FG Fuel pump testing

[ratter]

We quite often get asked about fuel system upgrades on FG as well as other models but this is about FG so will stick to talking about this model.

It has generally been accepted by most, that the stock FG XR6Tand G6ET fuel pump will flow enough to meet the demands that the standard turbo can require when running on 98 octane fuel, no matter what injectors are used.
We, as well as other tuners have seen dyno numbers around the 320 rwkw and still maintaining a good air fuel ratio, in fact Bels G6ET has been making 315-320 rwkw with a lambda of around .8-.82 no matter which injectors have been used, so the fuel pump appears to be keeping up with this flow. Any other FG’s we have seen with bigger power have normally had a surge-tank fitted so information is not relevant to this discussion.

Ok, based on this information we have to assume the stock pump is good for 320 rwkw+
Correct?

No!
Rule number 1.....................Never assume

As some of you already know, we recently purchased a fuel module for our dyno. This gives us the ability to check fuel pressure and flow in both the fuel feed line and the fuel return line whilst carrying out a dyno run. It does a lot of other things as well but these are the 2 that affect this outcome but one other thing worth mentioning is it will measure the ethanol content of the fuel being used and record it.

The reason we get into the feed and return lines is, these cars run a return style fuel system, by recording the fuel flow in both directions, we can actually see how much fuel the engine is using. If we just measured the feed line all we would know is how much fuel has passed the sensor. In a good system there should be some flow left in the return line which would mean the fuel system is not being maxxed out for the power level recorded.
I had some time the other day to do some testing, so I connected up the hoses and did a run.

I have chosen to show the dyno run in this case and include the lambda reading and injector duty cycle as recorded, not guessed which is what some have done in the past



Except for the injector duty cycle reading in place of the Manifold pressure reading, everything appears good.

Now if I show the same run, but display fuel flow in the feed line to the rail and fuel flow in the return line to the tank we start to get an idea of what is happening in the fuel system.



Now what we can see here is the amount of flow going into the fuel rail and then the amount of flow in the return line. Notice on the return line that the amount drops lower across the run indicating the amount of fuel being used by the engine, also notice how at around 4400 rpm it drops to zero. This shows that the fuel system does not meet the demands of this power level, whether restrictive filter, pipes too small or just pump not flowing enough fuel. On this car I know the filter is good, we also know from other cars that the fuel pipe size is up to the job so the only thing left is the fuel pump not flowing enough whether faulty pump or just too small.

Now there are 2 ways of correcting this, one is to increase the injector duty cycle if they are not maxxed out, this will open the injectors longer allowing fuel to flow for longer as the fuel flow/pressure starts to drop. Increasing injector duty cycle may lead to a motor leaning out as the fuel pump flow diminishes with age as they do and maxing injectors can lead to injectors running hot and in some cases injectors do not flow as much at 100% as they do at slightly lower duty cycle ranges
The other, and correct way is to replace the pump with a pump that is adequate for the job.

Having the ability to test the fuel system has shown us that the FG pump is not as good as we once believed and somebody contemplating 300+rwkw really should consider a replacement pump.
Yes we have done and seen many FG’s making good power and good AFR’s but now we have actual data of what is going on.

The above situation is probably more vital on E85, we recently tested Arvo’s 400+rwkw Tornado, we found his single 044 would not keep up and he decided to replace it based on this information, but there was already a little doubt about the operation of the pump as it was purchased 2ndhand.
Another interesting thing with Arvo’s car was we tested theE85 with a test tube type tester and got between 91-93% ethanol content, bu this gauge in the car showed 85% and our dyno gauge showed 84.9%

A wise man once said “information without data, is just an opinion”

[Herrod Motorsport]

Good report mick ! I am a great believer in fuel flow checking .

[russellw]

Excellent work - it's always good to have theory backed by solid data and that made an interesting read.

Cheers
Russ

[rednose]

Kinda makes me think I did the right thing going straight for an A1000 when a lot of guys said it was overkill.

Overkill in a fuel system is something I can live with.

Good stuff Mick, you are an asset to the forum.

[ratter]

Thanks guys for the comments

The A1000 could be an overkill in most cases, but me personally, I would prefer over kill compared to running things on the edge and doing damage

[Stazza_Brendan]

Would be interesting to see a stock pump + 044/surge combo at about 350ish kw tested in the same way. On pump fuel.

