Drag race fuel system

[Crosley.In.AZ]

Would you run a filter between the fuel tank and the electric Holley blue   pump if the tank is above the pump level... ?

the fuel should gravity feed towards the filter and pump?

[tomslik]

Would you run a filter between the fuel tank and the electric Holley blue   pump if the tank is above the pump level... ?

the fuel should gravity feed towards the filter and pump?

i would....for whatever THAT'S worth...
it saves the pump...

[wayne petty]

yes....

several options..

a normal inline fuel filter...

i think fram makes a high performance fuel filter...   i will have to check for a part number...


and a junk yard fuel filter housing...   off a 76 to 85 seville or eldorado both with fuel injection... they take a large replaceable filter element that is available at every parts store and even kmart... same element is found on the bottom of older ford pickup fuel pumps...
the eldorado/seville fuel filter assy mounts with 3 bolts... has 3/8 NPTF inlet and outlet.. but come on the cads with 3/8 inverted flair adaptors screwed in...


for everybody else..... there are bypass valves in holley fuel pumps.. (very much like oil pressure bypass valves but with light weight springs). they bypass excess fuel volume and pressure back into the inlet port..  if any dirt wedges in to that valve... and holds it open... the fuel pressure will drop to 0.... i had a friend who hated fuel filters... they used to clog on him...  the debris also took out the mechanical fuel pump...  so he installed a holley electric fuel pump...   every once in a while... the engine would die...  he changed pumps... finally instead of a fuel filter.. put two pumps.. side by side...  they both would fail...  at the same time...
when holley tech and a dozen other people finally convinced him that the performance fuel filter elements created no restriction... he finally had a fix...

the nice thing about the removable elements... is the ability to put magnets in the filter bowl... catch all the tiny red stuff that gets in the carb bowl...  if it is attracted to magnets... it is rust...

hope this helps....


so tony... got any junk yards out there with early sevilles...

i will be making a junk yard run this week...  want one...

[Crosley.In.AZ]

Wayne,

i am not looking for a filter.  Looking at opinions and thoughts on the setup.

I have always used a filter before the pump.  I usually ran the Fram HP filter as pictured.

My friend with the Henry J still  has a break up problem with his engine around 5400 - 5600 RPM..   331CID  chevy motor with plenty of good quality good fast stuff.

Everything has been rubbed on , replaced, changed. Carbs changed twice, Intake manifold changed,  spark plugs , plug wires, MSD box changed, Dizzy pick up replaced, MSD box wired direct to the battery per MSD.

The J was on the chassis dyno for 8 pulls on friday.  The last 3 pulls were from 2k to 7+k RPM with absolutely no crapping - no mis fire , noithing but balls to the wall.  The car was worked on by a long time racer - tuner here in Phoenix.  THe chassis dyno computer sensors detect no mis-fire in the ignition.  The timing wiggles a little at 6700 rpm - higher

At the track saturday the car still would crap out at the mentioned RPM.  The car will not drive through the crapping.. He tried that.

We were told the filter between the tank and pump was wrong setup by this guy, he feels the filter is a restriction to the pump..  the fuel tank is above the filter and fuel pump... the pump does not have to pull the fuel out of the tank.

We pulled the fuel lines at the track from the tank... ker - splash the fuel ran out the hose quite fast.

We checked for proper venting of the tank.  He is checking the fuel filter this week to see if there is a restriction some where.

Drag strip Scenerio:

at the drag strip the J leaves the line purty hard.  At 5400 - 5600 rpm in first gear the motor craps out... shift to 2nd gear the engine bangs back to life..... pulls hard  till 5400 - 5600 , then craps out again.  Shift to 3rd gear the motor pulls like crazy till that RPM.. then just craps it's self


:?:

[Hooley]

Just a thought Crosley. Does it have a rev limiter too low?  It sure looks like any trouble would have showed at the Dyno. Hooley

[Crosley.In.AZ]

Just a thought Crosley. Does it have a rev limiter too low?  Hooley

We took the rev limiter chip out... changed the MSD box  too

The engine pulled to 7400 rpm in gear  before lifting the throttle on the chassis dyno the afternoon before

[Hooley]

Does the Dist have advance or is it fixed?   Hooley

[wayne petty]

edit   i may have misread the reply... thinking the tank was below the pump... or it has a stock type tank....   does it have a round moon tank???
tryed rolling  it forward... so the outlet is farther back?

