Component Selection & Design for 500 HP Fuel System

[Indycars]

Im on a fuel pump quest as well. Considering going with an EFI setup for a 383 build I’m working on and have a fuel delivery question.

You are considering a EFI setup for a carburetor engine???
Yes, I have been looking at the all the TBI systems out there and realy like the Powerjection III w/spark control setup. I know a well tuned carb is hard to beat but my computer/electronics geek side is coming out. I'm probably stick with the carb initialy and go EFI as a 2nd. step.

Sorry, I quickly scanned your engine build thread and assume a Carb engine after seeing the manifold. I love the high tech geek side of cars...go for it. Why purchase a carb and then switch? But if you have to go carb first....then get the Speed Demon 750 w/ Vac Sec. That way you can give it to me, but you only have until next spring. Come hell or high water I WILL BE driving my TBucket, even if I have to push it down a hill, then jump in and make motor noises with my mouth !!!!!!

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Has anyone had success running an inline fuel pump (Walbro GLS392) with a top feed tank? I have a 78 vette and I'm seeing mixed reviews of gravity feed pumps with the top feed tanks. How big of an issue is this for a street car?

Most electric pumps are of the VANE type, which don't pull fuel nearly as well as they push the fuel. When you say "gravity feed pumps" are you referring to a VANE type pump ??? I'm probably referring to it incorrectly. My basic understanding is that most in line EFI pumps don't do a good job of pulling fuel. As you mentioned above. So, getting fuel out of a top feed tank could be a problem. It seems that if you keep the pump close to the tank and below it, you can get gravity/siphon feed to work.

I think it might work better than you think. I ran an electric AC fuel pump in the 1970's in a 1964 Nova with stock fuel lines that pushed the fuel to the stock mechanical pump. I don't remember having problems and I had a fuel pressure gauge mounted on the cowl. Made many 1/4 mile runs at the local drag strip.


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I have seen some recommendations to use a "Ford" in line pump because it will suck as well as push.

What type of pump is the ford inline pump ??? I believe is basicaly a stock 88 Ford truck external pump. I don't know enough about it but I've seen it refernced on the Corvette forum. Supposedly it does a good job of pulling fuel out of the tank.

It would have to be of a different design than a vane pump. There are pumps that can pull from the tank, but most I've seen run $400- $500 range, and are belt driven.


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The other recommendation is to use an 82 vette fuel pickup with an intank efi pump. The second option seems easier as I wouldn't have to butcher the stock fuel line?

Again, is this going to work with a carburetor. EFI operates at a much higher pressure, but maybe it's just a matter of using the right pressure regulator.
If I go EFI I'll probably get one of these http://www.ecklerscorvette.com/corve...pump-1982.html and use a 45PSI/255LPH in tank pump. Then use the stock supply line as a return and run a new supply line with the appropriate filter. This way I'm not butchering the stock stuff and could switch back to a carb easily.

So many options, I'm starting to get a head ache. GOOD LUCK !!!
BTW, the link didn't work, you just get a default page.

[bytor]

Sorry, I quickly scanned your engine build thread and assume a Carb engine after seeing the manifold. I love the high tech geek side of cars...go for it. Why purchase a carb and then switch? But if you have to go carb first....then get the Speed Demon 750 w/ Vac Sec. That way you can give it to me, but you only have until next spring. Come hell or high water I WILL BE driving my TBucket, even if I have to push it down a hill, then jump in and make motor noises with my mouth !!!!!!

I'm looking forward to seeing your build fire up for the first time. I'm not too far away. I have a Speed Demon 650 Mech. secondary carb on my current motor that I could use. I'm thinking it might be a lot to bite off doing a new build install, initial start and EFI all at once. Maybe for the initial start use the carb and make sure there are no mechanical issues to deal with. Takes a few unknown variables out of the picture as well. Then focus on the EFI setup. Thanks for the heads up on the link, I corrected it in my origonal post.
http://www.ecklerscorvette.com/corvette-fuel-sending-unit-without-pump-1982.html

[Indycars]

Yep when it fires the first time, there will be a grin as wide as the Grand Canyon AND will be there just as long too.

Makes good sense if you already have a know carb to be at least close to being correct tune.

