Bosch Vs Walbro

[SirRacer]

Was just interesting in getting some educated opinions on what is the best brand of fuel pump or in my case the one that will work.

I should be running around 350rwkws and are looking at the moment to buy one for my cefiro. I want to run a nice simple internal setup as i enjoy boot space.

The Walbro seems to flow more compared to the bosch 044 and is cheaper but most serious racers use a 044. Was wanting to know why and what is the difference.

Cheers

[Silver_r33]

Do a search champ, this has been discussed numerous times, including graphs and flow numbers.

[FOG35]

bosch every day of the week except wednesdays.

[sl33ek]

I chose bosch too but I'm not planning anything near 350rwkw so I went with 040

[chrissso]

I got a walbro as they fit better and I have only 200rwKW. - happy

Bosh will flow more. do a search - there are heaps or thread about the flow rates. bosh flow is rated at 12 volts where walbro 255l/h is at 15v. Therefore at 15v, the bosh will flow more.

Thats the gist. You will have to search for more acurate data.

[Al]

Don't only look at flow rate, even though the Bosch is actually better.

Rail pressure is also VERY important, and i have seen the Walbro fail to deliver with high powered set-ups.

Go with Bosch!! They are noisy but you'll get use to it

[Cubes]

The Walbro's are fine for low rail pressure low boost situations, as soon as you wind up the boost the fpr compensates rail pressure (base fuel pressure + boost pressure) as a result the walbro's flow drops substantially.

For example..

Base pressure @ 40psi + 18psi boost = a total rail pressure of 58psi.

Should you decide to push your injectors a little harder and run the base pressure @46psi + 18psi thats 64psi.

Now compare flow rates between the walbro and bosch items and see why walbro's suck.

If you are indeed running ~350rwkw then you will be running quite a lot of boost, you WILL want to replace all your fuel hose with nice high pressure gear, I've recently replaced all mine with 300psi hose + new efi hose clamps.

[SirRacer]

The Walbro's are fine for low rail pressure low boost situations, as soon as you wind up the boost the fpr compensates rail pressure (base fuel pressure + boost pressure) as a result the walbro's flow drops substantially.

For example..

Base pressure @ 40psi + 18psi boost = a total rail pressure of 58psi.

Should you decide to push your injectors a little harder and run the base pressure @46psi + 18psi thats 64psi.

Now compare flow rates between the walbro and bosch items and see why walbro's suck.

If you are indeed running ~350rwkw then you will be running quite a lot of boost, you WILL want to replace all your fuel hose with nice high pressure gear, I've recently replaced all mine with 300psi hose + new efi hose clamps.

so an 044 in tank will do the job nicely. what is the approx cost of fuel lines to replace my standard ones.

[R31Nismoid]

you wont need to replace stock lines

GTR's over 400rwkw use the stock lines, R33-t are no different.

I ran the factory lines in mine, 330rwkw, and will be doing so again with my RB26, 330rwkw approx

[Cubes]

so an 044 in tank will do the job nicely. what is the approx cost of fuel lines to replace my standard ones.

Not fuel lines, fuel hose.

10yr old fuel hose cracks, becomes crunchy and is not terribly safe to be pushing close to 70psi worth of fuel pressure through.

Ring around fuel hose varies considerably. Right up to $30-$50 per meter.

[Craved]

i replaced all my hoses too, cannot harm anything.. bit of piece of mind..

left overs are good for fixing split water hoses too

Edited March 23, 2006 by Craved

[SirRacer]

thanks for the information guys, has been a great help

with my power levels (hopefully) will i need to even consider running a surge tank or will my bosch 044 do the job?

i dont plan on really circuit racing the car (engines going in a cefiro) but will be attending the occasional drag event.

[chrissso]

so an 044 in tank will do the job nicely. what is the approx cost of fuel lines to replace my standard ones.

AFAIK Bosch 044 is external.

Bosch 040 is designed internal.

