4.5 litre v8 landcruiser correct fuel flow rate

Submitted: Tuesday, Jan 29, 2013 at 23:30
ThreadID: 100250 Views:11554 Replies:4 FollowUps:5
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G,day to all. can anyone help me with finding the correct fuel flow rate for the 4.5 v8 landcruiser . any reading material or correct info appreciated.
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Reply By: baz&pud (tassie) - Wednesday, Jan 30, 2013 at 06:46

Wednesday, Jan 30, 2013 at 06:46
Google fuel consumption of landcruiser or go to the Landcruiser owners website, you should be able to get the info there.
Go caravaning, life is so much shorter than death.

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Reply By: Ross M - Wednesday, Jan 30, 2013 at 10:21

Wednesday, Jan 30, 2013 at 10:21
G'day fairdingkum
It will be difficult to find the flow you want to know. It isn't clear why you want this info at the moment or what situation you are trying to cover.
However, There are a few situations to be aware of
1. The "normal flow" of regulated pressure through the system when you switch on the ignition and the pressure pump flow and makes full reg pressure. This goes back to tank.

2, The additional flow which is created after the engine is started. ie at idle.

3.The flow which is supplying the engine at road speed ie more than idle usage and possibly 15litre/hr or more.

4. The instantaneous flow rate which varies wildly with the application of he right foot.

So, you can calculate the usage rate per hour from the consumption figures while driving.
If you remove the diesel return hose to the tank, you can run the engine for 10 seconds and the fuel delivered to the bucket x6 will give you the idle regulated flow per minute and therefore per hour. Some allowance for the under load usage will need to be factored in.

Adding the driving usage rate to the return to tank rate, you should have a fair idea of what really goes on and have an answer to your query.

PS Possibly a 4wd diesel repair shop or perhaps maybe Toyota dealer may be able to give you some idea. Just don't expect too much from them though.
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Follow Up By: fairdingkum - Wednesday, Jan 30, 2013 at 11:45

Wednesday, Jan 30, 2013 at 11:45
G,day Ross thanks for your Reply .Mate the reason Im after the flow rate I have read so many opinions on fuel filter micron selection for a second filter. Some say to fine of filter RE-2 micron can starve the injector pump causing cavitation overheating it .The pump also requires ample fuel flow to cool the pump and fuel threw return . By basics v8 cruiser sitting on 100 clicks uses approx 10-15an hour depending on load so youd think a filter with 170 lph flow rate would be fine .the problem is when the filter start to block up the flow rate and pressures change thats whats niggling at me is this change going to be enough to cause damage to enjector pump ect threw loading it up trying to get fuel becuase of starvation .One fella on another forum quoted 60 litres per minute requied for fuel usage cooling and return ,3600 litres an hour or 18 - 44 gallon drums an hour its a strange world .I just want to get the correct set up without haveing to worry about causing another problem down the track .I have read many good comments of Mr funnel butt planning to do the big one arrond oz so need to get it right .I will ring toyota but we all know what thats like all the best .
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Follow Up By: Ross M - Wednesday, Jan 30, 2013 at 12:50

Wednesday, Jan 30, 2013 at 12:50
These are things I am aware of.
The OE filter should be sufficient for the vehicle re micron size so the addition of a second filter actually makes it the additional filter the first filter after the tank

An Isuzu Dmax flows flows around 35 litres/hr and has a filter which can handle aorund 70 litres/hr Isuzu figures with a fuel reg pressure of 6 to 7psi.
Your engine is 50% bigger and so can use proportionately more flow rate and fuel usage.
A very fine filter ie 2 micron is wonderful to have but it has to be very large indeed so as not to restrict the normal expected flow rate when it becomes a bit blocked with"stuff".
Although you can fit one of these fine 2 micron filters you may be changing it every fortnight. Not cost effective. It also should dewater the fuel as much as possible because that will damage things before the crap gets through any filter.
If you fit a pre filter which catches contaminants and dewaters and also has a micron size of 5 to 10, then it will remove all the" blowfly" sized particles and whatever gets through that will then be filtered by the OE filter. This leaves the oe filter to do only a small cleanup job and not the pick and shovel work.
Therefore the pre filter has to be of appropriate size in filter area and dewatering performance.
As mentioned recently, I use a P902976 Donaldson filter kit for mine which has a flow rate of 114lph. Two of these paralleled will give128lph and a slower fuel passing through rate and a lot of filter area to catch crap and far greater ability to dewater than just one filter. This also ensures negligible restriction to the ultimate flow rate the pump can produce while maintaining filtering and dewatering before the OE filter.
This leaves all original water and restriction sensing still operational as normal.
There are other filter setups available but most are three times the price too. Nothing is perfect but having something is insurance.

