Exhaust removal: VW Golf TDI and replacement with dual pipe GTI
How to remove your mk6 VW Golf TDI exhaust and install the GTI exhaust.difficulty: 1/5
This DIY shows how to swap the GTI exhaust downstream of any emissions components on a 2010 VW Golf TDI. The pipe diameter is slightly different. This includes the muffler and rear diffuser lip.
This article shows how to replace the VW Golf TDI muffler with the GTI Golf muffler. The difference in appearance is the split exhaust and lower spoiler. The parts are listed below. The TDI exhaust piping is 55mm and the GTI exhaust piping is 60mm. You could also install your own custom exhaust to get around this or delete the muffler entirely and just use your own GTI-style exhaust tips and rear spoiler (valance/diffuser). He did note that the GTI exhaust weighs, as a guess, 10-12 pounds. more than the TDI exhaust, most of that in the center resonator. The total cost for the author, including shipping and the fuel to pick up the used GTI exhaust - about $300. Since one shop quoted me $400 + tips to do a custom mufflerectomy and I'd still need the valance, I'd say this was the affordable way to go.
This procedure can also be used to remove the stock exhaust. The main difference is that the TDI piping is 55mm and the GTI piping is 60mm and expands to 65mm.
pics are by 6thVW-1stTDI and RPS99SHO Here is what they did, first 6thVW-1stTDI's car. He estimates the time spent as 90 minutes so this project is rated difficulty 1.
Here is RPS99SHO's car after. To give you an idea of the size of the muffler alone, here is his old muffler in the trunk.
Warning: do not tamper with any federally mandated emissions components. This is illegal and may cause your car to fail inspection. If you wish to learn more about how the emissions system on your mk6 Golf works, see 1000q: DPF FAQ. After the H2S converter the muffler can be safely removed without affecting emissions.
GTI exhaust or your own custom exhaust
2 longer bolts for the exhaust clamps if using stock GTI exhaust
Rear valance insert (VW calls it a "SPOILER") $129.54 VW# 5k6 807 521 h 9b9
Tow hook cover $8.57 VW# 5k6 807 441 c 9b9
Two extra screws (used at the far outer edges of the valance insert) $0.19 ea VW# n 909 747 01
exhaust hanger (VW calls it a "RING") $5.33 VW# 8d0 253 147 e
For some tips on how to read VW part numbers, see 1000q: how to read part numbers.
Procedure to install GTI exhaust on your VW Golf TDI
Here is the stock VW Golf TDI exhaust. The Sportwagen and Audi A3 TDI exhaust are a little longer to account for the longer body. The diameter of the piping is 55mm outer diameter to the rear muffler. While there are a matched pair of mount studs welded to the pipe at the inlet, the author's car only used the left-front mount and 2 muffler mount. The GTI exhaust inlet is 60mm outer diameter (where the clamping sleeve connects) and expands to 65 mm just past the clamping sleeve for the rest of the way to the rear muffler. The difference in pipe diameter is enough that VW actually flattens the GTI exhaust a bit for clearance just upstream of the muffler.
First jack up the rear of the car and support it on sturdy jackstands. The jack points for the demo car were the same as the mk5 Jetta. Here is an article showing the jack points on a similar Jetta: 1000q: mk5 jack stand points. Make sure your car is safe and secure before getting underneath it at all!
Loosen the two bolts on the clamping sleeve that connects the cat-back to the pipe out of the H2S catalyst, support the rear muffler with a floorjack, pry off two of the three hangers (front and left rear), and unbolt the bracket for the remaining rear right muffler hanger from the body.
With the muffler supported by the jack, the whole thing is quite easy to slide off the cat-pipe and out from under the car.
Swap the valance insert while the exhaust is off of the car. 6thVW-1stTDI had thought that might be easier than doing it with the GTI exhaust in place but found that it didn't make any difference since it was so straightforward.
The TDI clamping sleeve is obviously designed as 55 mm I.D. on both sides and the GTI exhaust inlet is 60 mm outer diameter. The existing sleeve can be swelled or expanded to accommodate the larger size pipe on one end. 6thVW-1stTDI did that himself using a cam-type stud extractor, but using the cam to go outside and swell the sleeve. This got the job done and he was able to clamp it down on both pipes.
Remove the bolts from the band clamps and wedge something inside the sleeve so that it can be expanded to fit on the GTI exhaust. You could also do it very easily with any type of cone-shaped tool. Becuase the GTI exhaust piping is larger you'll also need to replace the clamp bolts with longer ones. There are only 4 nuts/bolt that need a wrench or socket - the two bolts on the clamping sleeve (carriage bolts and nuts), and the two bolts that attach the right rear hanger mount to the body. All four are 13mm.
His notes: I must admit that I'm not totally happy with the result, I'd rather find a sleeve or pipe reducer that was actually designed for the two different pipe sizes. But whether I'm happy or not, it did work, and seems to be sealing fine at this time.
The GTI exhaust installs exactly the same as the original came out, with the addition of one extra hanger at the center resonator. No drama at all.
The GTI exhaust has an extra mount stud on the resonator, presumably due to the extra weight. The body mount stud is present on the TDI body, so all you need to use the extra mount is the rubber hanger itself. The GTI exhaust also has the matched pair of studs at the front, I do not know if the GTI uses both, or just the one as our TDIs do.
Installing the GTI spoiler -diffuser on your VW Golf TDI:
This was the easiest part. Remover the original diffuser by removing the two screws in the lower edge (red arrows in the above picture) and tug at one side to unclip it from the bumper skin.
Then snap the GTI part in place. Replace the two screws you removed in the same spots, and use the two new screws into the corners. The holes they go into are already present in the bumper cover. No drilling is necessary.
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