Although you could probably run either in either situation.

not an expert.

[Busky2k]

You gotta get the "high pressure" version of the 255L/h Walbro. Then that thing can really power through high pressures, as good as the 040 easily. If its not the high pressure version, then its not as good.

Personally I'd go bosch. I just hate the noise though..

[MerlinTheHapyPig]

i've been using walbro gss-341 "high pressure" 255l/hr pump for last year, no problems at all.

Still using stock wiring, so I'm going to upgrade this at the next chance, but the pumps been going strong for 12 months daily driven / drifted roughly once a week.

there were a lot of fake walbro's floating around on the market, it seems to have given them a rather bad reputation...

[Cubes]

I think the main issue here is 350rwkw.

I'd use it as a lift pump for my external bosch.

A few tips to keep the noise down that I know some of you already know.

1. Rubber mount the thing.

2. Run a dedicated feed fromt he battery activating via a relay.

My external bosch pump has always been rubber mounted, cool days it was fine, only a slight buzz that I would consider to be as loud as a VS 5ltrs fuel pump.

Nothing could be heard inside the cabin only out side.

Roll along the hot days and the thing would become so noisy it would send a type of vibration through the floor pan driving me insane.

I rewired it to receive full voltage, this made the pump sound as if it was spinning noticably quicker, the best part was the noise/vibration is now gone, even on hot days I can't hear the pump inside the cabin, outside who cares.

[SirRacer]

I think the main issue here is 350rwkw.

I'd use it as a lift pump for my external bosch.

A few tips to keep the noise down that I know some of you already know.

1. Rubber mount the thing.

2. Run a dedicated feed fromt he battery activating via a relay.

My external bosch pump has always been rubber mounted, cool days it was fine, only a slight buzz that I would consider to be as loud as a VS 5ltrs fuel pump.

Nothing could be heard inside the cabin only out side.

Roll along the hot days and the thing would become so noisy it would send a type of vibration through the floor pan driving me insane.

I rewired it to receive full voltage, this made the pump sound as if it was spinning noticably quicker, the best part was the noise/vibration is now gone, even on hot days I can't hear the pump inside the cabin.

ok so you would reccomend the standard pump flowing into a surge tank and then a big bosch external going from there to the engine?

ill also rewire it so it gets a few more volts. is it possible or advisable to run an internal pump at these power levels. id just rather have one as its a bit more discreet + i like carrying spare tyres with me

[Cubes]

Keep plenty of fuel in it and you won't need a surge tank.

I'm not going to run one as it never sees the track due to my poor full time Uni finances.

I run the standard r32 pump in tank which is very tired, I then run the external bosch that is rubber mounted inbetween the diff and petrol tank underneath the car, so nothing can be seen from the boot.

I've ran a nice 8ga ( I think it was.. ) cable from the battery to a nice big fuse in the boot that then continues on to a relay, the relay is triggered by the origional wiring that has been snipped from both the intank and external. I then run the 8ga wire from the relay to the external pump, the intank pump wire is spliced in to the + feed.

I've then ran a nice 8ga wire from the external pump to the internal fuel pump (spliced once again) then earthed it via the chassis.

All the parts were grabbed at Jaycar.

I posted my results of measuring voltages on this forum some time ago, I believe before the wiring mod under load the fuel pumps were only seeing 11.2v. After.. They see the full alt charge that is 13.8v when warm or 14.2v when cold.

[Craved]

rewired mine very similar to Cubes,

only im running mine with separate relays for each pump with their own power feeds to and from the relay.

std R33 pump filling the surge tank, then 044 feeding the engine.

i do take it to the track, hence my running it this way.. all the tank and lines are up on the shelf above the fuel tank, with the battery moved to the side of the actuall boot.

[supadan]

just one question it is a bit off topic but hay.

i have a r32 gtst and the fuel pump is realy noise out side the car. all i know is that it is a stock one should the stock one make noise????

thanks