btw if you max out the pg pump, adding an intank pump would do s***. If your theory was valid, adding a intank pump would help the stock cdfp, which it doesnt.
I don't see your logic, or how you have tested this. How are you so sure it doesn't increase the potential of the stock CDFP? Considering that I'm the only one that has done this, and that I have seen improvements, I would say it deffinately has an effect on it.
Negative... Unless you would like it to be referred to as " Head. "
Volume, an amount of fuel that is pushed by adding two pumps whether parallel or in a series. The volumes pressure, will not increase with 2 pumps. Only volume will ( IE: the amount of fuel being pushed from the tank, through the lines, into the FP regulator, out to the rail and into the injectors.) Adding two pumps in a series or parallel doesnt double the flow, head or volume characteristics of the liquid, but it does increase it by almost 50%.
In a normal forced inducted, fuel injected motor, volume is extremely important as boost taxes the supplied fuel volume. IE: Lightings and Cobras use 2 pumps via Y fitting to add volume to the supply, fuel pressure is not important in that application.
The difference in the MS3/6 application is that volume is adequate for now. Pressure is the problem since this is a direct injected engine. Removing the restricted high pressure pump via cam drive and replacing it with a larger pressure pump, allows more fuel to be sprayed into the engine as boost is increased. This results in a more efficient power making recipe.
Ken pointed out that Mazda obviously engineered the fuel system to meet the demands of the stock spec's with probably no more than +10% overhead ( IE: MS CAI and CBE .) Since this is mazda's first DI engine, im sure they are learning alot, just like we are. Maybe in the future, they will give a little more head room to support more mods from their MS parts. Who knows, but the PG replacement pump does work and its needed for anyone wishing to make 30 - 50%+ power out of their car.
You cant increase the fuel pressure little man if you dont have volume to back it up in a fuel injected engine. Now, we are dealing with DIRECT INJECTION, which is a whole different ball game. The entire internals of the PG pump is redesigned and cnc milled replacement if that means anything to you. The only thing left remaining in stock form is the actual fuel pump housing.
I'm not sure why you keep deffending the CDFP as I have not disagreed with one statement about it. The only thing I've disagreed with was the statement that upgrading the in-tank fuel pump is a waste of time and money. It clearly isn't. By your reasoning, the CDFP doesn't need an in-tank fuel pump at all. It would be able to feed the motor all the fuel it needs on it's own. If that was the case, Mazda wouldn't have put a pump in the tank at all, let alone a descent Denso unit (the stock one is identical to a denso at least from the outside).
And you are right, someone WILL max it out down the road, but that problem can be dealt with much easier than before. Your insight about increasing the volume of the in-tank pump to fix the fuel pressure problem at the engine holds no merit and is NOT the fix for the stock DI pump.
If you would like to plan ahead, build a larger cam driven pump that holds a larger volume of fuel using incoming #AN fittings, larger fuel rail, 3/8 line and a aeromotive inline pump from the tank. Goodluck on that venture and your " book . " You're going to need it (drinks)
I didn't reset my ecu, so my interpretations of the it's effect aren't false. I'm not making ANY claims about throttle or boost. The hesitation upon tip in...gone. Fuel cut...seems to have subsided. Just this morning, I did a WOT pull from low in 2nd to about half way through 5th, all shifting at 6000 rpm (where I always do when I'm "getting on it"). I also dug out from 2500rpm in 5th gear. I was unable to trigger a fuel cut by either of these "tests", even though it was 24*F outside acording to my ambient temperature display. I used to get fuel cut anywhere between 3000 and 4500 rpm anytime it got below around 60*F (with and without the ATP boost cut eliminator which is now removed). I'm not exactly sure what to make of that, because right after I swaped out the pumps, I would still hit it high in the rpm range, but only until I removed the ATP. I was expecting it to cut out and I was even waiting for it, but it just didn't happen. That's with an intake, a TBE, my E-01 (set to hold 18psi), and the fuel pump. No tuner. I'll try it again at 19psi on my lunch break if you want. I'm not saying I won't ever get fuel cut, because I don't have any data to make such claims, just like you don't have any data to make the claims that you are. I don't have a laptop anymore since it was stolen, but I still have my AE logger, so if anyone around St. Louis/St. Charles MO wants to do a ride along with thier laptop to log at least what it's doing now, I'm game. We could compare those with logs posted of an MS6 with similar mods. I know it's not the same as using pre-fuel pump logs from my own car, but it's all I can offer at the moment and it could give us a vague idea of what is going on. I had plenty of pre-fuel pump logs on my laptop, but like I said, it was stolen.
BTW, adding an in-line pump has the same effect as upgrading the in-tank pump (sending more fuel to the CDFP). So, if upgrading the in-tank pump is a waste of time and money, then so is adding an in-line pump.
All I'm saying is that more data needs to be collected and examined to draw any credible conclusion about the in-tank pump. As it stands right now, I'm the only credible source that has any experience with a better fuel pump in the tank. Others are soon to follow, and I'm sure at least one of them will be doing before and after logs.
Also, if PG or CP-E wants to bench test thier upgrades with stock supply vs. upgraded supply, I'll send them my stock fuel pump to use, then they only have to get a Walbro unit (which I'm sure they can get ahold of for cheap). At the very worst, it'll work as normally, at the very best, it could push thier pump a little farther. No one knows until it's been tested. I've handled the real world, everyday testing, and have come to the conclusion that not only is it operational, but, at least on my car, it has made thing alot smoother. If you need more proof, talk to CP-E or PG about bench testing or wait until someone that can log gets done with it.
lol I'll be the first to break into the 11's.... in tire chains to insure traction....lol.
