the_big_1

iTrader: (1)

Hi All,

Will the standard fuel pump on a 2006 STI require uprating for a remap?

skinner

If it just a re map i would say no but if your up rating your exhaust and air filter id say yes it does need 1.

the_big_1

iTrader: (1)

The re map will be a de-cat. I have a K&N panel filter the car came with and it has the center resinator removed with a Ninja II back box.

greatgonzo

iTrader: (1)

Was told by JGM that the fuel pump on the 2.5 litre is very strong and didn't need replacing if your running sensible power I'm running 333 bhp with no problems at all.

addison

http://www.andyforrestperformance.co.uk/27671.html
This will tell you all you need to know

greatgonzo

iTrader: (1)

Should see between 320-360 bhp good luck

the_big_1

iTrader: (1)

Hard to know now as you say, JDM seems to say not needed up to like around the 320 - 360 but Andy Forest says needed?

skinner

Mine has a up rated pump i would fit 1 with your mods as you have up rated you exhaust and air intake its not much more cost to put 1 on i think mine was £77.

the_big_1

iTrader: (1)

Couple of questions.
My car came with the panel filter already fitted, should it be remapped or is it ok?
If I fit an uprated fuel pump without the re map, will it be ok etc?

skinner

You will be ok with just a panel filter.

SunnySideUp

In my opinion this is one of the biggest myths on SN.

The standard pump delivers so much fuel that a vast amount is returned to the tank, unused.

No-one, ever, has presented the flow figures for the standard pump and the so called 'uprated' pumps ... the figures for what the standard engine needs and also what it needs following mods is also strangely missing.

I think it's a load of bollox .... if you are upwards of 400 BHP then you know whether you need another pump or not - anything meek and mild like a de-cat and panel filter doesn't need another pump ..... again, in my opinion.

It would be nice to see some technical figures.

the_big_1

iTrader: (1)

Yeah I never seen what the standard pump runs at?

skinner

I am sure the flow rates of a standard pump are in auto data books as i had to find a pump to suit my vauxhall when i did a red top convershion years ago.

the_big_1

iTrader: (1)

Anyone got one lol

the_big_1

iTrader: (1)

In the workshop manual it says "More than 140L per hour"

SunnySideUp

It defies logic and science that an engine needs more fuel supply - unless it has different injectors with a larger bore, or, the injectors are open longer than the manufacturers designed them to be at any point in town.

There is absolutely no other way that extra fuel can enter the cylinders ... hence absolutely no need for any so called 'uprated' fuel pump.

the_big_1

iTrader: (1)

All I could think of is, more bost requires more fuel but no idea if the standard fuel pump at 140l and hour is not enough, which would mean its on the edge as standard. also, its keeping the fuel pressure in the fuel line at its correct pressure but again, is the standard so close to the edge? An uprated fuel pump is 255L so 115L needed for an extra 80 BHP?

SunnySideUp

The uprated pump may as well be 200,000L per Hour .... it doesn't matter if the engine doesn't need that delivery.

I suspect that many pumps have been replaced when all the buyer has done is to deliver even more fuel back to the tank! Utterly pointless and a waste of time and money if this is the case.

the_big_1

iTrader: (1)

I guess so too. But be nice if someone knew required fuel rate for standard setup and mapped setup at say 350 bhp. No idea if anyone has tested it?

greatgonzo

iTrader: (1)

And the uprated ones buzz a lot which would get on my nerves

skinner

I dont know at what point a car needs a bigger fuel pump but andy forest thinks it does at 350hp.A car with more boost is putting more fuel and air into the engine so a uprated pump makes sence.

greatgonzo

iTrader: (1)

But there's loads of Hawkeyes running 350bhp and over with standard pumps with no problems. If it wasn't delivering enough fuel surely it would fail straight away and create load of problems

SunnySideUp

Skinner:-

Only makes sense if that extra fuel and air has somewhere to go .... if it is still through the same bore injector then I suspect that there will be little improvement.

SunnySideUp

That's because the BHP isn't the measure you should use .... it's the rate of flow required by the mods employed.

The number of perfectly decent and capable pumps lying in garages by the misguided must be legion.

skinner

I supose it up to each person weather or not they go for this mod but its always there for the future mods if you go for 1.

SunnySideUp

In 99.9% of cases I suspect that this Fuel Pump Upgrade is simply not needed at all.

It's the same as me spending £1million building a nuclear bunker under my house, just in case, in the future, I will be glad I did. I'm not going to do it unless there is an imminent risk that I will need one.

Nah, forget all about uprated fuel pumps .... you will know, by what your car tells you, if you need one or not - until then, keep your money in your pocket and your brains in your head

360ste

iTrader: (1)

From earlier car experience it is not the flow rate that matters it is the pressure drop. As the pump pushes fuel through faster it cannot produce the same pressure. A pump flowing 150 litres per hour at (for example) 40 psi, could drop the pressure to 30 psi if the flow increases to 200 litres per hour. That iswhat I understand the reason for uprating the pump is. On a car I had 20+ years ago I gained 10 bhp (1300cc engine) by fitting a FSE electric pump to replace the OE mechanical pump.

the_big_1

iTrader: (1)

lol how would you know if you needed one?
Like most of you guys, I like to work on fact and figures, being an engineer.
Be nice for some facts.
For example:
Standard injectors in standard set up require a fuel line pressure of XXX at 5000 RPM.
With the extra boost, extra fuel requirement of mapping means fuel line pressue needs to be XXXX at 5000 RPM.
The standard pump provides a contstant fuel pressure of XXX wich is enough, not enough to run at mapping.

SunnySideUp

Fuel pumps supply fuel volume; they do not create pressure in the fuel lines. In a return-line system, the fuel pressure regulator restricts the return fuel flow in order to create pressure in the supply line.

Trevcoss

simple question is how much fuel can the pump supply per minute compared to how much fuel the injectors can use at about 80% duty, do the math and decide if a pump may be required