum/index.php?topic=30776.0

Reply #1March 29, 2012, 05:21:10 pm

R.O.R-2.0

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Re: Exhaust heat shields on a Diesel? (possibly a stupid question).
« Reply #1 on: March 29, 2012, 05:21:10 pm »
The shield should be there and they are made of aluminum so they shouldn't really rust. Exhaust runs hotter in a diesel so I'd recommend getting one in there asap.

at cruising speeds, diesels hardly make enough heat to maintain operating temperature...

gassers run WAY hotter with all that waste heat they make..
92 Jetta GLI - Black, 1.6D w/ GT2056V turbo..
86 GTI - 4 Door, Med Twilight Gray, Tow Machine..
86 Audi Coupe GT - Tornado Red, All Stock.. WRECKED.
89 Toyota 4Runner - Dark Grey Metallic, LIFTED!

Turbo: exhaust gasses go into the turbocharger and spin it, witchcraft happens and you go faster.

Reply #2March 29, 2012, 05:35:39 pm

Trips_B

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Re: Exhaust heat shields on a Diesel? (possibly a stupid question).
« Reply #2 on: March 29, 2012, 05:35:39 pm »
My 86 Jetta has heat sheilding from the engine to just after the rear seats.  Its probably there for a reason but you've been running without it on your rabbit already.

just leave it out and call it poor man's heated seats   :D

Reply #3March 29, 2012, 05:53:34 pm

R.O.R-2.0

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Re: Exhaust heat shields on a Diesel? (possibly a stupid question).
« Reply #3 on: March 29, 2012, 05:53:34 pm »
my 84 rabbit doesnt have one, come to think of it, none of my diesels ever did, just the gas cars!

i know my 84 didnt have one, because i got it from the original owner, and all the original pieces were still on the car. even the under-car shifter boot was still there!
92 Jetta GLI - Black, 1.6D w/ GT2056V turbo..
86 GTI - 4 Door, Med Twilight Gray, Tow Machine..
86 Audi Coupe GT - Tornado Red, All Stock.. WRECKED.
89 Toyota 4Runner - Dark Grey Metallic, LIFTED!

Turbo: exhaust gasses go into the turbocharger and spin it, witchcraft happens and you go faster.

Reply #4March 29, 2012, 05:54:40 pm

CRSMP5

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Re: Exhaust heat shields on a Diesel? (possibly a stupid question).
« Reply #4 on: March 29, 2012, 05:54:40 pm »
on a na no issue to not have them... on a td... if you do keep them..

why....

on a mk1 diesel td/na they do not have them... way back in 01 my 83 td coupe rusted a few holes in the center muffler td's have.. the egt escaping from said holes was enough to melt the handbrake cables in the tubes into the floor pan.. :(

my 1st b3 1.6 td sedan experiment i built in 02 ate the rear muffler.. aka fell off.. in 05.. i ran it thru 06 and in jan 06 the fuel tank melted a HOLE in it from egt.. :( 2 mo later i put it all in my b3 wagon... and well when wagon exhaust failed i straight piped it.. to prevent melting of stuff.. best upgrade ive ever done btw..

so with that info... id be weary of heat sheilds on turbo exhaust...

Reply #5March 29, 2012, 06:47:47 pm

745 turbogreasel

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Re: Exhaust heat shields on a Diesel? (possibly a stupid question).
« Reply #5 on: March 29, 2012, 06:47:47 pm »
Gas burns hotter, especially if you have a cat.(exc. regen burn of the new stuff.)

Reply #6April 05, 2012, 04:05:30 pm

DarkwingDork

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Re: Exhaust heat shields on a Diesel? (possibly a stupid question).
« Reply #6 on: April 05, 2012, 04:05:30 pm »
Thanks, all for the input. I kinda figured the TD's could use them (which I plan to add boost some day). I noticed the Wolfsburg has two several studs with nuts down the center line to hold the shield up (in addition to the rivets)...I looked under the old car and saw no sign of such studs. I went ahead and pulled it off for now, figured it couldn't hurt to check the state of the metal behind it and paint the snot out of it before putting the shield back on. How on earth would one shoot a rivet through the floor? Any suggestions on how to re-attach the edges?

Thanks again :)
1984 Rabbit Wolfsburg 1.6/5-speed
My Mk1 FAQ/DIY site:
http://mk1ultra.com
My build thread:
vwdiesel.net/forum/index.php?topic=30776.0

 

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