[Doug007]

Originally Posted by havand

I had this same thought when I read part 1.

So, if the system regulates the input to the pump... seems bad. If it literally cuts the supply of fuel, the pump is pulling against a vacuum at high rpm, low load situations, (ie, coasting your speed down) or if the low side pump cannot supply enough fuel. To me, this seems like the root problem, not necessarily just a lowside fuel supply issue. It is a design flaw. The fuel supply issue could contribute, but even with a massive lowside supply pump, high rpm and low load would still do the pump in over time.

I am surprised that they do not circulate the excess fuel/pressure from after the hpfp pump back to the lowside supply. Running a pump with a dry input is bad. Especially if is force driven by the engine.

EDIT: I am kinda thinking what you are missing is causing the damage to the pump. Just my guess though and I could definitely be wrong.

I did a bit more investigation and the HPFP is a bit different than most tilted disk plunger pumps I've seen before (they use a similar type of pump for pressure washers and actually gas turbine inlet fogging, basically water injection for a large industrial gas turbine).

Some details are revealed in this BMW document: http://www.e90post.com/forums/attach...8&d=1165592709

Note that the plunger does not act on the fuel directly but fills diaphragms with oil that expand to apply pressure to the fuel in the compression chamber. Check valves allow flow only in the high pressure direction. The fuel control valve basically controls the inlet pressure behind the low pressure check valve.

The pump has a decent volume of fuel that stays in the pump even immediately after the point of peak pressure. Basically, only the amount of fuel injected into the engine needs to be replace in each cycle to maintain a steady fuel rail pressure.

By reducing the pressure of the fuel immediately behind the low pressure check valve, the compression chamber pressure will need to drop to less than this pressure for the check valve to open. This allows the pressure in the fuel rail to drop.

Going the other way, if the pressure at the low pressure check valve is high, more fuel will enter the compression chamber and the fuel rail pressure will be increased.

The long and short of it is, the HPFP requires a good, high pressure from the LPFP to be able to achieve the high fuel rail pressure needed for direct injection at high loads where cylinder pressures are very high.

[Rob@RBTurbo]

There has been documented pressure drops of the LPFP pressure sensor signal on high HP pulls. Having the fuel available to the HPFP to do it's thing is pretty important, this all seems like a no brainer to me but especially for the bigger turbo guys... meaning those who are pushing the envelope. Those happy with their tune and FBO can probably just keep on keepin on and be "ok"...

[Rob@RBTurbo]

Again. A whole other topic thats not worth entering. We don't need another 4 part thread discussing fuel systems and methods of fuel control that don't even apply... Lol.

Originally Posted by maxnix

Well, a VH45DE V8 has a 3 stage fuel pump that varies between 34 psi at idle and just under 44 psi at WOT.

[Q4P]

Here is an idea; remove the DI system all together and install a standard head. Install a walbro 255 Pump, fabricate different fuel lines and larger injectors or use a double pumper system as one used in a Supra which is a 3.0L straight six twin turbo engine as well and re-tune for that...


Oh wait, this isn't the Toyota forums...

Not trying to be a troll but thinking realistically if someone put the time and effort into doing this in the first place, we might have had a 600-700 WHP 335i by now. This effort would surely have taken less than 4 years and created a simpler system as used in every other motor with great amounts of power.

I understand the advantages of DI are great (fuel efficiency, easy and quick power) but as of the current time being (2011, there is only so far that DI can get you, all Mazdaspeed3 and GTI's are in essence tied down by a complicated fueling system as is this platform. Evo's, Supra's and GTR's, dont seem to have any of these problems..... any connection to DI?

Btw, I did have a 335i and absolutely loved it for its ability to incorporate speed, class, and an amazing ability to DD. But in no way was the N54 built to be a drag racer 600-700 hp machine.

- A

[Brey335i]

Originally Posted by Questforpower

Here is an idea; remove the DI system all together and install a standard head. Install a walbro 255 Pump, fabricate different fuel lines and larger injectors or use a double pumper system as one used in a Supra which is a 3.0L straight six twin turbo engine as well and re-tune for that...


Oh wait, this isn't the Toyota forums...

Not trying to be a troll but thinking realistically if someone put the time and effort into doing this in the first place, we might have had a 600-700 WHP 335i by now. This effort would surely have taken less than 4 years and created a simpler system as used in every other motor with great amounts of power.

I understand the advantages of DI are great (fuel efficiency, easy and quick power) but as of the current time being (2011, there is only so far that DI can get you, all Mazdaspeed3 and GTI's are in essence tied down by a complicated fueling system as is this platform. Evo's, Supra's and GTR's, dont seem to have any of these problems..... any connection to DI?

Btw, I did have a 335i and absolutely loved it for its ability to incorporate speed, class, and an amazing ability to DD. But in no way was the N54 built to be a drag racer 600-700 hp machine.

- A

I'm sorry, but that is just the most epic first post I've ever seen on this forum

[dzenno]

Originally Posted by Questforpower

Here is an idea; remove the DI system all together and install a standard head. Install a walbro 255 Pump, fabricate different fuel lines and larger injectors or use a double pumper system as one used in a Supra which is a 3.0L straight six twin turbo engine as well and re-tune for that...


