diesel questions

[nathantheengineer]

Afternoon all,

Just a quick post.  It has been a long time since i have owned a turbo diesel and even longer since i have tuned one!!

I have increased the fuelling on my AAZ and turned the boost up a fraction.  My boost gauge reads 10psi now and i think i am correct in saying that they are ok up to 15 psi without fitting an inter-cooler?

If i turn my boost up will the injector pump add the requisite additional fuel now that i have adjusted the fuelling or do i have to adjust it again?

my vaguely remembered diesel theories tell me that the fuelling is metered not the air and so adding more boost without  more fuel will end in tears. is this right?

Thanks all

[keaton]

I have increased the fuelling on my AAZ and turned the boost up a fraction.  My boost gauge reads 10psi now and i think i am correct in saying that they are ok up to 15 psi without fitting an inter-cooler?

an intercooler always helps.

my vaguely remembered diesel theories tell me that the fuelling is metered not the air and so adding more boost without  more fuel will end in tears. is this right?

NO. you can add more air its fine, that is how you lower EGT's.

on a gas engine if you add more air and do mot match it with fuel, your run lean and can ping/pre detonate which kills a gasser but is the working principle of a diesel

[JamesT]

If you have a stock LDA pin, it will not add additional fuel with more boost. With a 1.6 pin or a custom pin, it will add more fuel until the pin bottoms out.

No tears. My K14 has seen repeated 20+lbs*in^-2 and survived well. You should be fine.

[nathantheengineer]

Thanks very much,

I will do the pin mod once i have driven the car for a few weeks with 15psi boost.   It is already a fair bit quicker than when i bought it.

As it is my daily and i am about to start rebuilding my vr6 i would like to spend money over a period of time.

Would my best course of action be:

1. turn boost to 15 psi.
2. fit FMIC
3. Fit new pin
4.enjoy annoying newer cars

Does this sound like a good way of going about things or are there any suggestions?

Thanks for the help.

[lloydbiker]

Not that I want to jack your thread, but maybe you can answer a question I've had ever since I got my AAZ. When I got it, the pump was supposedly rebuilt (and it looks like it was), but here's the peculiarity: If I run up over 3000 with my foot in it, I can make all following traffic disappear in a black cloud. My 1.6 TD would barely smoke under the same conditions. Perhaps I'm just not getting enough boost under full throttle condition for the fueling? 

[theman53]

FAQ:

http://www.vwdiesel.net/forum/index.php?topic=645.0

http://www.vwdiesel.net/forum/index.php?topic=579.0

[JamesT]

Not that I want to jack your thread, but maybe you can answer a question I've had ever since I got my AAZ. When I got it, the pump was supposedly rebuilt (and it looks like it was), but here's the peculiarity: If I run up over 3000 with my foot in it, I can make all following traffic disappear in a black cloud. My 1.6 TD would barely smoke under the same conditions. Perhaps I'm just not getting enough boost under full throttle condition for the fueling? 

I'd suggest you make your own thread for this one. The LDA is boost controlled, so no boost, no additional fuel. Sounds more like a fuel screw in a bit far.

[nathantheengineer]

It does sound like the fuel screw is wound in too far, my car doesn't smoke at all so perhaps i should be thinking about adding more fuel but as the backbox is not connected, (i.e. the mid section has snapped and the box is just there for show until i get the welder out). it could be smoking but i just cant see it as the exhaust dissapates before getting out from under the car.

However, seeing some of the smoke trails that are possible i would notice that even if i only had a downpipe!!!!!!

[JamesT]

It does sound like the fuel screw is wound in too far, my car doesn't smoke at all so perhaps i should be thinking about adding more fuel but as the backbox is not connected, (i.e. the mid section has snapped and the box is just there for show until i get the welder out). it could be smoking but i just cant see it as the exhaust dissapates before getting out from under the car.

However, seeing some of the smoke trails that are possible i would notice that even if i only had a downpipe!!!!!!

You could be right. My resonator fell out, and left me with an under/side exit exhaust. It didn't look too smokey, but my rear left rim was black.