PD100 Downpipe - Page 2

hondaguy · November 17th, 2009, 18:23

Quote:

Originally Posted by ryanp

http://www.thsperformance.co.uk/prod...Cars_THSTDDP-1

2.5" is plenty!

does this downpipe bolt up to a 06 tdi?

Street Toys · November 17th, 2009, 18:43

Quote:

Originally Posted by hondaguy

does this downpipe bolt up to a 06 tdi?

It might help if you said what kind of 06 tdi, Passat, Toureg, Golf, Jetta, these all have different downpipes.

hondaguy · November 17th, 2009, 20:39

06 tdi jetta..? lol my fault im not a vw guy my buddy is. but i know more around cars so im tryin to help. but yea its a 06 tdi jetta

MhVW · November 25th, 2009, 07:53

Ok, so it looks as if I will have to go the custom route on my '06 Polo PD100 downpipe.

Now my question is do I use stainless steel or mild steel to fabricate the downpipe?

An exhaust shop told me to keep clear of stainless if I where to build headers or a manifold, but wasn't sure about a turbo downpipe.

MhVW · December 3rd, 2009, 01:21

Any thoughts between using mild steel or stainless steel for the downpipe?

Bought a gasket the other day from VW and drew it in Acad.
Now I can plan my flange.
Going to try and match the turbo outlet and downpipe for better flow.

Another question seeing that I have the opportunity, would anyone recommend adding some socket for future instrument installations?
And what size?

Street Toys · December 3rd, 2009, 06:54

Quote:

Originally Posted by MhVW

Any thoughts between using mild steel or stainless steel for the downpipe?

Bought a gasket the other day from VW and drew it in Acad.
Now I can plan my flange.
Going to try and match the turbo outlet and downpipe for better flow.

Another question seeing that I have the opportunity, would anyone recommend adding some socket for future instrument installations?
And what size?

Hello MhVW,
Mild steel can be used but it will not last a long time specialy if you have a high humidity factor.
409 Stainless is a very good media to use. 409 is designed for heat cycles in the automotive exhaust sytem but will turn a light brown over time.
304 Stainless is a little more than 409 but not that much. It is a higher gradeStainless steel in that it has a lot less iron than 409.(a magnet will not stick to it) It too is a good choice and will last a lot longer than mild steel but it does tend to crack over time.
439 and 439HP are also very good choices as well. Like 409 it is ferrous and will get less of an oxidation than the 409 grade. It has twice the nickle and chromium that 409 has and is the best choice IMO for the TDI exhaust system. The only issue with that media is the availability of mandrel bends.
Go ahead and google these 3 types of stainless steel and check for your local availability. Any one of these 3 will be a good choice.

Nick/StreetToys

JPDiesel · December 3rd, 2009, 16:03

As a chemist ,I know that the word steel means it is an alloy made mostly of iron. This link shows the alloying amounts for 304 stainless and it is a minimum of 65% iron (Fe). http://www.azom.com/Details.asp?ArticleID=965

Street Toys · December 3rd, 2009, 16:32

thanks JP, I corrected that.

JettaSportTDi · December 4th, 2009, 05:50

Quote:

Originally Posted by MhVW

Any thoughts between using mild steel or stainless steel for the downpipe?

Bought a gasket the other day from VW and drew it in Acad.
Now I can plan my flange.
Going to try and match the turbo outlet and downpipe for better flow.

Another question seeing that I have the opportunity, would anyone recommend adding some socket for future instrument installations?
And what size?

I have this drawn in CAD already...........do you what the file? For the PD 100.

MhVW · December 5th, 2009, 05:59

Quote:

Originally Posted by JettaSportTDi

I have this drawn in CAD already...........do you what the file? For the PD 100.

That looks really good.

Did you build a downpipe to that design?

That's more or less what I also have in mind.

Would you mind sending me your cad files?

I just love drawing stuff in CAD!

PM send

JettaSportTDi · December 7th, 2009, 10:59

I try and send you the CAD when I get home from work if I get the chance I have to drain my tank and install a new lift pump tonight, if not I'll send it to you tomorrow.

MhVW · June 8th, 2010, 04:58

Ok, so I finally got everything together to build the downpie.
The parts used

Firstly this is how badly the stock downpipe line up with the turbo

The above issue just had to be rectified. Difficult to see from the pics, but I tappered the edges of the new flange in order to lineup with the turbo out let on the one side and the ddownpipe tubing on the other side.

MhVW · June 8th, 2010, 04:59

The old

After a lot time it's all tacked together only 50mm connecting piece and carrier bracket to be added.

The old vs the new

And there it is finally finished

MhVW · June 8th, 2010, 05:00

And finally got round to putting the car on the dyno to see the effect of the my custom downpipe and decat that I did on the car.
( now I know the dyno graph is worthless not being done on the same day, but it is still interesting to see the effect. What ever it might be... )
Dynograph of before and after downpipe and decat:

Got a gain of 10Nm and 2.8kW.
In hind sight, I think a simple decat would have resulted in much the same gain.
The gain would probably be more when combined with software.