The sky is falling! The sky is falling!

gmctd · **Posted:** Tue Mar 11, 2008 6:17 pm

The sky is falling - everybody remember the story of Chicken Little, where an acorn fell on the idiot's head, whereupon he proceeded stirring up the local population with eyewitness accounts of disaster commencing with a falling sky?

Let's talk rail pressures and the ever-terrifying 'increased rail pressures' syndrome. Each time a power box is mentioned, it is always accompanied by some misgivings concerning raised rail pressures, with the implied thread of disastrous consequences, not limited to but including curdled cow's milk and stunted crops - this harks back to an era when men huddled in their caves as the gods railed at the earth with thunder and lightning - now, of course, we know that thunder results from lightning discharge, and even how there can be lightning with no thunder, as when heat-lightning plays amongst the clouds

Education makes all the difference in the world in man's reaction to the unknown

To those who would bar the door, lock up the women and children, and huddle fearfully in their cupboards and under the bedsteads, this: increased rail pressure is not a bad thing, nor a thing to fear.

To wit: Long ago, prolly B4 most of you were even born, engineers determined that increased injection pressure resulted in ease of combustion, cleaner burn, increased efficiency and increased power - unfortunately, then-technology was not suitable for those higher pressures, as compression is work, work is load, load is wear: work requires power, higher compression requires increased power, results in increased pump wear, not suitable for engines designed for million-mile service.

Today, high rail pressures based on new pump design are prevalent amongst common-rail Diesel engines, with 23000psi being common-place, and the new series engines running up to 30000psi - having looked for myself, I see no resultant great holes in the sky.

The problem with way high pressures is the loading on the injection pump and the increased power drain - for many years, auto transmissions had one big pump, draining specific power levels from the engine - cruising requires less overhead than loaded running, but that big pump did not allow for that - your 545RFE has two pumps, one for cruising, both for power loading, a setup promoting fuel economy - same concept on your injection pump: lower injection pressures at low rpm = less overhead loading equals more power to move the vehicle, thus less fuel required to move the vehicle = improved economy

Bosch, oem mfr of our CRD injection system, designed the CP3 injection pump with a maximum pressure limit of 23200psi, same as in the DMax, and the Cummins systems - system pressure up to that limit is variable per system demand, low rpm low power, low rpm high power, and high rpm low power to high rpm high power: ~4500psi is absolutely suitable for idle rpm, and 30mph, but unsuitable for 30mph at high load, even more unsuitable at 4000rpm under high loading - this is because Diesel fuel burns slowly resulting in a 'window of opportunity' with finite limits for the injection event, which varies within those limits according to rpm: wide at low rpm, narrow at high rpm - the higher the pressure, the quicker the injection event can occur, important at high rpm, when the piston doesn't stay in any one place for very long, rendering the window for the injection event and combustion cycle very short, indeed.
Thus, at low rpm high power events and high rpm power events, the fuel has a finite time to get in the cylinder, get combusting and make push - the higher the pressure, the quicker that can happen

Also, at greater power levels, the injected fuel rate can be so high that rail volume becomes unstable, even dropping below expected, resulted starvation felt as skipping, missing, hesitation - greater rail pressure will heal that, so increasing 2000rpm rail pressure levels to 4000rpm rail pressure levels can ensure adequate fuel for the increased power demand at lower rpm and quicker injection event at higher rpm - something DCJ didn't plan on, but is adequately addressed by the better power boxes, having both RP and MAP input.

Fuel economy? Yer asking me about economy, when you've got the go pedal nailed to the floor everytime you take off?
Ha!

So - next time you hear that a power box increases rail pressure, there is simply no need to bar the door, lock up the women and children, and cower shamelessly under your bedstead - you could series\parallel wire-in a thousand power boxes, and they will not increase rail pressure to any level greater than Robert Bosch authorized you to have - and nowhere even close to an order of magnitude less than a thousand-fold - you're stuck with 23.2Kpsi max outta the CP3, written in stone - the boxes simply allow for greater than oem programmed pressure at any demand event = more power, no problemo.

Word up, dudes....................

JIMMY JEEP · **Posted:** Tue Mar 11, 2008 7:08 pm

Nice informative write up ,thanks.

MACKJ · **Posted:** Tue Mar 11, 2008 7:38 pm

The sky isn't falling, the ground is...we are upside down here you know.
Good write up, fully understood.
It begs the question then, what power modules out there actually control (by stealth!) the rail pressure and boost?

gmctd · **Posted:** Tue Mar 11, 2008 8:39 pm

Good question, from down under - I can personally verify the Edge Trail module, as installed on #2 son's KJ - never even noticed the often-complained-about results of F37 with the module in-place - that little mule will scat like a quarter-horse, and beg for more, and that's with the switch in the center for-towing position, first position being stock, third position being 'race' - soon as I can find a spare ECM, I want to try the Inmotion reflash with Edge stack

ATXKJ · **Posted:** Tue Mar 11, 2008 8:40 pm

Well - I'm concerned about rail pressure - however it's more of a long term concern.
The pump and rail have joints and seals - the higher the pressure for a longer times - the more likely
you will have leaks & failure developing - not instantly - but over time
(I am less worried after learning the CP3 has internal pressure relief)
also if you're not doing a great job filtering the fuel - impurities will wear injector faster at higher pressures.

