NiceTry

iTrader: (1)

Call me for a good time..... We can talk dirty subsea intervention tooling math....
LOL

TheBlurLS1

iTrader: (8)

The 60psi you see in our car's fuel rails isn't because there's a huge flow restriction, it's because there's a regulator blocking it off until it hits 60psi. If the pumps can't keep up with the demand, the regulator closes down and the pressure starts to fall off. Dump the pumps into the suction of a McBadass pump and you can have your cake and eat it too (see above pictures lol).

Ever read a pump curve? Decrease head, increase flow. Decrease the required pressure the pumps have to discharge into (the surge tank), and you can increase the flow discharge of the pumps. A pump can only impart so much energy into the fluid, it can be either a flow increase or a pressure increase (and even a slight temperature increase).

I know that people have crept up on 1000rwhp with dual Walbro 255's, and that's with them being forced to maintain the correct rail pressure at the same time. Reduce their load to a lower pressure and you can increase their flow by a TON. Drop a Walbro into a gallon of gasoline and turn it on with the hose just hanging out of the top seeing atmospheric pressure. I promise you it will dump that gallon much quicker than 255lph.

The surge tank is probably there for "if you just want to be safe", assuming the magnafuel runs all the time. If it wasn't there, the line right before the Magnafuel pump would be at a really low pressure, with a really high flowrate with the Magnafuel acting like a "jockey pump". It also looks like that regulator on the side dumps back into the tank, which leads me to believe it's not the only regulator in the system, or the Magnafuel doesn't run all the time.

Cobra Commander

iTrader: (12)

Why not run just a big Magnafuel instead of all that?

NiceTry

iTrader: (1)

I just had a long response typed and my computer shut down...that sucks. Im going to bed now and will edit the post later. You are correct though the tank won't need to be worried about, the pumps will flow more not having to overcome the added head pressure of the manifold pressure. You can look at your pumps QH curve (flow v. Height) to determine this. The whole idea was- IN THEORY if the motor consumes more volume than the in tanks can flow will the surge tank run dry if at WOT long enough... at which point yes it will. Like I said if the amount of volume required was known along with the exact amount the pumps flowed it could be determined if this car would do it. I seriously doubt it though, like you said though two 255’s can support a lot of power, I have made just under/right at 1000 rw with them using a stock feed line. Feed them into a tank with no pressure, or suction and you will get the extra volume you didn’t get when they had to overcome the boost pressure…. But again, in theory since the amount of fuel needed is not known, if the motor required more fuel than the two pumps could move even under suction the tank could be run dry.
Pumps do not create pressure, they create flow. Restrictions create pressure. There is pressure because of a restriction in flow, the regulator is a restriction, so are injectors. Both are controlled restrictions. Just like you said you adjust the restriction of the regulator to increase pressure. Or you can increase the flow output of the pump which causes the regulator to become a greater restriction which causes greater pressure. Without a restriction in flow there would be NO pressure period. I will explain better tomorrow with a lesson in fluid dynamics. (or is this considered mechanics?)
Alright, what is the regulator doing when "blocking" fuel flow? Restricting it, therefore causing pressure. Close the regulator down more, what are you doing? Increasing the restriction. Therefore causing what? More pressure.
Now start opening the injectors and what is there less of? Restriction. This is where the pumps have to flow enough volume in order for the open injectors to be a restriction and cause rail pressure.
A step up regulator comes into play here. As manifold pressure (boost) is applied to the regulator is closes down creating more restriction which creates more pressure (assuming the pump can keep up). Now as pressure increases behind a restriction, in this case the injectors, what happens? Velocity and volume past the restriction is increases. But again if the pump doesn't create enough flow (injectors flow more) guess what you don't have? By now you should know....1. Restriction 2.Pressure.
Go outside and turn on a water hose, now how much pressure is in that hose? none(technically it depends on how high the end of the hose is off the ground and where you measure pressure in the hose but for ease of explanation we won't get into that and say zero) Now put your finger over the end of the hose. What are your doing? Restricting the flow of the water just like a regulator does fuel. What does this restriction cause in the hose (fuel rail)? Pressure. You could even go as far as to poke a hole in the hose which would be your injector so you can see the as pressure in the hose increases velocity and volume out the hole increases. Anyway I could go on and on and on but I'm not getting paid to educate people...... Although I do accept all major credit cards and cash.

