Big injectors and fuel pulsations
RX-7 Old Timer
Joined: Jul 2004
Posts: 321
Likes: 10
From: Ann Arbor, MI
This was an Aeromotive FPR, right? So it's safe to say that the inherent damping in the Aeromotive FPR is inadequate, with big injectors, on the rotary?
I have an aeromotive FPR, and was considering deleting the damper on my stock S4 rail. Now I'm thinking I'll keep it.
I have an aeromotive FPR, and was considering deleting the damper on my stock S4 rail. Now I'm thinking I'll keep it.
Thread Starter
Joined: Mar 2001
Posts: 5,269
Likes: 150
From: Floyds Knobs. IN
This was an Aeromotive FPR, right? So it's safe to say that the inherent damping in the Aeromotive FPR is inadequate, with big injectors, on the rotary?
I have an aeromotive FPR, and was considering deleting the damper on my stock S4 rail. Now I'm thinking I'll keep it.
I have an aeromotive FPR, and was considering deleting the damper on my stock S4 rail. Now I'm thinking I'll keep it.
Was present with an Aeromotive and Turbosmart.
I actually have the R model and just finished the installation last weekend, it's perfect because you can run it in-line like oem and it have a boost reference port, and base pressure is 40 psi.
Most of all i like of small this thing is and it can be mounted in the small areas.
Most of all i like of small this thing is and it can be mounted in the small areas.
F**K THE SYSTEM!!
Joined: Sep 2006
Posts: 2,591
Likes: 1
From: Florida
Was looking at the radium product and they suggest mounting on the fuel rail. I didnt see those inline basisI might get a pair of these and put tap one into each rail. I dont understand why we cant just use tue cheaper oem style without vacuum/boost reference like our factory ones. How much better does the the vac/boost source make it the fdp's
Full Member
Joined: Oct 2004
Posts: 161
Likes: 0
From: chicago
Each vehicle in which I personally have seen fuel pulsation side effects cause drive-ability problems, it occurred in very narrow RPM windows. This meant that it was only something noticeable to the driver during steady engine load and steady engine speed driving.
Basically each of the cars exhibiting obvious symptoms that caused misfiring and hesitation would have 2,3, or 4 different engine speeds that were "hot spots" perceived to be about ~20-30RPM wide. These were spots where pressure oscillation amplitude was bad enough (with anti-nodes overlapping injector firing events) that no fuel table adjustment would correct the problem to satisfaction. Plus, the EMS doesnt really have the fuel table resolution to combat such small window problems. So if you were extremely slowly climbing in engine speed, or trying to maintain speed at one of these indicated RPMs, the car would misfire and buck.
During any typical acceleration, and especially full throttle, the engine speed would fly right past these windows so quickly that symptoms were entirely unnoticeable.
Due to how quickly engine speed will pass the trouble spots any time a vacuum referenced FPD is putting in its extra work, I don't believe its going to have any noticeable improvements over a static FPD.
That said, its still a sound theory to keep the FPDs from bottoming out during full throttle. Looking deeper than driving characteristics, it could show fuel system performance linearity improvements at the high speed data acquisition level. So in short, I do not personally believe its going to improve driving characteristics to any perceivable level over a static FPD - but its very possible it might make tuning a little more pleasant for a tuner who is OCD about his VE table or etc.
I have not moved to using them yet, but I might one day. For the best of both worlds, add one of these standalone FPDs to a rail that already has a basic one!
Basically each of the cars exhibiting obvious symptoms that caused misfiring and hesitation would have 2,3, or 4 different engine speeds that were "hot spots" perceived to be about ~20-30RPM wide. These were spots where pressure oscillation amplitude was bad enough (with anti-nodes overlapping injector firing events) that no fuel table adjustment would correct the problem to satisfaction. Plus, the EMS doesnt really have the fuel table resolution to combat such small window problems. So if you were extremely slowly climbing in engine speed, or trying to maintain speed at one of these indicated RPMs, the car would misfire and buck.
During any typical acceleration, and especially full throttle, the engine speed would fly right past these windows so quickly that symptoms were entirely unnoticeable.
Due to how quickly engine speed will pass the trouble spots any time a vacuum referenced FPD is putting in its extra work, I don't believe its going to have any noticeable improvements over a static FPD.
That said, its still a sound theory to keep the FPDs from bottoming out during full throttle. Looking deeper than driving characteristics, it could show fuel system performance linearity improvements at the high speed data acquisition level. So in short, I do not personally believe its going to improve driving characteristics to any perceivable level over a static FPD - but its very possible it might make tuning a little more pleasant for a tuner who is OCD about his VE table or etc.
