Piper Exhausts turbo downpipe development thread

[HJ2]

In my experience:
21,5 is max porting size with standard flapper
More is possible with upgraded flapper (bigger ring welded to it) But no irl experience myself

Modifying the downpipe did the trick for me!

[ccb056]

One person has gone out to 22 mm: http://wikilec.9600.org/index.php/Boost_Creep

[HJ2]

With heavy boostcreep, the 0,5 mm extra is not gonna help

[surfboardfiller]

Sandra,
You have increased the internal pressure of the engine increased the amount of exhaust gas being forced out, but its trying to get through the same sized hole as a standard factory setup and it can't do it.

It's not a piper issue, you have modified so many parts of the system you now need to step back from them as individual upgrades and look at the system as a whole. The exhaust gasses can't escape quick enough through that tiny waste gate its a bottleneck in the system.

I don't think porting will go far enough, you may need to re bore the waste gate through and machine the lip off the back. Also look into fitting a manual programmable boost controller if you haven't already.

[HJ2]

Just finished the first test drive on peters car after the head gasket job and various upgrades!
The setup for the test drive:

The car is S2
Refurbished turbo with ported 21.5 mm wastegate
Stock Memcal (so NO everest yet)
Uprated intercooler
Samco hose to the intake manifold
Stock pipe between air filter and Turbo intake
Stock pipe between air intake and filter
Piper downpipe without any modification (not flowed, no deflector)
Stock exhaust without any modification (so WITH main cat)

With this particular setup there was no boostcreep (thanks to the porting)
Elanscan (results will be posted here soon) showed a slight overshoot of target pressure with peaks up to 0.8 bar. After the peak, the wastegate duty cycle went to 70% and pressure dropped, but the run was too short to see if it stabilized at 0.65 bar.
Since the control system is not real time, a little overshoot seems normal to me, but perhaps someone with more knowledge can shine a little light on this matter.

Hope this helps streamlining the discussion from here peeps!

[ccb056]

Can you attach the Elanscan data?

[HJ2]

(results will be posted here soon)

So Yes!

[surfboardfiller]

Just finished the first test drive on peters car after the head gasket job and various upgrades!
The setup for the test drive:

The car is S2
Refurbished turbo with ported 21.5 mm wastegate
Stock Memcal (so NO everest yet)
Uprated intercooler
Samco hose to the intake manifold
Stock pipe between air filter and Turbo intake
Stock pipe between air intake and filter
Piper downpipe without any modification (not flowed, no deflector)
Stock exhaust without any modification

With this particular setup there was no boostcreep (thanks to the porting)
Elanscan (results will be posted here soon) showed a slight overshoot of target pressure with peaks up to 0.8 bar. After the peak, the wastegate duty cycle went to 70% and pressure dropped, but the run was too short to see if it stabilized at 0.65 bar.
Since the control system is not real time, a little overshoot seems normal to me, but perhaps someone with more knowledge can shine a little light on this matter.

Hope this helps streamlining the discussion from here peeps!

Good stuff!

A peak of 0.8 (overboost) is healthy/normal at wide open throttle =/>3000 rpm and should come down to 0.65 Bar after a short period.
(Over 0.92 suggests boost control failure and the injectors will cut after half a second.)

[HJ2]

Thanks for confirming that!

[ccb056]

Steve A was experiencing boostcreep and subsequent overboost with a 20mm port.
He also had a 2 in exhaust with the downpipe (Paul Matty).
I do not know if he had a main cat.

It sounds like peter's car has enough restriction with the oem piping and cat to allow the 21.5 mm wastegate to control boost.

HJ, any plans to go with a less restrictive exhaust?

[rip]

Steve A was experiencing boostcreep and subsequent overboost with a 20mm port.
He also had a 2 in exhaust with the downpipe (Paul Matty).
I do not know if he had a main cat.

Steve's Elan is a UK SE, so it will not have a cat.

[HJ2]

Uhmmm... Was the downpipe Paul Matty's? or Piper!

[HJ2]

It sounds like peter's car has enough restriction with the oem piping and cat to allow the 21.5 mm wastegate to control boost.

HJ, any plans to go with a less restrictive exhaust?

Plans enough, but waiting for funding

[ccb056]

Uhmmm... Was the downpipe Paul Matty's? or Piper!

Downpipe was Piper. Exhaust was Paul Matty's.

[surfboardfiller]

Paul Matty's is a rebrand of something else like Miltek?

[Peter D]

LEC won't allow ECU files to be uploaded.
Export to Excel gives me an error message : Old format or invalid type library...

So please replace pdf the extention to ecu.

[ccb056]

I was able to export to Excel, see attached.

2013-12-01 Elanscan after HGJ - Copy.xls

Note, to bring the file under the 1 MiB limit I filtered out everything that wasn't 3rd gear 100% throttle.

Also see the attached graph (dual y-axis).

peter_3rd_gear_s2_exhaust_piper_downpipe.png

From this elanscan data you have proper wastegate control, which is excellent.
The good news is this is the first documented case of a successful Piper downpipe.
I suspect the success is likely due to the restrictive exhaust (Lotus crimp and catalyst downstream of the downpipe).

Now if we can find some data with someone who is also running a Piper exhaust with the Piper downpipe we can focus on the overboost problem a lot of people are experiencing. Surfboardfiller, how is that coming along?

[HJ2]

Good stuff!

That would be my configuration as well However: my piper is 'deflectored' by me!
Don't forget that Peter's car is ported now

Come on guys, get your elanscan out!

[Peter D]

I was able to export to Excel, see attached.

Is it my Excel 2007 on Windows 7, or my Elanscan that's causing the error ?
Any tips in how I can make the export work ?

[ccb056]

I used the beta elanscan on windows 7 with office 2010.