Twin 044's would be fed by a surge tank, the surge tank would be fed by an in tank walbro. Single 044 in series can be put in line and fed directly by the walbro in tank. Id say for under 650whp, id just do the in series 044 as it would be plenty of fuel, cheaper and easier.

 

EEK. Though that is relieving to hear for my own reasons, I was starting to wonder what I was doing wrong as from my experience of tuning E85 I'd not be able to safely find the fuel I'd need to mix with the air required to make that power.

 

So, since I've got an 8374 coming and I'll be targeting my 2.0L for a 30 psi tune on 100 octane unleaded. What fuel pump/injector setup should I be shooting for to cover both the 100 octane use and the possibility of eventually going E85? If someone could show me the math behind it, I'd greatly appreciate it as well. It sounds to me like I'd want at least a single Walbro 416 E85 pump and maybe even a double-pumper setup.

l8r)

 

single 416 will be a limiting factor
do a double pumper and forget about it

 

Ok this helps, thanks for the info!
The way I see it, single Walbro to single 044:
The 044 flows 320 LPH at 30psi, 13.5 volts.
The wally flows 325 LPH at 0psi, 13.5 volts. This is enough from the Wally to keep the 044 from having cavitation troubles at this condition (idle basically). As manifold pressure and fuel pressure go up, the 044 flow rate would decrease, there'd be some pressure at the 044 inlet, which I guess is ok.

Single Walbro to surge tank to twin 044's:
Guess I have to look at some surge tank system diagrams. Twin 044's could pull fuel out of the surge tank a lot faster than 1 Wally can put fuel in (if the 044's don't have speed control). Does the remainder of the flow to the surge tank come from an open line between the surge tank and main tank? Fuel can flow freely in either direction in that line?

 

Keep in mind with the walbro only free flows into the surge tank. Pumps flow a lot more volume at free flow vs. at 70psi. The fuel rail returns into the surge tank and only when its full will it drain into the main tank, so it should never dip a substantial amount in level let alone run out. As far as a walbro feeding an 044, its fine if the feed pump is lower volume, the big pump will pull it right thru without cavitating. My buddy has an a1000 sucking thru a walbro 255 and it flows enough for over 800whp. Only downside is the fuel gets hot after a few hours of running on the freeway.

 

The question is how limiting, though? I don't plan to run a kill tune - ever.

l8r)

 

run 2 pumps if you're running E and anything 7670 or bigger. Just my opinion... there are lots of twin pump options out there that are great and a new one that is being developed.

 

my evo is my daily-driver, so i do not plan to run a kill tune either. I wanted the simplicity of a single intank pump - no surgetank (thats for my race car) so I plan to try the 416lph with a Kenne Bell boost-a-pump and see where that will maxx out on E85. I can always put dual pumps in later, just want to try this simple setup out for now. will be interesting to see what this new idea RT/ernie is talking about

my race car runs dual 044s, off of a surge thank that is fed by a walbro 255. after some lapping the surge tank gets HOT

 

oops repost, sorry

 

Yes, that's why up in post #2091 I put the 044 flow rate at 30psi vs the Wally flow rate at 0psi. That was the worst case condition I could think of for comparing the 2 flow rates, and the Wally still came out flowing more. So, no cavitation worries at the inlet of the 044 (a single 044).

This sounded good to me and it kind of answered my surge tank question. But now that I read Geoff's comment in #2095, it sounds like there are problems to watch out for here too.

This one bothers me. It just sounds like a setup for cavitation on the inlet of the A1000. We're talking about positive displacement pumps here. Normally you don't expect to suck a whole lot of extra flow out of a positive displacement pump. Usually they aren't supposed to be that leaky. I suppose the way the extra flow gets through the Wally is mostly by over-speeding the wally motor. Since it is a DC motor, this is doable. The suction on the wally outlet pulls up the speed of the wally pump and motor.
Anyway, when you read the A1000 manual, some of what they talk about in there is aimed at setting everything up to minimize restrictions to the inlet flow, to avoid cavitation. You don't want a whole lot of suction going on there.

Yep, that's one reason why they offer speed control for these big pumps.

 

Log fuel pressure Geoff! That'll tell you when your pump isn't keeping up. If you get 5000cc injectors you can open them until your fuel pressure equals zero psi and then you're technically maxed out your pump.

my definition is when your fuel pressure can't maintain it's 1:1 ratio with boost... at any base pressure. I suspect you'll get some more headroom over what you have, but I know 1 walbro HP on E85 with upgraded wiring won't support the power that you're already making.

Do you run your 044's in your race car simulataneously on a quarter tank? or do you trigger the 2nd pump and run the 1st pump on low voltage under low load conditions? similar to how the Evo strategy is.

 

Just to say... You size your surge tank accordingly... if the 044's are pumping 100% at pressure (~70psi) and your intank walbro is going at 0psi...

AND THEORETICALLY your injectors are using 100% of the fuel that those two 044's are pumping out... you will begin to lower the surge tank volume. If you make your surge tank large enough to cover these enormous fuel flow conditions and say that you'll sustain them for 1 minute, before lifting on throttle. Then you'll be perfectly fine.

because when your 2150cc injectors DON'T go static, the FPR returns the fuel to the surge tank and fills it back up...

Which since we've all done racing we don't spend the whole time at WOT...even if we're drag racing (unless it's an auto... and that only lasts for sub 9 seconds)

Dumb math. 2150cc injectors x 4 are removing 8600cc or 8.6Liters of fuel in 1 minute if you're running them at 100% IDC. If you believe the walbro literature... a Single walbro at 0psi is 325+lph is 5.4L/min. So if you're injectors are static for 1 minute... your fuel level may drop 3.2L's in your surge tank.

If you use 80% IDC's... instead of static... that 3.2L loss turns into 1.5L loss.

Reasonable people will use 80% IDC's... and if you were to take an actual average of your fuel usage via a data log you might find that a realistic average IDC over the length of a course is much less than 80% IDC.

So using these logical deductions figure out that a liter sized fuel tank is more than adequate for these situations. But don't trust me... do your own math.

 

Surge tank/fuel cooler in one unit...
Hum...

 

^ exactly my thoughts.

Oh and funny that we should be talking about fuel pumps failing. My primary Walbro fuel pump is dying.