The 1.9L PD TDI powerquest

[gldgti]

So after some discussions with Viezu, we are going to be developing the tune for the new turbo shortly.

I will be doing some data logging this weekend (hopefully!!!) with my V race file, to give the techies in the UK some data - after that I will be swapping in the new turbo and it will be game on.

I'm looking at injectors, doing some research etc. I know you are interested in this Greg (kaanage) so hopefully, in time, I'll be able to take full advantage of the turbo.... full advantage being up around the 160wkW and 400Nm.

At the moment, Darkside developments seem to be the easiest number of clicks to owning a set of hi flow injectors that are calibrated properly... but at GBP 975 + postage its not exactly cheap. Nozzles by themselves are a fair bit cheaper, but then getting them fitted locally is an unknown. That is for Firad 80% (as in 80% more than standard flow!) nozzles.

You can also buy a set of 4 PD150/160 injectors (2nd hand) for GBP 300 which would get me to the power party at 200hp, BUT they are maxed out there.... Even so, it might be a good option because in reality - your not making 200hp every minute of every driving km. More like every now and then.....

I'm almost ready to commit to a set of nozzles and DIYing it, but I need to do some more research first.

[Buller_Scott]

my V race file, to give the techies in the UK some data

so you're working with them direct, instead of with Greg Roles? i'm out of the loop a little on here - is there a reason for this?

as for the fast road vs. track map, i found the fast road map better for dailying, simply because of the low down torque, which comes on very nicely.

after the last dyno day that both greg and i attended, me on race vs. greg on fast road, we did a radio prompted rolling start in 3rd gear (iirc?) @ 80km/h (private track, highway speeds, or whatever the w7nkers on all car forums justify their speeding with), and he spanked me, right off the bat.

race map is awesome for consecutive tight radius corners though, where our short power band demands that we're above 3500rpm on corner exit - the power comes into its own, there (plus, we still have torque).

my friday night contribution

[kaanage]

So after some discussions with Viezu, we are going to be developing the tune for the new turbo shortly.

I will be doing some data logging this weekend (hopefully!!!) with my V race file, to give the techies in the UK some data - after that I will be swapping in the new turbo and it will be game on.

I'm looking at injectors, doing some research etc. I know you are interested in this Greg (kaanage) so hopefully, in time, I'll be able to take full advantage of the turbo.... full advantage being up around the 160wkW and 400Nm.

At the moment, Darkside developments seem to be the easiest number of clicks to owning a set of hi flow injectors that are calibrated properly... but at GBP 975 + postage its not exactly cheap. Nozzles by themselves are a fair bit cheaper, but then getting them fitted locally is an unknown. That is for Firad 80% (as in 80% more than standard flow!) nozzles.

You can also buy a set of 4 PD150/160 injectors (2nd hand) for GBP 300 which would get me to the power party at 200hp, BUT they are maxed out there.... Even so, it might be a good option because in reality - your not making 200hp every minute of every driving km. More like every now and then.....

I'm almost ready to commit to a set of nozzles and DIYing it, but I need to do some more research first.

Yeah, if Simon was more definite about his guys being able to tune a highly modded diesel, then I would have already bought the Darkside exhaust manifold to fit the big turbo along with the set of +80% nozzle injectors and big intercooler that I have, all sitting in the shed . But now that the dollar has dropped, it might be a while before I get the funds (and permission) sorted so I'm more than happy to see how the Viezu team go sorting the Octy out.

Ryan (at Darkside) will probably recommend the +50% nozzles for you, though since he told me that those would be more than enough for my GTB turbo (I ended up going for bigger ). And opinions vary at TDiClub about whether you can fit the nozzles properly yourself or not - some claim to have done it just fine but a couple of people have posted that they later had them calibrated/pop tested and it made a big difference.

And my plan for mounting the EGT and boost gauges is almost identical to what you have done!

so you're working with them direct, instead of with Greg Roles? i'm out of the loop a little on here - is there a reason for this?

as for the fast road vs. track map, i found the fast road map better for dailying, simply because of the low down torque, which comes on very nicely.

after the last dyno day that both greg and i attended, me on race vs. greg on fast road, we did a radio prompted rolling start in 3rd gear (iirc?) @ 80km/h (private track, highway speeds, or whatever the w7nkers on all car forums justify their speeding with), and he spanked me, right off the bat.

race map is awesome for consecutive tight radius corners though, where our short power band demands that we're above 3500rpm on corner exit - the power comes into its own, there (plus, we still have torque).

my friday night contribution

That was a fun day (and the beginning of the end for me since it pulled me back to track days). I remember your PoD started catching mine up when we called it off around 130ish but it did take a bit for the race map to get going compared to the fast road. I think it was a 4th gear run, though - the race map is well into things at 3rd gear / 80km/h revs on the PoD. And up top, the race map made 4kW more with your car than the fast road map did in mine (though my car was still pretty new then so it may have been a bit tight).

Still, when we overlaid the dyno charts we pretty much predicted the 'road test' result.

Ya gotta come back to TDi, Scotty

[Buller_Scott]

Ya gotta come back to TDi, Scotty

ugh, the fact that you know your sh7t [and i know a bit about these cars, though nowhere near to the same extent]... seriously, it's back on the radar. maybe not as rough as i did with my girly blue PoD, but bigger turbo, more compliant suspension mods.... and the fact that with some care, these engines will last for ages......

grrr!

[gldgti]

I'm confident that the ability is there with viezu - its the data that they need to start from though that is the problem.

Even though, in Europe, people have been modding the diesels for years, its always been small tuners that have offered tunes for diesels with big turbo's and emission system deletes, for obvious reasons.

