Fast Intentions "Twin Turbo Kit" is here

TerribleONE · 02-20-2013, 06:36 PM

Quote:

Originally Posted by blackonorange

I don't get the fuel problem.... Why has no one else had this problem ? And what fuel pressure gauge do you have ?

From the research I have done it seems like almost EVERYONE is running into problems like this at this power level, they just may not be aware of it. To the best of my knowledge, up until this point no one makes a return-less fuel system that can handle this power level, we are going to try a few things and hope to make the impossible, possible! Also, while talking with Sebastian today he explained that even if you have a air/fuel gauge, by the time that starts to read lean, it is already too late. I will definitely be running a fuel pressure gauge in the center cubby as it is a small price to pay for the added protection.

TerribleONE · 02-20-2013, 06:37 PM

Quote:

Originally Posted by blackonorange

What kind of gauge you using or how you monitoring it?

It is a liquid filled XRP gauge, attached directly to the fuel rail.

elperuano · 02-20-2013, 07:17 PM

I have no problem with fuel at 540hp. Not sure why u would think every boosted ride has this problem yet doesn't know it??? And about the gauges, well that kind of defeats the purpose of even having them in the first place. If calibrated correctly they should work just fine. I datalog thru uprev and lookin at the gauge it's fine. 6k miles n runnin strong

F.I. Inc. · 02-20-2013, 07:29 PM

Quote:

Originally Posted by elperuano

I have no problem with fuel at 540hp. Not sure why u would think every boosted ride has this problem yet doesn't know it??? And about the gauges, well that kind of defeats the purpose of even having them in the first place. If calibrated correctly they should work just fine. I datalog thru uprev and lookin at the gauge it's fine. 6k miles n runnin strong

You data log what through UpRev? (Fuel Pressure) or Air/Fuel ratio? We are not having a problem with air/fuel, we are dropping fuel pressure. The reason I said most people do not know if fuel pressure is dropping is due to the fact that you cannot monitor fuel pressure through the UpRev software. That being said, please elaborate. How is your fuel system setup? Any feedback will be greatly appreciated.

Thank you, Tony

elperuano · 02-20-2013, 08:06 PM

Yes, air/fuel is what I meant. I'm not running lean at all at any spots on my band so there's not a problem with the fuel pressure. If I was losing pressure I'm sure I'd be running lean at spots and I haven't seen any. I know of only 2-3 people I believe that had to upgrade the fuel system but they are built motors.

Boosted Performance · 02-20-2013, 08:50 PM

Tony, what size is the fuel pump? I know that the 255lph fuel pumps will run out of steam at 500-550whp (with boosted VQ's). This is why I switched to the 340lph fuel pumps and larger (than normal) fuel injectors.

Dyno sheet is looking good too, keep up the good work.

Motion Lab · 02-20-2013, 09:18 PM

Quote:

Originally Posted by F.I. Inc.

I will elaborate later once I have a chance to sit down and explain it in detail. I can promise you that anyone at this power level with a stock style return less fuel system is having this problem. If I was a betting man, I would bet most people are not watching their fuel pressure. 99% of the time all that is watched is the air/fuel.

Thanks, Tony

Yep. Something not a lot of people realize or think of.

Thanks,
Alex Goodwin
AlexG@motionlabtuning.com

phunk · 02-20-2013, 10:00 PM

Restrictions in fuel system plumbing will cause a pressure drop between the fuel pump and the injectors. Every car will experience this to some degree. The amount of pressure drop between the pump and the injectors will be awfully dynamic and impossible to determine off hand.. you have to do individual testing per application.

At engine idle, or lower power needs such as cruising, there is less fuel flowing through the lines, and the pressure drop will be less. As power climbs, fuel flowing through plumbing in the vehicles starts to increase, and each and every restriction in the fuel system will start to manifest into a sum of pressure drop.