i need to read stuff more before i open my mouth and insert my fingers. hands and feet....

there is one thing....    if the fuel tank is aluminum.. stainless, and is perfectly clean...   the fuel hoses to the pump are new or flushed and brushed once in a while with a nylon oil galley brush... and fuel is poured in or pumped in through some kind of filter...  you can get away without a fuel filter for drag racing..  as there will be no dirt in the system to foul the pump....   one could always install several large diameter filters in series... so there is enough fuel in them when the pick up uncovers...


wayne...

i will leave the rest of the post for others


the fuel pickup in the tank is too short...

when you take off... the pick up uncovers....  when you shift gears.. the fuel sloshes forward...   the pump picks up a bit... then the fuel sloshes back out of reach.... again....

got a fuel pressure gauge that can be read during a strip run??   or video taped...    got a vacuum gauge  that can be mounted next to it.. tee'ed into the fuel pump pickup.??


pull the sender out of the tank... add some hose to the end... but be sure to take a dart out of each side of the end... so nothing can block it... ===<


a few years back top fuelers were running lean at the top end...  once crewchief had diamond p sports install an onboard camera looking at a clear tube the crew chief had installed just for this run...   there were cavatation bubbles showing up in the hose...   a new funnel outlet shaped tank  fixed that problem.,..   i would bet that there are also baffles in the tanks to prevent the fuel from sloshing forward during tire shake lifting...


maybe it's time... to pull the tank... but instead of cutting the bottom... put an open top box in from the top of the tank...   that bolts in  or welds in...  


so there is room for the pumps and filters to be mounted...  baffles and trap doors could be installed easily... or interior walls installed to reduce the fuel capacity perhaps in a tapered pattern... so the taper is smaller to the rear... keeps the pick up covered better...

a bolt on cover with a vent out the back of the car would prevent fuel leaks into the car... the exterior of the fuel tank would remain unchanged..

if you dont think that this is a problem... fill a clear box part way with colored liquid... mount it where you can see it ... then drop the hammer... watch the angle of the liquid...   then duplicate the angle in the tank... i bet that the pickup tube is just at the surface when plotted out...

wayne....

ps.. i wonder what happens to the fuel in a top fuel car or funny car tank during tire shake???/  think it gets aerated causing lean conditions?

[tomslik]

you sure it's a fuel problem?
i wonder if, under accel, a ground ain't grounding or something...
just a thought..

[Crosley.In.AZ]

you sure it's a fuel problem?
i wonder if, under accel, a ground ain't grounding or something...
just a thought..

Hooley:

timing is mechanical only.. Billet MSD dizzy in the engine. Total timing on this engine has been moved up and down.  Mechanical timing is operating properly per the dyno runs on friday


hi tomslik,

No, we are not sure what the problem is....     all idears are welcome

We went from the mode of :" we will get it fixed with plugs , jets , carbs, timing"  

to  the mode of : " what the hell is the problem ?"  

to the mode of : " #*&@%_@&$#@%$@ is the problem "

I told Bert saturday , I would start at the back bumper and check , look at , solder connections, anything and every thing.

4 different brand of plugs have been tried: cold , colder , warmer, OE level plugs .  No change in the crap out.  Plug gaps have been altered from .050 to .035

[C9]

Holley recommends a filter between tank and pump.

I run the red street pump and have had no problems feeding the 462" Buick engine . . . including 1/8 mile runs at the temporary airport dragstrip.

You may want to pull the Holley pump regulator (in the pump) and see if the internal regulator is hanging up.
Happened to me once and I had about a half pound to one pound pressure during highway driving.
Cured by sanding the bore where the Teflon regulator piston goes and smoothing things out a bit so it doesn't hang up.
Used 320 wet/dry works well.

I've noticed similar if the pump is exposed to heat.

Fuel lines on my roadster are #8 up to the fuel line splitter and #6 to the carbs whether single or dual quad.


Running a mechanical pump at the time this pic was shot, but am back to a Holley red.


Gives you an idea of how the splitter/coil mount is set up.


You can set up a nice, not too expensive fuel filter by using a remote oil filter base and setting up a Wix fuel filter that is the same size as the Fram PH8a which is the oil filter size most remote filter mounts use.


