Fuel pump up grade W124.

[optimusprime]

Just about to replace both m103 fuel pumps .I would like to fit one pump instead of the 2 i have at the moment . So is there anyone thats done this mod who knows what type of fuel pump they used and how to go about this . At the moment i have reason to think i am running on just one of the two pumps thats fitted .The one in the picture was fitted to a 3L TD diesel mercedes W124 that reached 181.2 mph .

 

[Bellow]

Don't go overboard on the supply. It will cost you as the excess fuel is needlessly pumped only to be returned. More modern cars use the ECU to control their fuel pumps to avoid this - and the subsequent electrical load which ultimately is taken from the crankshaft and wastes fuel.

 

[optimusprime]

Bellow i have been reading a review on Retro Rides about the Mercedes W124 that the engine this chap built up out of a newer mercedes al;long with a gearbox to fit his W124 nice read .He replaced his twin pumps for a single Bosch 044 fuel pump .But he used it to fuel his diesel turbo 3lt top speed was 181.3 mph see proof and all mods on the RR forum .

 

[Bellow]

Why do you want fuel supply fit for 180mph when you drive on the road at much more moderate speed? You'll just be squandering energy uselessly pumping fuel from one end of the car and back again. Pumping fluids at pressure is much more energy consumptive than people appreciate.
By all means replace the duplicated pumps (but there was a reason MB chose this configuration) with a single, but match it your fueling requirements. Most pumps have significant headroom is any case. A friend has a smart fortwo which originally had 60hp and now has a 185hp Honda Blackbird engine. Still runs from the original fitment fuel pump - and runs very well!

 

[grober]

When specifying a fuel pump there are two things to consider- throput and output pressure. Its also important to take into account what the fuel pump is feeding- the early W124's had the K/KE continuous injection system which relies on fuel pressure to operate. The later cars had the electronic JETRONIC L system which may have a wider tolerance to differences in fuel delivery? The reason Mercedes introduced the dual in series fuel pumps was to combat the formation of fuel vapour bubbles which may be more related to the suction rather than the delivery end?

 

[optimusprime]

For me, the reason i need one pump instead of two is the output of the old sheets or pounds .Why should i purchase 2 when i can buy one to do the same job ???. Simple to me .Not that i need to drive at a fast speed 110 is fast enough .Only done this once . I think old cars should be looked after not abused ..

 

[alabbasi]

You can buy an aftermarket pump for those cars for $40 and an OE bosch pump for $100. Just swap them both out and be done with it. Preferably with Bosch OE pumps and you won't have to worry about it for another 100k miles

 

[optimusprime]

I agree with all your replies .But thats not what i want . I need one pump not 2 .May be the usa forum might come up Trumps ha Trumps.

 

[grober]

Another word for the formation of fuel vapour bubbles is cavitation. Cavitation occurs when fuel is heated or more frequently when its pressure is reduced----lowering pressure causes it to boil at lower temperature than normal- this means the pump is pumping a gas rather than liquid- if the pump relies on fuel for cooling and lubrication it may fail prematurely. The most common cause of pump cavitation is a restricted inlet flow- the pump cannot suck enough fuel so the inlet pressure reduces causing the fuel to boil in the pump. Its why in-tank submerged pumps found in later MB models are a good idea [ except when they go wrong of course!] I know the W124 estates always had a dual pump system with the first pump much closer to the underfloor tank followed by a second pump in the usual position to combat fuel flow restriction. The saloons and coupes had rear bulkhead tanks of course meaning they should have been able to provide a good "gravity- head" of fuel but something caused MB to double up on the pumps- perhaps it was a build up of pump heat after a long time running or maybe for hot climates- maybe it was the best approach with the pump tech available at the time - remember this was a time they built them to last- who knows?

 

[grober]

Your answer may lie here?
fuel pumps replacement ? - 94 E320 coupe - Mercedes-Benz Forum

these guys would probably be able to advise you and supply any plumbing mods required?
Walbro GSL393 Out-Tank Fuel Injection Pump (Pump Only) | Walbro, Facet, Weber, Dellorto & more

 

[optimusprime]

Grober i am old school and i think it will be a pair of new twin Bosch pumps .This job is being done in the garage local to me, and time is £ s p as you know. And with the old system all the pipe work and fittings will be there all but the copper O rings, hope these will come with the new pumps . All of you have made my mind up , and i will stick to stock parts . Just need to sort out the numbers for these now.

 

[grober]

PART NO A0030915301 ?
FUEL PUMP PACKAGE MERCEDES 260 [Car] [CHASSIS] (EUROPA)
Fuel Pump A0030915301 OE Number buy online
Fuel Pump BOSCH 0 580 254 911 Electric buy cheap online

 

[Bellow]

In-tank pumps have the advantages of having their motors cooled by submersion in fuel and, as Grober alludes, much improved cavitation resistance.
When (in a front engine installation) an electric pump is chosen over a mechanical one. it is always sited as close to the tank as possible (when not inside it) as during acceleration the entire suction exposed length of pipe experiences even greater suction created by the inertia of the fuel in the tank.
The biggest problem with cavitation is that the liquid turns to gas in the form of bubbles and when it regains pressure as it passes through the pump those bubbles then collapse violently and cause damage to the components in their vicinity. Cavitation is the bug bear of all who have to engineer fluid systems (from propellors to pumps) as it is extremely damaging.

 

[optimusprime]

Grober thank you for the link its just what i wanted to calculate what parts i need before i get the pumps replaced . Bellow after reading your post i understand more about the fuel pumps and the work they do .