The 370z, in factory configuration, regulates fuel pressure off the side of the fuel filter housing, inside the fuel tank, immediately inline after the fuel pump. What this means, is that the pressure regulating system is regulating pressure at the fuel filter. Before any of the substantial drops in pressure on the way to the engine bay.

If you converted to a return system, you will now be regulating pressure in the engine bay. So instead of seeing pressure drop between the filter housing and the rails, you will see steady pressure at the rails, and pressure increased at the filter housing, to compensate for such the inline drops.

At what quantity of fuel does pressure drop begin in a stock 370z fuel system? There is only one way to find out. Place a fuel pressure gauge off the rails, and place a fuel pressure gauge off the fuel pump. Nobody has done this yet. But only by doing this will someone have completed the R&D to give accurate estimates to how much the 370z fuel system can push, before pressure drop is imminent.

This final number can only be accurately described as a measurement of volume, not HP. However, it would require too much additional R&D to translate this number to a volume of fuel, and then that information would be worthless to the consumer who would be unable to translate that back to a HP figure they can relate to. Injector spray quality, fuel temperature will somewhat effect how much HP you can say the factory plumbing is good for before pressure drop. Tuning and fuel type will *drastically* effect this number. As a couple degrees of timing can go plus or minus 25 HP without changing fuel requirements.

phunk · 02-20-2013, 10:05 PM

Simply because one persons 370z is not flowing enough fuel yet to show a pressure drop between the pump and rails (or so they do not believe, depending on what evidence they have to support this claim) does not mean other cars will not. To make such direct comparisons would be unwise. Example... I have an A/F gauge in my 370z. I have a fuel pressure gauge in the ENGINE BAY... nearly worthless. My car is making similar power to the test vehicle in questions here. Now, I dont THINK my car is dropping pressure... but how do I know? I dont. My A/F is good to redline... but I have 1000cc injectors and my pressure would have to drop quite a bit to not get the quantity of fuel I need. My pressure gauge, being in the engine bay, only allows me to make sure my pressure is correct at idle. For all I know, my pressure might be dropping by 20psi by redline. :shrug: I never had a reason to look! If this test car in question here didnt have an in-car pressure gauge, who knows if they would have even known.

As you reach the maximum output of just about anything in this world, you find that every tiny little detail begins to have massive effects on where the precise maximum is. This is why automotive manufacturers always build their cars to operate systems at much less than 100%. 100% is not reliable, and it is extremely distant from CONSISTENT.

I think that it is great that they are watching the details on this build. While I do not worry about my car blowing up, and I dont worry about their car blowing up... its a very different game when the car is in possession of experienced tuners. They can make sure its not going to break even when pushing it to the limit. BUT, they want to put together a high quality turbo system for the consumer, and some versions of that kit are going to include a tune I would assume. This means they need to watch and log everything within reason to make sure that the tune they build is going to behave the same on their customer's installations.

phunk · 02-20-2013, 10:15 PM

There are 2 options for working around a fuel pressure drop in the system in a scenario such as this, and you can optionally take both steps.

Option 1, increase the plumbing size to reduce pressure drops. This can get expensive depending on how far you take it... because a duration of the conservative sized plumbing is physically built into the inlets of the factory fuel rails. The fuel rails themselves are massive and do not need upgraded... however to cut off the ends and weld on different inlets isnt an option for customers who need bolt on solutions, and welding fuel rails is often prone to pinhole leaks. It just makes more sense to move to billet fuel rails so that its simple to add larger plumbing. Well, this gets expensive now.

Option 2: convert to a return fuel system. For one simple reason, to regulate fuel pressure as close as you can to the rails. How does this help you may ask?

Lets say you have a walbro 255, and you are running out of fuel on top. You might say to yourself... oh, I am running out of pump, so i need to put in a larger pump so that pressure doesnt drop anymore. Well, thats old school thinking... thats what it USED to mean when cars had return lines and regulators in the engine bay.

