Fuel Injectors

[Guest robbrugg]

Has anyone replaced the injectors with aftermarket?

 

Dyno results?

[antonio carroccio]

Should we?

[Guest davidb]

I replaced the fuel pressure regulator on my bmw r1100s. boosted from a 3.0 bar to 3.5 bar using a regulator from a bmw k1200. Higher pressure allows more fuel to be sprayed at the same time pulse.

[al_roethlisberger]

I replaced the fuel pressure regulator on my bmw r1100s. boosted from a 3.0 bar to 3.5 bar using a regulator from a bmw k1200.  Higher pressure allows more fuel to be sprayed at the same time pulse.

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I thought about doing the same when I had the original external fuel system on my '02, and was doing the project relocating my fuel pump to combat vapor lock.

 

Thread: 3.5 Bar Fuel Pressure Regulator - A good idea??

 

After some conversations such as noted in the thread above(and on Wildguzzi), I was counseled that although it will deliver more fuel across the map, it is at best a "gross" adjustment to the map. And at the worst, it would require a much faster cycle of the injectors if one wanted to actually tune it back in-line to maximize performance/efficiency, which may be detrimental to the longevity of the injectors and fuel system. Bottom line, I was recommended to stick with the specified pressure.

 

However, one alternative to address the potential issue of the stock regulator not quite giving a true 3.0 Bar, was to purchase the Evoluzione(www.evoluzione.net) adjustable fuel regulator kit. This kit allowed one to add an adjustment screw to the back of the OEM pressure regulator to dial-in the desired pressure, up or down.

 

Unfortunately Evoluzione doesn't market Guzzi accessories any longer, but the kit for the MG is the same as supplied for the Aprilia and Ducatis they also had a kit for. So I suspect that if one specifically requested the kit, it could be made available. Ask for Ken Zeller.

 

Of course, if one does still want to go with a 3.5 Bar regulator, one can simply change out the cartridge, as available from Weber.

 

See this thread: Source for our external fuel pump thread

 

The regulators are available here: http://www.redlineweber.com/html/fuel_air_..._regulators.htm

 

The blue "billet" regulator at the bottom of the page uses the exact same cartridge as our OEM unit, so all you have to do is purchase a 3.5 Bar replacement/spare cartridge from them. This is about $40 if I recall.

 

And if you do convert to larger injectors, to maintain the correct spray and volume, you probably will need a higher pressure regulator.

 

 

But once I converted to the 03+ in-tank system, documented in the 2003 Retrofit Thread, I no longer needed the external regulator, and spare catridges. I actually have a 3.5 Bar cartridge or two, a couple of the "billet" regulator bodies, and if anyone is interested the whole external fuel pump/regulator system as well.

 

al

[Steve G.]

I've ridden alot of bikes with fuel injection, and as far as I'm concerned, the Marelli EFI on these bikes is as good as any. Unless you have money to burn, what are looking to achieve?

Ciao, Steve G.

[Guest davidb]

The higher pressure was a good hp gain on my beemer. A few racers on the pelican parts r1100s forum had done it too with dyno results. bmw has a habit of very lean running coupled with surging and back rumbling. It was a good fix for me. My guzzi is already running slightly rich even with my custom stainless exhaust and ram air system idea I stole from the jap bikes. So I have no intention of boosting the pressure on it.

[luhbo]

How about using smaller jets/nozzles combined with higher pressure (and probably some map adjusting)? I think this could result in smaller droplets to make vaporising easyier. Here in Germany someone is selling a different system together with custom manifolds. The spray nozzles are pointing in a different direction. Not towards the valve but instead under the throttle blade. They promise improved responsivness especially under part load conditions. Experimenting this direction will satisfy you probably more.

 

Hubert

[O2 V11]

My guzzi is already running slightly rich even with my custom stainless exhaust and ram air system idea I stole from the jap bikes.

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Any chance of a posting a pic of your mods?

Rob

[JuhaV]

Hi all,

 

I made some fuel pressure measurements in my Sport 1100i and they showed that I seem to be running slightly low with original regulator: 2.8 bar instead of spec 3.0 bar.

 

During the winter I will install an adjustable fuel pressure regulator and do some testing in the pressure range 3.0 - 3.5 bar. I have fully adjustable My16M ECU so it is easy to match the map with the modified pressure.

 

I think that raising the pressure from 3.0 to 3.5 bars should not create any leak problems etc, because this change is anyway reasonably small. There should be larger

safety factor than that build into the fuel system components.

 

I'll have an pressure gauge installed permanently in to the cockpit so I will be able to monitor how the fuel pressure behaves in different driving situations. I am especially interested to see if there are any pressure drops at full throttle. My first experiments with the gauge showed something like this, but because those were made revving the engine at neutral and not driving on the road, I'll need to make further tests on the road to check this out.

 

If there are any fuel pressure fluctuations, it will be quite hard to create a "perfect" fuel map, at least without any kind of closed-loop control. By the way, I believe that the lambda-probe response time is in the order of tens of milliseconds, so closed-loop system is capable of correcting very fast phenomena. This means that closed loop, if correctly applied, can help also during accelerations, not only during steady state riding conditions.

 

br, JuhaV

[Guest davidb]

Rob, I have posted this somewhere before. Most owners go with the open air box, I prefer the forced air box.