Technical Stilo Abarth Uprated Fuel Pump

[Dax]

I need to uprate my fuel pump, which is currently supplying 90l/h. I found a formula on a web site that says:

In order to calculate whether your pump is up to the current or planned horsepower output use the following formula:

Fuel Flow (cc min) = HP x K

K = 5.6 for forced induction and 4.6 for Naturally Aspirated engines

You might like to work the other way round and see how much power your pump can deliver. If you had a 130hp N.A engine and you wanted 180 hp and you know the pump delivers 644cc a minute what power would the pump supply.

Fuel Flow / K = HP so for N.A engine this pump will deliver 140 hp.

I'm having a right 'Susan', If my pump delivers 90l/h would this not be 90,000cc/h and therefore this would equate to 90,000/60=1,500cc/min? and if you apply this to the formula, 1,500/5.6=267hp, this can't be right!! Or can it? Am I applying the formula wrongly? Does this mean I don't have to uprate my fuel pump?

 

[ABZSTILO]

I have to ask, why do you think you need to uprate the pump

 

[Dax]

I have to ask, why do you think you need to uprate the pump

It's due to the fact I have and in the process of doing a Turbo Conversion:

https://www.fiatforum.com/lets-talk-fiat/114183-fiat-stilo-abarth-2-4l-20v-turbo.html

https://www.fiatforum.com/gallery/showgallery.php?cat=1540

 

[ABZSTILO]

If you're going down that route (nice BTW) then you'll probably need the bigger pump but it should be easy enough to interpolate from what the standard pump on a Turbo coupe delivers, what you currently have and what you think you'll be needing.

Yes - in other words

Having had a look through the pics I'd toy with the idea of a bigger intercooler too, the JTD one might not be up to the job on a petrol turbo lump

 

[Dax]

If you're going down that route (nice BTW) then you'll probably need the bigger pump but it should be easy enough to interpolate from what the standard pump on a Turbo coupe delivers, what you currently have and what you think you'll be needing.

Yes - in other words

Having had a look through the pics I'd toy with the idea of a bigger intercooler too, the JTD one might not be up to the job on a petrol turbo lump

This has been going over in my head and I've gone through it a different way. In reality most pumps are rated well above the actual output of the engine in order to ensure the fuel injection system works correctly.

I have changed the injectors from the Stilo 2.4 ones (also fitted to the 2.0 NA Coupe), which deliver 182cc/min @ 3 bar, to the Coupe Turbo ones which deliver 347cc/min @ 3 bar. Therefore, if you apply the formula again, with allowance of 15 - 20% higher flow rate due to the reliability of injectors operating at around 85% duty cycle, it would seem that a fuel pump delivering 130l/h would be more than adequate?

This is not having a go, but in general I find it very hard just to except suggestions that something needs uprating just because your altering a component, without a sound technical reason, that can be analytically proven if possible. So fitting a Walbro 255l/h pump would seem a bit overkill, which is what has been suggested in the past. Plus it won't fit!

I have also looked into an uprated intercooler, I've approached a company called Allard Motor Company, and are just waiting on their advice. Again, I know the one I have is off a JTD, but why will it not be sufficient for the Turbo Conversion, what technical reason would there be for not using it? Unfortunately, the manufactures don't seem to have any technical details, other than the core sizes available, so I don't know how you determine what is a 'sufficient' intercooler. I have read an article that says 'The bigger the better', but I've also seen articles that say 'Size does not always matter', and that was a car related article!!

 

[ABZSTILO]

I think what I'm saying with regard to the fuel pump is (no pun intended!!) suck it and see I can only comment coming from 'old technology' supercharging and converting a standard installtion downdraught to a 45 sidedraught - I needed the bigger pump but the fuel was running through a pressure regulator. With an injected system I dunno - but I'd anticipate you will need more fuel delivery - depending on what the engine will ultimately deliver.