I have not moved to using them yet, but I might one day. For the best of both worlds, add one of these standalone FPDs to a rail that already has a basic one!
Last edited by phunk; Feb 2, 2016 at 03:23 PM.
Each vehicle in which I personally have seen fuel pulsation side effects cause drive-ability problems, it occurred in very narrow RPM windows. This meant that it was only something noticeable to the driver during steady engine load and steady engine speed driving.
Basically each of the cars exhibiting obvious symptoms that caused misfiring and hesitation would have 2,3, or 4 different engine speeds that were "hot spots" perceived to be about ~20-30RPM wide. These were spots where pressure oscillation amplitude was bad enough (with anti-nodes overlapping injector firing events) that no fuel table adjustment would correct the problem to satisfaction. Plus, the EMS doesnt really have the fuel table resolution to combat such small window problems. So if you were extremely slowly climbing in engine speed, or trying to maintain speed at one of these indicated RPMs, the car would misfire and buck.
During any typical acceleration, and especially full throttle, the engine speed would fly right past these windows so quickly that symptoms were entirely unnoticeable.
Basically each of the cars exhibiting obvious symptoms that caused misfiring and hesitation would have 2,3, or 4 different engine speeds that were "hot spots" perceived to be about ~20-30RPM wide. These were spots where pressure oscillation amplitude was bad enough (with anti-nodes overlapping injector firing events) that no fuel table adjustment would correct the problem to satisfaction. Plus, the EMS doesnt really have the fuel table resolution to combat such small window problems. So if you were extremely slowly climbing in engine speed, or trying to maintain speed at one of these indicated RPMs, the car would misfire and buck.
During any typical acceleration, and especially full throttle, the engine speed would fly right past these windows so quickly that symptoms were entirely unnoticeable.
i think i have experienced this.. usually happens at very light throttle. i had it happen back when i ran an rtek, then upgraded to haltech and had the same problem, on both FC and FD, all cases with no FPD. so definitely not related to fuel mapping
Good info. I'm about to replace my stock primaries with ID725 and will be losing the factory dampener. Upgrading my 1680's to ID2000 injectors and decided this was a good idea after reading the thread. Picked up the Radium inline unit and will install it when I do the fuel system next week.
Good looking out.
Good looking out.
I will be tying the OEM style first, as I can install one FPD on each fuel rail, for the price of one of one RADIUM inline FPD.
F**K THE SYSTEM!!
Joined: Sep 2006
Posts: 2,591
Likes: 1
From: Florida
I was searching for any oem units i could find. In rockauto you will notice i found plenty and many have.their own psi. Im assuming this is the idle fuel pressure?
Here you go. All.kinds good.prices.
https://www.rockauto.com/en/partsearch/?partnum=fpd
Here you go. All.kinds good.prices.
https://www.rockauto.com/en/partsearch/?partnum=fpd
Thread Starter
Joined: Mar 2001
Posts: 5,269
Likes: 150
From: Floyds Knobs. IN
Each vehicle in which I personally have seen fuel pulsation side effects cause drive-ability problems, it occurred in very narrow RPM windows. This meant that it was only something noticeable to the driver during steady engine load and steady engine speed driving.
Basically each of the cars exhibiting obvious symptoms that caused misfiring and hesitation would have 2,3, or 4 different engine speeds that were "hot spots" perceived to be about ~20-30RPM wide. These were spots where pressure oscillation amplitude was bad enough (with anti-nodes overlapping injector firing events) that no fuel table adjustment would correct the problem to satisfaction. Plus, the EMS doesnt really have the fuel table resolution to combat such small window problems. So if you were extremely slowly climbing in engine speed, or trying to maintain speed at one of these indicated RPMs, the car would misfire and buck.
During any typical acceleration, and especially full throttle, the engine speed would fly right past these windows so quickly that symptoms were entirely unnoticeable.
Due to how quickly engine speed will pass the trouble spots any time a vacuum referenced FPD is putting in its extra work, I don't believe its going to have any noticeable improvements over a static FPD.
That said, its still a sound theory to keep the FPDs from bottoming out during full throttle. Looking deeper than driving characteristics, it could show fuel system performance linearity improvements at the high speed data acquisition level. So in short, I do not personally believe its going to improve driving characteristics to any perceivable level over a static FPD - but its very possible it might make tuning a little more pleasant for a tuner who is OCD about his VE table or etc.
