Maisonvi's never ending build

So car is done tuning. Ran out of fuel at about 450 on 93 and put some E in the tank, tapped that out at about 460. I was hoping to get a fair bit more out of my system.

Talking to @WetzMS3 who is running almost the exact same set up but with slightly bigger injectors, he is making a fair bit more power without having to run out of fueling head room.

This leads me to believe I have something wrong with my system. First thing is fuel pressure, I had to make sure that my rail was seeing adiquate pressure at WOT. The following 2 videos are of WOT pulls. Rail pressure is about 60 at idle and cruise (bounces quite a bit as you can see) and at WOT, it drops down to about 50ish. No idea if this is normal or not.




Based on the place I bought my injectors at 43.5 psi I should see 630cc of spray and at 58psi it should be closer to 740cc.
ebay link for injectors:http://www.ebay.com/itm/291217100069?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT

If the DW300c pump is rated to 340 LPH, I need to re-look at @Enki's calculations to figure out how much head room Im leaving on the table.

If Im seeing 60 psi on the rail, the regulator should be fine right? Ive heard of people "crushing" it to gain a few more PSI, would that benefit me here? Maybe its the injectors and I just need to go bigger. Im not really sure the direction for a solution here.

 

Definitely do not need bigger injectors....mine are the same size and I have TONS more room for growth.

 

I'm planning to get a fuel pressure gauge to add onto my rail at some point after the track this weekend so I can see if my pressure acts similarly or not.

I've heard that the DW 300c pumps can have issues, but I have never had issues myself or seen any in person.

 

I have an in cabin digital gauge off of my FPR and it doesn't bounce like that at all. It could be because it's digital but it's usually a pretty smooth sweep.

 

What gauge are you using? I would assume being after the regulator would help too, but Im regulator-less.

 

STRi:
http://www.iagperformance.com/STRI-60mm-DSD-Fuel-Press-Gauge-Smoke-Amber-p/slm6035.htm

 

Well shit, Im not that much a baller. So that idea is out.

 

I got them off of a buddy for cheap. Matching boost and fuel pressure!

 

Is your fuel pressure regulator boost-referenced/rising rate? For instance, 60psi regulator pressure injected into a 2-bar atmosphere (28psi) will only effectively produce 32psi (60-28) @ the injectors unless the regulator sees and adjusts for additional manifold pressure created by the turbo.

(Please excuse my derp if you covered this earlier; I didn't read through everything recently.)

 

No aftermarket regulator. This is coming strait from the tank pump to the rail, returnless system

 

You should definitely have more fuel than that. The pressure you're dropping to is effectively below what most injector manufacturers will tell you is a minimum. You're basically "dropping off the map" of known flows. Obviously, you aren't flowing enough. Crush that regulator.

 

Before I go that route, I want to make sure my pump is not failing on me. There have been a few failures and I want to make sure Im not at the start of one of them.

 

Yeah, I definitely don't know too-too much about the nuances of supplemental PI application on our cars. I do know, however, that whatever pump pressure your WMI puts out, you have the subtract the boost level from that figure and reference the cc/min per pump psi chart to see what amount of methanol you're actually flowing. I know the same principle is true with PI, and I wonder how kit's like Kozmic's address that. From the bit of PI in boosted application research I've done, a rising-rate FP regulator is usually always used. PI are like DI in that if the pressure is insufficient, the spray pattern can be very compromised, which is less of an issue if injecting into the runners instead of the CC, but probably something that could be a factor.

 

Im not sure meth nozzles and injectors are an apples to apples comparison. The kit Im using is no different than kozmic's 5/6th port, just using more injectors at a smaller size.

 

This may not apply, but in my dealings with aftermarket boost systems, they almost always raise the fuel pressure as the boost increases.
This is done with either a Boost referenced regulator, or a pump booster.

Fuel pressure should go up as demand is required. You might see a quick dip, but i would expect 45-50 at idle and cruse, and 60-65 at WOT

 

So after a long discussion with @Enki today about my system and using his math and brain power, it turns out that @Redline was correct and my 25 psi is taking away from my fuel pressure so effectively Im only at 25 psi when my gauge drops to 50psi. Injectors are down to 477cc at that point.

So I need to look at A: my oem fuel pressure regulator and make sure its not suck open or something. Try and figure out why I dont have 60+ psi WOT. According to @ALPINEST4RS mazda oem spec is 60-71 psi.

B: Talking to DW to see if there is a way to test my pump and make sure it keeping up with demand.

If it is ok and the regulator is good, then I need to figure out a new plan.

 

Hope you get a complete solution easily and soon!

 

You could throw some massive injectors in there and let them dribble into the port like Kiwi on his milf game, but that's not really a very good idea.

 

We will call that plan B. And thanks for that mental image.....

Sent from my SM-G900V using Tapatalk

 

35psi boost out of 200 psi WMI is nbd. 35 PSI boost out of 50psi PI rail pressure is a no go. Big difference.
Kozmic's kit doesn't compensate for that. You have to scale up the PI IDC as the delta P across the injector drops. As long as you don't go below ~40 psi delta P from PI rail to IM, and you don't run out of IDC, you're good. Not the best way to do it, but is plenty functional, and well understood.

That is the ideal setup, but requires you to run a return line to the tank. You *might* also have to change the stock fuel pump setup with in tank regulator and tophat since you would have to delete or bypass the in tank regulator for this to work.

Reading your post again, it's very possible the pump is the issue. The regulator is controlling to 60 at idle and cruise, no reason it should change at WOT. Makes me think the pump isn't keeping up.