Fuel Pump

[FleetOz]

so I was watching the French grand prix last night and the commentators were talking about how the F1 cars run extremely high fuel pressure (something like 70 bar!) which results in better fuel atomization and of course which leads to more power.

so to my question - is there any merit in the idea of running with a very high performance fuel pump and regulator to deliver greater fuel pressure for my track car? I drive a Nissan 300ZX twin turbo.

Pete

[Peter Mallett]

Welcome Fleetoz

You need a good fuel pump for competition purposes but I doubt if you'd get any benefit from such a high pressure system.

This would be better in the technology forum.

[Tainan]

Also, you might want to consider the cost of increasing the pressure rating of all the hoses / fittings etc on the high pressure side. 70bar (>1000psi) isn't easy to contain - are you sure he didn't mean psi? It could well have been an Allenism!

[zefarelly]

70 bar, at a guess is dangerous ! 1 leak and you have a mobile flame thrower !

facet silver top and malpassi filter regulator seems to do the trick for me

[graham bahr]

70 bar is a very low pressure in the world of diesel but then they used ridgid metal pipes so i suppose an f1 car might use similar,

more likely i would of thought is that they ment 70psi which is still very high in terms of petrol injection, or possibly they were referring to the effective pressure of the fuel leaving the fuel injector nozzle, although i feel it most likely they said bar when they ment psi

[graham bahr]

Originally Posted by FleetOz

so to my question - is there any merit in the idea of running with a very high performance fuel pump and regulator to deliver greater fuel pressure for my track car? I drive a Nissan 300ZX twin turbo.

Pete

no not unless your cars modified, and then only if you cant get big enough injectors to flow sufficent fuel at normal pressures.

my turbo car runs a normal 3bar fuel pressure

[Chucky]

I don't think 70BAR is plausible. Although, the latest GDI systems run at anything from 50 to 120BAR.

I think most of them run at about 10-12 BAR (150-180psi). I've run engines at 8-10 BAR and with the right fuel pumps and it works a treat. You can get away with much smaller injectors which is the big advantage in fuel control. The atomisation is also much better but the enhanced injector control is the big gain.

[maddogf3]

[QUOTE=FleetOz]so I was watching the French grand prix last night and the commentators were talking about how the F1 cars run extremely high fuel pressure (something like 70 bar!) which results in better fuel atomization and of course which leads to more power.

Pete I have always found in motor racing -- never trust what anyone tells you especialy commentators . Teams will say anything to pretend they have an advantage or lead others away from what really is giving them an advantage ( Any one remember the Brabham fan car ) that fan which. happened to suck them to the track was for supposedly to assist cooling of the engine . it went about 2 seconds a lap quicker than anything out there at that time .
If they are using high pressues, then I would be more interested why do they use that pressure or where they are situating the injectors An engine running at 18k wouldn't have much problem with gas speed to atomize fuel at any pressure a bucket would work .
Delve a bit deeper and find out what they really have done

[1200Datto27]

GDI systems run fuel pressures of in the region of 70bar, to ensure that they have a fine atomisation of the fuel in the combustion chamber. This is done by having a electrical fuel pump feeding a mechanical pump.

[goforit500]

Noticed in the just published FIA F1 regs that the maximum fuel pressure allowed is 100BAR - Sort of makes you think that the 70BAR quoted is right....

[maddogf3]

Originally Posted by 1200Datto27

GDI systems run fuel pressures of in the region of 70bar, to ensure that they have a fine atomisation of the fuel in the combustion chamber. This is done by having a electrical fuel pump feeding a mechanical pump.

excuse my ignorance but what is GDI system ?????
This is what I was on about, using this higher a pressure, is normally only needed to atomise in the combustion chamber not outside and then you dont need sparks which then becomes a Diesel .I know someone who works for Mercedes Ilmor I will try and find out what is happening off Ian

[graham bahr]

GDI or FSI if its vw audi,

direct injection of fuel into the cylinder

[maddogf3]

Originally Posted by graham bahr

GDI or FSI if its vw audi,

direct injection of fuel into the cylinder

Thanks again Graham
Thought you might like to read this from my mate Ian at Ilmor

"70 bar sounds somewhere in the ballpark, I'm sure that some people may run even higher.
One of the main problems with an F1 engine is getting the fuel and air mixed together well and burn in the time available ( 1 rev is 0.0033 sec at 18000 rpm ). Most engines give increased performance if the fuel is injected in a quite small window of crank angle ( typically around 100° ), this equates to the need for a very high flow rate injector to supply the required mass of fuel in this time. By increasing fuel pressure then the flow rate of the injector is increased. Also raising fuel pressure results in smaller fuel droplets from the injector which helps the atomisation and combustion processes. Once you start running at these pressures then there is the potential to start doing clever things that boost performance - I probably can't discuss exactly what this is!
The injectors used are very similar to road car GDI injectors ( which also run similar types of fuel pressures )."

Well there you have it -- I think that answers everthing ,I only wish I new all that !!!

[FleetOz]

some very good information there!

Cheers
Peter

[maddogf3]

Originally Posted by FleetOz

some very good information there!

Cheers
Peter

Dear Peter, how about this ,
Ian sent me this
" F1 design. Valvetrain is critial part of engine - basic layout is 4 valve, DOHC, finger followers, pneumatic valves, hollow Ti valves. There are huge loads on the whole system and cams and followers have some trick coatings to make them live - cam lobes have been known to come out blue from the heat generated. A big problem with the valvetrain is torsional vibrations, some special dampers are required in the geartrain to smooth this out.

Pistons are also a weak link in the engine, bore sizes are getting bigger ( FIA imposed limit for 2006 is 98mm bore which gives stroke of 39.8mm if my maths is correct ) which means the piston is getting structurally weaker. The actual combustion pressure in an F1 engine are not that high ( probably less than an F3 engine! ), it just has a lot of events per minute. Pistons are still Ali ( Berillyum being banned a few years back ). The characteristic of ali is that its strength reduces very quickly at temps above 150-200°C so some very special alloys are required to make pistons survive at the 250-300°C they run at. The engines have elaborate squirt jets that spray oil on them to try and keep the temps down. Other piston related issue is control of the rings ( 2 rings only, one compression and one oil control ). Due to the high speeds they can 'flutter' which reduces sealling and increases friction, careful design of the ring profile, coating, piston ring groove, oil etc are required."

Well that about cover most of your questions. think you need 1 million pounds plus to use a 70 bar fuel pump on your Nissan Turbo
Best Regards Martin