Right but Dada's saying your data suggest you had a bad stock pump? im trying to see his perspective.
PG Pump Installed
- Thread starter laloosh
- Start date
Right but Dada's saying your data suggest you had a bad stock pump? im trying to see his perspective.
Darksun280
Member
- :
- MS3
maybe he did
Right! still trying to find out if this is the case and, how it was concluded?
dadasracecar
Member
Laloosh sent me one of his old datalogs with the stock pump. The graphs are below. YOu can see that his fuel pressure was dropping to just above 1000 psi. Contrast that with my stock pump and full bolt on car. I never get below 1500 psi. As others are posting FP data from the dashhawk and other systems it seems clear that his fuel system couldn't keep up with his motor. Whether he had a bad fuel system or a freakishly strong motor that needed more fuel is debatable. What is not is that his pressure was much lower than mine and all of the others I've seen.
same thing i got yesterday, thats why i think lalooshes info is just random or his pump was screwed up. my car has the sputtering problem even with great fuel pressure.
Could that be his stock pump reacting to upped boost?
Ok i see evidence in the 1st graph of it but the other two look normal if the red graph line is RPM/TS in his second and 3rd loggs, FP looks relative to RPM except in the first graph where his FP drops out in increased RPM.
I would like to have seen his PSI in that first graph. Something major happends on that second shift his FP hits a wall im thinking a high boost spike?
laloosh?
Dada?
Ok i see evidence in the 1st graph of it but the other two look normal if the red graph line is RPM/TS in his second and 3rd loggs, FP looks relative to RPM except in the first graph where his FP drops out in increased RPM.
I would like to have seen his PSI in that first graph. Something major happends on that second shift his FP hits a wall im thinking a high boost spike?
laloosh?
Dada?
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hey man do you have the piggyback thingy or are u runing stock ecu when this problem happens??
dadasracecar
Member
The first and second graphs both show high TPS voltages with increasing rpm and lower than normal fuel pressures. The specific regions are boxed in red. The third one is just the rest of the datalog in the interest of showing all of the data. Compare that to Nypest's data at the top of this page. http://www.mazdas247.com/forum/attachment.php?attachmentid=122448
lol talk about me in the 3rd person now ??? lol
dadasracecar
Member
sorry. lol
i wish we could read commanded FP...Happly i dont have FC or BC yet i suspect if i put my race pipe on ill have that issue im still waiting on my pump i have 12 or so FPvsPSI,FPvsRPM data runs.. Soon as i can get my pump on ill try to recreate the runs and see how she reacts. My car runs strong and im happy so far. I should get a track # or atleast a dyno.
dadasracecar
Member
I missed this earlier but it should be pointed out that the pump doesn't make pressure. The spill valve regulator makes the pressure. The pump merely flows more or less. I've got several 2200+ psi datalogs but all that means is the PID loop controlling the spill valve regulator has not been optimized for the new pump so there will be larger oscillations in pressure. It's not really bad or good, it just means the Proportion, Integral, and Derivative coefficients have not been optimized for the new pumps. The benefit of the new pumps is the flow, not the pressure and the only thing the pressure can tell you is if the flow of the pump is not adequate for the draw of the injectors, i.e. if the injDC goes up dramatically while FP goes down you know you need a new pump. It's a disservice to the community to discuss one fuel pressure datalog in relation to the capabilities of any fuel pump because, again, the spill valve controls the pressure.
you know what would be really funny if it turns out that its the intank pump thats the culprit, hahaha would be funny if it just wasnt able to supply enough fuel to keep up with the oem cam drivin pump up front, making it loose pressure. has anyone considered this???? just a thought...IDK
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- 2002 BJFW, 2007 BK3P, 1979 SA22C, 2005 BK3P
yes, this has been considered, but that is not how the cam driven pump works. posted in response to this in another thread as well. the in tank pump probably never exceeds 100psi at full throttle, especially if people are replacing them with Walbro GSS style 255lph pumps. the cam driven pump does not draw fuel pressure from fuel supply in the lines at the tank level. hence "cam driven". the cam driven pumps push eight to ten times more pressure than what the in tank pumps do. the cam driven pump does not have a provision built into it to see how much fuel is being supplied to it by the in tank pump either. the cam driven pumps are really pretty eloquent and simple in how they work and what is done to them to make them flow more pressure. if the in tank pump was starving the cam driven pump, then upgrading the cam driven pump would do nothing at all because the cam driven pump does not forcibly draw fuel through the line from the tank pump. if that were the case there would be no reason to have a redundant tank pump whatsoever.