Because pressure drop. While you might be losing pressure in the engine bay with your 255... you might NOT be losing pressure all the way back up the pump. If you arent, then upgrading the pump isnt going to do a dang thing, because the regulator is still going to be holding open at the same pressure in the back. BUT... if your regulator is in the engine bay, and you still have a pressure drop... a larger pump can actually fight the restrictions by flowing greater at higher pressure. Your regulator in the engine bay can hold pressure where its supposed to, and you just let pressure skyrocket at the pump to keep up, compensating fuel pressure drop across the lines.

Basically all I am saying here, is that nobody can argue unless they have *more than one* fuel pressure gauge in their 370z. You might be surprised if you knew how much fuel pressure can drop from one end of a fuel rail to the other, let alone across an entire car.

Dzel · 02-20-2013, 10:18 PM

Yep what he said

sparky · 02-20-2013, 10:25 PM

Quote:

Originally Posted by Dzel

Yep what he said

i knew all this too.

phunk · 02-20-2013, 10:32 PM

LOL I kept it short too

Which may backfire if any engineers read that and become displeased with the way I chose to simplify some things.

Dzel · 02-20-2013, 10:33 PM

So what can one do to fix this issue?

Boosted Performance · 02-20-2013, 10:38 PM

Charles, do you know the fuel line diameter on the 370z? I know the 350z's had a 5/16" line from the fuel pump basket to the fuel rails.

02-20-2013, 08:50 PM	#531 (permalink)
Boosted Performance The370Z.com Sponsor Join Date: Feb 2010 Location: Edmonton, AB Posts: 1,629 Drives: Z's Rep Power: 3382	Tony, what size is the fuel pump? I know that the 255lph fuel pumps will run out of steam at 500-550whp (with boosted VQ's). This is why I switched to the 340lph fuel pumps and larger (than normal) fuel injectors. Dyno sheet is looking good too, keep up the good work. UNKNOWN_370, Mr.Squeeze, Dzel and 2 others like this. __________________ 750WHP starting @ $7,500 to the door FOR DETAILS VISIT: http://www.the370z.com/members/boosted-performance.html FB: https://www.facebook.com/Boosted-Per...6303179791462/ IG @boostedperformanceyeg Last edited by Boosted Performance; 02-20-2013 at 09:17 PM.

02-20-2013, 10:00 PM	#533 (permalink)
phunk A True Z Fanatic Join Date: Mar 2009 Location: Chicago Posts: 3,668 Drives: 370 Rep Power: 974723	Restrictions in fuel system plumbing will cause a pressure drop between the fuel pump and the injectors. Every car will experience this to some degree. The amount of pressure drop between the pump and the injectors will be awfully dynamic and impossible to determine off hand.. you have to do individual testing per application. At engine idle, or lower power needs such as cruising, there is less fuel flowing through the lines, and the pressure drop will be less. As power climbs, fuel flowing through plumbing in the vehicles starts to increase, and each and every restriction in the fuel system will start to manifest into a sum of pressure drop. The 370z, in factory configuration, regulates fuel pressure off the side of the fuel filter housing, inside the fuel tank, immediately inline after the fuel pump. What this means, is that the pressure regulating system is regulating pressure at the fuel filter. Before any of the substantial drops in pressure on the way to the engine bay. If you converted to a return system, you will now be regulating pressure in the engine bay. So instead of seeing pressure drop between the filter housing and the rails, you will see steady pressure at the rails, and pressure increased at the filter housing, to compensate for such the inline drops. At what quantity of fuel does pressure drop begin in a stock 370z fuel system? There is only one way to find out. Place a fuel pressure gauge off the rails, and place a fuel pressure gauge off the fuel pump. Nobody has done this yet. But only by doing this will someone have completed the R&D to give accurate estimates to how much the 370z fuel system can push, before pressure drop is imminent. This final number can only be accurately described as a measurement of volume, not HP. However, it would require too much additional R&D to translate this number to a volume of fuel, and then that information would be worthless to the consumer who would be unable to translate that back to a HP figure they can relate to. Injector spray quality, fuel temperature will somewhat effect how much HP you can say the factory plumbing is good for before pressure drop. Tuning and fuel type will drastically effect this number. As a couple degrees of timing can go plus or minus 25 HP without changing fuel requirements. __________________ Charles @ CJ Motorsports : Website \| Facebook \| Instagram \| YouTube Home of the 9 second, stock longblock, stock drivetrain 6MT 370z. 9.91 @ 142mph Last edited by phunk; 02-20-2013 at 10:28 PM.

