Jump to content
SAU Community

Recommended Posts

My figures are based on injector flow at that power for correct air fuel ratio, with zero fuel returned to the tank absolutely flat out.

This might not be a good idea, but it is the theoretical absolute maximum limit for the whole fuel system and pump.

A fuel pump supplier might not feel entirely comfortable with this though, and specify the pump at a power level that allows 10% fuel return or some safe margin as a design centre figure. These days they could get sued and be liable, if a particular pump falls a wee bit short of any published specification.

So there is going to be a gap between a safe design figure, and absolute possible maximum.

Hi Zombie, did you read this on the Bosch web site................

"Bosch Fuel Pumps have their flow rates defined in N-Heptane as part of their engineering specification. N-Heptane is a pure chemical and does not have the same viscosity and density as standard petrol. Hence the N-Heptane flow rate figures stated should be used as a general guide for comparison purposes only."

and

"Operating voltage = 12v, test pressures indicated are also suggested maximum operating pressures."

So to use the 044 as an example:

^ at zero pressure using 13.8 volts, it flows 330 litre of Premium unleaded petrol, as per the table.

^ at 5 bar (73.5 PSI) of resistance using 12 volts, it flows 200 litres of N-Heptane as per the Bosch reference.

The reason why I quote 330 litres is, that is what they flow when you test them in the car with no resistance. Warpspeed’s method, although ultimately more accurate for assessing the flow of the whole system, is a bit tricky to use at the race track. So if I have a suspect pump, I can check it by quickly disconnecting the hose at the tank and checking the flow. It has been my experience that when a pump fails (or is failing) it shows up in the free flow test just as well as it does in a resistance (pressure test).

It is worth noting that the hoses from the pump have enough resistance (although quite small) for the pump to work against. In some applications with really large fuel hoses this may not be the case.

Plus as Warpspeed says, there is a difference between the rated flow of the pump and what they actually can do. The manufacturers are conservative by as much as 5% in my experience.

Hope that answers your question.

Hey I just realised, doesnt the skyline have a variable voltage fuel pump? So at idle, the pump wont be running at full bore, so that Warpspeed technique wouldnt be accurate would it? I know for a fact my 200SX doesnt, but yeah...

Hi Busky2K, I wouldn't run an 044 using the standard wiring, it won't handle the current drain. We use the standard wire as the switch on a relay and run a separate power supply from the battery that is capable of handling the 044 current requirements.

This is always a very good thing to do with any major pump upgrade.

Power for the stock pump will come via the ignition switch, and at least one relay, and other assorted crap. These circuits have other loads as well as just the pump, so the voltage drop at the back of the car might be a lot more than you expect.

Rewiring the whole lot is not a practical option. Sydneykid has the right idea (as always !). Use the original pump power wire to energise a pump power relay located at the back near the pump. Then run a really big fat cable right back to the main fuse-box.

The variable pump speed feature will then not work, and you might end up with a noisy pump, but perhaps not if you take special care in mounting it.

But even if you do nothing else, check the voltage right at the pump, it makes a vast difference to pump performance.

Another thing you can do that might not appeal to everyone, is to fit a second pump in series with the stock pump, and leave the stock pump as it is. The second pump relieves the in tank pump of just about all back-pressure, and it will then flow far more, getting twice the flow this way is not unexpected.

The second pump can be in the engine compartment, and hang by its rubber hoses, so there will be no extra noise. Also there are more volts at this end of the car if you use a pump relay as described above. You can even see and get to the damned thing as well.

I am not suggesting this is any better, just different. It certainly works, is easier to do, and it is something else to think about.

Im also chasing 200rwKw and right now I have my eyes on a Bosch910 pump

I read on previous threads that these arent recommended to be mounted in-tank

What kind of problems would I have if I tried to mount it using the standard brackets?

i.e. replace the standard in-tank pump completely

Has anyone mounted a 910 before? What's the average price on 910s nowadays anyway?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • For these last 7 years of ownership, I've always had to use a small scissor jack under one of the front tow hooks to raise the front just enough so my low-profile jack fits under to reach my subframe jack point. I'm beginning to get annoyed of always having to do this. Are there any lower low-profile jacks that fit under the gtr lip on a dropped car?
    • Seat of the pants assessment of the new intake: The car is way less "doughy" when hitting the loud pedal, especially off idle when stopped or in traffic, I did use a cheapo lazer thermal thingo to measure the temp around where the pod filter got its air, it was between 55 - 60°C, in saying this the car was shut off and not moving, so the OEM intake pipe was not supplying any fresh air to where the pod was when the car was at least moving A weird bonus was induction noise on the throttle in the cabin increased a bit,  I was worried that I was actually going to lose some of that induction noise I love so much, outside though, when I got the daughter to do a WOT drive by pass for me, the induction noise has increased alot when on the throttle, not quite ITB doort, but well up there I'm extremely happy with the results and have been exploring the country roads in the region  As for house mods: 1.New front fence is up and is awesome, it really upgraded how the joint looks from the street, and the added security is nice 2. Electricians have replace some interior lights, and with more lighting in the garage, a few new motion detecting lights out the front above the garage, front room, and at the front door, which I have already found heaps helpful coming and going, also now has fancy pants CCTV all round the house The only hold point for power though is the solar and batteries due to supply issues, although this will happen over the next few weeks 3. I have done a heap of landscaping out the front and I'm almost ready to do a new small retaining wall with some nice blocks to replace the brick and cemented in rocks around the raised garden beds cemented in river stone "was the fashion at the time" the house was built. I currently have a pallet of retaining wall blocks and 2 bulka bags of 20mm blue metal to replace the wood chip that is in the raised garden beds around the house 4. I now have 3 big raised garden beds for out the back to grow some vegetables, about 70cm high, 200cm long and 100cm wide 5. My 2 compost bins are already pretty full with brown, green and kitchen waste from the landscaping I'vedone so far, but they will probably take a few months to break down, so anything else that gets chopped, trimmed, and kitchen waste will just start filling the base of the raised garden beds to about 30cm before I start throwing 40cm of good compost, and stuff, for the vegetables to grow in, I'll need a few ton of compost and soil, but the local supplier can sent me bulka bags of the stuff Basically the logs, wood chips and a few strategically placed rocks for drainage, will give the beds some good organic materials down low to break down over time, and they will hold moisture during the warmer months to save the water in my big arse water tank if we don't get alot of rain So, all in all, the car and house mods are going well, and I'm really enjoying being retired, I sleep in too 0700 and slowly plod around inside until I feel like actually doing anything, and only work in the yard for as long as want, which has actually been alot over the last few weeks,  although when you look at it, it seems that not a huge amount of work has been done,  until I look at the before I started the work pics Happy days and good times indeed 
    • hahaha yeah. Plan is to get side skirts and probably just rear pods. But going to do them one-by-one. I've got a set that I really like from RHDJapen, but that one isn't shipped to AU. So need to find someone who can get it for me
    • Here's an idea, answer the questions I asked you as they are trying to work out WHY the LSD will be binding up in a straight line.
×
×
  • Create New...