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Question, using Hilborn cam driven fuel pump for street/strip turbo engine.

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Marks63Catalina:
I want to get your opinion on this combination. First, the reason for such an unusual combination. I was given this Hilborn pump off of an early top fuel dragster with instructions to find a way to use it if I could. It was originally on the late Johnny Lopers (Lopers Phoenix Speed Shop owner) top fuel dragster back in the '60's and early '70's. It was given to a friend who worked closely with Johnny at his shop. The friend wants me to find a way to use it instead of it sitting on a shelf collecting dust. With that said. I want to try to use it on the car I am building. It's a street/strip Gasser type street freak. 1960 Pontiac block .090 over. All new forged bottom end. Forged Ross dished pistons, aluminum GRP rods, splayed 4 bolt center caps, steel rod inserts from the center decks down into the waterjacket bottom for deck support, etc etc. So it is a well planned/serious short block for the task, not a throw together set up. I will be running twin 76MM turbos, twin air to water intercoolers, twin 750 blow thru CSU carbs on a Wenzler Tunnel Ram. All this is set up for pump E-85. I am shooting for a normally lower 1000 HP with intent to raise the boost under controlled situations for 1500 or more HP. I need a good fuel system. So this is my plan. Feel free to guide, critique, and or  shoot me in the head if you feel that it's just not doable. If I cannot use it as a pump I have an alternative plan too.

This is the "NOT" set in stone plan starting from the back of the car. I have 26 gal alum fuel tank from a boat (I have). I'll add a simple low pressure electric pump only to feed a front mounted Moon 3.5 gal surge tank ( I have). This Moon tank already has a provision welded on for a Holley fuel bowl. I also hope to install the tank close to and above the pump inlet to aid fuel flow. The pump is already mounted on the engine with a Moon front timing cover, cam driven using a custom made adaptor to use a BBC drive spud. The surge tank will be plumbed with AN -12 line to the pump. The pump is equiped with a shutoff/bypass valve on the outlet side, using AN -8 line/fittings. I plan to run the outlet side to an Aeromotive bypass 4 port regualtor set at 6-7 pounds, AN-6 lines to each fuel bowl. The bypass is to return to the surge tank thru a small air to air finned cooler if needed (to fight any fuel heating from the pumping and returning).
I know the pump will provide plenty of flow for my needs. The regulator should handle the flow to the carb bowls, and bypass the rest. The outlet -8 sized line is what they used on it for the fueler so I feel that should be fine. My questions are:
1. Am I nuts???? (Likely, yes).
2. If it is doable. Are my plans OK or do they need major revamping?
3. I wonder if the bypass from the regulator is better returned to the surge tank or to the inlet of the pump?
4. Do you think a carb based fuel regulator will be able to handle the higher RPM pressure profile of the pump to bypass and not flood the carbs?
5. Do you know if the pressure profile is such that it will not unduly stress the pump under idle and or cruise conditions? Meaning, if the pump profile, at say 3000 rpm cruise, is already making high pressure, will that hurt the pump for longer run times such as a drive thru the city. Or a steady state freeway/highway run of 30 to 60 minutes without a stop?  I'm trying to determine if the pump will handle this kind of environment. Since they're really designed for short high pressure runs. I mentioned the original bypass valve after the pump outlet because I could see during a cruise where I could actually run a manual cable to the bypass and open it for a bypass back to the rear tank to lessen the pressure and stress during a long cruise, plus that fuel being pumped and heated could return to the rear tank instead of the surge tank. Keeping the surge tank cooler.
I mentioned an alternative. If the pump just is not a good candidate for this kind of use, then I thought mounting the pump without the cam drive attachment. Then run a strong electric (Aeromotive A1000) pump under the surge tank, but plumb it thru the Hilborn pump with pump, fins removed to allow flo thru. The rest after the pump would follow thru.

