max boost on stock internals
EvoM Guru
iTrader: (50)
Joined: Mar 2006
Posts: 9,675
Likes: 132
From: Tri-Cities, WA // Portland, OR
I hate putting fuel system capacities in terms of whp, especially when we can put it in terms of things we can regularly and accurately measure. 
The stock IX pump (per AMS' testing) flows 167lph at 70psi. Assuming you're running stock fuel pressure (43 psi) and 25psi of boost, you're asking the pump to operate at 68psi at full tilt. So, assuming good voltage to the pump
, somewhere around 165lph is being supplied at that point, or to put it in terms of injector sizing, a maximum of 690cc/min per injector.
That's enough to support around 52lbs/min of air at 12:1, or 48lbs/min at 11:1 (assuming your injectors can keep up), and there's room to improve here if you have the luxury of setting a lower fuel pressure with larger injectors. An Evo IX turbo, if I'm reading the interwebs right, can operate in the neighborhood of 42lbs/min. So, the headroom on the stock IX pump looks pretty good to me.
(Going off-topic: I should point out for the archives that the IX pump is unique here; the VIII pump has a high-pressure bypass that causes it to crap out between 65-67psi. It means, quite literally, don't run more than 22psi of boost on a VIII turbo without doing something about the pump. I assume everyone in this thread already knows that, but just in case someone comes across this thread later, it'd be good to note it here.)
(Going a little further off-topic: notice that maximum flow on the pump is in the 690cc/min/injector range. That makes the stock injectors (560s) very weak for this turbo when considering it's potential; with stock injectors, you'd be limited to supporting around 42lbs/min at 12:1, or around 39lbs/min at 11:1. Since these are all maximums, you're pushing it with the stock injectors if you start winding it up. Mathematically, 720s would seem to make a very good match for the stock pump, since you'd only be running them around 80% IDC when the pump was at full tilt. Toss in 950s or 1000s for E-85 and be happy.
I'm surprised that Mitsubishi did so well on sizing the pump to the turbo, but so poorly on sizing the injectors.)
(Yet more off-topic: if you're running more than 25psi or so on the stock turbo, regardless of how good or bad an idea that might be, you're starting to push it on the stock IX pump. Again, assuming you're running stock fuel pressure; mildly under-pressurizing larger injectors can always get a bit more flow out of the pump, but atomization at the head will suffer.)
The stock IX pump (per AMS' testing) flows 167lph at 70psi. Assuming you're running stock fuel pressure (43 psi) and 25psi of boost, you're asking the pump to operate at 68psi at full tilt. So, assuming good voltage to the pump
, somewhere around 165lph is being supplied at that point, or to put it in terms of injector sizing, a maximum of 690cc/min per injector.That's enough to support around 52lbs/min of air at 12:1, or 48lbs/min at 11:1 (assuming your injectors can keep up), and there's room to improve here if you have the luxury of setting a lower fuel pressure with larger injectors. An Evo IX turbo, if I'm reading the interwebs right, can operate in the neighborhood of 42lbs/min. So, the headroom on the stock IX pump looks pretty good to me.
(Going off-topic: I should point out for the archives that the IX pump is unique here; the VIII pump has a high-pressure bypass that causes it to crap out between 65-67psi. It means, quite literally, don't run more than 22psi of boost on a VIII turbo without doing something about the pump. I assume everyone in this thread already knows that, but just in case someone comes across this thread later, it'd be good to note it here.)
(Going a little further off-topic: notice that maximum flow on the pump is in the 690cc/min/injector range. That makes the stock injectors (560s) very weak for this turbo when considering it's potential; with stock injectors, you'd be limited to supporting around 42lbs/min at 12:1, or around 39lbs/min at 11:1. Since these are all maximums, you're pushing it with the stock injectors if you start winding it up. Mathematically, 720s would seem to make a very good match for the stock pump, since you'd only be running them around 80% IDC when the pump was at full tilt. Toss in 950s or 1000s for E-85 and be happy.
I'm surprised that Mitsubishi did so well on sizing the pump to the turbo, but so poorly on sizing the injectors.)(Yet more off-topic: if you're running more than 25psi or so on the stock turbo, regardless of how good or bad an idea that might be, you're starting to push it on the stock IX pump. Again, assuming you're running stock fuel pressure; mildly under-pressurizing larger injectors can always get a bit more flow out of the pump, but atomization at the head will suffer.)
I hate putting fuel system capacities in terms of whp, especially when we can put it in terms of things we can regularly and accurately measure.