yes it would, even with a lack of fuel volume from the stock ITP, upgrading to the pg pump would still increase fuel pressure some, yielding some benifits. But Volume and pressure are two different things, and im wondering which of the two is causing the sputtering problem??
redrocketz
Member
the CDFP has nothing to do with line pressure from the tank to the pump on the engine that is not how the pump works. it's not like an old carbureted cars style of pump. the pump actually bleeds off any extra pressure that is sent to it.
ATE BALLER
Member
- :
- MAZDASPEED 6
No, that's done by the fuel pressure regulator in the tank. The stock itfp produces 71psi at 12.3v (what the relay sends when not idleing). The fpr in the tank is made to bleed that off to 65 psi constant. It never goes higher or lower while driving. When you introduce a higher rate of flow to that same regulator, the net supply pressure will undoubtedly increase. Whooosh is getting the stock pump's output tested vs. the new one this week I believe. Then we'll know how much more pressure is being delivered to the cdfp. The spill valve on the cdfp is dictated by the ecu as a function of an equation. There is no sensor to monitor the pressure on the low pressure side, thus that equation assumes 65psi is coming in, thus it opens the valve enough to allow enough fuel to get in at 65psi. If the pressure is actually higher, more fuel will make it in there. Then, when the piston in the pump crams it's load past the check valve and into the rail, more is going in. Most of the time though, none of this makes the slightest difference. The rail pressure regulator keeps all of it at or below 1885psi (or at least tries to). However, when it matters is when the ecu needs to demand more fuel. When the rail is usually being drawn short of pressure from the injectors, the rail pressure regulator is completely shut and the spill valve opens as much as possible trying to keep the pressure up, I can almost gaurantee it. With a stock fuel set-up, the rail is being starved causing the ecu to fuel cut. I think the fuel cut is primarily an automatic reaction to the rail pressure dropping. It's a safegaurd to what could happen if the pressure wasn't there when an injector fires. Once the rail pressure drops below whatever Mazda deemed safe enough for the injectors to do thier job, it shuts everything down to let pressure catch back up. Since upgrading either or both pumps will net a higher input into the rail, the pressure will last longer when the rail pressure regulator shuts.
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- 2007 MS3
I keep seeing terminology being used either incorrectly or when the figures don't really matter. For example, I keep seeing references to the fuel pressure supplied by the tank pump. This is meaningless to this discussion. All that matters is if it can deliver sufficient volume to the motor mounted pump. The CDFP will then supply that fuel at the correct pressure to the fuel delivery system.
I know this is obvious, but a modded engine requires more fuel per minute under load than a stock engine.
Assuming that two things are true:
1) The stock fuel pumps together deliver sufficent fuel at the required pressure for an unmodded engine to run properly. This assumption is challenged by some who maintain that the reason the engine power falls off at high rpm is due to the pumps not delivering sufficient fuel at high rpms. It is why I (and others) have called for a dyno comparison of an engine with the fuel pump as the only mod, so this can be settled once and for all.
2) The stock fuel pumps together do not deliver enough fuel to supply a modded engine sufficient fuel at required pressure under load. This second point is pretty much not debatable. I don't think any reasonable forum members believe the factory pumps are up to the job of supplying a modded engine.
If we accept point number two, then the question is: which pump is the weak link?
Somewhere in the forum is an engineer with the required knowledge to calculate the amount of fuel needed under load by stock/modded engines at different rpms. It must then be determined how much fuel the stock CDFP is capable of moving at the required 1800 some odd PSI. Either it meets the requirements or it doesn't. The next comparison is to the tank mounted pump. Within reasonable limits, its pressure output is essentially moot: all that really matters is its flow rate. Can it supply the necessary volumes of fuel to the CDFP?