Probably more worried now about EGT temps - if the mod only dumps more fuel with adjusting
the timing - it'll overheat the exhaust - also a reliability issue.

Back to MackJ's question -
This was the list I put together
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?t=26626&highlight=performance+module
they all say they modify fuel and pressure - but none of them say how much
- Actually I suspect that most don't know - it's way to easy to plug in a resistor into a sensor line
and get more power out of the engine - without knowing what you're actually modifying.

gmctd · **Posted:** Tue Mar 11, 2008 9:49 pm

And you have reason for concern, timing or no timing - Boost and EGR guages are absolutely necessary first upgrades when tuning for power, because increased fuel is increased BTU with increased EGT - written in stone, no way around that.

Picture Smokey the Bear, standing not in front of a burned forest, but a forlorn KJ, with a final wispy plume of antifreeze steam drifting up thru the edge of the closed hood (from the huge puddle on the ground underneath), saying "Only you.......can prevent piston melt-down"

DCJ has the engine tuned to prevent that scenario - first time you pop the hood with tools in hand and a gleam in your eye, it had better be to install the pressure tap and type K thermocouple for your new Boost and EGT guages, because from that point on, DCJ has lost all form of control and limit.

ECM uses various sensory feedback to excercise that control - how much better then can you assume control, with absolutely no sensory feedback?

Guages - guages - guages, would be my answer to your concern(s)

MACKJ · **Posted:** Tue Mar 11, 2008 10:18 pm

gmctd wrote:

...ECM uses various sensory feedback to excercise that control - how much better then can you assume control, with absolutely no sensory feedback?

Guages - guages - guages, would be my answer to your concern(s)

Ditto, ditto and ditto.
That is why I have an EGT gauge and plan to have a boost gauge.
No matter what the vendors say we need to monitor these things to protect our investment, and as most already know, the drive train also needs to be beefed up al la Suncoast etc.
The "monitoring" question is one of the reasons I have been looking at LPG (liquified propane gas) injection. The systems offered here in Oz have a true closed loop control that monitors boost and EGT so that you keep under turbo/piston "detonation" limits. The main incentive for this type of conversion is to increase economy but the added big benefit is a cleaner burn, with reduced emissions and increased power from the LPG fuel. Plus there is a Federal incentive if you carry out the conversion!
From memory the LPG injection rate is somewhere between 20 to 50%.
The challenge, should you choose to accept it, is to find a location for the gas tanks.

MrMopar64 · **Posted:** Tue Mar 11, 2008 11:23 pm

Since I'm tired of homework for the time being, I thought that I'd add some insight to this great topic of rail pressure, et. al.

First topic to cover is the pressure capability of the injection pump/system. The CP pump on the KJ engine is "rated" for maximum pressure output of 1600 bar, 23520 psi. That is not to say that the pump will bypass above 1600 bar and not push any more, quite to the contrary. If, by some means, it was requested to deliver 1800 bar, it would do it no doubt. Would it last very long at those levels? Not comparably in the long run if exercised there often and for long periods of time. In general engineering practice, a factor of safety is always applied to a solution so that, in general usage, a system is never asked to function in such a way that failure would occur imminently and in short order. It is within these safety margins that products like the Edge module operate in so as to use the extra capabilities of the system (even stated in the Edge literature). Does operating outside the 1st standard deviation of limits (or whatever the distribution might be) affect reliability and longevity? Of course it does. In terms of overall system delivery, yes the delivery rate can be so large that even with the metering unit at 100% duty cycle the volume can become unstable. However, in most cases, you must seriously exceed the manufacturer's ratings by a long shot or the engineer releasing that part is an idiot.

In terms of engine operation and how it is calibrated, rail pressure has a great influence on a great many factors: engine noise, NOx, soot production, efficiency, etc. It also has to do with the pure physical and operation limits of the hardware on the engine. Because the injectors are electronically controlled and fuel flow is the important thing, if the energizing time of the injector is held constant and the rail pressure is increased then the fuel flow delivery from that injector will also increase. Expanding this idea further, say that an engine is running at 3800rpm and you have a desired injection timing of xx deg BTDC. If you increase the rail pressure in this operating region then the energizing time for that desired injection quantity will go down, which means that the change in crank angle with regard to duration of injection will be lower. This means that the quantity of fuel is more precisely delivered within that prescribed time which is very important. Now, if the rail pressure is high at low RPM and the energizing time is very very quick, the engine will sound like an old tractor because the fuel is being delivered more or less instantaneously which causes the combustion event to result in a huge spike in cylinder pressure, thus resulting in the quintessential diesel clatter. However, if you lower the rail pressure in this same region, the injection duration becomes longer which results in the cylinder pressure trace to be much smoother, causing the clatter to be much reduced.