tollway bandit 1

iTrader: (2)

Everyones a expert. lol

ulakovic22

iTrader: (12)

My guess is that a big fuel pump will cause tuning issues when you are street driving plus with all that fuel cycling it will heat up a lot. With the small pumps feeding a surge tank with a larger pump you are able to get stock type drivability, idle with easy tuning and then when you need the fuel for those WOT runs you don't have to worry about running out of fuel because the motor has to use up the fuel in the surge tank before it puts strain on the intake pumps and like others have said you would have to be on a LONG WOT run to use up the surge tank faster than the smaller pumps can fill it. I think it would be neat to also use the surge tank for a DP nitrous setup too.

A question I was thinking about while typing is how do you run a surge tank.....with a return to the main tank? Do you just run a gravity feed type return or is there a regulator that actually acts as a return? Also do you run your fuel rail regulator to the surge tank to keep it full or do you cycle it all the way back to the main tank?

NiceTry

iTrader: (1)

LOL right....
I have the 8rib pulley at the house.

Black98Z28

iTrader: (8)

Hot damn that car is nasty!! Can't wait to see some vids of that beast, and more props on keeping it a street car, that's what it's all about!! Once my career in gambling pays me back a good chunk I will take my car straight to LMR lol

RCC

The car has to have pumps in the factory tank to make the siphon work work correctly( vettes have 2 fuel tanks).

khaos288

iTrader: (9)

numbers?

RCC

Steven will be posting dyno video and numbers tonight, I am happy with them to say the least.

3.8redbird

iTrader: (3)

yea subscribed

RCC

Link to new thread with numbers and video:

https://ls1tech.com/forums/texas-mem...-corvette.html

Bad Habit Bird

iTrader: (12)

SICK

Tiago

iTrader: (27)

baller!

TheBlurLS1

iTrader: (8)

NiceTry, retype that message and I'll read it again. It seemed like someone was rambling blindly and making an attempt to crawfish, when you probably don't even need to, but I'll give you the benefit of the doubt. I think you're misunderstanding my posts or something? Your post before your last one seemed like you were trying to say that a pump does not flow more GPM when it no longer has to push rail pressure as well.

http://www.lgmotorsports.com/catalog...oducts_id=1971

Read through that. If the stock fuel pump can flow enough up to that surge tank for that system to be able to support 1500hp, do you really think that twin Walbro 255's could not supply the volume required for the tank not to go dry? I would GUESS that they could, and I'd hope that you could too, considering you've personally had twins creeping on 1000rwhp before. This Corvette isn't making 5000hp dude.

I'm not quite clear what you're trying to say with the water hose argument? I fully understand that an injector with higher differential pressure across it flows more fuel. I understand that a boost referenced regulator (instead of an ATMOSPHERIC referenced regulator) increases/decreases the rail pressure in order to maintain a 58psi differential (normal for LS1's), even under manifold boost/vacuum. However, this was not the point I was making.

Here is all I was saying; your water hose flows more GPM without your thumb over the end, than with your thumb over the end. This is the same with a PUMP. This is why the in-tank pumps flow more GPM when their discharge pressure is lowered (into the suction of another pump, instead of up against a regulator). I would hope that you would also find this to be true. This is the concept behind the system. I was simply trying to clarify this to xfactor, who couldn't understand how the system worked and couldn't see how the in tank pumps could supply the system anymore. The statement about the surge tank not going dry is simply an educated guess, taking into account the KNOWN performance of a pair of Walbro pumps.


PS - I don't need any "lessons", and there's no need to bring out any douchebaggery. You're not really ready to stoop that low are you? That's almost always a sign of someone trying to dig out of a hole. I'm trying to have a conversation with you. Asking if you've ever read a pump curve was not meant to be rude, and I'll apologize if it came off that way. I'm gathering now that you're probably also an engineer, and I have a really hard time believing that you can't understand the flow/pressure characteristics of a pump. I'm trying to figure out what the miscommunication is, as I'm sure you really can't have that much of a skewed view of the way things work.