When it comes to the intercooler my arguement would be that you're running a high performance petrol turbo charged engine which will generate considerably greater temperatures than those found in a standard turbo diesel application. Therefore to maximise performance and reliability you want to keep the inlet charge temperature as low as you can so the cooled charge will be denser and will create more power in combustion by allowing you to optimise your settings.
So I'd hedge my bets and look at something with a bigger capacity for heat exchange or investigate water injection to dramatically reduce air intake temperatures pretty much instantly!
On the other hand you could always run the standard JTD/Mjet intercooler to begin with (again suck it and see) and if it's found wanting add to it a water misting system which (in the event of heat soak/power loss etc) could be activated to further cool the charge by helping cool the intercooler - complicated isn't it?!!
However, whilst I've done this before the problem is weight and space - you've got to find room for the kit (main problem is a water tank). A simpler option is usually to go 'large' out of the box staright away although I understand only too well you might want to try and keep as many OE type parts as possible.

 

[Dax]

I think what I'm saying with regard to the fuel pump is (no pun intended!!) suck it and see I can only comment coming from 'old technology' supercharging and converting a standard installation downdraught to a 45 side draught - I needed the bigger pump but the fuel was running through a pressure regulator. With an injected system I dunno - but I'd anticipate you will need more fuel delivery - depending on what the engine will ultimately deliver.

When it comes to the inter-cooler my argument would be that you're running a high performance petrol turbo charged engine which will generate considerably greater temperatures than those found in a standard turbo diesel application. Therefore to maximise performance and reliability you want to keep the inlet charge temperature as low as you can so the cooled charge will be denser and will create more power in combustion by allowing you to optimise your settings.
So I'd hedge my bets and look at something with a bigger capacity for heat exchange or investigate water injection to dramatically reduce air intake temperatures pretty much instantly!
On the other hand you could always run the standard JTD/Mjet inter-cooler to begin with (again suck it and see) and if it's found wanting add to it a water misting system which (in the event of heat soak/power loss etc) could be activated to further cool the charge by helping cool the inter-cooler - complicated isn't it?!!
However, whilst I've done this before the problem is weight and space - you've got to find room for the kit (main problem is a water tank). A simpler option is usually to go 'large' out of the box straight away although I understand only too well you might want to try and keep as many OE type parts as possible.

Just a thought that's been going through my mind, could you not install an air temperature sensor in the outlet pipe of the inter-cooler, that would switch an electric fan on which is connected to the inter-cooler core? Just thinking how the wet radiator cooling system works in the car as well as the heater core! Both these heat exchangers use electric fans to reduce or transmit heat? You would obviously have to calibrate the sensor to switch on a a certain temperature, but what temperature though, would it be the ambient temperature, which is always altering? Would you then have to have another temperature sensor measuring the ambient?

 

[ABZSTILO]

Just a thought that's been going through my mind, could you not install an air temperature sensor in the outlet pipe of the inter-cooler, that would switch an electric fan on which is connected to the inter-cooler core? Just thinking how the wet radiator cooling system works in the car as well as the heater core! Both these heat exchangers use electric fans to reduce or transmit heat? You would obviously have to calibrate the sensor to switch on a a certain temperature, but what temperature though, would it be the ambient temperature, which is always altering? Would you then have to have another temperature sensor measuring the ambient?

I like your thinking (practical) but I'm not so sure it would work very well in practice. If it did then I guess you'd already see it on other performance engines.....
It may have been done, but I haven't seen it

Ultimately an intercooler is a blunt instrument and not a precision tool, as yours is an experiment in progress I suspect there won't be a definative answer immediately available.

Mind you - isn't that the best of both worlds? Finding the answers out

 

[Dax]

I like your thinking (practical) but I'm not so sure it would work very well in practice. If it did then I guess you'd already see it on other performance engines.....
It may have been done, but I haven't seen it

Ultimately an intercooler is a blunt instrument and not a precision tool, as yours is an experiment in progress I suspect there won't be a definative answer immediately available.

Mind you - isn't that the best of both worlds? Finding the answers out

Just found this article:

http://www.autospeed.com/cms/A_2478/article.html

Seems like someone already thought of it, although for a slightly different reason!

 

[ABZSTILO]

Good link

 

[Dax]

I have been in contact with Bosch UK and they are unable to supply an in-tank pump, part number 0 580 454 021, to upgrade the factory one.

Bosch have suggested using an external pump? Is this feasible and if so, how would it connect to the in-tank unit and would I then have to have an external fuel filter as the in-tank pump is fitted to the in-tank unit which houses the filter.

Also, does anyone know what the flow rate is of the Coupe 20vt OEM pump is? Its manufactured by Walbro and its product number is MSS077, looked everywhere on the net, but can't find any information.