HJ2's Piper Downpipe assembly experience...

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HJ2's Piper Downpipe assembly experience...

Postby HJ2 » Tue 02.10.2012, 21:50

I thought I'd share some Piper downpipe experiences with my fellow LEC peeps.
As always: Warning! Picture heavy! Some of them better not to view with heart problems...

Let me start off with some of my experiences with Piper.
As you might have read I needed quite a few parts to restore the complete (well, almost as the back pipe was still OK) exhaust line after the discovery of a couple of cracks in the exhaust manifold :evil:

Since I had everything off the car to replace the exhaust manifold, I thought I'd swap the emptied pre-cat housing with a Piper PCE. There were some troubles with the ordering system on their website, but an email was enough to get the order done quickly. However... I followed the threads of the downpipe developments with great interest and it seemed to me that Piper almost had the pipe ready. So I emailed them and asked how things are looking (the car was disassembled so I needed parts desperately :-). It quickly become clear that development was ready and production was about to start up. So I took my chances and ordered one. After a week of uncertainty about production, the pipe was shipped to the Netherlands.

I want to add that dealing with Piper was fine and I would definitely deal with them again. One minor point of attention is communication which is, always, a difficult task (in life in general!) I always like bad news more then no news at all. In the end everything worked out perfect and I want to thank Piper for helping me to get the pipe so quick.

So... Here's what happened:

Let's get the old parts out first
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Here's what I received (outside)
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All shiny new parts with some nice welding. No complaints here!
But on the inside... You be the judge:
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So it needed 'some' work. After I cut away the big chunks with my Dremel, I went out to the tool store and bought an air grinder to get the rest out... this was not planned and not funny, but I wanted to have optimal flow and, equally important, no funny whistling noise!

Back to work:

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By the way: This is what caused the troubles! This is my ' old' PECO flex section. It was not very flush with the bottom of the Elan, but it was definitely the lowest part on the car (see flat part...)

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Yup, nasty!
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After a lot of grinding: This is what the result is, together with a new PECO flex part.
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Let's get it back together:
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The fitting was pretty straight forward. and fitments of the parts was good.
As a precaution I cleaned all the threads before assembling everything back together. I replaced all gaskets, including the full metal ones. Perhaps this was not necessary, but since everything was out anyway I took my chances :mrgreen:

After everything was back together, there was a small (or big?) bonus included: The new Cybox exhaust flex part was somehow shaped differently so the ground clearance improved dramatically! Since this was the root cause of all the troubles.... I am beginning to suspect that the initial one was not correctly bent! The lowest part of the pipe is now almost flush with the longeron so I gained approx. 40 millimetres which is a lot :clap:

Now I just need some tips to close the joint with the rest of the exhaust gas tight! Should I use gun-gum and then fit the pipes together, followed by tightening the U-shaped clip?

I took the plunge and decided not to coat just yet, and to fit only the top heat shield, as this one is close to the bonnet and the front clamshell.
The car goes up in the air after every drive, so I'll monitor the rest closely. However I predict that the heat-load is less than with the cast iron lump. Not because of the difference in emitting between cast Iron and rolled (or extruded?) stainless steel, but because the mass of the pipe is way less that the cast iron part, and the diameter is a lot smaller, so the distance to other parts has increased significant compared to the stock set-up.
Replacing the other stock shields won't work anyway, as the shape of the pipe needs an entirely different geometry and the fixing points are not there either...

Anyway...

My first impressions after driving around 100 kilometres:
* Performance boost... Just a little, but it can be between my ears only....
* Sound: Virtually no change from my initial set-up (it was loud anyway)
* Looks: From above it is almost impossible to spot the difference with the stock set-up. From below: Whooow! I can stick both of my hands where I would like! Improved access to the rest is a big bonus for me.
* Too bad there is no bracket is supplied to fix the top heat shield on at least 2 fixing points. I made one myself, so the OEM top shield is now fixed with the bolt on the manifold and the one on the RH, which I fixed on the bolt of the PAS pump. No heat damage just yet

Initial Set up:
1.It's an S2
2. 2.25" PECO (Cybox) exhaust
3. No Main CAT
4. Emptied Pre-CAT
5. Ported Wastegate (21.5 mm)
6. Everest Chipped
Oh, the piper downpipe is not coated (yet)

To buy or not to buy?

* In my limited experience: If you have a PCE... don't bother unless the design of the pipe is updated and the waste gate flow is separated over a longer distance (even a wastegate deflection shield welded in the downpipe, as per OEM will improve things here...
* If you doubt between PCE and downpipe: I'd go for the downpipe (see above)
* If you have the cash: Go for the Knox design
* If you want a cheap performance upgrade (free!) ... Empty the pre-cat. It also reduces the risk of a melt down thereabout...
* Would I do it again? Yes!
* Is the pipe worth the money? ... about just...
* long term experience will determine if this was a good idea.


To Piper:
1. Please have quality control check the inside of the pipe prior to shipment and change the production process so all edge,s and more important: all excess material, are removed and inside everything is flush!
2. Please weld in some sort of deflection part for the wastegate flow as per OEM downpipe, as this will dramatically improve the flow, won't cost a lot of engineering, and will attract a lot more potential customers! The lack of this deflection section almost eliminates the performance gain of the pipe all together, compared to my situation anyway. You can always contact me for details, production ideas and measurements!