I have not moved to using them yet, but I might one day. For the best of both worlds, add one of these standalone FPDs to a rail that already has a basic one!
Basically each of the cars exhibiting obvious symptoms that caused misfiring and hesitation would have 2,3, or 4 different engine speeds that were "hot spots" perceived to be about ~20-30RPM wide. These were spots where pressure oscillation amplitude was bad enough (with anti-nodes overlapping injector firing events) that no fuel table adjustment would correct the problem to satisfaction. Plus, the EMS doesnt really have the fuel table resolution to combat such small window problems. So if you were extremely slowly climbing in engine speed, or trying to maintain speed at one of these indicated RPMs, the car would misfire and buck.
During any typical acceleration, and especially full throttle, the engine speed would fly right past these windows so quickly that symptoms were entirely unnoticeable.
Due to how quickly engine speed will pass the trouble spots any time a vacuum referenced FPD is putting in its extra work, I don't believe its going to have any noticeable improvements over a static FPD.
That said, its still a sound theory to keep the FPDs from bottoming out during full throttle. Looking deeper than driving characteristics, it could show fuel system performance linearity improvements at the high speed data acquisition level. So in short, I do not personally believe its going to improve driving characteristics to any perceivable level over a static FPD - but its very possible it might make tuning a little more pleasant for a tuner who is OCD about his VE table or etc.
I have not moved to using them yet, but I might one day. For the best of both worlds, add one of these standalone FPDs to a rail that already has a basic one!
At 6000 RPM, a 2-rotor has 20 ignition events per second. I'd have to go back and confirm the data but, from memory, fuel absolute pressure dips of -30 psi for 1/2 second plus intervals were pretty common. Those 10+ ignition events with far less fuel could potentially be the answer to many "my junk blew up and I don't know why" situations. The bottom line is, dampers are CHEAP. Even a full boat Radium unit is relatively inexpensive. After seeing the data and results, I'm of the opinion no one should be without a damper.
Joined: Mar 2001
Posts: 31,837
Likes: 3,234
From: https://www2.mazda.com/en/100th/
Mazda had an MPV with a remote mounted damper, its the same damper that they use in everything, but with two 8mm hose nipples, and a little bracket, so it can be mounted anywhere. the MPV had it on the valve cover.
the Mazda part number is JF01-20-180D, from a 1991 MPV v6
the Mazda part number is JF01-20-180D, from a 1991 MPV v6
Full Member
Joined: Oct 2004
Posts: 161
Likes: 0
From: chicago
I wouldn't be so quick to dismiss issues as "if I don't feel it, it's not an issue". As I said originally, the car we got the data from drove fine and you couldn't feel any issues. But, while mapping it, experience said there was something up. High speed data showed an issue and saying it's only a data issue because you can't feel it or the engine passes through the trouble area so quickly is missing the bigger picture.
Originally Posted by phunk
That said, its still a sound theory to keep the FPDs from bottoming out during full throttle. Looking deeper than driving characteristics, it could show fuel system performance linearity improvements at the high speed data acquisition level. So in short, I do not personally believe its going to improve driving characteristics to any perceivable level over a static FPD
Last edited by phunk; Feb 13, 2016 at 05:36 PM.
Banned. I got OWNED!!!
Joined: Aug 2012
Posts: 1,666
Likes: 88
From: San Jose, CA
I wouldn't mind tee-ing off of each fuel line and running two of these, but I think I should run a vac/boost signal version. Ugh, this fuel system is continuing it's complexity once again.
Last edited by RGHTBrainDesign; Feb 19, 2016 at 06:39 PM.
Update result with R model. I just finished my turbo swap from T04s with BW 8374 iwg, before without the damper my injector duty cycle was 75% in 3rd wot witht he T04s setup. Yesterday i test both items out 8374 and damper. I have oem 550 injectors and ID 2.000, with SARD fpr (pressure set at 40psi) and now the damper, tested in 3rd gear wot injector duty is now showing 50%.
Thread Starter
Joined: Mar 2001
Posts: 5,269
Likes: 150
From: Floyds Knobs. IN
Looks like an over complicated mass of potential failure points. Absolutely no need for two dampers. And I'd never want the weight of that regulator supported by those unions.
Originally Posted by C. Ludwig
Looks like an over complicated mass of potential failure points. Absolutely no need for two dampers. And I'd never want the weight of that regulator supported by those unions.