injector pop pressure vs timing advance

CorneliusRox said:
I never knew that. You're saying that it gets air in it while going through pumps and what not, or it inherently has air as some kind of chemical property? This totally makes sense with a lot of things that have confused me over time with diesels though.
I've read through a couple ICE book and taken a class on it back in college days, but never came across that. If you've got the name of the book, you should PM me and let me know.
Click to expand...
I don't know how and when it gets there but that's the reason for compressibility, in theory liquids are not compressible. I have also heard that you can not get that air out of there no matter what those guys selling Airdogs or similar are saying.

That book was some old technical book about engines, it's in finnish language so not much help for you I think. The information must be originally from somewhere else so I think there's some english books about it also. Maybe Google finds something from internet ?
 
CorneliusRox said:
That's pretty interesting. How did you get those measurements. 2900psi seems like a pretty high number to get accurate readings at. Not being a dick, genuinely interested.
Click to expand...

Google found a paper done by a university in England that was testing viscosities and densities at various temperatures and pressures of five different diesel fuel samples. Some of their tests went up to 400-450 Mpa.
Page 10 starts showing the graphs.


And I mistyped in my original post, it was 200 Mpa, not bar.
 
I have a timing light.....it's an antique, being about 25 years old, but it works....You're welcome to it.


Chris
 
Chris, thanks for the offer! That makes 2 now.
looking forward to this a bit!
 
Tate said:
Google found a paper done by a university in England that was testing viscosities and densities at various temperatures and pressures of five different diesel fuel samples. Some of their tests went up to 400-450 Mpa.
Page 10 starts showing the graphs.


And I mistyped in my original post, it was 200 Mpa, not bar.
Click to expand...

WOW that’s about 7 to 10% more fuel density @ 250 Mpa. :thankyou2:
 
I didn't believe it either a couple years ago but fuel is actually a little bit compressible. Just remember at only 300 bar it isn't very much, maybe 2% of total volume.
 
straight 6 roar said:
I didn't believe it either a couple years ago but fuel is actually a little bit compressible. Just remember at only 300 bar it isn't very much, maybe 2% of total volume.
Click to expand...

But the injection pressure of for example P-pump is 1000+ bar, unit injectors around 2000 bar and latest high pressure commonrails close to 3000 bar.
 
I think the bigger problem with the small amount of compressable components in fuel would what is it made up of and what effect is it having on the system as a whole. Any entrained air in a high pressure hydraulic system is bad news, especially once it goes through the massive changes in pressure, like across reliefs etc. Even in hydraulic oil which has additives to encapsulate small air bubbles it can "breakout" or sort of expand, which is then circulated back theough the system. I think that in a diesel fuel system it would be more pronounced.
 
straight 6 roar said:
I didn't believe it either a couple years ago but fuel is actually a little bit compressible. Just remember at only 300 bar it isn't very much, maybe 2% of total volume.
Click to expand...

Everything is compressible. The part that people omit when talking about liquids is that they are VIRTUALLY incompressible. Day to day usage, the amount they compress is so slight that they don't need to be accounted for. But it is there.
 
we have a hyundai loader at work with the engine you want to build. vp44 and a 12v head on a storm block. so there has to be factory injectors to make this work right, unless cummins just uses regular 12v injectors. i can get you the engine# if that would help you at all.
 
I just want you to steal the injection lines off it!
ihave Cummins pn fit the line set. Aset from scheid I can bend are cheaper.
I have a set currently Zach gave me, just hoping they clear the hood..
 
What are you doing about the difference in the piston designs? Also, aren't the cam profiles different between the B series and ISB?

At the risk of sounding uneducated, what are your reasons for doing this swap? You've piqued my interest.
 
Zach asked me if I would/ wanted to..I said yes. He handed me a great starting point.

How else is this car going to stay unique?
 
Nothing wrong with being unique!

I've got an ultra clean 1st gen 4 runner with a removable hard top and solid front axle on 35s stashed in my barn. The motor is roached, and it is patiently waiting for my wife to run her 01 Beetle TDI into the ground so I can claim the motor for a conversion.
 
You must log in or register to reply here.
Top