So,
Here is the bracket I made from a strip of stainless to get the top heat shield fixed with at least 2 points.
Sorry guys, but my experience till now is that all 3 mounting points shall be used if you want the shield to be fixed vibration free!

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Last edited by HJ2 on Thu 11.10.2012, 19:42, edited 4 times in total.
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Re: HJ2's Piper Downpipe assembly experience...

Postby esprit888 » Tue 02.10.2012, 21:57

Maybe i missed it earlier, or its in the next email but you did port the wastegate right?
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Re: HJ2's Piper Downpipe assembly experience...

Postby HJ2 » Tue 02.10.2012, 22:13

It was allready ported by me earlier after replacing the stock exhaust and knock out the pre-cat
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Re: HJ2's Piper Downpipe assembly experience...

Postby steve matthews » Tue 02.10.2012, 22:29

HJ2,s you may also grind on the manifold entrance and exit to improve flow. :-D
Their appear to be many nasty ridges and extra casting. Grind the manifold openings to
gasket opening. My manifold was a good 1/16" to 1/8" smaller than the gasket.
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Re: HJ2's Piper Downpipe assembly experience...

Postby cliff » Wed 03.10.2012, 01:20

HJ, great job & pics, as always.

With the cast iron lump out of the way, it is reasonably easy to fit the manifold & turbo separately as there is so much more room. The down pipe also goes in without a problem. Then again I didn't have the benefit of a beautiful hoist lying around my garage. :D
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Re: HJ2's Piper Downpipe assembly experience...

Postby HJ2 » Wed 03.10.2012, 08:07

Thanks for the tips!

I did grind out a few 'nasty ridges' but did not port the entire manifold.
The downpipe however had some nasty chunks of steel that were not supposed to be there.

I will update my initial post when i have time so you have the whole story so far :-D
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Re: HJ2's Piper Downpipe assembly experience...

Postby Steve A » Wed 03.10.2012, 10:30

The downpipe however had some nasty chunks of steel that were not supposed to be there.


Yes I was somewhat "surprised" to find the same nasty chunks :roll:
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Re: HJ2's Piper Downpipe assembly experience...

Postby paulsmithmk » Wed 03.10.2012, 10:34

Steve A wrote:
The downpipe however had some nasty chunks of steel that were not supposed to be there.


Yes I was somewhat "surprised" to find the same nasty chunks :roll:


Didn't see mine as was sent direct to garage mmmm wondering now!
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Re: HJ2's Piper Downpipe assembly experience...

Postby Steve A » Wed 03.10.2012, 10:47

It's no big deal to me as I can take the grinder to it, but I shouldn't have to :roll:
"If everything is under control, you are going too slow."
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Re: HJ2's Piper Downpipe assembly experience...

Postby HJ2 » Wed 03.10.2012, 10:55

That's my point. :cheers:

by the way, i only assembled the downpipe to the exhaust for a fit check ;-)
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Re: HJ2's Piper Downpipe assembly experience...

Postby steve matthews » Wed 03.10.2012, 13:03

You bought this pipe to improve flow and therefore performance.
Any disruption in flow causes turbulence. This would have shown up on a flow
bench test if one was done. Data is a very important thing those getting
ceramic coating are in for a bigger surprise.
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Re: HJ2's Piper Downpipe assembly experience...

Postby HJ2 » Wed 03.10.2012, 13:10

Uhm... What surprise?
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Re: HJ2's Piper Downpipe assembly experience...

Postby superbad » Wed 03.10.2012, 15:01

If he told you it wouldn't be a surprise, would it?
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Re: HJ2's Piper Downpipe assembly experience...

Postby HJ2 » Wed 03.10.2012, 15:41

Well then, is it a good thing or a bad thing not to have a ceramic coating....
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Re: HJ2's Piper Downpipe assembly experience...

Postby Steve A » Wed 03.10.2012, 15:56

How flat was you down pipe joint face to turbo :?
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Re: HJ2's Piper Downpipe assembly experience...

Postby HJ2 » Wed 03.10.2012, 16:03

Flat where it should be.

Optical not the best perhaps if that is what you mean, but fully functional and it is a surface i do not hope to see any day soon again!
Last edited by HJ2 on Wed 03.10.2012, 16:12, edited 1 time in total.
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Re: HJ2's Piper Downpipe assembly experience...

Postby Steve A » Wed 03.10.2012, 16:05

What exhaust are you connecting to ?
Is it all 2 1/2 inch like the down pipe ? :poke:
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Re: HJ2's Piper Downpipe assembly experience...

Postby HJ2 » Wed 03.10.2012, 16:11

Yep, all 2.25" PECO (or Cybox these days).
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Re: HJ2's Piper Downpipe assembly experience...

Postby Steve A » Wed 03.10.2012, 16:27

HJ2 wrote:Yep, all 2.25" PECO (or Cybox these days).


Does that not result in the step as it leaves the down pipe ?
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Re: HJ2's Piper Downpipe assembly experience...

Postby HJ2 » Wed 03.10.2012, 17:27

Yep. Small, but nevertheless a step.
The step is a lot smaller that the one in the original combination of parts. The bend more fluently. The step is also further downstream where the gasses have cooled more and have slowed down. The effect of the same step is significant less if the speed difference is lower.

A more smooth transition would however be preferrable!
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