Oh wait, this isn't the Toyota forums...

Not trying to be a troll but thinking realistically if someone put the time and effort into doing this in the first place, we might have had a 600-700 WHP 335i by now. This effort would surely have taken less than 4 years and created a simpler system as used in every other motor with great amounts of power.

I understand the advantages of DI are great (fuel efficiency, easy and quick power) but as of the current time being (2011, there is only so far that DI can get you, all Mazdaspeed3 and GTI's are in essence tied down by a complicated fueling system as is this platform. Evo's, Supra's and GTR's, dont seem to have any of these problems..... any connection to DI?

Btw, I did have a 335i and absolutely loved it for its ability to incorporate speed, class, and an amazing ability to DD. But in no way was the N54 built to be a drag racer 600-700 hp machine.

- A

ok, so you do that and what have you actually done in the end, everything that's been done before with port injection...well, BORING! I totally appreciate what's being done here as I'm sure many others are...put in a standard head?? wtf?? total fail for the 1st post, welcome to the forum

[Q4P]

Originally Posted by dzenno

ok, so you do that and what have you actually done in the end, everything that's been done before with port injection...well, BORING! I totally appreciate what's being done here as I'm sure many others are...put in a standard head?? wtf?? total fail for the 1st post, welcome to the forum

Originally Posted by Brey335i

I'm sorry, but that is just the most epic first post I've ever seen on this forum

One post gentlemen does not mean one user name, I have been around a while

I appreciate Vishnu's efforts, my 335i was Procede tuned but I have yet to see what can be done with direct injection reliably at those power levels unless you're in a massive diesel truck. I see that the goal here for most is to create maximum power safely within fueling limits, I just seem to think this would be easier done without DI. The only reason to upgrading the fueling system at this point would be for power as in going go over that 550-600 WHP barrier where daily drivability of a vehicle of this class will becomes a topic for another discussion. At those power levels, it is difficult to say how other components of the vehicle's engine will hold up; someone better start making upgraded rods, pistons, and possibly cams.

Point being made, if an upgraded fueling system comes out; it will be for hardcore 550-600 WHP guys not most Daily Drivers where the benefits of DI are not worth the difficulty of getting to those power levels or having to wait 4 years already when perhaps a much simpler option could have been devised...

[Rob@RBTurbo]

I agree this is not the best platform for a drag car. But I do believe achieving approx. 600-650HP at the crank will be possible at a relatively fair price with all the creature comforts and class to boot. If a fairly simple mod to the fuel system can get us there, why not retain it all? Personally I like the idea of something simple, bolt-on, and reversible. You get to the point of that kind of work you are in it to win it, that go big or go home philosophy is great but you better have lots of time and a bottomless pocketbook. The reason why it took 4 years to get anywhere is because no one has taken a second to dissect the fuel system and look at the most obvious part as being a weak link.

[dzenno]

Originally Posted by Questforpower

One post gentlemen does not mean one user name, I have been around a while

I appreciate Vishnu's efforts, my 335i was Procede tuned but I have yet to see what can be done with direct injection reliably at those power levels unless you're in a massive diesel truck. I see that the goal here for most is to create maximum power safely within fueling limits, I just seem to think this would be easier done without DI. The only reason to upgrading the fueling system at this point would be for power as in going go over that 550-600 WHP barrier where daily drivability of a vehicle of this class will becomes a topic for another discussion. At those power levels, it is difficult to say how other components of the vehicle's engine will hold up; someone better start making upgraded rods, pistons, and possibly cams.

Point being made, if an upgraded fueling system comes out; it will be for hardcore 550-600 WHP guys not most Daily Drivers where the benefits of DI are not worth the difficulty of getting to those power levels or having to wait 4 years already when perhaps a much simpler option could have been devised...

1 post means nothing but you're definitely not well informed when it comes to the N54...a while ago ppl were talking about 14psi being the limit for this engine, then there was talk of the ceiling being 400whp...at the same time companies have already developed rods, pistons and upgraded heads for this engine, as well as upgraded turbos and even a single turbo (although this one never saw light of day in any customers hands for whatever reason)...N54 is currently gated by fuel and a solution is days if not hours away at this point...do some reading man I know what you're saying and that it'd have been easier but that's total speculation...if it was THAT easy and worth it, it would've probably been done already...

[prelude2perfect]

Do you know how much work (and money) it would take to do a total overhaul of the fuel system and do port injection? That makes no sense at all. Improving the current system is a much better idea. I agree that port injection is better when it comes to the ease of making more power but if a thousand hp car is what you want then buy a supra until we figure things out over here

[Brey335i]

I believe Shiv said they had tested several solutions, not that they were gonna test. That, to me at least, implies that they have already conducted this testing. I'm very curious as to what the end result is....

now if he could only hurry up

[wren57]

at the idea of ripping out the DI. That would be an insane amount of work and $$$.

[boostd92]

^ Not to mention that the N54 is a HIGH COMPRESSION motor (compared to port fuel FI cars) simply because the DI allows it to be. Changing to port injection would actually LOWER the power potential (on pump gas) unless you want to use a ridiculously laggy huge turbo making no boost.

