Euro GT TDI 170 tinker thread from Australia

[Greg Roles]

42DD Inlet Air Temp mount....




42DD O2 spacer, should limit the CEL's hopefully.





The good news is as the USA are now copping DPF's on their TDI's and they are already onto developing aftermarket solutions. I am hopeful they will provide better DPF options, as I do want to keep one long term, but a cheaper, rebuildable, higher flow, less invasive regen one. The new MK6 has split the cat and DPF apart, thus lowering the cost of DPF replacement. That's GREAT news, and the path I would go if the DPF clogs and you want to stay OEM, retrofit the MK6 system.

[Greg Roles]

Well it starts and runs fine, seems to be a little louder induction wise, but not as bad as I expected. I drove it carefully till the regen kicked in once warmed up, and it ran fine for about the normal 10 mins which absolutely amazed me. Temps on my EGT were as per normal, couldn't believe my luck. Then as it finished it threw an error code up and the coil light started flashing, which really freaked me out. I pulled over and checked under the hood, looked at all the gauges, and it all "seemed" fine, so I kept going carefully. I stopped up the top of a hill as I thought I heard something drop out of the engine bay like a bolt or something, and I was already on high alert, so I pulled over. It all seemed fine and I couldn't see anything on the road. Started her back up and the coil light had gone away, but on the way back the engine shaped light CEL illuminated, but it continued to run as per normal.

A VagCom once back home showed the engine symbol CEL to be the typical "insufficient EGR" and that's to be expected, as now there's none at all. The earlier coil CEL was " Mass Air flow during Regen too low" and that makes sense as I have removed the flap that part closes during regen to help the DPF reach higher temps.




I can part close my QTP flap, but will monitor my soot loads via VagCom, and force some regens if it gets too loaded. The EGT gauge tells me it is reaching suitable temps, just the ECU isn't seeing the increased airflow speed with the closed flap during regen. Will have to find a way to make this work as HOLY COW does it feel much meatier to drive now!

Errors and potential problems aside, it feels quite different, and I haven't even given it the berries as yet. Before the turbo would spike at 23-24 psi and then settle back down towards 20 or so. Now it spikes at 21-22 and stays there, no more peak and drop off! It feels like the normal 1800rpm wack, but then just doesn't let up, friggen amazing for a still stock ECU and exhaust. Very noticable, fatter mid range, can't wait to give it an all out effort. I figured that flap / EGR body was restrictive, but WOW, I didn't expect that much difference on the stock exhaust. Really can't wait to get onto that now, and then get her tuned. ooo baby!

[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 and fit it up properly.

[Greg Roles]

EGR removal is 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.

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]

It's been interesting driving the car for 2 weeks now.

1. It's dramatically smoother, more eager, and feels like it's had a new lease of life.
2. It has as yet to do another regen! In theory taking the EGR out shoukd raise EGT's and in return drop soot production, plus help the DPF run hotter, so it should passivley regen better. I'd have to say that in it's current odd state of quite frequent regens after the pressure sensor replacement, it;s odd to have gone this long without a regen. I'm putting in on Vag Com for the drive home just to check soot levels.
3. I've got a tiny leak through one side of the QTP flap, so will have to sort that out before I go methanol.
4. Injecting just water my manifold on the engine is cool to the touch after running the car. Amazing.

Heavily into the exhaust pipe now.....Final stages coming together.....3" resonated mid pipe from 42DD today....to add to a 2.5" cat back "just lying around"... : )

Also fitted an electronic QTP flap controller, so have much better control of the intake flap for regens, and emergency shutdown.

Hope to never use that!

[Greg Roles]

Just to let everyone know, it's impossible to complete a standard DPF regen without the EGR mechanism hooked up to the loom, albeit hanging in the breeze. Anyone considering an Allards EGR delete, if you have a DPF, it's going to cripple the regen cycle, and while I had mine unhooked the DPF load got up to a all time high of 60% and I had to hook the EGR mechanism back up ( only to the loom ) to complete a regen with my QTP flap. The DPF light came up at this level of loading ( first time for that one ) and the engine light is on due to the low EGR flow error.

The electronic controller has been impossible to calibrate, so I have had to go back to a simple switch, but it works fine for regens. Hope to get the QTP controller to work so I can close it a bit more accurately than just counting 2 seconds and hoping it;s about half way ( takes 5 seconds to fully close ).

[Greg Roles]

took a video if the induction noise in my TDI, it gives you a fair idea to just how crazy it really is, and I drive it real quiet in carparks and other public enclosed spaces ( it's a bit embarassing at my age ), but I'm certain there's a lot less restriction between the intake and the engine than VW delivered it with!

The filter I am using made a lot of difference to the induction noise, as it has an open front design.



Induction noise video:

http://youtu.be/iGQuvqm0C1k

I've gone back to a K&N oiled one, as I was finding some fine dust in the intake from the Apexi, even though I've been swapping them out at about 30k's. I'd rather possible MAF issues from the oil over dust chewing out the poor TDI's innards.

[Greg Roles]

Spent Saturday arvo making up a jig to fab up my experimental DPF dump pipe. My plan is to put the experimental partial flow core into the stock housing, fix up the restrictive outlet, and bolt it up to the 42DD mid pipe where their dump systems join. I based the wood jig on the Miltek delete pipe I have currently borrowed, and the stock DPF I have been cutting up.

[Greg Roles]

And here is the challenge, to get a flex and 3" pipes between the DPF body, and the 42DD flange.






Amazingly there is a ton of room below the DPF outlet, and the only real concern is the final pic showing the steering that the stock pipe weaves around, when viewed from the front, directly underneath - the engine is at the top of the photo. The only point that gets close is right down near the 42DD flange, so I'm quite confident a decent pipe will fit with nice mandrel bends straight out of the DPF cannister.

[Greg Roles]

I have to organise my custom DPF core, but as soon as that is here and I weld it all up, she's going for a tune.

I can get cores made in different % flow, so am going to try a 50% and see how the DPF delete tune goes with it in place. Will still soot a little, but should be half as much as a delete car, and with all my extra breathing mods, should be less again, especially on water meth. I'd like to be able to offer a high flow DPF pipe that suits your "delete" tune, and hopefully it's something we can get clean enough to pass transport / public acceptance. That's the goal anyway....

Should flow OK, as the plan is 3" DPF out, 3" mid pipe and 2.5" axle back, all straight through. I want a funnel out of the bottom of the DPF, the stock pipe is just horrible, and crazy given the space there is!

The great news is these cores never clog, so there's no need for active regens, passive is plenty.

Fingers crossed!!!