First THANK YOU for bringing this thread back up, I had forgotten all about it, It is one of my SITE peeves that members start a thread like this and NEVER share the results and here I am doing it, SORRY, will try not to let it happen again.
It was real easy to change the button, I have been told that it can be done with the ip installed, now in my case, I had to pull the pump to reseal it so did the button swap at the same time, I would recommend that you pull the pump, it makes it a lot easier where you can see everything, a lot LESS dirt to deal with,, and you might as well REseal (one less thing to worry about down the road because of the dry fuel).
It took me less then a hour to reseal and change the button, it took more time to get the freggen ip off and back on then it did then the ip redo.
If you reseal, change BOTH seals.
The gasket I had was wrong as it was for a wrecker ip, where the 819 has the standard ip (should be the wrecker ip) so I made one out of the same thickness gasket stock, It is IMPORTANT that if you need to make gaskets, that they ARE the SAME thickness as the OE.
REMEMBER IPs DO NOT LIKE DIRT, not even a little bit.
I dropped the button from the stock 27 button to a 22 button, WHAT a difference, where I had to down shift from 5th to 4th I now run 5th, the 36.000 lb 819 REALLY wants to pull, putting out some black smoke on the pull (smoke is good), also makes the hole between 3rd and 4th almost livable, I have NOT installed a pyro yet, lack of funds but I really need to do it before I have a melt down, I have to remember to get out of the throttle on LONNNNNNNNNNNG pulls. My speed has not really increased by any great amount but my PULLING power is WAY UP.
As far as rail pressure goes, these engines will handle a number 5 button BUT about anything under a 22 needs to be used with a turbo other wise the EGts WILL get extremely high, real quick, the reason the Canadian 809s run a 20 is there engines HAVE a turbo, if you ARE running a 20 button without a turbo, keep a CLOSE eye on the EGTs
Another thing, the lowering of the button does not really raise the rail pressure much if at all, what it does do is allow MORE fuel to the injectors at the existing rail pressure, at least that is how it was explained to me.
I also after I installed the ip, I turned my idle to 650, a LOT smother idle, REMEMBER when ever you do any adjustment to the ip, it MUST be at operating temperature. to much idle will result in slow rpm drop when the foot is taken off the throttle.
For those that were at to 13SSGAR, heard the 819 idle, and saw it run down the road, any rpm over 1000 requires hearing protection because of the 4" straight pipe.
Well I hope this brings everybody up to date, should have done this a lot sooner, like a year ago,
yes, that is correct...
over all i think that changing the button is the simplest way to get a few more ponies. now as for what number button to drop down to on a 250 not sure i dropped 12 but mine started life as a 230 and i had #42 and dropped to a 30. as for the pyro id deff put the probe at the collector toget a good overall temp your cylinders are running. most pyro equiped trucks are located there or just passed the turbo (that we dont have lol)
