(originally posted in "Garage" - I guess this is where racing stuff is supposed to be?)



Hey guys,

I'm installing a fuel cell in my car this weekend, and need to add a fuel pump.

Any racers out there have good experience with a certain brand/type of pump?

I've got dual Webers, and up until now the car has run great using the stock pump/tank (but have to put in a fuel cell). I may just leave the stock tank in there for now and plug it off. Anyway to still use the stock pump?

Thanks,

Pen Pendleton

PS – Any 914 racers planning to race at the Vara race at Cal Speedway next week?

Holly Red seems to be the pump of choice for Carbs. Make sure you mount it up by the tank though.

Why?

Mine is mounted to the lower firewall under the battery. Zero issues.
The amount of fuel that flows out of that line without a pump would likely run the carbs if there wasn't a gravity issue.
You can drain the entire tank in about 5 minutes into a fuel can with the line open.

Also, use the Holley one-in-two-out fuel pressure regulator.



I suspect that you bought the car with the carbs installed?
The stock pump produces something like 35-40 PSI. Webers only need 3.5-6 PSI. ( depending on who you ask )
Likely your car has a little square shaped Facet pump.

The stock pump feeding the carbs at high pressure would cause the bowls to overflow and...


KT

Because you can run the carbs out of gas with wimpy pumps mounted at the back.. also HEAT soak.. does not occur when the pump is up front. Which is why Porsche moved it there in the 75-76 cars.


B

run a -8 supply line to the pump at the firewall. -8 to the pressure regulator and -6 to each carb.
DO NOT WIRE THE GROUND STRAIGHT TO THE CHASSIS. Yes it will run but it will also draw huge amps and kill the pump motor. Run a ground wire back to the battery - side.

Wow - I would have never thought of that. Thanks.

Race car: carbs already installed. Previous owner assumed the stock pump was used, but the owner before him did all the race prep work. But I sure don't see an aftermarket pump anywhere. I'll know what's up this weekend when I put the fuel cell in. But the stock FP pressure comment makes sense because it being a FI car, originally.


Street car: single carb already installed when I bought the car. Car has a very small fuel pump in the engine bay, a little red cube - very lightweight; doesn't seem that there's very much to it at all. I never paid much attention to it, so I don't know what brand it is. Loud little sucker though...

Here's what I have:

Holley Red pump and big Canton filter up front.



Another small inline filter, Holley regulator/splitter, and pressure gauge in back.

Well, there is indeed an aftermarket electric fuel pump. It's at the firewall, it's a smaller inline pump. It's hooked up to one of the original fuel lines at the firewall, with the second line capped off. The previous owner road raced the car in SCCA vintage series in the Oregon region last summer and the car did very well. No doubt that the Holley pump mounted in the front with the cell will be the better set-up (which I plan to do), but this set up did at least work OK for the last two owners (one was an Autocross racer, the other a roadracer).

Also, how do you guys route the fuel line from the cell to the engine? Did you use the original tunnel where the original two fuel lines ran, or run the line through the cockpit, or under the car?

Thanks.

My fuel line runs through the tunnel in stock fashion, but is metal tubing. It is AN-6 braided hose everywhere but inside the tunnel.

I run a -6 line from the tank, through the tunnel, to the pump.

I capped one of the outlets on the tank.


KT

You'll need a fuel pressure regulator if you don't already have one. If I'm not mistaken, the webers and PMO carbs like really low pressure (3 to 5 pounds) and even the Holley Red "low pressure" pump is way too high of pressure (like 12 pounds I think).

I looked and most regulators only go as low as 5 pounds. I know PMO has a regulator that goes very low, but it is designed to utilize the return fuel line and high pressure pump.

On my race car I have the Holley Red fuel pump with no return line.

Here is mine. It is a faucet pump grounded to the chassis, never had any issues.

-Britain

technically a recirculating fuel system is always better

since I race and take racing seriously... I would only recommend a recirculating fuel system to anyone else that takes things seriously...

cooler fuel
more hp

every ounce and every hp counts.
brant

So what regulator did you wind up using? I don't see one.

My car has a Barry Grant (BG) regulator. It only goes as low as 5 pounds. The PO that built the car ran it in this configuration. I bought the car needing ignitions and induction, and I simply put the car back together as the PO had it.

When I first started the car the fuel pressure was like 7 pounds. I have set it to 5 pounds.


Sorry, the regulator isn't visible in the pics. Here's a pic

If you are not using a heater, run the fuel lines in the heater duct. Fuel will drain out the duct if there is a leak. If there is a leak in the tunnel, fuel will drain into the cockpit. I think this is a safer solution.

Brad, one more question. If I install the "Blue" pump which technically has "too much" pressure for the Webers, is that compensated by the regulator that comes with the Blue, or do I buy a separate regulator that goes down to 3psi?

And just so I'm clear on the mechanical logic, it will be better to have a pump capable of higher pressure (the Blue) with a regulator as opposed to a pump that is already at a lower psi (like the "Red" or a Carter)? In your first post to me on the subject in the "Garage" section, you said that the issue is volume capacity, not PSI, could you give me a quick explanation?

The PO had the Carter rotary pump which seems to have died, and he said it ran great; maybe it's because we're vintage racing, so he was a little less balls-to-the-wall compared SCCA/NASA/POC racing? He was using the stock tank with the bottom feeder lines, while I will have a fuel cell with lines coming out the top.

