timing vs. fuel pressure.

[IDIoit]

im curious to know how much timing is effected by fuel pressure.
anyone ever done any testing?
I did the ole google/oilburners search, and netted, nothing.
thoughts? comments? trash talking?

 

[03wr250f]

Funny you should bring this up. a buddy of mine on the fb idi page and i were just talking about this.
We also shot around the idea of possibly "tuning" a idi. In the fact of running lower fuel psi (lower timing) for a tow "tune" and then jacking pressure up (timing increased) for a hot "tune". Discussing with a few other idi guys, the consensus was generally that the most efficient timing should also be the most powerful. I just got my stage 3 fuel system in, and will be installing saturday. I do plan to do some testing with this. I also will need to buy a timing pickup in order to monitor what fuel psi changes make on timing, but I plan on investigating.

 

[gandalf]

It seems to me that Mel has done some work in this area, and found that changing the fuel pressure does indeed affect the timing. There was a thread on this, somewhere in the forum. It's been a while, so your best bet is to either wait for somebody who can id the thread, or ask Mel.

 

[Dieselcrawler]

Yep mel tested it on his bench tester. More fuel pressure into the injection pump did advance the timing. But no long term affects have ever been tested.

 

[Thewespaul]

I can shoot a video this evening of adjusting fp with the timing light connected, should show the difference quite well

 

[03wr250f]

I would love to see that @Thewespaul

 

[snicklas]

Here’s the thread that Mel posted about inlet pressure and timing....

https://www.oilburners.net/threads/official-test-results-of-fuel-inlet-presure-timing.34636/

If it reads a bit strange the way Mel is referring to the builder, this was BEFORE Mel owned Conestoga Diesel.......

 

[SebastIDIan]

My 91 used to knock like a powerstroke before I removed the electric pump the PO installed out of a sterling truck That thing had some serious pressure.

 

[Thewespaul]

Sorry gents, I got home to the house late from the shop and the Internet wasn’t working and didn’t have the energy to mess with it (excuses excuses I know )
I’ll upload it before i leave the shop today

 

[IDIoit]

Sorry gents, I got home to the house late from the shop and the Internet wasn’t working and didn’t have the energy to mess with it (excuses excuses I know )
I’ll upload it before i leave the shop today

slacker!

 

[OLDBULL8]

According to what Mel is saying ( in Snicklas post above) the inlet IP pressure has little effect on the timing to a point.

My thinking
The internal IP pressure is derived from the fact that the return lines and IP check ball (housing pressure regulator) can only unload so much pressure (Volume), if the internal IP pressure would go hi enough, then the IP would be fully "saturated" and cease to function at all. But what that pressure would be, that would have to be tested.

 

[Thewespaul]

Well I did the comparison, you probably can’t hear me at all but here’s basically what I did, first video is at 0 psi and it idles at about 13* next video is at 10psi and I got about 14.5* at idle. Pretty much mimics what Mel posted.

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[Clb]

I had subscribed to a thread ,ip,intercooler, timing????
That mel recently posted in about testing input psi and its result on timing..
Short answer was more input psi= advance in the ip
I cannot however seem to access my subscriptions.

 

[snicklas]

Clb,

That thread is the one I linked to 4 or 5 posts up.......

 

[Clb]

Sweet
That is the one.
Watched threads.......Never mind, I got it figured out.