Injectors and Fuel Pumps

[spyderturbo007]

Alright, I've decided to spend some time at work and crunch some numbers on the most commonly used injector and fuel pump sizes. The list below will provide you with the maximum amount of air that a give fuel system component can handle. There are some assumptions that I had to make for the calculation to function. Such as:

1) Everyone is running 93 octane fuel @ a base pressure of 43psi.
2) The Denso stock replacement fuel pump supplys the same flow, at a give pressure, as the stock Mitsubishi pump.
3) Everyone's fuel pump and injectors are working at peak performance.
4) Target AFR is 11:1
5) I can't have everyone's injectors flow tested, so we have to assume that if you bought 550cc injectors, that they flow 550cc/min.

On to the numbers

Injectors

390cc @ 100% IDC will support 27.99lbs/min
390cc @ 80% IDC will support 22.39lbs/min

450cc @ 100% IDC will support 32.30lbs/min
450cc @ 80% IDC will support 25.84lbs/min

550cc @ 100% IDC will support 39.48lbs/min
550cc @ 80% IDC will support 31.58lbs/min

580cc @ 100% IDC will support 41.63lbs/min
580cc @ 80% IDC will support 33.31lbs/min

650cc @ 100% IDC will support 46.66lbs/min
650cc @ 80% IDC will support 37.32lbs/min

660cc @ 100% IDC will support 47.37lbs/min
660cc @ 80% IDC will support 37.90lbs/min

720cc @ 100% IDC will support 51.68lbs/min
720cc @ 80% IDC will support 41.34lbs/min

750cc @ 100% IDC will support 53.83lbs/min
750cc @ 80% IDC will support 43.07lbs/min

780cc @ 100% IDC will support 55.99lbs/min
780cc @ 80% IDC will support 44.79lbs/min

850cc @ 100% IDC will support 61.01lbs/min
850cc @ 80% IDC will support 48.80lbs/min

880cc @ 100% IDC will support 63.17lbs/min
880cc @ 80% IDC will support 50.53lbs/min

950cc @ 100% IDC will support 68.19lbs/min
950cc @ 80% IDC will support 54.55lbs/min

1000cc @ 100% IDC will support 71.78lbs/min
1000cc @ 80% IDC will support 57.42lbs/min

1150cc @ 100% IDC will support 82.54lbs/min
1150cc @ 80% IDC will support 66.04lbs/min

1600cc @ 100% IDC will support 114.85lbs/min
1600cc @ 80% IDC will support 91.88lbs/min

Fuel pumps

Numbers will be arranged in the following format:

"X psi = Y lbs/min"

where X = Boost and Y = Max airflow supported by pump

Stock 2g pump

10psi = 33.29lbs/min
11psi = 32.61lbs/min
12psi = 31.90lbs/min
13psi = 31.17lbs/min
14psi = 30.41lbs/min
15psi = 29.63lbs/min
16psi = 28.84lbs/min
17psi = 28.01lbs/min
18psi = 27.16lbs/min
19psi = 26.28lbs/min
20psi = 25.38lbs/min
21psi = 24.46lbs/min
22psi = 23.51lbs/min
23psi = 22.54lbs/min
24psi = 21.54lbs/min
25psi = 20.52lbs/min

Stock 2g pump (Rewired)

10psi = 42.08lbs/min
11psi = 41.51lbs/min
12psi = 40.92lbs/min
13psi = 40.30lbs/min
14psi = 39.67lbs/min
15psi = 39.00lbs/min
16psi = 38.32lbs/min
17psi = 37.61lbs/min
18psi = 36.88lbs/min
19psi = 36.13lbs/min
20psi = 35.35lbs/min
21psi = 34.55lbs/min
22psi = 33.72lbs/min
23psi = 32.88lbs/min
24psi = 32.01lbs/min
25psi = 31.11lbs/min

Walboro 190lph

10psi = 46.48lbs/min
11psi = 45.89lbs/min
12psi = 45.26lbs/min
13psi = 44.58lbs/min
14psi = 43.86lbs/min
15psi = 43.09lbs/min
16psi = 42.28lbs/min
17psi = 41.43lbs/min
18psi = 40.54lbs/min
19psi = 39.60lbs/min
20psi = 38.62lbs/min
21psi = 37.60lbs/min
22psi = 36.53lbs/min
23psi = 35.42lbs/min
24psi = 34.26lbs/min
25psi = 33.06lbs/min

Walboro 190lph (Rewired)

10psi = 60.68lbs/min
11psi = 59.85lbs/min
12psi = 59.01lbs/min
13psi = 58.16lbs/min
14psi = 57.29lbs/min
15psi = 56.40lbs/min
16psi = 55.49lbs/min
17psi = 54.57lbs/min
18psi = 53.63lbs/min
19psi = 52.67lbs/min
20psi = 51.70lbs/min
21psi = 50.71lbs/min
22psi = 49.71lbs/min
23psi = 48.68lbs/min
24psi = 47.64lbs/min
25psi = 46.58lbs/min

