This question is actually in response to my fuel system for my Procharged Camaro, but since almost everyone here uses a single 044 stock pump, or adds a second 044 inline pump, I thought this would be a good place to ask.

In hindsight, I should have gone with a bigger single in-tank pump (like the Aeromotive A1000) for my setup, but I went with a 044 Bosch. And my narrowed custom tank is already done and installed. Now I see a single 044 pump is rated up to 685-700 hp, depending on the source.

Since the motor basics are similar in a way (fuel injected, forced induction, intercooled) I thought the theory might be the same in essence.

Any motors here doing 750 or 800+ crank hp on a single 044 pump?

thanks

 

I can tell you that even w/ my old turbos, hybrid GT 28's w a K 16 hotside, I dropped a full second off my 60-130 time when I went from a stock fuel system/5bar to upgraded injectors/rails/and secondary 044. And this does not incude the added safety. Double 044's are a top notch set up, IMO.

I have a big single aeromotive on my M3 and it should be called a locomotive, because it is about that loud

 

Consider dual Walbro 255 Hi-pressure pumps. Supra guys use pairs of these all the time (sometimes 3!) - I did. An advantage to them over Bosch was that they didn't pull super high amperage, when you go dual pumps pay attention to the amperage draw. A pair of Walbro pulled less juice than a single Supra pump did and functioned better over a wider voltage range. The Bosch pumps I looked at pulled pretty good juice, make sure you check these, I think they are the ones I rejected in favor of the Walbro. I haven't looked in awhile but when I did I was able to find at least one or two sites with flow comparisons that included pressure, voltage, and amperage. Some pumps REALLY do not like to run under very high pressure or at low voltage.

Oh and make sure the return is big enough. I used a good SX FPR on that car with large fittings but after the pumps broke in they overwhelmed the regulator's ability to return at idle and had to be staged - the size of the return was likely the issue. You can really chase your tail trying to tune a car who's fuel pressure isn't where it's supposed to be! That car made 720RWHP and fuel pressure was ROCK steady as I nearly maxxed out 6x 72lb injectors.

P.S. I'd second staying away from the big coffee grinder pumps. They are big, noisy, easily overheat, and often fail at the worst times. The OEM style stuff is made to last for many many miles if you can manage to plumb them...

Edit: Doing some searching. Walbro seem to indeed draw a LITTLE less amperage. 11 vs 13, not sure at what pressure the 13 was measured but possibly a lower pressure. Another site claims that the Walbro flow falls off much faster than the Bosch. I know the Bosch pumps are bigger physically, if size is a concern I'd still look at the Walbro. Have you seen anything to indicate the pump you're using isn't supporting the power level you're at? Maybe a Bosch and Walbro setup together? Is this a FI vehicle or will pressure stay "low"? My pumps supported the power level above at around 2BAR boost on a mid 40PSI base pressure. So at least 70PSI or so...

 

Well I am not sure what an apples to apples comparo is here. My 406 sbc has fuel rails and 75# injectors and 1 044 pump. I originally had an external A1000 pump but scrapped that when I decided to get a aftermarket stainless tank with in-tank pump (still coulda put in a A1000 but didn't after seeing a lot of bad reviews on them overheating and failing).

The A1000 is a monster piece and is noisy but I would never hear it over my exhaust anyway.


Thanks for the info. I would love to not have to remove the tank and get inside it again since it's done and installed. And I think you may be right on using 2 good pumps instead of the big A1000 which has many failures to its credit.

Size isn't really a concern here (that's what she said) so I think either the Walbro or a second Bosch pump would be the easiest to add to the existing system.

This is a Procharged/intercooled 406 small block chevy with Holley EFI (rails, intake, and 1000cfm throttle body) and RC Engineering 75# injectors.

This run about 2 years ago for 900 miles in a similar 1st gen Camaro as mine and was used with a A1000 pump. It did a little over 700rwhp on the dyno @ about 14psi. I have added an intercooler to my car, and we have a water injection kit we may install. We are firing up the motor again this week and will be road testing soon after. We have a FAST ECU which can datalog so we'll take a close look at the vitals right away. But I anticipate needing a second pump to make this thing safe. Running lean as we know is a major enemy of a FI motor.

So, you think a Walbro pump added inline with separate fuel lines is the way to go it sounds like?

thanks

 

On my Supra I ran the two pumps in PARALLEL with each one feeding a different end of a long fuel rail and the return was in the middle. I would suggest trying to feed of the rails at the furthest ends to equalize flow. My pumps were staged but the second came on before the length of the rail could become an issue - well before WOT. HP is HP when you're talking fuel needs with the exception of BSFC which will vary and change needs from one car to another. I do not know that I was ever sure what the BSFC was on my Supra but likely not the same as your car with a belt driven supercharger for better or worse.

