Different Tubo = Better Mileage?

Different Turbo = Better Mileage?

I've looked around the forums before posting but didn't see a lot of info pointing towards what a turbo upgrade could do for a 1.9 TDI in terms of fuel efficiency.

To my understanding, at about 500,000 km the turbo should be replaced. I figure if I am going to replace the turbo, I might as well put a good one in that might give me more bang for my buck.

Anyone has any info, war stories or links to visit, I would highly appreciate it.

if you are looking for fuel economy and not power, i would say that your best bet is to buy a stock replacement or at least something that is a direct bolt on affair.

Wanting economy means you want to save money, doing anything other than direct fit replacement will cost you money beyond the simple maintenance expenses that cant be avoided. You will need to drive ALOT to recoup any small MPG gain you get from upgrading the turbo to something that requires any sort of fabrication.

Stock is KP39 on your 2004 jetta
Alternative is the more robust VNT17 (almost a direct fit)
I have also read of some ppl actually downsizing to a VNT15 with a smart actuator.

bottom line, id stick with stock if i were looking for good economy, both monetarily and fuel consumption

Good advice above. GDE has an Eco tune also.

I don't see where the OP has a 2004 Jetta, what am I missing? Yes, a tune can likely increase FE, but going to a larger turbo will not.

KetchupShirt88 from what you are saying however, there can be some moderate improvements in fuel economy though, correct? I will likely need to replace the turbo anyways so I might as well get a good one while I'm at it. Some do make direct bolt on models that are larger to my knowledge.

(Also, running a 2000 Jetta TDI, sorry I didn't mention that. Not sure if that affects things or not.)

sorry about that, i combined "2000" and "mk4 jetta " and turned it into 2004 jetta... my bad.

same applies to a 2000 jetta though, but makes things even easier as far as selection. You still wanna stick to bolt on stuff because of the cost of custom work.

Look at Frans from dutch auto parts and you can see a number of very nicely priced rebuilt units. he has rebuilt VNT15's for $450 or Modified VNT17's that use a milled out VNT15 compressor housing ($575) to make them a nice and simple bolt on affair while being bigger.

If your turbo is still working properly at any mileage there would be no reason to replace it as "maintainence" as long as there wasn't abnormal shaft play or such. Actuators can now be replaced separately if/when they rust out or fail.
When I did the gas to TDI conversion project last year I inspected my 2003 donor (previous daily driver until totaled with 225K miles) with the intention of swapping in an almost turbo I've kept as a "spare" for years. Shaft tolerances seemed great, so left it in there.
Monitor oil consumption and pay attention to unusual noises.
No turbo swap/upgrade by itself on a relatively stock ALH will get you better mileage, or certainly not enough to ever cover the replacement cost.

The amount of backpressure caused by the little tiny turbine side does naturally cause a little dip in efficiency (mine was usually sitting at 8 PSI exhaust, 2 PSI intake at 70mph cruise)

you could grab the manifold off an 8v gas motor at the junkyard, later model obd2 cars had a real nice tubular one, run that, block off the oil feed and return, get a naturally aspirated tune set up not to smoke, you'd probably gain half a mpg and lose 30 hp. Still totally driveable.

Or just drive it until it actually warrants attention. Maybe have it properly rebuilt by someone you know has a VSR, to the tune of about $150

TDIFan1989 said:

Anyone has any info, war stories or links to visit, I would highly appreciate it.

Click to expand...

I don't think there are any turbo's that will increase fuel efficiency all on their own. As for bang for buck, you can buy a Mahle VNT15 in Canada for about $800 bucks, plus tax of course. I installed one in my Golf a couple years ago and now have 110,000 kms on it. At the time, it was $500 cheaper than a Garrett, so I decided to give it a try.

On a 2000 Jetta, there's a good chance that you'll have the early style VNT15, so to install a new turbo, you'll also have to add a lower mount bracket and bolt, oil return line, and oil return line fitting in the block. (I don't know at what point the turbos changed on these cars, but my 2000 Beetle had the early style).
With a new turbo, you'll also likely need a new oil feed line if it hasn't been replaced previously. On top of the turbo costs, you can easily be into a few hundred bucks in associated parts.

And, as the others have mentioned...I wouldn't replace it unless it becomes a problem.

Turbo upgrade

TDIFan1989 said:

I've looked around the forums before posting but didn't see a lot of info pointing towards what a turbo upgrade could do for a 1.9 TDI in terms of fuel efficiency.

To my understanding, at about 500,000 km the turbo should be replaced. I figure if I am going to replace the turbo, I might as well put a good one in that might give me more bang for my buck.

Anyone has any info, war stories or links to visit, I would highly appreciate it.

Click to expand...

When I installed a new turbo, I went with the 17/22, but I also installed a new SS down pipe, and a new complete mandrel bent SS 2.5" exhaust system, without a Cat. However, before I was able to gauge mpg improvements, on that alone, I installed a set of Nokian very low rolling resistance tires, and about a week later, casually checked my mileage. I was startled to see 68.1, and "knew" it had to be a mistake. So, before saying anything to anybody, I closely monitored that for about a month, and confirmed that I was consistently getting between 55 and 65 mpg's. The lowest I got was when I was driving To Florida, and interstate speed was averaging 85 MPH. At that speed, I was getting 48.2 mpg's. At between 55 and 60 mph, on cruise, I generally got over 65 mpg's. For me, a tip from Rocket Chip, years ago, that cruise will improve mpg's was spot on. Hope this helps

I would not just replace the turbocharger "just because". The Garrett VNT15 unit on the ALH from the factory is a very good turbo, they last quite a while. If you have no problem with it, leave it alone. That right there will save you a bunch of money.

Check out my sticky thread atop this section to make sure your car is in tip top shape first, because as they left the factory the ALH + manual gearbox is a pretty tough combo to beat for frugal use of fuel.

There are likely some things you could do to better that, but really the driving style is as much a factor as any modifications you could make. I put a set of good used automatic ALH injectors in a 5sp car (customer's request) and it did indeed net him about a 3 MPG improvement, but it left him with a car that felt like it had a 15hp deficit...and with only 90hp on tap to begin with, I'd have left it alone. But he was happy.

I think any realistic "improvements" to the ALH's fuel efficiency will be more costly than they are worth, and/or have some negative side effects like the injector swap mentioned above.

The tuners have some fuel miser tunes, as that has been a request of some driver's in recent years, but I do not have much experience with them.

My own ALH seems to hit 50 pretty easily, with an 11mm pump, MAF delete tune, no EGR, and a slightly hotter thermostat. Still takes a long time to warm up, but I drive mostly long(ish) distances and grew up with an air-cooled Volkswagen Bus as the family car, so wearing a coat when you go somewhere is a non-issue for me.