Walboro 255lph

10psi = 63.53lbs/min
11psi = 62.88lbs/min
12psi = 62.20lbs/min
13psi = 61.48lbs/min
14psi = 60.72lbs/min
15psi = 59.93lbs/min
16psi = 59.10lbs/min
17psi = 58.23lbs/min
18psi = 57.33lbs/min
19psi = 56.39lbs/min
20psi = 55.41lbs/min
21psi = 54.39lbs/min
22psi = 53.34lbs/min
23psi = 52.26lbs/min
24psi = 51.13lbs/min
25psi = 49.97lbs/min

Walboro 255lph (Rewired)

10psi = 72.15lbs/min
11psi = 71.47lbs/min
12psi = 70.77lbs/min
13psi = 70.04lbs/min
14psi = 69.29lbs/min
15psi = 68.52lbs/min
16psi = 67.73lbs/min
17psi = 66.92lbs/min
18psi = 66.08lbs/min
19psi = 65.22lbs/min
20psi = 64.34lbs/min
21psi = 63.43lbs/min
22psi = 62.50lbs/min
23psi = 61.55lbs/min
24psi = 60.58lbs/min
25psi = 59.58lbs/min

Walboro 255lph HP

10psi = 64.64lbs/min
11psi = 64.19lbs/min
12psi = 63.74lbs/min
13psi = 63.30lbs/min
14psi = 62.86lbs/min
15psi = 62.42lbs/min
16psi = 61.99lbs/min
17psi = 61.56lbs/min
18psi = 61.13lbs/min
19psi = 60.71lbs/min
20psi = 60.29lbs/min
21psi = 59.87lbs/min
22psi = 59.46lbs/min
23psi = 59.05lbs/min
24psi = 58.64lbs/min
25psi = 58.24lbs/min

Walboro 255lph HP (Rewired)

10psi = 74.29lbs/min
11psi = 73.86lbs/min
12psi = 73.43lbs/min
13psi = 73.01lbs/min
14psi = 72.58lbs/min
15psi = 72.15lbs/min
16psi = 71.72lbs/min
17psi = 71.28lbs/min
18psi = 70.85lbs/min
19psi = 70.42lbs/min
20psi = 69.99lbs/min
21psi = 69.55lbs/min
22psi = 69.12lbs/min
23psi = 68.68lbs/min
24psi = 68.24lbs/min
25psi = 67.80lbs/min

Denso US EVO 8 Stock Pump

10psi = 39.96lbs/min
11psi = 39.10lbs/min
12psi = 38.12lbs/min
13psi = 37.31lbs/min
14psi = 36.39lbs/min
15psi = 35.45lbs/min
16psi = 34.48lbs/min
17psi = 33.49lbs/min
18psi = 32.49lbs/min
19psi = 31.47lbs/min
20psi = 31.47lbs/min
21psi = 29.35lbs/min
22psi = 28.26lbs/min
23psi = 27.15lbs/min
24psi = 26.02lbs/min
25psi = 24.87lbs/min

Denso EVO 8 Stock Pump (Rewired)

10psi = 51.23lbs/min
11psi = 50.36lbs/min
12psi = 49.48lbs/min
13psi = 48.60lbs/min
14psi = 47.72lbs/min
15psi = 46.85lbs/min
16psi = 45.97lbs/min
17psi = 45.09lbs/min
18psi = 44.20lbs/min
19psi = 43.32lbs/min
20psi = 43.32lbs/min
21psi = 41.55lbs/min
22psi = 40.67lbs/min
23psi = 39.78lbs/min
24psi = 38.90lbs/min
25psi = 38.01lbs/min

Denso Supra 260

10psi = 70.70lbs/min
11psi = 70.06lbs/min
12psi = 69.42lbs/min
13psi = 68.77lbs/min
14psi = 68.12lbs/min
15psi = 67.45lbs/min
16psi = 66.78lbs/min
17psi = 66.10lbs/min
18psi = 65.42lbs/min
19psi = 64.73lbs/min
20psi = 64.03lbs/min
21psi = 63.32lbs/min
22psi = 62.60lbs/min
23psi = 61.88lbs/min
24psi = 61.15lbs/min
25psi = 60.41lbs/min

Denso Supra 260 (Rewired)

10psi = 82.91lbs/min
11psi = 82.38lbs/min
12psi = 81.83lbs/min
13psi = 81.28lbs/min
14psi = 80.73lbs/min
15psi = 80.17lbs/min
16psi = 79.60lbs/min
17psi = 79.03lbs/min
18psi = 78.46lbs/min
19psi = 77.88lbs/min
20psi = 77.08lbs/min
21psi = 76.71lbs/min
22psi = 76.11lbs/min
23psi = 75.51lbs/min
24psi = 74.91lbs/min
25psi = 74.30lbs/min

Although these are the maximum values that the fuel system components can support, I do not advocate running the fuel pumps at their maximum flow. I also don't recommend running your injectors above 80% IDC. Why, you might ask.....

