I just wanted to update this thread since I was posting some info in it about a year ago.
Increased pop pressure to 2200psi saw no gain on the dyno over 1800psi, and Im sure the 2500psi sticks would have seen no gain either.
These pumps simply don't like high injection pressures, and will...
3500pop is probably killing the flow of the pump. Too much pop pressure raises injection pressure beyond what the plungers will seal.
I know with lots of tinkering, at least on our IH's, 2200pop is just about ideal for injection duration without increasing total injection pressure past...
No, the closest we have is the difference between my 7.3 Dyno, and NMB2's 6.9 dyno. NMB2 had stock 6.9 precups, which have smaller throats, and he put down 365whp@2800RPM on 130cc of fuel. That's pretty damn good for our IH's, and about a 2.8hp/cc ratio.
Im just not convinced that changing...
Is there any solid back to back dyno proof on that around here?
I know there is a lot of talk, and a lot of people that say it added seat of the pants power, but a dyno is the only way your going to measure that, and its hard for somebody to dyno without making other changes....
That's Odd... This is the one I have, but mine does have the boost reference port.
http://www.summitracing.com/parts/qft-30-900/overview/
You can actually see the "boss" where the nipple goes in this pic...
http://www.quickfueltechnology.com/bypass-regulator.html
Im just running a Quickfuel FPR I got from summit, the cheaper one with NPT inlets/outlets. I have to put a small air regulator inline with it though, I was seeing upwards of 37-38psi of inlet pressure, and that had me very nervous, as well as contributing to a blown HG by maxing out the timing...
Yes, at least with my pump... Don't get me wrong... The dyno figures I made (342whp/759wtq, Even clutch aside) were with a 160cc peak pump, and a pretty primitive fueling curve (For the times)... Ive done so much since, that I destroyed my first pump with fuel load, had to figure out a solution...
Matched injectors are great, its amazing how smooth these engines run when the sticks are within 50lbs.
The other thing to look at as far as you DD guys pop pressures/injection duration goes, is you have a shorter stroke, so reducing injector duration helps apply more combustion pressure in...
By All means, if more pop pressure makes your vehicle run better, its absolutely worth it.
That's really what it comes down to, tuning. The only thing to watch out for, is even though something might feel better, the dyno could read something totally different.
Bottom line is that if it feel...
If the pump fueling is stock, I don't see any reason to bump pop pressure. The only reason would be to be able to retard timing a bit so you can reduce a bit of drag on the engine, but I haven't done enough testing with a stock pump to know if it warrants it or not.
Exactly,
Stock injectors are set to a pop pressure that delivers the stock quantity of fuel in the duration deemed to have the most efficient burn.
If you increase pop pressure without increasing fuel, your injection duration will be too little, and you will be wasting a lot of heat energy by...
Just to throw my angle in here.... Yes, The R&D pump flow is legit, and I welcome anybody to test their R&D on a stand. The 110 peaks out about 115-116cc, does 109-111 at 2800RPM, 105@3300RPM, and tapers to 99-100 at 4K. The RD4's aren't as flat, but still fuel out well, my own pump on my...
It certainly increases the amount of bleed past the pintle guide, but its miniscule in terms of injection volume, that I would say it makes very little difference in power.
Im not sure about your guys Bosch type injectors, but our Stanadyne type injectors have more than enough nozzle area...
Interesting thread, but I have a few things to throw in for you guys to ponder.
I am actually of the opinion that the Pre-cups themselves don't make too much of a difference from one another, that the throat area is only as important as your ratio of Chamber volume to displacement. As long as...
I am confident an IDI could withstand those numbers with very little modification but I am building my 6.9 to take whatever I can throw at it. The details are in my thread on FTE, but the breakdown is as following:
-86 6.9 block Bored .040, Decked
-Screw in freeze plugs
- 93/94 IDIT rods...
Physically pump for pump, You are correct. However, the hydraulic heads and internal parts are all interchangeable, so the calibrations and fancy parts can be done in a GM pump as well.
Look guys, I don't wanna start a big contentious argument, but my question is.... Why do you still continue to think in the past?
I am looking at .31 pumps putting out 110-120cc's slipping to 99cc's at 4000RPM... That is just my 2 plunger pumps (WITH leaf spings btw).... The 4 plunger pumps...