1.9L VW/Audi/Skoda/SEAT Diesel Mod alert! :)

[Arragonis]

Originally Posted by euromodder

So it made the same power on less fuel, i.e. by leaning it.

I've tapped this elsewhere but maybe worth it here.

One of the techniques on older NA diesels (Pug 205 - where are you now ???) was to balance throttle against what the engine could make use of in terms of fuel. The theory was that if you overdid it, the effect was like smothering a fire with too much material. What you needed to do was balance it against usage to get the best. There was definitely a point where you got no more benefit from either higher revs or more throttle vs easing back and changing up.

As I understand it a turbo kind of reverses this - there is always too much air for the fuel being injected - unless you use the old fashioned (rotary pump) trick of turning up the fuel. That gave you more power but at the expense of smoke from the less than efficient burning fuel.

[Julian Edgar]

Do you have any idea why acceleration wasn't better through the whole rpm scale, but was actually worse below 1500 and above 4000rpm, even though the pressure drop was greatly reduced?

My idea for this is explained in the article.

[Julian Edgar]

I have made a slight change to the story, based on material on page 60 of the Bosch publication Diesel Engine Management (3rd edition), 2004, which covers power and fuel injection mass.

[Piwoslaw]

Originally Posted by Piwoslaw

Do you have any idea why acceleration wasn't better through the whole rpm scale, but was actually worse below 1500 and above 4000rpm, even though the pressure drop was greatly reduced? Would this imply that just swapping the intake for something larger would harm performance and/or fuel economy when the driver's style keeps rpms between 1000 and 2000?

Originally Posted by Julian Edgar

My idea for this is explained in the article.

OK, I went back and studied the graph and text again, and I see that I was in error! Acceleration is actually better below 1500 rpm than with the stock intake. The y-axis of the graph is in g's, not in seconds, as I had thought.
My bad, terribly sorry about that.

[Piwoslaw]

Crossposting:
Diesel mods and testing

[dcb]

Originally Posted by Julian Edgar

New intake cost very little - maybe AUD$30

That homemade intake was my favorite part pvc, sacrificial coolies, and tape...

...and a cherry picker, and some vice grips and a wooden plug

http://autospeed.com/cms/A_112211/article.html

[ConnClark]

Part 3 is out on this series. Browser Warning

Its amazing how the ECU keeps making performance worse and worse by starving the engine of fuel. Even so I still think that mileage should be up though.

[COcyclist]

Part 4 is out with nice results. Fuel economy "appears" to have improved by 5% with a nice increase in power.

http://autospeed.com/cms/A_112228/article.html

[JasonG]

Here is the link Browser Warning

[Arragonis]

I suspect that if you have a custom remap to a 1.9 TDI you would get these results even without the other changes.