Guide/suggestions for affordable mk1 n/a exhaust/dp/etc?

[ldeikis]

Hello all.  I'm sure this has been rehashed to bits but I've searched without much luck...  everyone's got turbos it seems.  My 81 n/a rabbit just cracked his exhaust just forward of the muffler.  The car's got no forward resonator and has been running a NAPA muffler since the one the PO put on rusted out 2 years ago.  The system that's on there is 1.5" all the way from the downpipe to the muffler, with a joint about where I believe the OEM resonator is (judging from Bentley).  I don't know if it's where the resonator is meant to begin or end, or what the OEM diameter was, so I don't know what might fit the car.  When I got the muffler I actually had to slide a sleeve in between it and the intermediate pipe to make the thing fit, making me think this is an even smaller exhaust than stock?!  The PO said the exhaust is all stainless and it does look clean, but has cracked just ahead of where the muffer connects, forward of that support, and the crack isn't getting any better.

I'd been fantasizing for years about turboing this car, but I've made peace that with the fact that it will never be the smart play.  

I'm trying to figure out if I can afford to replace the entire exhaust with something a little more freeflowing--and if so, what?--or if I should just accept this 1.5" madness and take it to a shop to have them bend me a new intermediate pipe.  I'm not unhappy with the sound of the exhaust (before the crack)--it's quieter than my n/a 7.3 F250 anyway.  I don't know much about DP's and systems on these cars to know what fits what.  I know my DP is one big flange with a divider in the middle that's visible inside, held to the manifold with those funny spring c-clamps.  

Can anyone point me towards a thread or guide on what is what and what fits what in DP's and exhaust?  I'd also obviously be interested in anyone's straight up suggestions if you want to make them.  Cost is a huge factor for me right now, as work has been really slow, our farm got flooded bad, and other stuff in life is in the way of spending play money on the rabbit...  but I obviously have to spend SOMEthing before this gets worse--unmuffled n/a's are too brutal for me--so I might as well spend the right something.  

EIDT:  I have no means of bending tubing, but I have a MIG and can weld mild steel easily enough.  I'd like this to last a good 3-4 years of year round upstate NY salt and dirt, but too much longer than that and I imagine the rest of the car will have fallen apart.  I suppose I could buy just joints and straight sections at autozone and build my own intermediate out of non-stainless?


Thanks!

Luke

[burn_your_money]

http://www.vwdiesel.net/forum/index.php?topic=4391.0
third post from the bottom

[92EcoDiesel Jetta]

Has anyone tried to bend exhaust piping by filling it with sand, cap the ends and heat it up with an oxy acetylene torch to cherry red then bend? Does the sand support the pipe enough so it won't collapse? I've heard that you can only bend seamless pipe. The ones with a welded seam may crack at the seam if you try to bend it.

[CRSMP5]

eco.. buy mandrel bent pipe if you can do the sand thing... weld it together with a few v bands life good..

stock bosal works.. its just a na.. if turbo straight pipe it.. but you said keeping na.. so any aftermarket ones should work.. BUT your downpipe will be the smaller pieces unless you buy a header.. which will break/crack.. so.. for my dd 1.6na.. i just use the toilet bowl manifold with stock parts..

[745 turbogreasel]

On the cheap, I'd get  the full system used off a GTI.
Or weld the crack.

[mystery3]

Look on vortex for a used header and exhaust. Should net you a few horses and be reasonable cost-wise. Anyone have an idea how much it costs to ship a header/exhaust for a rabbit across the country? I have one sitting in the garage but I think shipping costs maybe prohibitive.

[ldeikis]

Thanks, Tyler.  I remember finding that thread 3+ years ago when I bought the car, but it slipped my mind in this latest wondering.  

I don't think I can weld stainless with my MIG without getting trimix and a SS spool, which is outside the budget.  So I can't weld up the crack.

If I can get the muffler off the cracked intermediate I might be able to cut off the cracked bit and replace it with a NAPA prebent scrap using clamps (if they carry anything that small) to get me back on the road.  If I can do that cheap enough and get into the fall I might be able to score a new dp at a junkyard and try welding a bigger dp to it.  I like that idea.  

Luke

EDIT:  I managed to patch that crack with some of the wet gauzey style muffler patch pretty effectively.  Held most of a year.  Then the midpipe cracked, up near where the resonator would be if it hadn't been deleted at some point.  Finally bit the bullet.  Bought a 2" cheapie exhaust from TT and welded up a 2" downpipe onto the stock toilet bowl.  It's only a NA so I think 2" is adequate--it's nearly twice the cross section as stock.  It really made a big difference in the car, actually, and I like the sound.  If you go for it, just take your time and fit and refit.  Your downpipe has to be just perfect or the whole thing won't tuck into the tunnel nice.  Mine is a little lower than stock and is definitely the lowest thing on the car.  I kind of wish I'd been more careful and got it perfect, but it hasn't tore off yet.

[92EcoDiesel Jetta]

What are v bands

eco.. buy mandrel bent pipe if you can do the sand thing... weld it together with a few v bands life good..

stock bosal works.. its just a na.. if turbo straight pipe it.. but you said keeping na.. so any aftermarket ones should work.. BUT your downpipe will be the smaller pieces unless you buy a header.. which will break/crack.. so.. for my dd 1.6na.. i just use the toilet bowl manifold with stock parts..

[the caveman]

I have a dual outlet manifold for sale cheap if you want. I never got around to installing it in my vanagon

[CRSMP5]

v band... its 3 pieces of stainless kinda like a tbolt clamp for intercooler piping/hoses.. 2 flanges for each end of the pipes you wanna connect and a v groved clamp design to hold them together like how a t clamp works.. lemme see if i got pics..



after down pipe before flex..



the flange..

no leaks.. easy to take apart.. thats my temp exhaust on the toaster..

[bajacalal]

Shop around for a custom exhaust shop in your area. There is a little family run place near my house that does great work and cheap and does a lot of custom work, stuff that more corporate places like Midas will balk at (or charge you $$$). If you walked in there, they look kind of sloppy and unprofessional (pin-up girls on the wall, loud Mexican music playing) but they do great professional work and cheap, it was like $250 to have my whole exhaust done from including materials and the muffler. It came out really nice and doesn't rub anywhere, the bends are all real smooth. So talk to people that have custom cars even if it's someone with a Chevelle.

They told me that a 2.5" exhaust would be about as big as would comfortably fit (on a mk2, I think a mk1 is similar) and that you would not really see anymore horsepower gains after that for the size of engines we have. That seems to agree with everything I read here.

I have a straight-through muffler meaning the exhaust goes through it in a straight line with no obstructions, this really helps on a diesel. It's a little loud though so I am considering adding a resonator in the middle section of the exhaust, techtonics sells one that is about the right size.