The 1.9L PD TDI powerquest

[kaanage]

So, heres a challenge for those with Viezu tunes - can you do a bit of a fuel consumption comparison between your perf map and race map for me?

Not sure it this helps since my car allows such a different driving style (hypermiling - very rarely exceeding 1500rpm except on downshifts and freeways) but I have found pretty much no difference between the race, performance and economy maps with my suburban commute - maybe the race map uses 0.1 l/100km more than the other 2 but all 3 give about 0.5 l/100km less fuel usage than the stock map (about a 10% improvement).

This is with multiple tank refills - not quoting from MFD readings.

[gldgti]

Not sure it this helps since my car allows such a different driving style (hypermiling - very rarely exceeding 1500rpm except on downshifts and freeways) but I have found pretty much no difference between the race, performance and economy maps with my suburban commute - maybe the race map uses 0.1 l/100km more than the other 2 but all 3 give about 0.5 l/100km less fuel usage than the stock map (about a 10% improvement).

This is with multiple tank refills - not quoting from MFD readings.

Thanks Greg. Most likely if you spend a lot of your driving time hypermiling then you'd struggle to see the difference. My commute is 70% on hilly 110km/h zones, with about 5% 60km/h and the rest 70-80-90 - so you can imagine that I'm working the engine fairly well most of the time.

Out of interest, what kind of economy do you get then?

Tank to tank now I'm seeing 5.1-5.3l/100km.

[kaanage]

Yeah, I reckon the turbo is barely boosting most of the time I drive (which provides a good reservoir of soot for when smartar$e$ want to tailgate)

I normally get about 5.0 l/100km with a daily suburban (but not inner city) ~38km total commute in peak hours with a bit of suburban driving on weekends. On the Fiat Club Economy Run last year, on a 115km course over a mix of flat and hilly, suburban and country roads, the PoD managed 3.99 l/100km (using a fill at the start and the end). We actually got lost for about a 1km or so which meant actual mileage was a touch better.

I manually stop/start in traffic which gains about 5% too.

I'm currently trialling delaying my upshifting until 2000rpm and my mileage is about 15% worse on the MFD than when hypermiling. I feel like a hoon, too

[gldgti]

Yeah, I reckon the turbo is barely boosting most of the time I drive (which provides a good reservoir of soot for when smartar$e$ want to tailgate)

I normally get about 5.0 l/100km with a daily suburban (but not inner city) ~38km total commute in peak hours with a bit of suburban driving on weekends. On the Fiat Club Economy Run last year, on a 115km course over a mix of flat and hilly, suburban and country roads, the PoD managed 3.99 l/100km (using a fill at the start and the end). We actually got lost for about a 1km or so which meant actual mileage was a touch better.

I manually stop/start in traffic which gains about 5% too.

I'm currently trialling delaying my upshifting until 2000rpm and my mileage is about 15% worse on the MFD than when hypermiling. I feel like a hoon, too

haha! From the sound of it your commute must be a pretty bad one for economy. I'd be interested to know how you went cruising in a lower gear so the rpms were higher - I think, with all my diesels, the key to good economy has been to be able to cruise at peak VE of the engine... trouble with the vnt TDI's is that i think the standard turbo sizing gives an indication of maximum VE that is significantly lower than the sweet spot for the engine in terms of its real peak..... so for instance, the best VE might be at 2200 but because of the huge amount of boost available at lower rpm your peak torque is around 17-1800.

I would almost bet that for a city style commute and a driver like you who is able to listen to the engine and manage your acceleration, you'd get better economy with the vanes always fully open! (now theres a challenge for you!)

Or better yet, fit that GTB

In other news, the data furnished to Viezu is good so I'm likely to be fitting that turbo this weekend

[kaanage]

I'd be interested to know how you went cruising in a lower gear so the rpms were higher - I think, with all my diesels, the key to good economy has been to be able to cruise at peak VE of the engine...

That's the essence of what I am doing this week

I'm currently trialling delaying my upshifting until 2000rpm and my mileage is about 15% worse on the MFD than when hypermiling.

I would almost bet that for a city style commute and a driver like you who is able to listen to the engine and manage your acceleration, you'd get better economy with the vanes always fully open! (now theres a challenge for you!)

I did that for a couple of days when I disconnected the vacuum line to the vane actuator (I started a thread just prior to make sure that the default position would be fully open). I really didn't notice any difference except that when I wanted to accelerate harder than just to keep up with normal traffic, I had to rev out to about 1800rpm before it would start to pull strongly.

