Is there a way to find out exactly what the SL55AMG fuel pump actually flows in gallons per hour at 60 psi. I dont have the finances/resources to buy it unknowingly and do the test myself other wise i would.

On my walbro 255 the number means 255 liters/hr but if im reading this chart correctly at 60 psi(where our factory regulator is set) it will flow 52 gallons per hour.

I want a direct comparison for the SL55 AMG fuel pump...

 

Pierburg pump flows 75-80 g/h at idle and 95-100g/h at redline all operations are within our factory FPRV
Last time I answer a question without getting paid

 

The stock pump and stock regulator can flood the engine even with stacked pullies, I did it.

Fuel flow is due to the low line pressure, up it and youll get all you want. It is not about the injectors, its the pressure differential on the injector - in to out.

Woody

 

Low line pressure comes when approaching redline with the injectors constantly firing, The SL55 pump flows about 25-30 gallons more per hour then the factory pump. It is a proven solution for going lean. That is why AMG in Germany installed the pump in SLK32Germany's car. I have also corrected my lean issue also 13.5-14.2 @ 5500rpm and up.I am now 11.5-11.7 straight across the board. Based on what you say woody it would be impossible for the SL55 AMG pump to work but yet it has, can you explain this?

 

What is your fuel pressure at the rail?

 

Bulldogger thanks for the info, and i remember you posted this somewhere but i searched and couldnt find it. Please realize i am questioning you in a courteous manner but where are you getting this info from...got a link? To say that the sl55amg pump (Pierburg?) flows 75-80 g/h at idle is assuming that the said manufacturer knows what application its going on and the fuel pressure at the rail at idle...they dont normally post graphs in this manner or have this info. Saying that it supplies 95-100 g/h at redline ASSUMES they know all the other variables like what our redline is and how much boost we are running...what if i can rev to 8000k and am pushing 40psi, there is no way they could provide data based on these variables.

And the difference in correcting your issue from 14.1afr down to 12afr is quite different than correcting my issue of 20+afr down to 12afr. Im glad it worked on your car though. Everything ive read on the DSM forums say the walbro will handle a conservative 500whp minimum, we are nowhere close to that. 2 walbros are said to handle 1000whp. I will gladly spend another $100 and run two walbros in line but i have a hunch the car will still run lean just like it did with one walbro.

I need to know at 60 psi what g/h the pump provides in order to compare it to my Walbro. Thanks again for all your help and pm's.

 

I just wrote out a 2 page response and lost it in the computer. Bottom line the car can not injest more than about 25 GPH WOT and at 18 PSIG boost, NO WAY.

Geee I wish that answer was not lost I got woozy reading it. Poop

Woody

 

Quote:

Originally Posted by waldig

The stock pump and stock regulator can flood the engine even with stacked pullies, I did it.

Sorry Woody just couldnt handle the 5000 point font so i reduced it lol. I also respect your opinion greatly and i realize you and Rob are working on a fix. When we spoke on the phone and through pms throughout the last year i duplicated some of your findings by adding boost back into the fpr and even ran a return style setup with an Aeromotive FPR. I was able to crank my fp up to 90+psi. However when i did this it ran horrible under in the lower and mid rpms(too rich). Thats why i got pissed and abandoned the project. Well now a year later i have calmed down and want to actually fix the issue so i can run my 25psi on the 185 and have a perfect afr. So why would you sacrifice pre 5500rpm afr's going pig rich just to get them closer to where they need to be up top? Would it not be a better idea to scale back the injectors at lower rpms then open them up on the top end?

 

In a word Zeitronix computer control. Woody

 

I understand calling for more fuel pressure when the car goes lean as per a solenoid linked to a specific reading. But what about the afr graph...how smooth will it be will this activating/deactivating through the gears and on/off of the throttle in real life driving.

The KenneBell Boostapump is $229 and works via increased voltage under WOT, but from what your saying even with the factory pump plenty of fuel pressure is available you just have to increase it. Do we even know what the max safe fuel pressure is for our stock fuel system and injectors. Im sure it all has a rating before something fails.

 

Thats the art of the thing, its taking time to get it all sorted out, and will operate within 10% of the stock pressure as I see it, possibly less. Woody

 

Don't know,did feel the need to test it. The SL55 pump info was given to me from SLK32. It was installed in his car by AMG. It solved his issues and it solve mine. We both ran at about 14.1-14.5 afr up top. We both corrected our AFr's to 11.5-11.7. So as far as I'm concerned I'm done my fueling issue is corrected and LET also stated there was plenty of fuel left if I did additional mods down the road.

 

You're running a 181 and the SL airboxes though. Us guys running a 185 and dual NW intakes are seeing more boost and even higher AFRs above ~5500RPM.

 

Worked on a couple of our cars too. Pretty straight forward.

Something everyone needs to remember is that these cars are not immune to all the things that work for other cars. Fuel pumps don't pump enough, injectors don't flow enough, lines can't hold enough, just because its MB doesn't mean these rules don't apply. The easiest fix is usually the best. In this case a larger fuel pump/injectors works. Stock injectors are fine to very high levels IF you add a larger pump.

 

I am 95% sure I will go this route Dave. With the SL55 and the BAP there should be zero problems. As much as I give Woody and Rob credit and would love to support their product, I just cant justify the $1000 it will cost me for the mod. I do not have a zeitronix and have no plan on getting one.

 

Yeah, Im only a 178 and duals and im lean. Can't imagine with the 185 and duals what you guys are seeing!

 

Sheldon, I don't know what to tell you. I never had 20.1 afr. To me this implies another problem. I would first have the injectors flow tested. Next I would check the rail for some sort of blockage and I would also change the fuel filter and check the FPRV. I disagree with Woody on this point. I don't feel more pressure is the answer I feel more volume is. Too much pressure is just pissing back into the tank as it opens the relief valve. Volume is what is necessary. Lean is not enough fuel, higher volume pump means more fuel and no lean condition, worked for me and others. Pressure and volume do not go hand in hand.

 

You don't need bigger injectors to make this work. I've seen the data and our stock fuel system has enough headroom. It just needs to be tweaked and easiest isn't always the best.

 

SL55 boxes are flowing just about the same as NW intake plus I have a Highflow exhaust with about zero restriction. If you don't think it works don't use it. SLK32 runs stacked and NW Intake how come it worked for him??

 

Sounds like you already have it figured out so what is the answer??