The heat shields shown would work better if they had a fresh air scoop, but they're working fairly well.

The filter in the pic is smaller than a PH8a and requires a custom nipple.
Standard oil filters are 3/4-16 both ends and this one takes a 5/8-NF I believe.
Gasket size is the same as the PH8a.

Nice part about the larger filters is they last a long time.

Be sure to install a quality ball valve between tank and filter so you can change the filter and pump with the fuel shut off.

My tank is a top outlet and there's always a siphon going on.
Same deal with the bottom outlet tanks, gravity fed etc.

With some of the funny things I've had happen with Holley pumps - partly my fault due to low voltage which was rectified with a relay and 10 gage wire to the relay and 14 gage to the pump it looks to me like a different Holley pump may cure your problem.

[C9]

I meant to add, put a fuel pressure gauge in the car.

They're a great diagnostic instrument and will tell you a lot whether at the track or on the road.

Use a mechanical gauge and be sure to place an isolater between gauge and wherever you tap into the pressurized fuel line.

Autometer makes a nice gauge/isolater combo.

There's also a smaller isolater than Autometer sells, but I don't know who makes it.
The speed shop got this one for me.

[chimp koose]

What is the difference between the chassis dyno and the track? ACCELERATION. There are G forces applied to everything in the car. Fuel will climb up the back of the tank . Gravity may feed your fuel pump sufficiently through a filter on a dyno ,but when you accelerate,the forces are no longer just straight down.OEM's have the fuel pump in the tank pulling fuel through a screen . The filter is down stream from the pump.I run the filter after the pump on my stuff.Electric pumps should have an unrestricted supply from the tank. Electric pumps are good fuel PUSHERS ,mechanical pumps have better draw.This is why electric pumps are located as close to the fuel tank as possible.Is the pump lower than the fuel level in the tank?Is the pickup in the lower back end of the tank?Is there a large enough vent to the tank?  I do not think enough fuel is getting past the filter to the pump during acceleration,causing a lean condition at about the same rpm in each gear.Try bypassing the filter for one pass and see if the problem goes away.If the problem is with the fuel system ,at least it is giving you evidence of a problem.Many cars have a fuel delivery problem that goes unnoticed until a fuel system change eliminates a problem and the car picks up power.  Another possibility could be the ignition wiring but I doubt it. Do you have the MSD powererd through a relay? I have seen relays malfunction due to vibration before. Last summer a buddy had a strange misfire problem that would occur at certain rpms . It ended up being a relay that was used to power the MSD box. Vibrations at certain rpms would cause the relay to cut in and out .That little oops cost a set of head gaskets.good luck with the search and let us know what you find.

[dragrcr50]

I cant add much , but i had a similar deal in a stude race car i had , it would crap out when i shifted gears every time.  after the same stuff you  have done i ran a new wire to the pump sure enough it had a break in it along the route to the pump and would open at the shift point for some reason and then would run ok back to the pits.   and I dont use a filter on any of my cars and never have without any problems .  i have 1/2 line to regulator and 2 number 8s to the carbs  on mine.

[C9]

Good points on the accelleration bit.

Probably a non-problem if he's running a fuel cell.

The top feed cells have the pickup at the right rear corner.


Sufficient venting could be a problem as well.

Crosley, what kind of tank/cell are you running?
And what size is the vent line?

~~~~~~~~~~~~~~~~~~~~

MSD recommends wiring the amplifier box directly to the battery sans fuse.
Figuring if the box failed the engine was going to quit anyway, I used a short length of fuse-link wire for mine.
No relay needed since the MSD is under the dash and 3' from a battery source.

~~~~~~~~~~~~~~~~~~~~

My experience with not running a fuel filter was with my little brothers drag racing Henry J.
He didn't want one due to it added weight.

Sure enough, one night at Terminal Island he got a chunk of grit in the needle and seat that held the needle open.

The engine wouldn't hardly run it was flooding so bad.

We won the race with a 30 something ET.

That because the guy in the other lane did a burn out past the line which was forbidden for the class we were running and eliminated himself.

Starter told little brother if he could make a complete run he'd get the win and go on to the next round.

Nice thing about Holleys is their externally adjustable floats.
We rinsed the needle out at the cool down station and went on to win class.

Little brother has run a filter ever since....