Or better yet, fit that GTB

Yeah, yeah
I might look for a blown VNT-15 and see if I can get the manifold cut and shut so that the GTB can be bolted on. It won't be as good as the sexy, Darkside, tubular manifold but it would be HEAPS cheaper.

In other news, the data furnished to Viezu is good so I'm likely to be fitting that turbo this weekend

Don't skimp on the details!

[gldgti]

I wont!

With regard to your GTB - you could use just about any 8V 4cyl VW exhaust manifold - depending on what amount of the standard stuff you wish to retain (EGR circuit?)

If you dont want to go for the tube manifold, the next thing I would try is any of the OEM or aftermarket 8V turbo manifolds - you can get aftermarket T3 manifolds but the angle of the outlet flange might be a problem. Better would be the early TDI k03/GT15 manifold, or the OEM diesel T3 manifold.

The cast turbo manifolds of OEM origins have a very high silicon content. I havn't personally tried to weld one but I would think it would be tricky to do it without weld cracking. I'd be very willing to give it a go for you though if you find one (Gratis for the diesel love )

Best bet would be to use 304SS for whatever you wanted to join onto it.

[gldgti]

Today was the day - swapped in the GT1749VB.

First, I have to say, I have misled myself and everyone else. My Octavia did not infact have the VNT15. Nor did it have the KKK bv39.

What it did have was the Garret GT1646V - a turbo as you might guess is somewhere between the GT15 and GT17! Whoda thought!

This means that I have a tune for a turbo that I dont have anyway, which is probably on the conservative side of things.... I guess all that means is that I can expect (relatively) even more once I am tuned for the GT17.

So, heres how it went:

First, car on ramps, disconnect the downpipe and shove it back out of the way. The idea is to make some room so you can manouvre the RHS driveshaft out without removing suspension components.


While the car is still on the ramps, undo the axel nut.


Now, if you are a dodgy bugger like me with an awesome floor jack, you can jack up the car on the drivers side to take the weight off the wheel while you undo the inner cv joint bolts. Once done, you should be able to pull out the driveshaft with a bit of juggling and swearing.


Once the driveshaft is out, you can pull out the downpipe you shoved down behind the subframe before. Now you've got plenty of room to get to the turbo and actually pull it out once everything is undone.

Remove the boost piping and the intake pipe for obvious reasons. Undo the EGR pipe form the turbo manifold to the cooler. 17mm spanner to undo the oil line fitting on the turbo, which you cant see from below but its easy enough to feel whats going on.

You'll also have to remove the airbox and intake piping so you can get to the other end of the oil feed line near the oil filter housing - the feed line is solid so you need ot undo both ends of it and the two clips that hold is in place so the turbo can be remooved.

You can use a 1/4 inch ratchet with a 12mm socket and a long extension bar to remove ALL of the securing nuts for the turbo itself. You'll also have to pull off a small heatshield.

viola!


The two nameplates:




Intakes - note the same compressor housing, but the inducer onthe GT17 is slightly larger than the 16:


Exhausts - quite a difference here:


Unfortunately, these two turbo's arent quite a direct swap. The EGR port on the GT17 is closer to the turbine housing, by about 20mm, which is way too far wrong to make my original EGR pipe fit. So for now its blanked off. To make a flange - I used some 6mm 304SS flat bar - use a gasket to mark the outline:



Bore the holes a little on the large side.. if you have a good bit, go for 8.5mm, if not, go for 9mm . When drilling stainless, use firm pressure, dont go too fast, and make sure the bit is sharp. You want to be cutting all the time. Oil helps cool the bit and the work:


Its a good idea to drill the holes before you go cutting the whole part out of the bar.

The finished part:


I also had to attache a little flange I made at work to the old downpipe. This is a semi temporary jobby, I may end up fabbing a new DP. Sorry no pics of the mod.

New turbo all bolted up:


Thats it - took it for a drive, gently at first then got bored so gave it boot - just as responsive, bit louder growl on hard acceleration and more acceleration right through the rev range - can't wait for the new tune!

Will be doing more logging shortly to that end!

[gldgti]

Well, broke an inner CV joint last night....

[kaanage]

Any updates on how you're going?

[gldgti]

Yeah, I've been slack!

I have been wanting to do the post turbo swap logging required for the new tune for 2 weeks now and I still haven't done it!

Perhaps I will do it tonight.... maybe! I've had quite a lot of other car stuff to do lately - the cabriolet has had its injector pump out and apart twice in the last 2 weeks, which has taken up most of the 'car time'

Thanks for the kick along Greg