Which fuelpump for PTE 880cc??

[alice]

I just picked up a set of PTE 880cc injectors and I am wondering if I should go with the Walbro 190lph or the Walbro 255lph?? I will be running an E316g about 17-18psi and I have DSMlink.

Thanks -Jeremy

 

[turbolover10]

Imo, 255+afpr and be done with it, specially if you plan on taking advantage of those 880's in the future.

 

[2gGSX]

You will need the 255+AFPR.

 

[daren_p]

If you did some searching (very minimal searching that is ), then you would know pump selection depends on your power goals. Both those pumps will work fine for 99% of the people who run an evoIII. The 190lph is good for about 400 whp, so if you see yourself making that kind of power in the future, might as well get the 255HP to start with but will cost you abit extra as it does require an aftermarket FPR (such as Aeromotive).

 

[alice]

I did search but did not find anything concrete as to my specific question. All info I found here was fuel pump in relation with amount of boost or HP goals, not fuel pump to 880cc injectors.

I am shooting for around 300hp so I will probably just go with the 190 even though it makes more sense to go with the 255 and AFPR like torbolover10 said. I think I will do that now that I think about it, thanks all. -Jeremy

 

[daren_p]

I did search but did not find anything concrete as to my specific question. All info I found here was fuel pump in relation with amount of boost or HP goals, not fuel pump to 880cc injectors.

I am shooting for around 300hp so I will probably just go with the 190 even though it makes more sense to go with the 255 and AFPR like torbolover10 said. I think I will do that now that I think about it, thanks all. -Jeremy

As I said, pump choice is usually based on power goals & not which injectors you are running. If you are simply asking what pump is needed to max 880 injectors out, then the 255 would be your answer. But you won't be maxing 880's out with an evoIII, so that shouldn't be the question your asking

 

[b00stedtalon2]

I have PTE 880's as well and also using 255HP lph pump with AFPR.

 

[Splitpi]

Using my good friend Algebra,

Base 2G fuel pressure = 43.5 psi.
Desired Boost Pressure = 17 psi.
Fuel pressure at boost = 43.5 + 17 = 60.5 psi

According to this link by RRE for flow rates:

wally 190
58 psi @ 12 v = 145.11 ltr/hr
73 psi @ 12 v = 88.96 ltr/hr
58 psi @ 14 v = 162.78 ltr/hr
73 psi @ 14 v = 104.10 ltr/hr

Interpolation for 60.5 psi @ 12 v: y = 154.11 + (60.5 - 58)((88.96-145.11)/(73-58)) = 135.8 ltr/hr

Interpolation for 60.5 psi @ 14 v: y = 162.78 + (60.5 - 58)((104.10-162.78)/(73-58)) = 153 ltr/hr

wally 255
58 psi @ 12 v = 201.89 ltr/hr
73 psi @ 12 v = 147.00 ltr/hr
58 psi @ 14 v = 230.92 ltr/hr
73 psi @ 14 v = 182.97 ltr/hr

Interpolation for 60.5 psi @ 12 v: y = 201.89 + (60.5 - 58)((147.00-201.89)/(73-58)) = 192.7 ltr/hr

Interpolation for 60.5 psi @ 14 v: y = 230.92 + (60.5 - 58)((182.97-230.92)/(73-58)) = 222.9 ltr/hr

800 cc/min = .8 ltr/min = 48 ltr/hr

There are 4 injectors in the engine so:
48 ltr/hr * 4 = 192 ltr/hr

Thus the Wally 255 with rewire is the only option. The Wally 255 with stock wiring at 12v is too close to the calculated value and could cause issues if the injectors flow more than stated.

Edit: You may notice I used 800 cc's. PTE overrates their injector flow by increasing the duty cycle to 90% versus FIC or others who measure at 80% duty cycle. Thus I used 800 cc's for a more apples to apples calculation.

 

[DGajre777]

Thus the Wally 255 with rewire is the only option.

Good post. However, that would be only true if the member plans to max out the 880ccs which won't happen on the Evo III turbo.

Jeremy - As said before, the answer to your question is very simple. If you don't ever plan on buying a bigger turbo, get the 190. If you ever plan on going bigger get the 255. You may also want to look at the 255HP which is similar to the 255 but flows more at higher pressures. Both the 255 and 255HP will require you to get an AFPR.