If you can eliminate some of the water by a Mr Funnel before it hits your tank, then that is more insurance, but it doesn't stop emulsified water in the fuel at all so the dewatering + filter is handy to have.
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Follow Up By: olcoolone - Wednesday, Jan 30, 2013 at 14:20

Wednesday, Jan 30, 2013 at 14:20
Standard filters in CRD engines are a 2 micron filter and are quite small.

The thing is running a filter before the main filter will only make the original factory filter last a bit longer.... it will not offer any better filtration

There is no real benefit running a pre filter other then stopping big particles before they get to the main filter...... it's not going to save an engine or make it last longer.

The factory 2 micron filter have a very big filter area in a small package.

The biggest problem with CRD engines is water, water becomes very abrasive especially under extremely high pressures, this is what causes damage to the mirco finished surfaces.

A water trap filter would be a better investment and I would highly recommend it.

In a CRD engine if you had restricted flow from fitting a too smaller filter more then likely the factory fuel filter restriction light would come on...... it's not going to over heat or wear anything out if it is restricted and Im sure if it was that restrictive you would find it very hard to drive the vehicle with it's lack of power (that's if one was a stupid to ignore the filter restriction light).

We have driven 1800 kilometers with the restriction light on and with no loose of power.

Classic example of over engineering resulting on zero improvement or gain.
FollowupID: 780363

Reply By: Racey - Wednesday, Jan 30, 2013 at 10:28

Wednesday, Jan 30, 2013 at 10:28
We have a 2007 GXL and around town the consumption is 12-13. On a trip we get 10 and when towing a 2.7 ton caravan it ranges between 15 in flat country to 19 in varying terrane up to 23 with a head wind. Generally tow at 95-100klm/hr. Last year I fitted a Scanguage which I have set up to display instantaneous fuel consumption, Average ltrs/100k, boost pressure and transmission temperature. Using the guage(s) as a guide I have found an improvement in economy; often driving in 4th gear in lieu of 5th to ensure lock up of the torque converter resulting in lower transmission temperature and better fuel consumption.

The bottom line is if you drive conservatively you will get good economy; with a lead foot it will be thirsty.

AnswerID: 503618

Reply By: Member - Serendipity(WA) - Wednesday, Jan 30, 2013 at 20:23

Wednesday, Jan 30, 2013 at 20:23
Maybe some one can help with the maths on this.

The toyota manual for VDJ V8 says the fuel pump should have between 50 to 75megapascals (Mpa) pressure at 3000rpm with no load. So if it uses that pressure and the feed pipe is 12.5mm one could work out the required flow rate of fuel. Just not sure on the maths equation here.

Not a maths guy.


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AnswerID: 503671

Follow Up By: olcoolone - Wednesday, Jan 30, 2013 at 21:04

Wednesday, Jan 30, 2013 at 21:04
10900 psi..... I think they are talking rail side and not fuel tank side.

In theory there are two fuel pumps in the Toyota system, one is an aspirator type pump mounted in the fuel tank that uses the venturi method of liquid transfer at about 5-10 psi and the other is the common rail pump (sort of) that increases the pressure from the 5-10 psi up to 20000 psi plus.

Any fuel line to do with high pressure has to be in steel..... rubber is low pressure.
FollowupID: 780413

Follow Up By: Ross M - Wednesday, Jan 30, 2013 at 21:08

Wednesday, Jan 30, 2013 at 21:08
I think you are reading about the injector pump pressure for no load.
The actual injection pressure at the injectors at no load.

That is on the high pressure injector side of the fuel system, the output of the High Pressure pump. Roughly 7500psi.

This is the low pressure side of the system.
The filtering input side of the fuel system which also has a feed/supply pump in tank is regulated to around 7 psi may be a bit more.


FollowupID: 780416

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