Std Fuel Pump Capability

[gtstii]

Hey guys,

just needed to know how far the fuel pump can go SAFELY!

Is it ok using the stock fuel pump with 12psi and around 190 - 200rwkw's?????

thanks fella's

[gtstii]

ok, before you all tell me to go out and do a search cos this has been covered before etc etc....

I found the info i wanted and was looking now at something like a bosch 910

Quote:

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*GTST pump is 135 litres per hour and supports 300 bhp at standard pressure

*GTR pump is 190 litres per hour and supports 420 bhp at standard pressure

*Bosch 910 pump is 200 litres per hour and supports 450 bhp at 73.5 PSI # 0 580 254 910

*Bosch 975 pump is 228 litres per hour and supports 500 bhp at 73.5 PSI # 0 580 254 975

*Bosch 984 pump is 228 litres per hour and supports 500 bhp at 73.5 PSI # 0 580 254 984

*Bosch 044 pump is 330 litres per hour and supports 730 bhp at 73.5 PSI # 0 580 254 044

*Bosch 040 pump is 235 litres per hour and supports 520 bhp at 73.5 PSI # 0 580 254 040

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how much can i expect to pay for this and are they very noisy??

[KamikazeR33]

it actually sounds kool when the pump loads up when u turn the key

[R33man]

I got a standard pump and 192rwkw no worries. I would not go much over 200 though to be on the safe side.

[gtstii]

I needed to know what the main difference is between the bosch 910 and bosch 975???

they flow similar amounts but the 975 is a lot more expensive? Is it true that the 975 is just a newer model?

Which is better???

Which would be quieter???

thanks

[benm]

I got a standard pump and 192rwkw no worries.  I would not go much over 200 though to be on the safe side.

I was using the standard R33 GTS-T pump in my car (1995 GTS-T with standard ECU and Turbo). At 7psi everything was fine but soon as I switched to 12psi my car would surge and cough n splutter (keeping in mind I have no aftermarket computer or fuel computer). I then had a Bosch 040 fuel pump installed (supplied + fitted for $340) and instantly noticed a difference. I can now run on 12psi and its as smooth as running on 7psi just by changing to the bigger fuel pump.

The standard GTS-T Fuel pump is rated at 300bhp and this is brand new from the factory (most GTS-T's are 7-10yrs old). Now 300bhp is approx ~180rwkw (using a 20% drivetrain loss figure which is quite lenient). Now in the last 6mths i've used 3 different Dyno Dynamics Dyno's and have registered 203rwkw, 186rwkw and 180rwkw so I guess its safe to assume that I was maxing out the standard GTS-T fuel pump or maybe some other restriction or pressure was in place. I may have only needed to get a PowerFC and have my car tuned but I know that in the future i'll be going beyond the standard fuel pumps capable limits so it was a cheap and easy mod.

Note that this is only my own personal experience which may differ with other cars or mechanics but I certainly wouldn't be going over 200rwkw on a standard GTS-T pump. I think its often a component that many people forget to think about in their list of mods.

Edit: Having the fuel pump mounted in-tank will muffle most of the pumps sound. With the 040 I can hear it pump for about 5 seconds when I turn my ignition on but as soon as I start my car (even with mp3 player off and windows down) I cannot hear the pump.

[gtstii]

anyone know what the main difference is between the bosch 910 and bosch 975???

[Sydneykid]

Thanks gtstii, saved me posting my fuel pump table. I am trying a couple of Vortex fuel pumps in the new year, I will have to add them once I have solid results.

[Zombie]

Sorry to dig up an old thread.

I have a question regarding the fuel pump pressure table. What is the standard pressure for a GTR or GTSt?

Also what is the pressure value stated with each of the pumps? is it the pressure when they are working at their max? and do other components such as fuel pressure reg and the fuel system on a whole effect what pressure the fuel system can handle?

I hope that makes sense.

Adam

[Sydneykid]

Hi Zombie, Skylines run standard fuel pressure at 38 psi above boost. So if boost is zero then fuel pressure is 38 psi. If boost is 10 psi, then fuel pressure is 48 psi.

The Bosch pumps are rated for their flow at 73.5 psi. So using the 044 as an example, it will deliver 330 litres per hour at 73.5 psi. You could express that as 38 psi plus 35.5 psi of boost. Or 50 psi plus 23.5 psi of boost.

