Pressure and Pulse Width

[wdino73]

Hey guys, I've got another dumb ???? Let's say u do McRat's 20/20( which is just read an enjoyed it very much. thanks Pat) In the tutorial u add 20% across the board now I know u just can't keep doing that cause u will start to get lope at idle a smoke at low throttle pos. an so on. anyway after u do the 20% on the main injection which will add around 50hp, how much will u gain if u add 20% to the fuel base pressure, cause I'm thinking if u add pressure to the base then in theory that will add more fuel without changing pw??
So if u add 20% to pw an 20% to fuel base how does that calculate, LOLOL.
I just confused myself:rofl::rofl:

 

[THEFERMANATOR]

More pressure allows for less pulse width to get the same amount of fuel. The problem comes into play that some CP3's just can't hold alot of pressure. I can run some large pulsewidths(2500 or so) on my stock LB7 CP3 and hold 150 or so for rail pressure, but it won't hold more than about 1600 pulsewidth and maintain 165 for rail pressure. Also higher rail pressures require different timing, and there is always the pesky problem of injectors cracking. I haven't heard of this so much with the DMAX, but I know the CUMMINS guys run lower rail pressures as much more than 180 and there injectors will fracture is what I was told. Theres a fine line with everything as to how much you can give it and have it take it.

 

[stacks04]

With the exception of changing the limiting tables, you can make a full on race tune changing only a couple boxes in as few as 3 tables. to make the smoothest tunes concentrate on the bottom right of the tables. Or anywhere from 50mm3 and 100mpa and down/right. That leaves low and most mid throttle stuff alone and gives you nice acceleration from there on. I have set my tune to command 170 mpa and it will hold 140 at 3000 ms. The timing table is the only one I would adjust below the above, and you can fien tune it for mileage.

 

[DIESELMAFIAPER.LB7]

GMy cp3 with Just a reg mod will hold 21.2-5kpsi with 45% overs at a 2000 pulse width it go up to 26k but falls off till bout What I already said thinking ill pull it down to a 1900 pw or even 1850 to get better pressure even at that pulse I am running as much or more fuel then my stock ones did at 3200pw I just need to get the rattle outta mine im learning how to do this myself still.
Also what could be done to lower egts to?

 

[wdino73]

Thanks guy, with the tune I dynoed the other day I had no rattle even on the road, I spent alot of time tweaking that out, I know it's a fine line, I"m just trying to learn more an more, I've got a big head so I can hold alot of Info.. lol

 

[S Phinney]

GMy cp3 with Just a reg mod will hold 21.2-5kpsi with 45% overs at a 2000 pulse width it go up to 26k but falls off till bout What I already said thinking ill pull it down to a 1900 pw or even 1850 to get better pressure even at that pulse I am running as much or more fuel then my stock ones did at 3200pw I just need to get the rattle outta mine im learning how to do this myself still.
Also what could be done to lower egts to?

It depends on where the egt's are? WOT or driving around? WOT would require less fuel or more efficient turbo and driving around would require more timing.