[grumpyvette]

while an engine like the one built here for the T-bucket can get by with AN#6 LINES (3/8") as your not likely to exceed the potential flow restriction limitations of that size fuel line, and you only need about 100 gph pump and about 6 psi, IVE ALWAYS PREFERRED THE LARGER AN#8 fuel line size and an ELECTRIC fuel pump that puts out a minimum of 140 gph mounted back as close too the fuel cell or fuel tank,and as low as possible and used with a return style regulator.
my current EFI 383 has a walpro 255 that provides 40 psi but uses 3/8" lines , and it will supply the required fuel to maintain about 500 hp.
keep in mind Im using an extensively ported stealth ram base with a custom plenum and throttle body and and 36 lb injectors on my 383 SBC
on my 496 BIG BLOCK I found the larger size fuel lines and larger pump with a fuel cell installed mandatory, as the smaller lines allowed the engine power to drop noticeably by the time I had reached the 100 ft from launch point, swapping to the larger fuel pump helped noticeably, and its generally a good idea if you plan to exceed about 550 hp


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[Indycars]

IVE ALWAYS PREFERRED THE LARGER AN#8 fuel line size

Did you use aluminum or steel fuel line ???

Do you have a source for 1/2" steel fuel line, all I can find is aluminum in 1/2" ???

[grumpyvette]

I used the flex line with braided stainless weave in my last race car , I had the line professionally fabricated and ran it thru STEEL tubing for mechanical protection , this required very careful measurement and sliding the protective tubing over the flex tubing before the ends on the flex tubing were fabricated by the local hydraulic supply shop, check with the local professional hydraulic supply




viewtopic.php?f=55&t=4381

[bytor]

my current EFI 383 has a walpro 255 that provides 40 psi but uses 3/8" lines , and it will supply the required fuel to maintain about 500 hp.

What EFI setup are you running?

[grumpyvette]

viewtopic.php?f=32&t=430

[Indycars]

Filter Selection and Mounting Episode:


I've been looking at filters that could be used in my 500 HP fuel system. From what I've
read, it’s standard practice to have two filters. The first filter is a "pre-filter"
goes between the fuel tank and pump and should filter out any particles bigger than
100 microns. A Micron is "One Millionth of a Meter". One Micron is .00003937 inches,
so a 100 micron filter should stop anything larger than 0.003937 inches (0.004") or
slightly larger than the thickness of a piece of paper. Notebook paper is normally
about 0.003".

The pre-filter purpose is to stop anything big enough to damage the pump. But it cannot
be very restrictive or it will cause the pump to cavitate, hence the reason for only
filtering down to 100 microns. The filter element is usually a pleated stainless mesh
that can be cleaned and reused. Unlike the main filter that is paper and is just replaced
with a new filter when it becomes too dirty and restrictive.

http://www.utahbiodieselsupply.com/blog/archives/1444

stainlessmicronsamples2.jpg

stainless100.jpg

Like everything in automotive you can pay as much or as little as you want. The
manufactures don’t have any standards that are required of the numbers they
report and they all seem to have a different way of talking about how restrictive
their filters are, such as; flow rates(GPH), flow rate(GPH) @ x psi, good for x HP,
and pressure drop without flow rate. Count your self lucky if you get the pressure
drop across the filter at some flow rate. But even when you do it doesn’t help much
when the others don’t do the same so you can compare apples to apples. In the end
you have to rely on the manufactures name or if you can find someone that has
experience with the product in question.

I plan on installing two filters……one with a 100 micron and one with a 5-10 micron
rating. I’ve narrowed it down to those filters listed below. The 100 micron filter will
be an “Inline” filter and the main filter will be a “Canister” type.

You can download the Excel file for the the chart below. It has links to Summit for
all the filters:

Fuel Filter Specifications.xlsx

FilterSelectionChart01.JPG

I don’t have room for an inline filter between the pump and carburetor. The TBucket
is too short and there are so many things going on along the frame rails that it will
have to be of the canister type because they are shorter horizontally. Between the
tank and pump I have a vertical drop of 9 inches, here I can use an inline filter and
it will fit very nicely in the area shown in the photo below. After measuring for the
canister filter , I may have to relocate the pump as far as I can to the rear (about 6”),
so I can squeeze in the 10 micron canister filter before the fuel line goes inside the
frame. The canister filter is 3.25” without any fittings, I’m planning on needing
4.5” to 5” total with fittings.

