Best mechanical fuel pump for 900 plus sc engine
 

title pretty much says it.

Can't remember the ones that were discussed last fall nor could find the thread but wanted to go with the ones that were mentioned in a couple threads. Seemed like they came in 130 gpm and choice of 15 or 30 psi.

Procam from Baker ?
http://www.bakerengineeringinc.com/P.../Pro-Cam-Parts
Ask I see dead people - think he got the low psi one and had fuel psi (volume) issues, then got the high psi one and that was fine...obviously with regulator.

Best pump out now I believe is the CV Products Nascar pump. It's like $600-$800, :)

pro cam 9351,baker pump[googel it].

That's it. Part #9375/15 psi. Tks for the response. also curious what MT did about a fuel regulator. I have 6 port fuel log and plans to run hose to each bowl from rear of engine but not sure what to do about regulator. Was also considering 4-port regulator. Just don't want to do this once and right. Restriction from regulators concern me.

SB if I absolutely had to I would. Lol.... when I did google BBC fuel pumps and bakers never showed up when I when to images and scrolled. I do recall icdedppl fuel pressure dropping to like 2 pds during long hard runs.

Looks a lot like the one Teague sells only theirs is the 7-9 psi #9373. Thought it looked familiar.

if i remember correctly joe used the low pressure pump,im sure he will chime in sooner or later.

I am using the low pressure version.

If you are going to use the high pressure version, I would definitely use a return style regulator, and return the fuel to the tank, rather than use a dead head regulator.

My buddy Matt on here is using the low pressure pumps as well, his engines made 1020hp. So far so good. Mercury used the same pumps on the 900sc engine.

Fuel pressure is a sticky subject. Many years ago, before widebands, all we had was fuel psi gauges. Back then, if you saw any drop in fuel psi, you assumed fuel starvation issues, and made changes. However, there are alot of variables on whether or not there is sufficient fuel being fed to the engine. Obviously, the wideband will help tell that story. Aside from this, things like needle and seat size, needle and seat quantity, and so on.

Example. Lets say you have a single carb B&M 250 blower setup. Someone put .097 Needle and seats in it. Its a stout engine build, with good heads, cam, exhaust , and so on. You run a marginal fuel pump. You have a -6 line from pump to carbs. You hook a fuel psi gauge to the fuel line, and see good fuel pressure. Engine still can go lean.

Scenerio 2. You have a twin carb setup. Now this one has .130 needle and seats in all 4 corners. You have a -10 line feeding the log, and -6 to the bowls. At wot, your fuel psi gauge drops from 6.5psi to 5psi. You immediately think "LEAN", but that isnt always the case. While you are seeing a drop in pressure, you arent necessarily seeing a drop in FLOW. Carbs arent efi. They like flow, not pressure. Prostocks were running as little as 2psi of fuel psi thru the traps. Not much pressure, but gobs of flow.

Needle and seat diameter and quantity of needle and seats , is often overlooked . A .130 N&S, can flow a chit ton more fuel than a .097 N&S, at 6psi of pressure. Four needle and seats (twin carb), can flow...well double what a single carb can.

Those six valve baker style pumps, can flow a ton of fuel. But they arent going to do their job, if the tank pickup is too small, restrictive fittings, small lines, and what not are used.

The small diameter n&s assembles can tolerate more fuel psi, without coming off their seat, than the larger ones. The small N&S and excessive psi = lots of fuel bowl aeration (not good). If you wanna go a step further, BLP has bottom feed needle and seats. Not only do they flow great, they do so with very little aerating of the fuel.

Pressure, flow rate and volume are oftentimes misunderstood.

Also, with line size.....the relationship of line diameter and cross sectional area is not linear.
That is to say, a 1" line flows way more than twice that of a 1/2" line. same goes with any oriface, I.E....carb jets

I'm using the baker pump. 15 psi with a return style regulator and I'm set for just a tick under 6 psi on the gauge.
-10 feed to the water / fuel filter
-10 to the pump
-8 to the log
-8 log to regulator
-6 return line to the tank.

Dead headed 7-9psi pump and no return I used to run out fuel pressure at 5700, let off it would come right back.

I ran everything in -10AN
15 psi pump baker and tank return. No more issues

That pump simply has a lower set bypass spring, than the high psi version. If you use a deadhead regulator, you simply force the pump to go into bypass mode all the time. If you use a bypass regulator, the pump doesnt have to be internally bypassing all the time.