[KERMIE DA FG]

good work micky

is 150lts/per hr the expected level of flow for a stock unit at idle?
is there anyway it could be broken down to ltrs/per min at the righer r.p.m?

what would be the expected/safe level of return flow ltrs/hr be?

concidering it was just one pull lasting all of say 5 seconds thats not a very good result,but isnt it a fairly safe "suggestion" that a stock pump is good for a tune only at best on a modified turbo?

intank is usually first thing on the list of mods for most workshops as a safety thing we can definately see why now

good work with making the effort to share this info

[T4ME]

5ltrs+ per hour return would be acceptable imo.

[ratter]

The ltrs per hour can be changed on the dyno or to gallons etc, depending on what you wanted to display, but for this case just divide the ltrs per hour by 60 and you would get the number.

everybody would have a different idea of what is required to be in the return, but the main thing is to have fuel in the return to guarantee the fuel pressure reg is able to control pressures in the rail to the correct pressure to keep the afr correct, it also allows for a little wear in the pump to where it may not pump as it once did

[KERMIE DA FG]

Have u done a test with an up graded intank to see the return line have flow?

Will be intresting to see many different intanks used and to prove wich one can supply and return the best and remove the guess work with wich intank is best suited to the plus 300 kw turbos

[ratter]

No not at this stage

[Dash_XR]

Originally Posted by KERMIE DA FG

Have u done a test with an up graded intank to see the return line have flow?

Will be intresting to see many different intanks used and to prove wich one can supply and return the best and remove the guess work with wich intank is best suited to the plus 300 kw turbos

Stumbled on this the other day, points out a clear winner between the Bosch and Walbro.

http://realstreetperformance.com/sto...on-test-5.html

[GTBenny]

There is a bigger and better 400lph intank Walbro available now.

Benny.

[Foylema]

Good Work

[05_ENFORCER]

Originally Posted by BABenny

There is a bigger and better 400lph intank Walbro available now.

Benny.

Just got two delivered yesterday


.

[GTBenny]

Got one for the GT myself.

Benny.

[Theo@BluePower]

Good work Mick, nice explanation for the masses.

[STINKY NINJA]

Ratter,was the stock fg pump the original one from the factory?
If it was,do you think a new stock pump would be any better

[ratter]

my testing was done on my Wifes G6ET which had the factory pump in it still and only 16 k on the odometer so would have been in good condition still

[ratter]

This is still current and correct information that many have not seen, so reporting it is a bit of a silly move don't you think?

[STINKY NINJA]

Originally Posted by ratter

This is still current and correct information that many have not seen, so reporting it is a bit of a silly move don't you think?

If this post is for me im not sure what you mean,i only just asked about the pump?
Has this post been reported for some reason?
If it has it wasn't me.

[ratter]

No mate not directed at you at all, it was reported by another member as a thread mine.

I'm glad you brought it back up, some newer members might learn from it

[STINKY NINJA]

No probs, like you said,this info is still very usefull and relevant,it was another helpfull member in the turbo section who alerted me to this thread which I personally have found very enlightening and helpful.
I guess you cant please anyone these days...

[QIKESP]

I only re-linked an interesting thread over to the turbo section that I thought may be helpful to other members that may not have seen it. It's rare that someone takes the time to document that kind of testing for the benefit of others.
If I have offended you by re-posting the link, my apologies.

[ratter]

I'm not offended at all and are flattered that people want to pass on the info, another member reported the thread

[shoogyboom]

Just wondering what in tank pump people are recommending for 320+rwkw?
Not looking to go above that at this stage but doing cooler, exhaust and retune and was thinking may as well do pump while we are at it.
Thanks

[GTBenny]

A Walbro 460 will do the job and give you plenty of head room.

Benny.

[Qik6]

Hi guys this a question for ratter or anyone else that has done any testing or even knows is the fg f6 pumps are the same as rhe xr6t in flow and also does anyone also know what the std fg f6 injectors can be taken to in rwkw.
Also love the graph on real world flow figures on the pump.

[99AUXR]

Ford list same Part number for XR6T/F6 Fuel pumps.

[Qik6]

Thanks 99auxr do you know about the injectors.