Well I hope I didn't leave anything out. Sorry for the long (possibly boring, lol) description. Everything hinges on the pumps ability to work within these confinments/requirements. Plus it's longevity as a viable pump for many more miles than it was originally designed for. I have seen others using it for the street but they always had it on a real Mechanical Fuel Injecton (non forced induction or carbed) system set up almost exactly as designed. I also don't know what kind of miles their pumps sees.
Thank you Spud for your time and expertise on this matter.  It is much appreciated.

Mark L               

Spud Miller:

 Hi Mark,

 While not practical, this is doable...and sometimes we do things for reasons that are impractical and have a great time with them! Heck, race cars aren't practical. I've designed a couple of similar setups - at least up to the point where you're sending the result to the carbs.

 The Hilborn pump will be cooled by the fuel going through it and as long as the bearings are in good condition, you'll do fine with some highway driving. I wouldn't suggest putting 1000's of mile a year on it, but cruising it across town or to a nearby town shouldn't hurt the pump a bit.

 You didn't mention how big it is...is it a -2 or a -4? A -4 pump makes 17-18 GPM of output at 8000 engine RPM, so hopefully a -2 is stamped on it. Smaller would be great too!

 The carb float bowls on the surge tank may be marginal at 1500 HP with E-85. Of course, you have a reserve there for probably half a minute before your surge tank drops to a dangerous level so it might not be a big deal. I can't speak for those carbs on the motor. I can't even spell car-burr-ayter :)

 In my opinion, the best way to do this type of thing is to supply a sealed surge tank up front with a healthy electric pump in the rear. But instead of using floats, just plumb another -8 line from the surge tank to the main tank. This way, the surge tank fills and the unused fuel just flows right back out again. The surge tank never really is "pressurized" as long as it can get back out through that big return. You can size the electric pump accordingly or use a pump controller to dial down a pump that's too big. No regulators needed this way either. The pump at the main tank is just a free-flow transfer pump.

 The only thing that worries me about this deal is that the regulator after the Hilborn pump better be a biggie! If not, fuel will back up and your carbs will get drown in fuel. You might use a regulator on the supply line to each functioning carb to make sure you have a lot of bypass volume.

 Have fun and let us know how it goes!

 Spud

Marks63Catalina:
Thank you for your thoughts and expertise. It is much appreciated. I never expect to do any kind of long term high fuel flow need runs, other than the usual 1/4 or 1/8th mile runs. That's why I felt the 3.5 gallon front surge tank would be adequate for my needs. My pump is a PG-150A. There's 1-4689 stamped on the pump so I assume it's a -1 pump. It was used on an early top fuel dragster so it probably flows a lot of fuel. If this all works and I can use the pump, would it be a good idea to send it into Hilborn maybe every or every other year for inspection and rebuild? Can it be rebuilt? I had a little brain storm (brain fart??). With the cable operated bypass at the exit of the pump, I could  incorporate a linkage/cable attachment to the carb linkage and it could open and close the bypass along with the throttle position. That would take stress off the pump, the regulator, and that bypass could go back to the pump inlet? Just trying to figure out the best way to make this thing work. It looks great on the front of the motor, and it would save me buying a big expensive electric  pump for the rear of the car. Plus I know I would never run out of fuel because of the pump. Call me whacky!! Thank you again for your time and help.  Mark L

Spud Miller:

 Good! It's a -1 pump. That's only 6.2 - 6.8 GPM (at 4000 pump RPM) or so and plenty manageable.

 Other than the bearings, that pump can be serviced, tested and rebuilt. FIE can do that for you! :) Annually would be a good thing for that pump. The bearings on the "A" model are no longer available and are not sealed - they do fling their grease out. If serviced regularly, they'll last many more years.

The pump/carbs will be fine with a regular sized bypass-style regulator like you mentioned earlier...it's a fairly small pump. No need to actuate a shut-off with the linkage or anything fancy.

 You will still need a pump in the back of the car to fill the surge tank, but it doesn't need to be a giant expensive thing.

 Spud

 

Marks63Catalina:
Good news then Spud. Thanks for your help. Sounds like unless I have a mechanical problem with the pump it should all be good. Thanks again for your help. 
Mark L

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