Love all the advice, just trying to reconcile how the advice has been so wildly different!

Also, do you put the regulator in front with the pump, or in back by the carbs?

Thanks,

Pen

Go red!!

Search on Summit.


KT

When you run a fuel pressure regulator it's a lot better to run a recirculating type, the kind that has a return line to the tank to dump the excess fuel/pressure. The simple restrictor type of regulator (single input, single outlet) has limitations especially at higher flow rates.

Scott

Holley installation pdf

I know that the Holley and the facet have become very popular, and I have been using them for many years. We used to plumb two with seperate switches so we could finish a race when one failed. A series of check valves created a fail safe system, and I thought for many years I had found a system that was fail safe. But it wasn't, so I went looking for a better solution. My suggestions are for a race car only.

As far as I am concerned, the only pump that anyone should be using is the Mallory gear rotor pump. This is a low pressure pump that moves 70 GPH and the internal pressure is pre set at 6psi. The other pumps are diaphram pumps and produce a couple negative things you do not want when providing fuel to carbs. One of them is a pulse pressure wave which can cause some issues with the the needle or needle check valve. While it is normal to have these pulses dampened out, it is not always possible depending on the run on the fuel line and fuel filter and pressure regulation.

We have to have a few things to consider when providing fuel to a race engine. Keeping it as cool as we can, providing proper volume, proper pressure and keeping it clean.

Lets start with keeping it cool:

Being that we are dealing with air cooled engines, we have a nice area in front of the fan to have cool air being drawn across the area at the front of the engine compartment. If you buy the typical 6an T pressure regulator (which has no gauge) you can mount this though the firewall so the T regulator is on the engine side of the firewall, mounted just above the forward shelf. The -6AN male fitting will stick through to the cockpit, Yes (cockpit). The run from the -6 An fitting on the passenger side of the firewall must be stainless braid and runs to the front mounted tank. Pick the holes in the front firewall you want to, use proper clamps and secure the braided line to the chassis at least every foot. So now, you have two outlets for, you guessed it, TWO carbs. With the 6 cylinder units, it is very easy to swap around the carb inlets PMO or what you have. Using some small clamps on the front side of the engine compartment, you can have any braided line run you need to get to the carbs.

Keeping the fuel cool:


At this point, using some thermal reflective housing over the braided line works very well to keep the fuel cool until it gets to the carbs, and unless you have built a tray for the carbs to sit in, they will always be the hottest part of the system due to the radiant heat from the engine, so building a recirculatory fuel system really does not help very much. While you may geta few degrees, if the fuel line that serves the carbs runs around the back of the compartment, it is just heat soaking it and the recirc system is a waste of time. This is not the case when you are fuel injected, and you must have a recirc system for an injected car. Close attention must be paid to the positioning of the front mounted oil cooler and how the heat from the cooler is routed, hopefully away from the fuel cell???

Keeping it clean:


This starts right from the start. Clean the fuel cell, completely once a year, replace the foam every two years, it really isn't that hard, just stinks. Use a painters filter to strain out the crap you get at the pump. Make sure you drain the last 1/4 inch of fuel into your lawn mower, and clean the inside of the fuel jug. I use lint free rags and compressed air. if you see water, you getter get another jug full. Water is the brown spots at the bottom of the tank. IF you use the Mallory you can put the -6an fuel filter (with replacement cartridge) between the fuel cell and the pump. Now some people will jump up and down and say you can't put the filter on the scavenge side, but with the Mallory, you can, I would suggest it with a Holley pump, and never with a facet.


Volume:


There are several fuel pumps from Mallory available. The size of the line is always a concern as well. But my guide lines are -6AN 250 hp and below, -8AN for 251 and above. The line sizes to the carbs I always have -6AN. The pump, fuel cell lines all the way to the pressure regulator T fitting at the bulkhead. 70 GPH will serve a 250 hp engien without problems, but upgrade to the 90 GPH when you have above 250

Pressure:

Your engine tuner will have the details on what PSI he/she wants to use for the carbs. For me, I use 4PSI and tune from there. I have once used 5 PSI, but found some issues with Weber float valves at this PSI. One thig must be said for the fuel cell. It is very important to use a surge box inside the fuel tank. I like the fuel safe one with the small check valves, and pull all of the fuel out of this surge tank.

Venting:


I have always vented the fuel cell into the right front wheel well. Reason one, it is not on emy side of the car, Reason two, its easy to do and I have never had an issue. Just loop the vent line once and have it on a small incline so it will self drain, install a small valve cover K&N filter on the end, and you are done.


Thats about all I can remember. Good luck, take my advice o the pump, it is the finest I have ever used.


Erik Madsen

Erik,

Thanks for all the good detailed info! With my previous engine/carbs and the Holley Red pump, I had problems with the needle valves several times and I wonder if this was related to the pump or to the pressure being set too high at some point. They were sticking/jamming and I thought there was gunk or particles getting into the system despite the two filters, but I never found a definitive cause. Knock-on-wood it has not happened with my new engine/carbs thus far.

I know I need to service my fuel cell soon and I'm also going to put some insulated covering over the fuel hose from the bulkhead to the carbs.

Cheers,

Great info! Thanks.