Lets say you are running on the 190lph Walboro @ 20psi and are flowing about 37lbs/min of air. At that point you are within the tolerance of a perfectly functioning pump. For some reason your voltage drops because of a bad alternator, or the boost starts to creep for some reason. Now you are pushing more air than the pump can support and the car starts running lean. At that point there is a chance of melting something, which we would all like to avoid.

Anyway, I just thought I would crunch some numbers so that everyone has a reference.

Also, if anyone sees any errors, let me know and I will make the appropriate corrections. There was a lot of numbers to crunch and transpose, so it is possible that I made a mistake.

EDIT -> Added additional data for injectors (750cc, 850cc, 950cc and 1000cc). Also, please note that these flow rates are calculated at the fuel pump outlet and not after traveling through the system. Just another reason not to try and approach the maximum limits listed above.

I just added the US EVO 8 stock pump and the Denso Supra 260 as requested.

I also adjusted the injector calculation because I screwed up the mass of 1 gallon of water in my calculation, which led to the incorrect mass of 1 gallon of fuel being used.

[CanadianTSi]

I know from experience that your 450 and 650 numbers are pretty much dead on.

I was actually maxxing out my 650's around 44-44.5lbs/min but I think this is due to my fuel pump still being run on the stock wiring so It can't maintain pressure up top.

This is a Great thread and Should be Stickied

[fwdeclipse]

Im confused on the pump calculations.IT has a psi next to lb/min what does it mean.for example it said


10psi-62lb/min
25psi-50lb/min
What is the psi meaning because the lower the psi the higher the lb/min.
Sorry if I sound dumb but not quit gettin it

[CanadianTSi]

Fuel pressure rises along with boost (1:1) The pump has to work alot harder to flow the fuel at the higher pressure.

[Staytuned]

Bingo ^^ higher FP means lower pump output.

[2gGSX]

I've actually got a tech article that works in a similar manner: A Primer on Upgrading your Fuel System

However, would you mind explaining how you got your numbers? There are some differences between our numbers, which makes sense for fuel pump flow but is sort of worrysome for injector flow since that is a more straightforward calculation. For example, a set of 450cc injectors at your listed conditions I would expect to support (at 100% IDC) 450 x 4 x .76 / 454 x 11 = 33.14 lbs/min airflow, or (at 80% IDC) 26.52 lbs/min. This varies from your 31.42 lbs/min and 25.14 lb/min by about 5.2%. I'm not saying you're wrong, I was just wondering what method you used to get your numbers and if it's more accurate than what I'm doing.

[steve]

Originally Posted by spyderturbo007

Also, if anyone sees any errors, let me know and I will make the appropriate corrections. There was a lot of numbers to crunch and transpose, so it is possible that I made a mistake.

First thank you for putting the effort in to do this.

It's tough to decide if there are errors without you providing a sample calculation so we can verify all your assumptions as well as check the math.

Who's flow rate charts did you use?
Did you allow for pressure drops in the fuel system between the pump and rail?
Depending on the restrictions in lines and filter running stock 2G base pressure at 25 psi boost could cause the pressure relief in the non-HP pumps to open and greatly reduce the flow rate.

Steve

[spyderturbo007]

Originally Posted by steve

First thank you for putting the effort in to do this.

Not a problem. I figured something like this might be helpful.

Originally Posted by steve

It's tough to decide if there are errors without you providing a sample calculation so we can verify all your assumptions as well as check the math.

I went pretty straight forward with the calculation and didn't get too detailed. Basically I just converted the amount of fuel that could be delivered by the pump, at that boost pressure, to the appropriate airflow number using a 11:1 AFR.

I used RRE's actual measured flow rates as opposed to the manufacturer's quoted rates. You can find them here:

http://www.roadraceengineering.com/f...pflowrates.htm

Plugged those numbers into Excel, created a curve and used the slope to calculate the flow rates from the points that werent' directly measured by RRE.

Something like this (2g stock pump @ 10psi)

Excel gives me a flow rate of 112.15l/hr @ 53psi (base + 10). Converting this to gallons (multiply by 0.26417) you get 29.62g/hr. Using the mass of water at 8.06lbs/g and a SG for 93 octane of 0.76, you can calculate that fuel weighs 6.13lbs/g.

This means that we can flow 181.57lbs of fuel every hour. Using an AFR of 11:1, we can support 1997.27lbs of air every hour. Divide by 60 to get lbs/min and the pump can support 33.29lbs/min airflow.