The 7psi version, is bypassing a majority of the time. Obviously at idle, the pump is no where near moving the amount of fuel its capable of. In order to keep 7psi of pressure, it simply bypasses internally. Once you get to the point the pump stops bypassing internally, (high rpm), you likely would see a change in fuel pressure on the gauge. Not necessarily a bad thing, as a ton of fuel is now being moved, because all the valves are open so to speak (needle and seats).

Theres a big difference in dropping fuel psi because the pump is starving for fuel, and dropping fuel psi because the bowls are filling properly. Keep in mind, pump output decreases with line pressure. A pump with 4.5psi of line pressure, will move more fuel than at 8psi of line pressure. take the pump out of the equation, and yes you will move more liquid thru a line with more pressure, but we are talking about the pumps output capability. And that decreases with an increase in line pressure. Hence why a electric pump that can do both carb and EFI, generally can support a chit ton more power with a carb setup, vs an EFI setup.

Pressure regulator.
 

I see many with a one per carb as well as some with one per two carbs via twin SC app. I lost that pic again of your set up MT. Also are you running boost ref regulators? I have the fuel blocks and would like to run one 10 AN reg per engine right before fuel blocks.
I would imagine one per carb is ideal but wanted to ask anyway.
john

just thought about it and wondered since your using the lower psi pumps if you even using regulators.

Wonder if you could just run the return to a T on fuel filter inlet rather than tank?

You'll start to see the limits of a single carbs fuel flow capability at a certain to level. My buddy Joe had to upgrade to dual needle and seat bowls on his blowthru setup. It just couldn't keep up with the standard setup

You only need a boost referenced regulator with a blow thru setup. The fuel pressure must rise proportionally with boost on those , because the float bowl is being pressurized. On a draw thru, it's not needed.

As​​​​​​ for mine, I am running -10 from tank to the big wix water separators. -10 from separator to pump. -10 from pump to a 4 port manifold mounted in the back of the blower. Then -6 to each bowl. I like this setup better than the hard line setup, as it allows you to remove bowls for jet changes without needing to take off the bowl inlet lines. Just remove the 4 screws and bowl hangs by the an line

I've never done that , some have I believe. Me and Dan talked about that on his setup, but returning it to the tank makes the most sense.

For one, There shouldn't be a restriction on the return side. I can see where plumbing back into a filter, can restrict the fuel flow. Most modern vehicles use a return line, that goes back to the tank.

Dan returns his to his tanks. The setup he has simply works.

I just want add you have to increase fuel pressure 4x to double the flow. Some think that if you double the pressure you will double the flow. It is not linear.

I agree, no good reason not to return the fuel right to the tank.
i plumbed mine to a stainless "T" fitting in the fuel fill hose. I bought the fitting from Teague or Hardin, I can't remember which one.
Anyhow, it makes for a clean install.

I know there's alot of guys running a simple enderle style bypass valve . Clay Smith sells them, like 65 bucks, preset to 7psi. If I was to do the higher pressure spring pump, i would use one of these for my bypass regulator. Simple setup.

By-Pass Check Valve (AN #8) - Clay Smith Cams
I installed a low fuel psi sending unit on my fuel log. I have yet to wire it in to the led warning light on the dash , but my thoughts on that, is who has time to stare at a fuel psi gauge when running balls out ? And chances are by the time you ran out of fuel psi and saw it, the Pistons would be fubared . If it falls below 4.5 psi, the light comes on. Fuel psi gauges, mainly electric but also mechanical, are notoriously wrong. You're talking about differences of 1 psi with such low pressure we run with a carb. I believe mercurys range of acceptable fuel psi on the carb sc engines was a max of 7psi, and minimum of 4psi .

You could still find the NLA holley 6 valve low psi pumps they used on the 800 and 900sc, for around 200 bucks in the mercury box.

Besides baker engineering, C&S specialties also sells this pump with some upgrades to it. Roger at C&S can tell you what these pumps can handle HP wise.

I will run bypass lines back to tanks. I can see that would be the best unless I end up running lower pressure pumps. Regardless I like the idea of the red lights on dash for low pressure rather than gauges. I'll place another order with cp.

less than ideal but i did it at 1100hp w zero issues. I buffered the return by sending it to inlet of fuel filter/suction line connection so pump would have a little cushion from any erratic flow. I also used sm as ll oil cooler as a fuel cooler after pump so motor would get a cooled fuel supply, Smitty

Be sure to put the light where you can see it in the sun of day. Someone here was super happy with the light but couldn't see it in the sun until it was too late.