Viezu are big on the 'stage 1' diesel tune and we all know they do it very well. Its something else again to offer tunes for highly modified engines.... especially when your not developing the tune with the car on a dyno, AND you are still concerned with providing a tune that is clean and green. Thats the major hurdle for diesel tuning as we know. Its one thing to tune for power... another thing entirely to make it powerful and clean!

So, we're working together on this one and I'm sure it wont be too long before you can put all your good bits to the test kaanage! That will be a fantastic build for a polo..... I'm salivating just thinking about it.

I'm very happy that a major tuner is taking an interest in us diesel enthusiasts!

So Greg - you bought the whole injectors with the fitted nozzles??! Awesome!
Looking at the turbo's on offer.... and the prices.... I'm surprised you didnt go for the 2260vk!

***edit*** no, I dont think my engine will be 'highly modified' with the vnt17 on it!!!! (one of the paragraphs above might read like I do!)

[kaanage]

Oh, I'm sure Viezu could tune it eventually if given enough time and data. My issue is that the PoD is my daily drive and I was intending to sell my motorbike to finance the fitting kit but I might keep it now which would make an extended tuning process more tolerable.

My other alternative was to go to another tuner like Malone who are very familiar with big turbo TDi's but I'd rather stick with Viezu if possible.

I eBay'ed some used PD100 injectors in the UK and had them shipped to Darkside for the nozzle upgrade but you can buy them from Darkside complete for not much more (+ less hassle).

As for the turbo, I don't want too much lag so I wasn't keen on the 2260 and felt that the compressor seemed overly large for the turbine in the 1756 so when a used 2056 came up on TDiClub, I snapped it up. I'm pretty sure it's the optimal size for my requirements. Gotta get it fitted to be sure, though.

Ryan said that they're working on some hybrid VNTs that would bolt straight on to a transverse 1.9 PD but they haven't appeared, yet.

At the moment, I'm all talk while you're getting on with the business. Kudos to you

[getjet]

Just get the tune done through Darkside and be done with it.

I tried to get a tune locally and it just didn't happen. Those guys specialise in diesels....

[Buller_Scott]

Just get the tune done through Darkside and be done with it.

I tried to get a tune locally and it just didn't happen. Those guys specialise in diesels....

was there much back-and-forthing involved?

[getjet]

was there much back-and-forthing involved?

No. On the second revision of my tune and no problems.

Very easy to deal with but you'll need to take logs etc.

[gldgti]

So this afternoon I had a very successful experiment.

Problem

VNT's are actuated using vaccum which is controlled by the ECU and the N75 valve assembly, which basically switches vaccuum to the diaphragm o nthe turbocharger to move the vanes. When vacuum is applied, the vanes close up and the turbo spins faster.

However, adjustment of the pre-load on the actuator, how effective the vaccuum system on the vehicle is, and the response of the N75 valve all contribute to the possibility if big boost spikes on acceleration.

Over the past couple of weeks since I installed a boost guage, I have seen the boost spike to 28psi!!!! under only moderate acceleration. Whats more, it will stay above 20 psi for a few seconds on occasion before, FINALLY, the vanes open up and the turbo spools down a bit.

This is a commonly talked about issue with tuned TDI's as some of us know, but the only solutions I'veheard about involve adjusting the actuator preload, or getting a bigger turbo!

Hypothesis

I thought, if all you need to do is get rid of the vaccuum in the actuator line when the boost is too high, then the most efficient way to do that would surely be to use a mechanical valve that opens and lets some air in there!

Further, a readily available valve for hat kind of thing already exists - a manual boost controller (MBC). The best known and best one I've ever used is a turbotech - $30 on ebay!

Method

The idea is to use the boost signal which my boost guage already uses, to provide the boost pressure 'signal' and also the 'air supply' to the boost controller. Simple - tee off the boost gauge line, you've got a boost signal. This goes into the MBC as per usual.

The other side is equally simple - tee into the vacuum line running from the N75 to the turbo vane actuator, and connect it to the other side of the MBC.

Now, we have a small problem.

The MBC has a bleed hole, which when used on a normal system, allows the boost pressure to bleed back out of the wastegate actuator line so that the wastegate can close again.

However in our system, the actuator needs vacuum to close the vanes. The bleed hole would not be very useful in this case - so the simple thing to do is to block the bleed hole. I did this with a little bit of 5 minute high temp epoxy.

Presto - your done!

Results

Spectacular! While the MBC was on the bench, I used an old boost gauge and a bike pump to set the 'opening pressure' of the MBC to about 26Psi - Why? Well, I want to stop the boost spikes, which occur when there is still some vacuum in the line. This means that in operation, there might be say, -10psi guage pressure in the actuator line. That would mean the valve would open and a boost pressure of about 16psi, or thereabouts.
As it turns out, that vacuum pressure in my car must be more like -6psi gauge, because on acceleration, the boost goes up to 20psi and not a bit more.... ever..... at all!

I just did a test drive down the road and back with plenty of varied throttle applications, and no matter what, the boost just stops at 20psi.

So, as the boost comes on, it reaches the opening pressure for the valve, lets in some air to the actuator line and bam - no more vacuum - the vanes open instantly (no waiting around for the N75 valve!) and no boost spike.

I cannot tell if there is an increase in spool time. It certainly isnt noticable if there is one. Tomorrow hopefully I'll do some logging and I will have some numbers to compare.

Conclusion

If you are concerned about boost spikes on your TDI, the above solution takes about 10 minutes to implement, costs about $40 including vacuum hose and tees and an MBC, and it works GREAT.

I'm a happy boy this evening!