The replacement CDFPs being discussed are not helping (if they are - and the results indicate they are) by increasing pressure. They are solving the problems by increasing the volume of fuel being delivered at the required pressure. The increased pressure available is simply a side effect of the greater volume being moved by the pump.
This would indicate that the stock tank pump is capable of supplying enough volume to the CDFP to supply a modded engine under load.
It may turn out that as the modding gets more intense, both pumps will need to be upgraded, but only time will tell.
At least those are my thoughts, but I could be wrong.
I know this is obvious, but a modded engine requires more fuel per minute under load than a stock engine.
Assuming that two things are true:
1) The stock fuel pumps together deliver sufficent fuel at the required pressure for an unmodded engine to run properly. This assumption is challenged by some who maintain that the reason the engine power falls off at high rpm is due to the pumps not delivering sufficient fuel at high rpms. It is why I (and others) have called for a dyno comparison of an engine with the fuel pump as the only mod, so this can be settled once and for all.
2) The stock fuel pumps together do not deliver enough fuel to supply a modded engine sufficient fuel at required pressure under load. This second point is pretty much not debatable. I don't think any reasonable forum members believe the factory pumps are up to the job of supplying a modded engine.
If we accept point number two, then the question is: which pump is the weak link?
Somewhere in the forum is an engineer with the required knowledge to calculate the amount of fuel needed under load by stock/modded engines at different rpms. It must then be determined how much fuel the stock CDFP is capable of moving at the required 1800 some odd PSI. Either it meets the requirements or it doesn't. The next comparison is to the tank mounted pump. Within reasonable limits, its pressure output is essentially moot: all that really matters is its flow rate. Can it supply the necessary volumes of fuel to the CDFP?
The replacement CDFPs being discussed are not helping (if they are - and the results indicate they are) by increasing pressure. They are solving the problems by increasing the volume of fuel being delivered at the required pressure. The increased pressure available is simply a side effect of the greater volume being moved by the pump.
This would indicate that the stock tank pump is capable of supplying enough volume to the CDFP to supply a modded engine under load.
It may turn out that as the modding gets more intense, both pumps will need to be upgraded, but only time will tell.
At least those are my thoughts, but I could be wrong.
dadasracecar
Member
Dyno comparison:
The tunes are different and I lost 7 whp because we took out the timing that was added with the prior tune (+2 deg). Adding timing can be dangerous especially at high rpm when knock sensor become less/ineffective. The +2.2 degrees didn't seem to be worth the 7 whp when the car was already running 10-12 deg adv. You can see that the upgraded pump reduced the lean hump and magnitude of the oscillation. I don't have the turbo yet to really push it. Looking at the graphs I probably should have pulled a little more fuel but I was paying and we were going long.
cp-e's position is that the hpfpump is not a necessary mod for stock turbo speed6s. They're experience with several 3071 modded speed6s is that much over 310 awhp, a drop in fuel pressure is accompanied by a large increase in injector pulse width. They take this to mean the injectors are opening longer to deliver the fuel necessary b/c the fuel pressure in the rail can't keep up with demand. This scenario has not been observed on stock turbo cars, namely mine. I do plan to go big turbo in the near future. I was in the right place at the right time and got to be the beta tester for the cp-e pump.
The tunes are different and I lost 7 whp because we took out the timing that was added with the prior tune (+2 deg). Adding timing can be dangerous especially at high rpm when knock sensor become less/ineffective. The +2.2 degrees didn't seem to be worth the 7 whp when the car was already running 10-12 deg adv. You can see that the upgraded pump reduced the lean hump and magnitude of the oscillation. I don't have the turbo yet to really push it. Looking at the graphs I probably should have pulled a little more fuel but I was paying and we were going long.
cp-e's position is that the hpfpump is not a necessary mod for stock turbo speed6s. They're experience with several 3071 modded speed6s is that much over 310 awhp, a drop in fuel pressure is accompanied by a large increase in injector pulse width. They take this to mean the injectors are opening longer to deliver the fuel necessary b/c the fuel pressure in the rail can't keep up with demand. This scenario has not been observed on stock turbo cars, namely mine. I do plan to go big turbo in the near future. I was in the right place at the right time and got to be the beta tester for the cp-e pump.