GoldRust

iTrader: (2)

The funny thing is that I dont think either of you guys fully understand the way the fuel system works on a C6 vette. Now you guys are just hijacking RC's Thread with your bickering.

NiceTry

iTrader: (1)

You are correct. I at least cannot 100% tell how you have it set up by the pictures. As far as a stock one, well you know I have taken both tanks completely apart. Hell I have the GM books..... Like I have always said, it isn't rocket science making cars go fast. If it is we underestimate the intelligence of rednecks lol. Hot damn Billy Joe got that fastest Camaro... he used some of that there technology from his work in the space program.
Anyway, the setup looks good well done.

JMBLOWNWS6

iTrader: (17)

Who cares as long as it works.

NiceTry

iTrader: (1)

Blur maybe we miss understood each others point. My point was from the post before last was that the Walbro 255's do not flow enough to support the power the car is making by themselves but it is because they do not flow enough to make the pressure, they do not output pressure. Yes the pumps will be moving more fuel through an open ended line vs. one that is restricted at the end but the fact that the rail pressure drops is a result of the restriction being gone. If the motor were NA and rail pressure went to zero, you would be flowing the same amount of volume out the injectors as you would an open ended line. Maybe more if it created enough vacuum in the intake (just like you said how you get more with a larger pump creating suction in the surge tank). But this is a FI setup, now that injectors and FPR are no longer a restriction to cause pressure the head pressure you are now trying to overcome is the manifold (boost) pressure. This is where you are going to get more flow out of the pumps going into an open ended line, because you no longer have to overcome the XXlbs boost pressure. I used the water hose as an example but, maybe I didn't elaborate enough. Not that I was trying to be smart ***. (That was the whole teaching part lol) But for better reference you have your water hose with your finger over it to simulate the regulator, fuel lines and pump. Now when open yes your are flowing X gpm with low head pressure. Put your finger over it and you know down the flow out tremendously. Now to simulate the car running out of pump flow, punch holes in the water hose to replicate open injectors until your loose pressure at your thumb. How much volume is flowing out of the holes? The same as what was flowing when you first started. Now is this car using injectors large enough/that much fuel to get to the point of no rail restriction I doubt it, there are just so many factors we don't know. Like you said though this isn't a 5000hp car.
I was also thinking from your statement that "The 60psi you see in our car's fuel rails isn't because there's a huge flow restriction, it's because there's a regulator blocking it off until it hits 60psi" you didn't understand that a pump does not put out pressure, it puts out flow which has to have a restriction to cause pressure.
As far as the LG setup goes, I personally don't think that at 1500hp those bosch pumps aren't using more fuel than the stock pump is providing to fill the tank. The most I have made on a stock C6 pump is 745rw and that was with a BAP. I don’t know if I can see the second pumps pulling another 600 hp through the stock one. But hey their headers also pick up 1 BIIILLLLIIOOONN horsepower over anyone else’s (yet they copied ARH and Kooks with their new knock offs) They have to know what they are talking about right? (That wasn't supposed to be smart *** comment to you. I just can't tell you how many times I swapped peoples cars from kooks to products from these "header experts" (who had someone else build them) and didn't gain squat. Or how many G5xR2D23ps cams I installed that made no more power than a 224/224 cam. Although I did forget the light wheels, portable AC blowing on the intake, race gas and 30+ degrees of timing after the installs)

As far as being a douche, no. I am an *******, an arrogant one at that, I think it comes from having to be around and deal with divers all the time lol. It could be worse though, I could be an engineer. I'm just messing with you. I deal with operating and installing subsea tooling and pumps which constantly involves flow/pressure calculations etc etc. Give me your email and I’ll send you a video from a couple weeks ago where we sucked a 3.5-4 foot grouper through a 12 inch pipe... If you really want to see something really impressive though take that water hose and a golf ball up to LMR and hand it to Josh! I know you can take a joke right Josh?