different injector types AND cleaning injectors

[vwmike]

Over spring break I plan to put the turbo on my truck along with the turbo pump, and change the motor mount (obviously not for the whole time), but for now I am tempted to just change the injectors in the hopes it might run a bit better. The miss is pissing me off. I have 3 sets kicking around. One is out of a TD Rabbit and they say NA11X on them. Under the tag you can see they're 130 bar...so those are NA injectors. I have some TD injectors (155 bar), and some Peugeot injectors I got from the wrecking yard just to check them out. They're 150 bar. According to the micrometer, the pintle sizes are all about the same. What really is the advantage to the different breaking pressures? I would guess there would be better atomization with the higher pressure, but if that's the case then why didn't they do it on the NA diesels? Will I have to adjust the pump if I go from the 130 to the 155 bar injectors? I wouldn't mind cleaning them before I install them, does anyone have any suggestions?

[jtanguay]

best guess is to add more fuel during boosting.  Makes up for the 10 psi of boost?

[vwmike]

best guess is to add more fuel during boosting.  Makes up for the 10 psi of boost?

adding 25 bar to compensate for 10 psi doesn't make a whole lot of sense to me though. That's a difference of 367.5 psi.

[Hammy]

I'm not sure that I would try turbo injectors without having a turbo in the first place. I have not tried this myself, but have only heard bad reviews. But, whatever you try, be sure to clean the injector threads, and head threads, and donnot overtorque. I snapped the corner of the head off of mine because I didn't clean them out enough. I had a poor fitting socket , and I never reached the torque spec. Trust me this is easily done! Be careful, cause it will cost you a head job, and not the kid we like, either. :oops:

[Hammy]

I'm not sure that I would try turbo injectors without having a turbo in the first place. I have not tried this myself, but have only heard bad reviews. But, whatever you try, be sure to clean the injector threads, and head threads, and donnot overtorque. I snapped the corner of the head off of mine because I didn't clean them out enough. I had a poor fitting socket , and I never reached the torque spec. Trust me this is easily done! Be careful, cause it will cost you a head job, and not the kind we like, either. :oops: I made a spelling error on the previous post. It is supposed to read "kind", not "kid". Sorry!

[racer_x]

best guess is to add more fuel during boosting.  Makes up for the 10 psi of boost?

adding 25 bar to compensate for 10 psi doesn't make a whole lot of sense to me though. That's a difference of 367.5 psi.

But wouldn't the 10PSI of boost be multiplied by the mechanical compression ratio when the piston comes up? So the actual pressure in the combustion chamber (and prechamber) would be 230psi higher at a minimum, and there's an additional pressure boost from the heat from compression. The difference in operating pressure in the combustion chamber between a normally asthmatic diesel and a turbodiesel at 11psi of boost could well be 20 bar or more.

[vwmike]

best guess is to add more fuel during boosting.  Makes up for the 10 psi of boost?

adding 25 bar to compensate for 10 psi doesn't make a whole lot of sense to me though. That's a difference of 367.5 psi.

But wouldn't the 10PSI of boost be multiplied by the mechanical compression ratio when the piston comes up? So the actual pressure in the combustion chamber (and prechamber) would be 230psi higher at a minimum, and there's an additional pressure boost from the heat from compression. The difference in operating pressure in the combustion chamber between a normally asthmatic diesel and a turbodiesel at 11psi of boost could well be 20 bar or more.

I suppose that's true, I forgot about the whole diesel injecting directly into the combustion chamber thing. I normally do gas stuff.  

[vwmike]

I just installed the 155 bar injectors without changing the pump or adding the turbo. The truck seems to run MUCH better. I think it's louder, and vibrates more at idle (passenger mount is bad, I was going to replace that when I do the pump and turbo over spring break). It doesn't seem to smoke anymore, and it runs a lot smoother off idle....granted it's 65 degrees out right now. The true test will come in the morning when it's cold out (cold, meaning colder than it is now....which might be a warm daytime temp for some of you guys).

[chrissev]

new injectors don't make that much difference if you're running an old pump.  Actually, very little if any difference.  I didn't notice a big difference in my car until I put the rebuilt fuel injection pump in, then it was like driving a new car.  It was so peppy that it felt like the car would get torn right out of my hands.  It just took off from traffic lights and the engine was so free revving it was unbelievable.  It had this first gear power surge around 2800rpm that was never there before and it continued into higher gears, so I had to learn to drive it all over again (I kept clunking the clutch and transmission because I wasn't used to the extra power and the free reving engine).  That was the first time also that I really felt the turbo.  Above 3000 rpms it really pulled (good thing the pump has a rpm governor).  Rebuilt injection pumps are the greatest.

[vwmike]

These weren't even new injectors, they were just some turbo injectors I had from some other TD stuff I'd bought. It's just that my old injectors were THAT bad. 160k, and I'm sure they were never even touched.

[dieseltech]

your pump must have not worked propely before it was rebuilt, i have seen many turbo diesels that the pump fails to give extra fuel under boost, bad lda on the pump. new injectors in a properly running car will pep it up a bit and overall run better. i think vw injectors are good for about 75,000 miles and shuld be replaced or tested at about 100,000miles

new injectors don't make that much difference if you're running an old pump.  Actually, very little if any difference.  I didn't notice a big difference in my car until I put the rebuilt fuel injection pump in, then it was like driving a new car.  It was so peppy that it felt like the car would get torn right out of my hands.  It just took off from traffic lights and the engine was so free revving it was unbelievable.  It had this first gear power surge around 2800rpm that was never there before and it continued into higher gears, so I had to learn to drive it all over again (I kept clunking the clutch and transmission because I wasn't used to the extra power and the free reving engine).  That was the first time also that I really felt the turbo.  Above 3000 rpms it really pulled (good thing the pump has a rpm governor).  Rebuilt injection pumps are the greatest.