[sneaks]

Yeah, would need shorter con rods or always run on race ga$. Its not as simple as pulling out the DI

[Clap135]

Originally Posted by boostd92

^ Not to mention that the N54 is a HIGH COMPRESSION motor (compared to port fuel FI cars) simply because the DI allows it to be. Changing to port injection would actually LOWER the power potential (on pump gas) unless you want to use a ridiculously laggy huge turbo making no boost.

Not exactly, just picture any NA that was turned to FI and you will realize DI is pretty USELESS.

[Jeff@TopGearSolutions]

Originally Posted by Questforpower

Here is an idea; remove the DI system all together and install a standard head. Install a walbro 255 Pump, fabricate different fuel lines and larger injectors or use a double pumper system as one used in a Supra which is a 3.0L straight six twin turbo engine as well and re-tune for that...


Oh wait, this isn't the Toyota forums...

Not trying to be a troll but thinking realistically if someone put the time and effort into doing this in the first place, we might have had a 600-700 WHP 335i by now. This effort would surely have taken less than 4 years and created a simpler system as used in every other motor with great amounts of power.

I understand the advantages of DI are great (fuel efficiency, easy and quick power) but as of the current time being (2011, there is only so far that DI can get you, all Mazdaspeed3 and GTI's are in essence tied down by a complicated fueling system as is this platform. Evo's, Supra's and GTR's, dont seem to have any of these problems..... any connection to DI?

Btw, I did have a 335i and absolutely loved it for its ability to incorporate speed, class, and an amazing ability to DD. But in no way was the N54 built to be a drag racer 600-700 hp machine.

- A

Easier said then done as Ive said this myself.

But then it entails a whole new tuning solution and crack at the DME.

I think DI is over-hyped marketing with its "responsiveness, and fuel efficiency, etc"

[Q4P]

Originally Posted by prelude2perfect

Do you know how much work (and money) it would take to do a total overhaul of the fuel system and do port injection? That makes no sense at all. Improving the current system is a much better idea. I agree that port injection is better when it comes to the ease of making more power but if a thousand hp car is what you want then buy a supra until we figure things out over here

I thought this was a BMW forum $$$?? lol

$100K's have been invested in Evo's and Supra's and the BMW community can't find anyone...

Originally Posted by boostd92

^ Not to mention that the N54 is a HIGH COMPRESSION motor (compared to port fuel FI cars) simply because the DI allows it to be. Changing to port injection would actually LOWER the power potential (on pump gas) unless you want to use a ridiculously laggy huge turbo making no boost.

At that point, you're possibilities are endless... E85, Cams, someone would have to eventually make a proper single snail upgrade, twins would cause even more problems and you'd have to deal with twice the headaches. Big power would come in a single turbo (it always does)... Maybe the N55 will make this actually easier but someone has to jump on it.

Imagine a port injected, GT45r / FP RED / Black / Green 335i running at like 30 PSI with upgraded rods and pistons.

I mean either go big or go home. A simple fueling upgrade "a la" a stronger fuel pump will only solve a small problem until someone asks for more power, at that point you're causing yourself headaches again by still keeping twins and stock ecu. Someone has to go all the way with this platform, fully build engine, proper single upgrade and finally tune using a haltech or AEM standalone, this is the only way we will see the full potential of this motor.

After fueling, I would be highly shocked if all of a sudden all of your problems were solved, this is why it has to be done properly from the ground up.

[Rob@RBTurbo]

And there you have your $30k in mods and prepped drag car. Now let's start addressing what we need to put all our newfound power to the pavement. Or better yet, start a new thread. Those looking for a modestly built 500-600whp street car can continue to follow along here. Lol.

[jpsimon]

Originally Posted by RobBeck

And there you have your $30k in mods and prepped drag car. Now let's start addressing what we need to put all our newfound power to the pavement. Or better yet, start a new thread. Those looking for a modestly built 500-600whp street car can continue to follow along here. Lol.

thank you!

either way all the speculation will soon be a moot point when part(s) 3 (and 4?) are presented.

[Q4P]

Originally Posted by Clap135

Not exactly, just picture any NA that was turned to FI and you will realize DI is pretty USELESS.

+1 A speed3 which is notoriously hard to tune due to its fueling and DISI is crap when it came to making real power.

On the other hand, some boys in PR put a big turbo on the standard port injected mazda 2.3, same year and ran 11's all day...


Thank You...DI

Just a simple point.

[Jeff@TopGearSolutions]

Originally Posted by RobBeck

And there you have your $30k in mods and prepped drag car. Now let's start addressing what we need to put all our newfound power to the pavement. Or better yet, start a new thread. Those looking for a modestly built 500-600whp street car can continue to follow along here. Lol.

Wider Fenders?
Rear End?
Trans?
Suspension?
Axles?
Engine internals?

heh

[OpenFlash]

Any tuner will a lot of experience tuning a wide range of engines will tell you that the benefits of DI are obvious. The solution isn't to downgrade to conventional EFI but rather understand what needs to be done to the DI system to achieve the power goal without sacrificing the things that DI does so well.