FuelLineTank&FilterToPump01.jpg

The 9 inch drop will also add some head pressure (0.23 psi) feeding the pump that
most cars don’t have with their gas tanks mounted low in the frame. That’s not a lot
of pressure, but it is a positive pressure and not negative. Also that’s with the tank
nearly empty, with the tank almost full that adds another 12 inches. Along with the
added head pressure, 100 micron free flowing filter and the 1/2 inch line that feeds
the pump, I should never have to worry about cavitation.

PumpTo-FuelLineExit.jpg

http://www.engineeringtoolbox.com/pump- ... d_663.html

p = 0.434 h SG
where
p = pressure (psi)
h = head (ft)
SG = specific gravity [SG for Gasoline ~ 0.72 ]

[grumpyvette]

please don,t think this comment is negative, its more of thought designed as a discussion starter on the subject,
now not that it really matters a great deal in this application, but Im rather curious why you ran 3/8" tube 30" inside the frame at that point, I can see the potential for extra fuel line protection in the area from 15" behind the firewall to 15" in front where I usually use the EMT metal tube or a bit of 1" roll bar cage tube, to give a bit extra protection in case the blow proof bell housing fails in a clutch/flywheel failure/explosion, but back that far I don,t see the reason?? and I also don,t see the reason to reduce fuel line size before the fuel rail entrance.
and yes the two quality fuel filter design, is a really good idea. but Id put some though into mount location and easy access, because you'll be replacing them occasionally and if possible access without needing a lift is a good idea.
you might also consider a hidden but fairly accessible fuel line cut-off near the fuel tank, as it makes fuel filter swaps less messy and potentially dangerous from spilled fuel and its also a secondary security measure to make driving your car off without being authorized a far less doe-able deal for thieves

[Indycars]

please don,t think this comment is negative, its more of thought designed as a discussion starter on the subject,
now not that it really matters a great deal in this application, but Im rather curious why you ran 3/8" tube 30" inside the frame at that point, I can see the potential for extra fuel line protection in the area from 15" behind the firewall to 15" in front where I usually use the EMT metal tube or a bit of 1" roll bar cage tube, to give a bit extra protection in case the blow proof bell housing fails in a clutch/flywheel failure/explosion, but back that far I don,t see the reason?? and I also don,t see the reason to reduce fuel line size before the fuel rail entrance.
and yes the two quality fuel filter design, is a really good idea. but Id put some though into mount location and easy access, because you'll be replacing them occasionally and if possible access without needing a lift is a good idea.
you might also consider a hidden but fairly accessible fuel line cut-off near the fuel tank, as it makes fuel filter swaps less messy and potentially dangerous from spilled fuel and its also a secondary security measure to make driving your car off without being authorized a far less doe-able deal for thieves

Some great questions Grumpy!

The 3/8" fuel line was run that way 15 years ago, before I even thought about having an engine with enough horsepower to possibly come close to needing a larger 1/2" fuel line. Street rods are not just about going fast, but also about looking great. Keeping the installation of all systems clean and out of sight. Where a race car is all about function over all other priorities.Once you have cut one hole in the frame for entry of fuel line, you have to cut another to exit with. So why not run it the full length ?

To make sure we are all talking about the same components. When you say "I also don,t see the reason to reduce fuel line size before the fuel rail entrance", do you mean the RED components should be 1/2" and the 3/8" is the reduction in size you are pointing out. Or do you mean all the 3/8" from the pump forward until it reaches the carburetor float bowls???

I was planning on 3/8" from the pump forward to the carb. My 1/2" lines would be.....tank to pump and the return line.

Drawing - Fuel-System02.jpg

I do have plans for a 1/4 turn ball valve for the convenience during filter changes. It's just having to decide where to start and stop a post to the forum. It took me an 1-1/2 - 2 hours to create that last post, with taking the pictures needed, putting comments on the picture, doing research for head pressure calculations, writing the text and getting examples of what 100 microns looks like ....etc .....etc.

[grumpyvette]

THANKS FOR THE DARN NICE, and CLEAR FUEL LINE DIAGRAM, THIS IS ONE MORE IMPRESSIVE AND HELPFUL THREAD!