Have you got a fuel pressure gauge in the car? I actually used an "electric" oil pressure gauge to track down my initial issues, later I fed the pressure reading into a 5volt I/O on my AEM for datalogging purposes. If you have programmable I/O you may be able to do this and setup a warning light as well in case pressure falls but lowest warning threshold will be tricky since it moves with boost. I would suggest trying some pulls in a high enough gear that things don't happen too quickly where you or a passenger can watch the pressure gauge for movement, you MIGHT be okay with one pump even. You'll see some fluctuations as there will be pulsation but the regulators actually do a pretty good job. When my second pump jumped on I'd see a SLIGHT bump in pressure in my logs that was immediately damped - it was impressive and didn't even move A/F as the pump came on and off driving around. Quiet as can be too :-)

Oh! Vac test your regulator! I found that mine leaked air in the adjustment screw. A hand pump on the nipple using either vac or pressure helps to find this. I had to put liquid teflon on both the nipple threads and on the adjustment screw of my FPR to seal it - I had 3 and they ALL leaked! Boost leaks suck and while not major I tried to get rid of all of them, you want a good accurate signal to that diaphragm.

 

Man that is quite a bit over my head I must admit! No fuel pressure gauge in the ****pit, no.

I think for safety we are going to install at least a 2nd pump before really cranking it up. Probably another 044 I would guess....

 

****

 

Got it.

 

Honestly? If this car is as nasty as it sounds a way to monitor fuel pressure while driving would be a good idea. I wouldn't run a fuel line in there with you - no way - and I really hated the Autometer "isolators" so look for something electric. An oil pressure gauge can be made to work but the fuel may break down the diaphragm inside the sender eventually. There are a bunch of different Japanese gauges that work and by now maybe even Autometer has something. the little gauges filled with goo that sit on teh rail to adjust initial pressure don't do much good while driving, they also tend to leak and die in short order I found - grr!

Anyway, a second pump won't hurt just make sure you have the power for it and a heavy enough gauge run to the both of them. Hopefully you won't flow so much fuel you overwhelem the return line or regulator either. Chasing that down is a PITA but if you have a gauge where you can see it it's easier...

 

2 fuel pumps in series with stock 3.8 Fuel pressure with 60 lbs injectors has been done many times over.... no need to reinvent the wheel....
I have 2 044s parallel runing 4.2 bar...

 

Well, maybe he is asking on the wrong forum as this is a Porsche forum. and the displacements we run are under 4 liters. With a Chevy he's probably closer to 6L at least.

Here's the thing and here is how I look at it. Volume is one thing and pressure is another. You can have pressure, but once the valve is open the volume to fill that opening might not be enough to sustain the pressure. In series if the "booster pump" fails it becomes an obstruction to the primary pump and vice versa. It has been done many times, but in boosted applications you cannot say it is a bulletproof concept especially that one of the pumps works harder than the other. Parallel pumps are not bullet proof either but at least you know that the load is evenly distributed.

IMO, get one pump to sustain the demand or fail and not provide fuel at all, beats a chance of running lean.

 

Haha you too huh? I blew a motor going lean when my ghettometer gauge filled with goo decided to crack and spray fuel everywere in the hot engine bay. Lesson learned...... not a good idea to hang a rail on the end of a rail. Electric , in the car is the only way to go.

 

Thanks guys... lotsa opinions here and on the other musclecar/pro-touring forums I spend time on.

If I could do it over again, I would go with 1 big pump intank, but being where I am today the easiest route is probably a 2nd pump, most likely parallel. Just wanna make this thing safe!

BTW, my little small block is about 6.6L

 

The Bosch 044 flows a maximum of 200 Ltrs per hour at 72PSI pressure, i.e. 317lbs of fuel per hour.

The 996TT on average has a Brake Specific Fuel Consumption of 0.55, meaning it requires 0.55 lbs of fuel per hour to produce 1HP.

With that being said, the Bosch 044 has a maximum output of 317/0.55 = 576 FWHP.

This is the maximum the Bosch fuel pump can produce even with the best injectors in the world.

With the Stock 996TT injectors (44lbs) and the stock FPR 3.8 Bar, the 996TT can produce a maximum of 460 HP at 85% duty cycle (540 at 100% theoretical).

Therefore if you have a 044 with stock injectors and stock FPR, your car will see a maximum of 460HP since you will be limited by the injector size.

If you move to a 5 Bar FPR with stock injectors and the 044, your new limit will 526 HP at 85% duty cycle (620fwhp at 100%) limited by the injector and FPR size.. So you are reaching the limits of the fuel pump and should upgrade.

All the numbers above are Flywheel Horsepower. Hope it helps.

 

so your saying that the the stock pump can only produce 576 bhp at the flywheel? Are you only considering the actual mechanical pump and not the venturi effect part of the pump that flows additional fuel?

Just about every tuned hybrid or k24 car is running more horsepower than that with no issues, so how can your number even be remotely true?