02-20-2013, 10:05 PM	#534 (permalink)
phunk A True Z Fanatic Join Date: Mar 2009 Location: Chicago Posts: 3,668 Drives: 370 Rep Power: 974723	Simply because one persons 370z is not flowing enough fuel yet to show a pressure drop between the pump and rails (or so they do not believe, depending on what evidence they have to support this claim) does not mean other cars will not. To make such direct comparisons would be unwise. Example... I have an A/F gauge in my 370z. I have a fuel pressure gauge in the ENGINE BAY... nearly worthless. My car is making similar power to the test vehicle in questions here. Now, I dont THINK my car is dropping pressure... but how do I know? I dont. My A/F is good to redline... but I have 1000cc injectors and my pressure would have to drop quite a bit to not get the quantity of fuel I need. My pressure gauge, being in the engine bay, only allows me to make sure my pressure is correct at idle. For all I know, my pressure might be dropping by 20psi by redline. :shrug: I never had a reason to look! If this test car in question here didnt have an in-car pressure gauge, who knows if they would have even known. As you reach the maximum output of just about anything in this world, you find that every tiny little detail begins to have massive effects on where the precise maximum is. This is why automotive manufacturers always build their cars to operate systems at much less than 100%. 100% is not reliable, and it is extremely distant from CONSISTENT. I think that it is great that they are watching the details on this build. While I do not worry about my car blowing up, and I dont worry about their car blowing up... its a very different game when the car is in possession of experienced tuners. They can make sure its not going to break even when pushing it to the limit. BUT, they want to put together a high quality turbo system for the consumer, and some versions of that kit are going to include a tune I would assume. This means they need to watch and log everything within reason to make sure that the tune they build is going to behave the same on their customer's installations. __________________ Charles @ CJ Motorsports : Website \| Facebook \| Instagram \| YouTube Home of the 9 second, stock longblock, stock drivetrain 6MT 370z. 9.91 @ 142mph Last edited by phunk; 02-20-2013 at 10:24 PM.

02-20-2013, 10:15 PM	#535 (permalink)
phunk A True Z Fanatic Join Date: Mar 2009 Location: Chicago Posts: 3,668 Drives: 370 Rep Power: 974723	There are 2 options for working around a fuel pressure drop in the system in a scenario such as this, and you can optionally take both steps. Option 1, increase the plumbing size to reduce pressure drops. This can get expensive depending on how far you take it... because a duration of the conservative sized plumbing is physically built into the inlets of the factory fuel rails. The fuel rails themselves are massive and do not need upgraded... however to cut off the ends and weld on different inlets isnt an option for customers who need bolt on solutions, and welding fuel rails is often prone to pinhole leaks. It just makes more sense to move to billet fuel rails so that its simple to add larger plumbing. Well, this gets expensive now. Option 2: convert to a return fuel system. For one simple reason, to regulate fuel pressure as close as you can to the rails. How does this help you may ask? Lets say you have a walbro 255, and you are running out of fuel on top. You might say to yourself... oh, I am running out of pump, so i need to put in a larger pump so that pressure doesnt drop anymore. Well, thats old school thinking... thats what it USED to mean when cars had return lines and regulators in the engine bay. Because pressure drop. While you might be losing pressure in the engine bay with your 255... you might NOT be losing pressure all the way back up the pump. If you arent, then upgrading the pump isnt going to do a dang thing, because the regulator is still going to be holding open at the same pressure in the back. BUT... if your regulator is in the engine bay, and you still have a pressure drop... a larger pump can actually fight the restrictions by flowing greater at higher pressure. Your regulator in the engine bay can hold pressure where its supposed to, and you just let pressure skyrocket at the pump to keep up, compensating fuel pressure drop across the lines. Basically all I am saying here, is that nobody can argue unless they have more than one fuel pressure gauge in their 370z. You might be surprised if you knew how much fuel pressure can drop from one end of a fuel rail to the other, let alone across an entire car. Zat_Zuma, G37sHKS, Mr.Squeeze and 3 others like this. __________________ Charles @ CJ Motorsports : Website \| Facebook \| Instagram \| YouTube Home of the 9 second, stock longblock, stock drivetrain 6MT 370z. 9.91 @ 142mph Last edited by phunk; 02-20-2013 at 11:09 PM.