Like I STATED EARLY in THIS THREAD< THIS IS MORE OF A SUGGESTION THAN SOMETHING THATS REQUIRED OR MANDATORY IN THIS CASE, the area I high -lighted (BADLY) in purple is the area ID have also made in 1/2" or AN #8 but its not likely to be overly restrictive ,the area I high lighted in light yellow/orange, near the fuel tank fuel line feed, is where ID stick the fuel cut-off, but if it was my car ID keep it all consistently AN#8 up to the fuel rail

[Indycars]

The only reason I'm saying it will be 3/8" is that it is already in place. It' s totally
possible that when it comes time to actually install the system, I may find that
it's just easier to remove it. If I do remove the line it will go back as a 1/2" line.
I'm also wondering if I can flare it to 37° while it's still in the frame. If I
can't and I have to remove the 3/8" line, then I will go back with 1/2".

[Indycars]

Probably not a big concern for you guys with an OEM fuel cap and vent.....but if you
are starting from scratch like on my TBucket then I've learned there is much more
to consider.

But then again if you have built that record breaking engine for your factory car......
your fuel tank vent may not be keeping up with your fuel system and keeping it from
performing like it should. Go ahead and buy 300 GPH fuel pump for $500, but it
maybe as easy as fixing your fuel tank vent.

If I got you wondering, then tomorrow I hope to explain. BUT until then think about it .......

[grumpyvette]

sure sounds like you found out that if the tanks not vented, to allow air to enter to fill the space that fuel leaving the fuel tank left,you can reduce the fuel tanks internal air pressure enough to cause fuel flow issues, you very quickly find you can,t get the fuel pump to suck fuel and prime the pump or continue to pump fuel.
theres plenty of vents that are designed to allow air to flow into a fuel cell but prevent fuel from draining out of the vent in case of a roll over.

thats what they make ROLL OVER VENTS and one direction air vents for

https://www.pegasusautoracing.com/group ... HECKVALVES

http://pitstopusa.com/c-135667-fuel-sys ... vents.html

http://www.bing.com/images/search?q=Fue ... 0663496171

http://www.bing.com/images/search?q=Fue ... 2EA755CB26

[Indycars]

I wanted to take a closer look at fuel tank cap I was using and how well it might be venting the tank. Since the engine that I’m putting in the Tbucket now will use nearly twice as much fuel under WOT, then venting could become a problem.

Safety was another concern after looking at the cap I was using. It clearly wouldn’t take much for it to come off, especially in a roll over situation. Not the way I want to leave this world ……slowly in a fire.

FuelTankCap_OldSetup_3327

FuelTankCap_OldSetup_3327.jpg

FillerNeckDimensions_3341

FillerNeckDimensions_3341.jpg

When fuel is leaving the tank, then air must enter, so the tank doesn’t develop a vacuum. This condition would certainly NOT help the fuel pump stay up with demand. Watch the YOUTUBE videos to see how no venting will affect your fuel flow.

http://www.youtube.com/watch?v=ou-i32eM ... re=related
http://www.youtube.com/watch?v=2WJVHtF8GwI


I have three caps in mind that I found, not sure how easy it would be to weld on the cast version of the three caps. The CB Performance cap is already vented, that would certainly make things easier. What ever I use will have to be welded in, to replace what I have now.

http://www.cbperformance.com/catalog.asp?ProductID=1268
CB Performance_FlipTopCap_6522

CB Performance_FlipTopCap_6522.jpg

http://www.meziere.com/ps-136-120-pn6500.aspx
http://www.summitracing.com/parts/mez-pn6500
Mesiere6500N_Cap&Specs

Mesiere6500N_Cap&Specs.jpg

http://www.speedwaymotors.com/Weld-On-A ... 34154.html
SpeedwayMotorsFillCap&Neck_91076409_L

SpeedwayMotorsFillCap&Neck_91076409_L.jpg

Roll over vents are made in a couple of sizes. Can’t remember where now, but I read the the vent line should be the same size as the inlet line to the pump. So I will probably go with a -8 AN valve.

http://www.speedwaymotors.com/tip-valve ... 8,451.html
SpeedwayMotores_RollOverVent_458364_R

SpeedwayMotores_RollOverVent_458364_R.jpg

http://www.summitracing.com/parts/mrf-mp-3125
MagnaFuel_MP-3125_w

MagnaFuel_MP-3125_w.jpg

Since I don’t want dirt getting into the fuel system, I will run a line somewhere and put a valve cover breather on the end.

http://www.summitracing.com/parts/vpe-2166
Filter_VPE-2166

Filter_VPE-2166.jpg

If I locate the vent valve as shown, should I be concerned about how I route the vent line ???

VentValveLocation_3331

VentValveLocation_3331.jpg