Originally Posted by steve

Did you allow for pressure drops in the fuel system between the pump and rail?

Um, no...... Based on what it said on RRE's website I assumed that is the fuel that would be delivered to the injectors. They had them tested by RC Engineering. I went to their website and "assumed" that RRE had them tested under load, which would account for any pressure drops in the system and provide us with the flow at the injector.

http://www.rceng.com/service.htm#PUMP

I could be wrong......

Originally Posted by steve

Depending on the restrictions in lines and filter running stock 2G base pressure at 25 psi boost could cause the pressure relief in the non-HP pumps to open and greatly reduce the flow rate.

Steve

Not sure about this one.........damnit Steve, you're killing me.

[tstkl]

what about me with my 1000cc injectors?

seriously though, can you do one for the denso supra fuel pump and (not as important ->) the denso 3000gt fuel pump?

[steve]

Originally Posted by spyderturbo007

Um, no...... Based on what it said on RRE's website I assumed that is the fuel that would be delivered to the injectors. They had them tested by RC Engineering. I went to their website and "assumed" that RRE had them tested under load, which would account for any pressure drops in the system and provide us with the flow at the injector.

No, these number are raw at the pump flow rates. Not at the end of 6 ft worth of 3/8" tube and a factory filter. Don't feel bad I dom't know what real number are for the pressure drop so at best we have to fudge these factors when sizing the system. I wrote a post last year when took the numbers RC and AEM suggest for injector and fuel pump sizing to work out the requirements with some large safety factors based on target HP. If we had some typical numbers for 4G63T BSFC we could do another spreadsheet for sanity checking your swags.

Steve

[spyderturbo007]

I guess I should go back and add another disclaimer at the end of the post.

[andymoraitis]

Disclaimer or not, this is great stuff Nathan. Thanks for putting in the effort.

[DSMunknown]

You may also want to consider adding flow rates for the Lancer Evolution VIII fuel pumps (or similar OEM model pumps). I understand that with a rewired fuel pump, the Evo can pump similar ratings as the 190, but it still would be interesting to see any subtle differences.

[2gGSX]

Originally Posted by tstkl

what about me with my 1000cc injectors?

seriously though, can you do one for the denso supra fuel pump and (not as important ->) the denso 3000gt fuel pump?

Unrewired Supra fuel pump can be modeled with the equation y=(-.23484)x^2 + 24.9919x - 382.38 where x is your fuel pressure in psi and y is fuel flow in lph (again from the pump not after the fuel filter and lines), with a 100% Pearson correlation value from 43 psi to 73 psi fuel pressure. Some examples...

Psi Flow
43 258.05
58 277.15
63 260.03
68 231.17
73 192.57

For a rewired Supra fuel pump, the equation y=(-.0084)x^2 - .91826x + 351.54 does the same.

Psi Flow
43 296.52
58 270.02
63 260.35
68 250.26
73 239.74

I don't think I have any data for the 3000GT Denso pump to run these figures through though.

[2gGSX]

Originally Posted by DSMunknown

You may also want to consider adding flow rates for the Lancer Evolution VIII fuel pumps (or similar OEM model pumps). I understand that with a rewired fuel pump, the Evo can pump similar ratings as the 190, but it still would be interesting to see any subtle differences.

Evo 8 stock: (-.03504)x^2 + (.84748)x + 187.97. Pearson correlation of 1.

Psi Flow
43 159.62
58 119.25
63 102.29
68 83.574
73 63.108

Evo 8 rewired: (-.001422)x^2 - (-2.80035)x + 324.93. R^2 = 1
Psi Flow
43 201.89
58 157.73
63 142.86
68 127.93
73 112.93

[DSMunknown]

spyderturbo007, if you could add 580cc injectors to the original list, that would be appreciated.






EDIT:

Originally Posted by spyderturbo007

I can't have everyone's injectors flow tested, so we have to assume that if you bought 550cc injectors, that they flow 550cc/min.

Isn't it true that when Ben Franklin decides to buy (for instance) 550cc injectors, he is not actually getting what he pays for? In other words, the name "550" is just an "approximation", right? For example, when buying a set of four fuel injectors, could Ben recieve injectors that flow 547, 551, 552, and 555?

Obviously, the manufacturing company of the fuel injectors tested the flow rates of their products, but isn't this the reason why people have their injectors flow-tested, to determine exactly how well or poorly the injectors are flowing?

[spyderturbo007]

Originally Posted by DSMunknown

You may also want to consider adding flow rates for the Lancer Evolution VIII fuel pumps (or similar OEM model pumps).

Originally Posted by DSMunknown

spyderturbo007, if you could add 580cc injectors to the original list, that would be appreciated.

Man, you're a demanding little bugger, aren't you.

Just kidding!

Both have been added.