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What's my cat. pipe size ????

604 Views 7 Replies 5 Participants Last post by  Mein Rotes Jetta
I'm sorry for the cross-post ... really !!

With the search feature down for the count , I have no other choice but to just ask ... What size cat. converter pipe do I have ??
I'm going to be ordering a new exhaust for my Jetta , but everywhere I look , I have a choice of pipe sizes at the cat . Is there a simple way to figure this out , short of jacking it up (possibly disconnecting) & measuring ??? It seems it could have either a 50mm or 55mm pipe coming out of the cat (although I read something somewhere about a 45mm pipe too ?) .
Here's what I know about this Jetta so far :
91 Jetta
"RV" engine prefix
single downpipe

anything else you need to know ??
I'm not 100% sure which system I'm getting (eurosport or autotech) , but I want to order an exhaust in the next week or so and I have to figure this out
. With all those aftermarket exhausts out there in A2 land , someone must know
Thanks in advance !!
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Re: What's my cat. pipe size ???? (Mein Rotes Jetta)

TT's site should have the right size for your car.. I think it's 50mm..
Re: What's my cat. pipe size ???? (Mein Rotes Jetta)

Yeah, 50 or 55mm. Not 45. I have a 92 Jetta GL, RV engine, and mine was a 50mm, small flange. But, form what I understand, both sizes were used on our cars, so to be positive, you have to get under the car. Look on www.tttuning.com they have measurements of the circumference of each, so you can just wrap a piece of string around the outside of the pipe and not disconnect anything.
Re: What's my cat. pipe size ???? (vdubpunk)

If you're doing your exaust and you have the money, might be a good time to add on a dual outlet manifold and downpipe.
Thanks guys
! I'll go there & look for that info & I'll just have to shove my arse under there
Another quick question : Will going to the dual downpipe affect the size of exhaust I need also ?? Like , if I end up with the 50mm exhaust & then change to dual downpipe , will I end up being screwed by needing the 55mm size for the "update" ?? That would not make my day
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Re: What's my cat. pipe size ???? (Mein Rotes Jetta)

No, they also have 60mm inlet/50mm outlet cats for use with the dual downpipe.
To find out whether your cat outlet is 50mm or 55mm, go out and crawl under your car with a piece of string. Measure how much of the string it takes to wrap around your cat outlet. If the pipe circumference is close to ~157mm, your cat outlet is 50mm. If pipe circumference is closer to ~173mm, your cat outlet is 55mm. Circumference= 2 x pi x radius http://****************.com/smile/emthup.gif
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Danke schön
http://****************.com/smile/emthup.gif - you rock ! I would like to do the dual downpipe , just not right now . The old system is HAMMERED
& I don't want anyone choking to death in the thing
(well , it's not THAT bad ... yet) . The dual-down is gonna be a back-burner project till I scare up the parts (& the $$) .
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Just an FYI for any of you playing along at home

I jacked the car up tonight & put the trusty vernier caliper on the outlet pipe of the cat. converter & came up with a measurement of 50mm . Looks like that's the measurement I'll be using when I order my exhaust this week
Just thought I'd let ya'll know what I found out ...
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