If you run less than 73.5 psi fuel pressure, then an 044 they will supply more than 330 litres per hour of fuel. If you run more than 73.5 psi then they will supply less than 330 litres per hour.

Injectors are normally rated for their flow at around 38 psi, if you have more pressure (using an adjustable fuel pressure regulator) then they will flow more. An example would be if you had 270 cc injectors rated at 38 psi and you used 50 psi they might flow say 320 cc's. This is how you can make a slightly smaller injector flow just a bit more if necessary. I never go more than 10% over the rated flow, as the injectors are more likely to fail and the result on your engine is not pretty.

Hope that helps

[Zombie]

Thanks heaps Sydneykid. Makes it a bit clearer.

So if i were to use a bosch 910, and run say 15psi, the provision of fuel before the injectors come into play would be enough for the rated 450bhp?

Adam

[Sydneykid]

Sorry Zombie I must have missed something, 15 psi is lower than the injectors are rated at so they would flow less than their rating not more.

In a 6 cylinder engine, 370 cc injectors are good for around 370 bhp (275 kw or 225 rwkw or 300 rwhp) at their rated pressure 38 psi (above boost). If you reduced the pressure to 15 psi then they would handle way less than 370 bhp because they wouldn't flow 370 cc at that low pressure.

Hope that makes sense

[sweetr33]

sometimes a splutter when upping boost on r33's shouldnt be pointed at the fuel pump straight away. Mine will do this when boost exceeds 14psi and the finger was pointed at some boost cut thingy. Weird coz i can override it buy keeping it nailed through the gears but once i let the revs drop down and stay in that gear to accelarate quickly it hits this so called boost cut. Hit it on the dyno and the graph was amazing lol. But i just learned how to put on the power and no probs now

[Zombie]

I meant 15psi of boost pressure

[muaythailuke]

Sydneykid, do you know what an RB25DET injector is rated at? Sorry to change subject guys :headspin:

[Zombie]

I was just looking at the bosch website in the motorsport section and it has all the specs of their fuel pumps. The flow figures seem to differ a little from what is stated in the above table posted in this thread.

Here is the link Bosch Fuel Pump pdf

Am I missing something? :freak:

Adam

[Warpspeed]

Your best bet is to actually measure fuel pump flow in the car. It takes into account ALL the factors. Things like voltage at the pump, pressure drop across fuel lines and filter, and so on. Do the test and you will know for sure what you actually have.

Disconnect the fuel return line after the regulator on the fuel rail, and extend the line into a clean plastic bucket or something similar.

Remove the rubber hose between the top of the fuel pressure regulator and the plenum, and feed in some compressed air at whatever boost pressure you plan to run into the top of the regulator. If you have a compressed air supply airline and a spray painting regulator you are set. If you do not, you might be able to do something really clever with the spare tyre and a bit of hose, and a pressure gauge (maybe?).

Anyway, the idea is to fool the regulator on the fuel rail into thinking there is actually full boost pressure in the plenum.

Start the engine and run at a fast idle so the alternator light goes out. The fuel pump will have a higher voltage than with the engine not running.

Using a graduated cheapy plastic hardware shop measuring jug, measure the fuel flow from the return line with a stopwatch. Convert this to cc's per minute. Divide cc's per minute by 5.6 to get horsepower.

So, two litres/minute, is 2000/5.6 = 357 BHP for example

The fuel pump will be working at its normal working voltage, against a back pressure of around 38psi + boost pressure. You can see how good your fuel pump actually is, not what you think it might be.

It is also easy to check on how much improvement an upgrade actually gives you as well.

[Busky2k]

Warpspeed, thats a good way to get a rough idea!!! The best way is to just see how much fuel return there is on the dyno, at full boost at peak power.... but that costs money haha

[Warpspeed]

Sure, there is no substitute for doing it for real on a dyno. But if you know your injector sizes and pump flow are o/k before you put it on the rollers, it is one less thing to worry about on the day.

It is pretty easy to test all this at home, and fix the fuel system in your own (free) time.

[Zombie]

So does anyone know if the fuel pump table is wrong or if there is a proper reason bosch's figures are different from the ones posted here?

Adam