02-20-2013, 10:18 PM	#536 (permalink)
Dzel A True Z Fanatic Join Date: May 2011 Location: Midland, TX Posts: 3,884 Drives: 11 370Z PW M6 Rep Power: 23	Yep what he said __________________ 10secWS6 IF YOU CAN'T SWING IT THEN DON'T BRING IT! Check out Domestic Performance C.C.

02-20-2013, 07:17 PM	#528 (permalink)
elperuano A True Z Fanatic Join Date: Oct 2011 Location: Southwest FL Posts: 1,374 Drives: G37S Rep Power: 29	I have no problem with fuel at 540hp. Not sure why u would think every boosted ride has this problem yet doesn't know it??? And about the gauges, well that kind of defeats the purpose of even having them in the first place. If calibrated correctly they should work just fine. I datalog thru uprev and lookin at the gauge it's fine. 6k miles n runnin strong

02-20-2013, 08:06 PM	#530 (permalink)
elperuano A True Z Fanatic Join Date: Oct 2011 Location: Southwest FL Posts: 1,374 Drives: G37S Rep Power: 29	Yes, air/fuel is what I meant. I'm not running lean at all at any spots on my band so there's not a problem with the fuel pressure. If I was losing pressure I'm sure I'd be running lean at spots and I haven't seen any. I know of only 2-3 people I believe that had to upgrade the fuel system but they are built motors.

02-20-2013, 10:32 PM	#538 (permalink)
phunk A True Z Fanatic Join Date: Mar 2009 Location: Chicago Posts: 3,668 Drives: 370 Rep Power: 974723	LOL I kept it short too Which may backfire if any engineers read that and become displeased with the way I chose to simplify some things. DEpointfive0 likes this. __________________ Charles @ CJ Motorsports : Website \| Facebook \| Instagram \| YouTube Home of the 9 second, stock longblock, stock drivetrain 6MT 370z. 9.91 @ 142mph Last edited by phunk; 02-20-2013 at 10:54 PM.

02-20-2013, 10:33 PM	#539 (permalink)
Dzel A True Z Fanatic Join Date: May 2011 Location: Midland, TX Posts: 3,884 Drives: 11 370Z PW M6 Rep Power: 23	So what can one do to fix this issue? __________________ 10secWS6 IF YOU CAN'T SWING IT THEN DON'T BRING IT! Check out Domestic Performance C.C.

02-20-2013, 10:38 PM	#540 (permalink)
Boosted Performance The370Z.com Sponsor Join Date: Feb 2010 Location: Edmonton, AB Posts: 1,629 Drives: Z's Rep Power: 3382	Charles, do you know the fuel line diameter on the 370z? I know the 350z's had a 5/16" line from the fuel pump basket to the fuel rails. __________________ 750WHP starting @ $7,500 to the door FOR DETAILS VISIT: http://www.the370z.com/members/boosted-performance.html FB: https://www.facebook.com/Boosted-Per...6303179791462/ IG @boostedperformanceyeg

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