The stock IX pump (per AMS' testing) flows 167lph at 70psi. Assuming you're running stock fuel pressure (43 psi) and 25psi of boost, you're asking the pump to operate at 68psi at full tilt. So, assuming good voltage to the pump, somewhere around 165lph is being supplied at that point, or to put it in terms of injector sizing, a maximum of 690cc/min per injector.
That's enough to support around 52lbs/min of air at 12:1, or 48lbs/min at 11:1 (assuming your injectors can keep up), and there's room to improve here if you have the luxury of setting a lower fuel pressure with larger injectors. An Evo IX turbo, if I'm reading the interwebs right, can operate in the neighborhood of 42lbs/min. So, the headroom on the stock IX pump looks pretty good to me.
(Going off-topic: I should point out for the archives that the IX pump is unique here; the VIII pump has a high-pressure bypass that causes it to crap out between 65-67psi. It means, quite literally, don't run more than 22psi of boost on a VIII turbo without doing something about the pump. I assume everyone in this thread already knows that, but just in case someone comes across this thread later, it'd be good to note it here.)
(Going a little further off-topic: notice that maximum flow on the pump is in the 690cc/min/injector range. That makes the stock injectors (560s) very weak for this turbo when considering it's potential; with stock injectors, you'd be limited to supporting around 42lbs/min at 12:1, or around 39lbs/min at 11:1. Since these are all maximums, you're pushing it with the stock injectors if you start winding it up. Mathematically, 720s would seem to make a very good match for the stock pump, since you'd only be running them around 80% IDC when the pump was at full tilt. Toss in 950s or 1000s for E-85 and be happy. I'm surprised that Mitsubishi did so well on sizing the pump to the turbo, but so poorly on sizing the injectors.)
(Yet more off-topic: if you're running more than 25psi or so on the stock turbo, regardless of how good or bad an idea that might be, you're starting to push it on the stock IX pump. Again, assuming you're running stock fuel pressure; mildly under-pressurizing larger injectors can always get a bit more flow out of the pump, but atomization at the head will suffer.)
The stock IX pump (per AMS' testing) flows 167lph at 70psi. Assuming you're running stock fuel pressure (43 psi) and 25psi of boost, you're asking the pump to operate at 68psi at full tilt. So, assuming good voltage to the pump
, somewhere around 165lph is being supplied at that point, or to put it in terms of injector sizing, a maximum of 690cc/min per injector.That's enough to support around 52lbs/min of air at 12:1, or 48lbs/min at 11:1 (assuming your injectors can keep up), and there's room to improve here if you have the luxury of setting a lower fuel pressure with larger injectors. An Evo IX turbo, if I'm reading the interwebs right, can operate in the neighborhood of 42lbs/min. So, the headroom on the stock IX pump looks pretty good to me.
(Going off-topic: I should point out for the archives that the IX pump is unique here; the VIII pump has a high-pressure bypass that causes it to crap out between 65-67psi. It means, quite literally, don't run more than 22psi of boost on a VIII turbo without doing something about the pump. I assume everyone in this thread already knows that, but just in case someone comes across this thread later, it'd be good to note it here.)
(Going a little further off-topic: notice that maximum flow on the pump is in the 690cc/min/injector range. That makes the stock injectors (560s) very weak for this turbo when considering it's potential; with stock injectors, you'd be limited to supporting around 42lbs/min at 12:1, or around 39lbs/min at 11:1. Since these are all maximums, you're pushing it with the stock injectors if you start winding it up. Mathematically, 720s would seem to make a very good match for the stock pump, since you'd only be running them around 80% IDC when the pump was at full tilt. Toss in 950s or 1000s for E-85 and be happy.
I'm surprised that Mitsubishi did so well on sizing the pump to the turbo, but so poorly on sizing the injectors.)(Yet more off-topic: if you're running more than 25psi or so on the stock turbo, regardless of how good or bad an idea that might be, you're starting to push it on the stock IX pump. Again, assuming you're running stock fuel pressure; mildly under-pressurizing larger injectors can always get a bit more flow out of the pump, but atomization at the head will suffer.)
And yes. I thought he was talking about whacking a hole in the intake tube.
I almost cried.
All good now tho.
The bad thing about the bypass valves in the pumps is that they just slam open. So everything is fine and then BAM no fuel pressure. Then it takes the wideband a quarter second to respond to the problem, but usually the motor has already started misfiring. Theirfore you can't always datalog the problem because you have sensor lags.
At any rate an 8 should have a pump as a first mod IMO. The 9 can usually keep the stock pump until you upgrade injectors.
At any rate an 8 should have a pump as a first mod IMO. The 9 can usually keep the stock pump until you upgrade injectors.