I was looking into that Clay Smith bypass that MT mentioned but haven't figured out how to plumb it off of my QF as it has flare(?) fittings. I'm sure there's a tee but I haven't found it yet.

I like cool fuel method. Often wondered about that. Nice...

Good point. Maybe buzzer alarms be better. Also are the Jegs adjustable fuel pressure sensors adequate regardless of the red lights or buzzer. I may be over doing this slightly however I just don't want any melt downs due to something that could have been easily avoided. Afr gauges will be in dash also but like MT said flying across the water with a lot potentially going on I don't really care to be eyeballing gauges constantly.

Could maybe do a combo of dash light and buzzer. Boat is old school 12 meter so there's not really any other buzzers etc.

I would use the buzzer with a light as if you're too focused to watch a guage then a light can go unnoticed until it's too late as well. The light will indicate which buzzer is going off if you have multiple alarms.

I still have the teeny stock Merc oil cooler. Is it worthwhile to run fuel through it in a N/A set up?

Question is probably more directed to Smitty but depending on what engine and power your running it could be advantageous. When I was younger in my 1/4 mile racing days I use to cool my fuel with a coiled up copper tubing inside of a number 12 size canister filled with ice prior to making a pass down the strip. Whether it ever made a difference what so ever I'm not sure however I liked the concept to cool the fuel. If anyone has dyno proven results it would probably be Smitty.

Smitty???

I have the Baker 15# pump on a 850hp engine with a bypass regulator. It supplies plenty of fuel, but you can see every pulse of the pump in the pressure gauge. I have a mechanical gauge on the fuel log and an electric gauge in the dash, sender is in log as well. Both needles swing wildly and it destroys the little liquid filled mechanical gauges in short order. I even plumbed in a large spin on fuel filter between the regulator and carbs, thinking it might calm it down a bit. Didn't change a thing, but I guess that since liquids don't compress, I should have known better. Does anyone else have this problem?

"Between the regulator and carbs" ? Shouldn't the return regulator be after the carbs ? Most are.

only problem I have with a buzzer, it it better be friggen loud. Could be a bit hard to hear at 90-100mph with twin 900s, blowers, and wind screaming in your eardrums. A bright led light on the dash, will catch your attention.

Has anyone had any luck using a command center where the mech pump lifts it in a basin, and an electric pump shoots it to the carb/Fi? FiTech makes one but seems to be crap in execution. I think edelbrock makes one as well though.

During the day, you can`t miss em, at night they are blinding, usually have to throw a towel over them.
Since we have headsets the buzzer wouldn`t work.



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True and agree so if I am going to both . I see no reason why not. I tend to zero in on oil pressure and AFR's. A little time and wiring is worth the potential meltdown. Might be overkill but so be it. I am not sure where enfines are going to come in at hp wise so just want to be certain. I have to be honest 1,000 hp engines are something I'm not use to running so rather safe than sorry. All else fails it will be fun.

I should be more concerned about drives than engines to be honest...

Why not build a "shut down" circuit that kills the ignition if fuel or oil psi falls below a threshold?
bells and whistles are good indicators, but a human still has to recognize them and then react.

what am I missing here?

I think the dash warning lights will be fine. Likely it won't be an issue anyway but just want to be on the safe side. I can react and back out of the throttles with a warning and go about my day but cutting an engine out at 90 plus is disaster. Been there twice and it's not what I would say is a good time. You can have your hands full in a hurry. Lol...

doesnt merc racing use a shut down circuit on their electric fuel pumps?

Maybe a circuit that initiates a visual and audio alarm and simultaneously picks a time delay shutdown relay. You could program any delay you wanted, so you could get the alarm and have a chance at throttling back. If the alarm is ignored, the relay times out and saves the engine / engines.

That'll do it! Lol.

Merc
 

they very well might. These are custom builds so to speak and going into an 12 meter so anything and everything will have to be well thought out and rigged as I see fit. Not my first SC engines but my first with the kind of power we're looking to achieve. I'm just looking to take some precautions cause I know how fast things can happen yet I like simple also.

Tks guys.