 

[2gGSX]

In my opinion, a linear regression is not the best estimation of fuel pump output. With a quadratic regression, the R^2 values approach 1.0, whereas with a linear regression has a R^2 value of around .94.

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With that said, the flow numbers that I got...
Walbro 190 12v
15 psi boost (58 psi fuel pressure)- 145 lph
17 psi boost - 139 lph
20 psi boost (63 psi fuel prsesure)- 130 lph
25 psi boost - 111 lph
30 psi boost - 88.9 lph

The differences are reflected your 14v calculations, as well as the 255 numbers.

I do agree though that a rewired 255 would be the best choice (although it's hard to say whether or not that would be enough for 100% IDC even).

Most people who get to the point of needing this much fuel will hopefully know how to deal with their fuel setups on their own, but for the people who are still learning would benefit from reading these posts. Once you start getting into the really large injectors (which I would define as greater than 750cc/min), the choice of fuel pump really becomes slim--255hp, Supra, inline, etc. This is especially true once you start moving away from the 16g's and into the larger turbos which like more boost pressure. In these situations, the fuel pump dropoff starts becoming truly exponential. Thus, the best choice of action as far as I can see, is to overcompensate with your injector choice and DECREASE BASE FUEL PRESSURE (while keeping it high enough to ensure correct atomization in closed loop operation).

 

[Splitpi]

In my opinion, a linear regression is not the best estimation of fuel pump output. With a quadratic regression, the R^2 values approach 1.0, whereas with a linear regression has a R^2 value of around .94.

You must be logged in to view this image or video.

With that said, the flow numbers that I got...
Walbro 190 12v
15 psi boost (58 psi fuel pressure)- 145 lph
17 psi boost - 139 lph
20 psi boost (63 psi fuel prsesure)- 130 lph
25 psi boost - 111 lph
30 psi boost - 88.9 lph

The differences are reflected your 14v calculations, as well as the 255 numbers.

I do agree though that a rewired 255 would be the best choice (although it's hard to say whether or not that would be enough for 100% IDC even).

Most people who get to the point of needing this much fuel will hopefully know how to deal with their fuel setups on their own, but for the people who are still learning would benefit from reading these posts. Once you start getting into the really large injectors (which I would define as greater than 750cc/min), the choice of fuel pump really becomes slim--255hp, Supra, inline, etc. This is especially true once you start moving away from the 16g's and into the larger turbos which like more boost pressure. In these situations, the fuel pump dropoff starts becoming truly exponential. Thus, the best choice of action as far as I can see, is to overcompensate with your injector choice and DECREASE BASE FUEL PRESSURE (while keeping it high enough to ensure correct atomization in closed loop operation).

Thanks for the quadratic interpolation, I just choose a quick and dirty linear method as it suited the needs. All injector duty cycles as listed are at 80% IDC except PTE who uses 90%. And of course as DGajre777 pointed out the assumption that the owner has a large enough turbo to make full use of the injectors of 800cc's at 80% duty cycle. Obviously if IDC is increased beyond 80% more flow is required as the Injectors flow more. However it is is not fully linear increase, though it can be estimated quickly using a linear method.

Also decreasing base fuel pressure decrease the the fuel flow rate from the injectors. So you need larger injectors to compensate... but as you stated the fuel pump is able to flow more by the decreased pressure. SQRT(New pressure / Old Pressure) * Old flow rate to be precise. Example 800cc @ 43.5 psi measured ran at 38 psi causes them to flow SQRT(38/43.5) * 800 = 747.7 cc/min @ 80% idc which is roughly 7% less. BUT... the fuel pump is flowing @ 38+17 = 55 psi versus 60.5 psi and thus able to actually flow more fuel. So its a good point that 2gGSX makes about decreasing injectors, so long as you account for it correctly.

 

[alice]

Definetly some good information here. Thank, for all of it. I do plan on upgrading in the future, I can already tell. However, I want to just "test the waters" of something better than the T-25 and the E3 16g is the route I have chosen. Either way, since I do plan on upgrading to a FP3065 as my interest in boost grows, I will be going the Wally 255 rewired with a FUELAB AFPR and gauge combo. Again, thank you for all of the calculations and flow rates, it has made my decision obvious now.

-Jeremy