Let the tinkering get serious!!....

[poyta]

Must say I'm excited!!!

Me too Greg, well done.

[Greg Roles]

I've hooked up a switch to be able to alter the QTP flap, so I'll try and force a regen and play with the flap position till I get the magic 700 degrees pre turbo on VagCom. It's going to keep throwing errors, but so long as I keep an eye on the DPF soot levels, and force regnes if need be, it should be all good in my mind. Seems the lappie is going to be my passenger for a while......as there's no WAY I want to go back to stock, can't wait to get the right silicon joiner in the post ( probably tomorrow when I am in Cairns all day ) and fit it permanently.

Now to get Parso ( hopefully ) to rid me of the excess bits hanging uselessly in my engine bay!

[Greg Roles]

Success! Completed a successful error free regen on the way to the airport with vagcom monitoring and closing the QTP flap about half. Yay!

[h100vw]

Sweet! 10 characters

[jazd]

So you have removed the EGR and made it possible to manually control the QTP flap?

What does the EGR do and what are the benefits of removing it? Likewise with manually controlling the QTP flap?

[Greg Roles]

It's not something that is either easy, or recommended you do. It raises the EGT's and done wrong, that can melt your turbo. It's why i have spent years increasing the cooling capacity of the system, and added water meth, plus I'm prepared to rebuild my grenaded engine should it do so. It also seriously messes with the DPF, and done wrong, again will quickly destroy a $4k part.

If you read back through the thread I go into it all, but basically EGR is recycled exhaust that is there to lower the available O2, lower the combustion temps, and thus NOX emissions. Thing is this both drops power, and paradoxically raises soot production. The EGR valve body is also a major restriction in the intake, and the factory flapper actually causes a restriction to assist exhaust to be drawn into the inlet.

I now just have a much larger manually controlled flap purely for run away situations, and the bonus has been I can use it to run successful regens like I did today.

[Buller_Scott]

that's mad.

so, in the event of run away, when you close the flap the intake mani will only be accepting EGR, is that correct?

if so, when the flap's fully closed, i presume it's a very tight seal, unlike the stock setup in the polo (whereby it's only around 80% shut, by the looks of things)?

keep it up man!

[Greg Roles]

There's no more EGR mate. My inlet is now 100% oil blowby and EGR free. Next step is to remove the entire EGR plumbing and bolt a plate to the manifold, should aid spool a bit, as the log manifold volume is a LOT bigger with the entire EGR circuit bolted on.

[Greg Roles]

Well I'm driving around rather quietly, as I'm not 100% finished with the last 45 degree copuler into the QTP flap, and the hose that turned up from ebay is rubbish, so it'll be a little bit yet till I can let rip.

What is interesting is how much smoother and responsive the car is at part throttle, and on transitions. Before the stock TDI was a bit jerky down low, espcially when driving slow and transitioning from on-off light throttle applications. Anyone with a stock ECU manual TDI will know what I mean, especially the GT, it isnlt the smoothest car. It would seem to me that the stock flap is doing all sorts of things in the inlet at part throttle, and the jerkiness has simply vanished from my car, even first feels good now! The car seems quite willing to respond to small, part throttle applications, and the turbo response is quite instantaneous and apparent. Amazing drive quality difference, even still pushing through a stock DPF and exhaust. It's not massive, but the car feels quite perkier.

[Greg Roles]

Yeehah!