Fitting A Des Stainless Gpn

[GLPoomobile 958]

My exhaust has just arrived, and as I won't get a chance to look at fitting it until the weekend (IF it's not pishing it down!) I just wanted to check a couple of things, as it doesn't look like a straight forward 'fit and forget'

 

So, it's a DES stainless steel Grp N. I told Neil it was purely for road use, so noise regs are not an issue, and so what I have is a single rear box design. It's quite a long cylinder silencer. There is a short length of front pipe (which Neil told me will probably need to be cut to length to fit my downpipe) which joins the rest of the system with a bolt together 'flange'.

 

My two concerns/questions, for anyone who has fitted one of these DES systems or has seen one on a car, are:

 

1 - The exhaust hangers look a bit funny. In particular, the ones on the back box just don't look like they are going to line up properly and I reckon I could be in for some swearing when it comes to making this thing fit.

2 - With the flange, how should I seal it? Will normal exhaust putty be fine, or should I use a particular liquid gasket (recommendations?)

 

I'll take some pics tonight if that helps.

Edited May 29, 2008 by GLPoomobile

[vern 0]

On my DES system I had trouble sealing the joints, I take it you mean where the exhaust parts join together in a 2 bolt flange joint. If it is, I didn't use putty as it kept breaking out of the joint under the movement of the exhaust. I used black silicon sealer and has been fine for over a year now. I can post a pic of the hangers on my back box if it will help?

[GLPoomobile 958]

Yes, I do mean that joint. And yes, if you could post a pic of your hangers that would be great

[Dj_mini 7]

I also had a problem with the two bolt joint exhaust paste didnt work neither did a gasket so i did the same bit of silicone and its been fine ever since.

All my mounts lined up great and even stay on not sliding off like most.

[vern 0]

Pics as promised if you need any others let me know.

 

 

 

 

[GLPoomobile 958]

This afternoon I went out with a view to cracking off the old exhaust. I wasn't going to fit the new one yet, just check how it lines up etc, and they maybe do it at the weekend.

 

Anyhoo, it does line up fine and looks like the hanger are in the right place BUT I have another problem.

 

The original exhaust is a mild steel DES group N. Now, having not properly been under the car before, I assumed it was the same as the Grp N on my previous 205, as in it would have a mid pipe bolted to the end of the downpipe, and then a back box bolted on the end of the mid pipe.

 

No. No such luck for me. Bloody typical . Apart from the back box, the rest of the system is one piece, as in joined permanently to the down pipe. The downpipe itself doesn't look like it's been shortened or re-angled, and the only bit that looks like it could be a welded join is much further back than where I'd expect a normal 205 downpipe to end. So I'm wondering if this is how DES made it - single piece from manifold to back box.

 

So this gives me 2 headaches now. 1, I now have the utter joy of cutting the original exhaust in situ. I'm hoping that the point where I choose to cut it won't have a central divider, as I've done that before on a BX and cutting through that bit is a complete c*nt (had to use Mr Angle Grinder. Not nice doing that lying on your back under a car with the disc inches from your face ). 2, I'm concerned that when this is all fitted up there will be no provision in the system to allow for engine movement. The only bit of flex will be at the manifold to downpipe gasket. Are there any simple solutions to this?

 

Another thing is, I will need to use a joiner on the downpipe and the front pipe that DES provide. They are cheap enough from Car Builder Solutions, but I'm wondering if I might have some grief with the sizes. I measured the circumference of the original exhaust to calculate the diameter, and I've got 65/66mm at it's largest (bottom of downpipe) or 56mm at a narrow point a few inches on. The DES front pipe is 58/99mm. I could use a normal joiner but would have to go for an ID of 57.5mm, which may not fit over the DES pipe. Or I could go for a stepped joiner to connect to the larger art of the exhaust, but again the IDs aren't perfect.

 

Before anyone suggest it, I can't weld, and my car is not MOTd so I can't take it anywhere to get the system fitted.

[GLPoomobile 958]

Any opinions on the above, gay boys?

[GLPoomobile 958]

The exhaust is on, and oh what fun!

 

Actually, fitting it wasn't so bad, it was removing the old one that pissed me off. As I didn't want to remove the downpipe, I had to hacksaw through the exhaust in situ under the car. I must note at this stage, that rather than just jumping in with both feet, I did actually take measurements first to make sure the new system would actually mate up with the downpipe. My conclusion was that the downpipe diameter was very slightly smaller than the new system, and that it may cause a problem mating them, but was hopefully so insignificant that lots of tightening and exhaust paste would work.

 

So I hacksawed the old one off, then hung the back section in place, which went on a treat. Then I mounted the front section to work out where I needed to cut that to fit my downpipe. Had to hacksaw about 8 inches off I think. Cutting stainless steel is fun .

 

Then, to join the two together I used a pipe from Car Builder Solutions, about £5, plus 2 fancy exhaust clamps that were about £7 each . For the flanged joint between he 2 parts of the new system I used Locktite grey silicone gasket stuff. Time will tell if that works or not.

 

Unfortunately, my suspicion about the mating of the pipes was correct. The downpipe is just under 55mm diameter and the new system is just under 57mm, so nearly 2mm difference. It clamped together OK, but there is a slight blow at the top. I'll try and remedy that but if no joy I'll just have to hope my MOT guys are feeling lenient again. Might just get the adaptor sleeve welded to the downpipe one day.

 

Sound wise it sounds just like the old mild steel Group N. Once I've driven it I'll have a better opinion though. The little, understated, shiney tailpipe looks brill though!

[GLPoomobile 958]

I haven't given it beans yet, but so far it sounds pretty much the same as the old mild steel Grp N that was on it.

 

One thing to note, is that it seems to hang a bit too low in the middle. I'm only lowered 25mm, but it catches on some of the bad speed bumps etc, in the middle. I think it's the flange that's scraping. I never had a problem with the Grp Ns on my previous GTIs and they were 40mm lowered.