Quick exhaust question

[Sonner]

My exhaust middle and rear sections need replacing, as do my cat. i am buying the 1.9D exhaust parts because there 50mm bore not 42mm. i want to change the front pipe but can i order the deisel front pipe or is the flange that bolts to the manifol different?

will it fit or do i have to get a 1.6 front pipe?

[TrevorB33]

would have thought the downpipe would be different,

[RobinSLXi]

Very different. The diesel has a 4-1 manifold on the wrong side of the engine.

[Sonner]

okay understood, but are the connecting flanges the same?

[RobinSLXi]

As I mentioned, the diesel manifold is a 4-1, compared to the 1.6's 4-2, so the flange is indeed different. The downpipe to mid-section joint is a clamp on both systems (only the 1.3 has flanges there), although the arrangement is slightly different too. Essentially a diesel downpipe is of no use unless you have a diesel engine in there

TeflonTom posted some pictures recently of his setup - Polo stainless 1.6 manifold/downpipe joined to Felicia diesel centre and rear sections - I forget exactly which thread but I seem to recall most of the details were explained.

[Sonner]

yep that is exactly what im doing! thanks for the help.

[Sonner]

Im doing a sport cat aswell

[TeflonTom]

the diesel doesn't have a flange on the front of the centre section, it has an expanded section which has an ID of 50mm which fits over the plain pipe on the back of the downpipe.. the spacing/length of the centre pipe and dowpipe are completely different on the 1.6 and diesel models

edit: you will have to do some wholesale bodgery to get the diesel system to join to the 1.6 manifold/cat.. the diesel centre section is about 1 foot too short iirc

Edited 29 November, 2010 by TeflonTom

[Sonner]

Okay Tom

I will let you know what i have purchased and you can let me know if i need anything else hopefully.

1.9d rear section

1.9d centre section

universal 50mm 100 cell sports cat, 310mm long, 90mm high, 135mm wide

1.6 front pipe section

Stainless manifold as recommended by Tom(i think it was)

All these parts will be brand new, they are all purchased and i am awaiting delivery of the parts

my only concern is the front pipe, i bought a cheap one because they cost alot more than the centre and rear, its costing me approx £50 inc delivery but being a cheap one it doesn't incorporate a flexi joint.

Let me know if im likely to need extra lengths of pipe

[TeflonTom]

front pipe?? they don't have a front pipe? there is a downpipe that is formed as one piece with the catalyst, is that the one you mean?

i recommend buying a 50mm ID flexi-joint to weld on too

[Ben Cordy]

Rather than starting a new thread I thought I'd just ask one this one as my question is pritty much linked. I'm considering doing the diesel exhaust swap on my 1.3 mpi but being a cheap skate and not having welding gear I considered the following. my plan was to buy a diesel mid and rear section then get a clamp fitting reducer to step down the bore size. Chop the diesel mid section half way between its final bend and the cat (or what ever it next joins to is a diesel setup) then use the reducer to join it to a chopped off section of the petrol mid section (effectively just to add the triangle shaped 3 bolt bracket sort of thing). Plenty of gum gum later it's be left with a 50 bore exhaust from just after the cat.

Looking at the schematic drawings it all looks possible my question is would it be worth it? I understand what I'm doing effectively means for the first part of the exhaust the airflow is as before but then again lots of people drive round with sports back boxes connected to their stock setups so really its better than that for starters. I'm not after huge gains just aware my exhaust is on it's way out and I fancy doing something a bit interesting, plus i figure the bigger bore might give the 1.3 a nicer note, then again that could jut be the boy racer in me. What do you guys think?

Appreciate your ideas guys!

[djaychela]

Not sure it'll be worth it or make any difference with a standard setup? The manifold is the most restrictive part of the stock setup, so unless something is done with that I doubt it'll make any significant odds, and even then the standard engine doesn't put a great deal of flow into the exhaust anyway from my experience.

[TeflonTom]

again i agree with the above, it needs to be the other way round, large bore manifold into a smaller bore exhaust pipe for the best power... as the gas leaves the manifold it cools as it runs along the exhaust system meaning you can get away with a mismatch in sizes, sometimes it's actually better for power delivery to have it set up like this rather than the same size all the way through