How this all interacts with aftermarket programmers is another case for disagreement. Lets take the Edge EZ for CRD as an example. It's only inputs are the rail and MAP sensors with outputs which hook into the factory harness connectors for those sensors. There is no other power source and the power stages in the ECU aren't designed to support the powering of any circuitry so we'll presume that there is no microprocessor in the box. Because the only connection is to the rail pressure sensor and the MAP sensor, the only possible solutions for increasing power is to manipulate the sensor signal such that the rail pressure is increased (remember, hold energizing time constant and increase rail pressure = increase in injection quantity) and the boost pressure is increased. How this is accomplished varies from manufacturer to manufacturer, but a simple voltage divider where the "level" switch connects a different bridge would very easily serve the purpose.

However, the topic of rail pressure and the max delivered rate again comes into play. Because the box claims a certain hp and tq increase, we'll focus on only the WOT points of interest since the rest of the operating points will follow a similar principle. While every engine manufacturer tailors things differently based on what the engine has to do, at some point in the curve the rail pressure setpoint will be at the max "allowable" pressure with the metering unit duty cycle adjusting to accomodate the desired rail pressure and the rail total flow rate. Now, the ECU is only going to allow what it "thinks" is the max rail pressure; however, if the box were to send the ECU a signal saying that the rail pressure is 200 bar lower (or some other value) than what is actually present, the ECU will adjust the metering unit duty cycle such that it "thinks" it is operating again at the correct pressure. Since the injector energizing time is the same and we've increased rail pressure, voila!-we get more fuel and make more power. Now, is this necessarily safe for the components? So long as you don't exceed the safety factor margins then you'll be more or less okay since the time you spend at WOT is fairly minimal. However, longevity and reliability are still compromised to some degree. And whoever thinks that the system is stuck with the 1600 bar max is gravely mistaken - exceed it too far, and you'll watch your rail fail, the sensor fail, pump fail, fuel pipes fail, etc. It is capable of more pressure, yes, but not smart to really take advantage of it.

On a separate note, something else to think about is the pressure inside the combustion chamber. This engine is not a cummins, it has an aluminum head and its capabilities are not near as "work-horse-ish" as the cummins. If we increase the fuel delivery and the boost pressure, we will of course make more power, that is a given. However, it also means that we are going to increase the cylinder pressure by some figure. To put it in perspective, as it stands now, cylinder pressure at rated horsepower (WOT @ 3800rpm) is in the neighborhood of mid-100s bar. Obviously with an aluminum head, the limits of combustion pressure are going to be vastly different than what an iron head on something like a CUmmins can handle. If you increase power too much, the combustion pressures will no longer be within a range of values deemed "reliably safe" in terms of head life and head gasket life. Just something to think about for the long run.

gmctd · **Posted:** Wed Mar 12, 2008 12:15 am

Excellent input - agreed but with several points of contention -

a.) The DMax does fairly well with not one, but two aluminum heads and two CP3 IP's, horsepower in the 1200hp range

b.) The output of the CP3 can be increased to over 23.2kpsia, but not by the ECM or an add-in power box - requires some mechanical manipulation which we need not go into at this juncture, but internal seal failure has been caused by little more than increased pressure at the lift pump inlet, so additional steps are required for a major output pressure increase to ~26kpsi

c.) Actual volume\stroke can be increased mechanically without raising output pressure, usually done to stabilize rail pressure at increased flow rates

Yep - it's in there, but ECM ain't gonna do anything more than Robert intended - wouldn't you agree?

Threeweight · **Joined:** Mon May 14, 2007 5:57 pm **Posts:** 679

Question -- how do you folks think an ECU remap like the Inmotion affects EGT's and long-term durability? They claim to simply be mapping it to "European specs," but looking over info on Jeeps sold w/ the 2.8 VM in the UK, their factory specs look the same as ours.

MACKJ · **Posted:** Wed Mar 12, 2008 2:07 am

Threeweight wrote:

Question -- how do you folks think an ECU remap like the Inmotion affects EGT's and long-term durability? They claim to simply be mapping it to "European specs," but looking over info on Jeeps sold w/ the 2.8 VM in the UK, their factory specs look the same as ours.

Well the US specs are the same as on the Australian models. Doesn't make sense why they would change it for Euro versions and not the domestic or other export markets.

Uffe · **Posted:** Wed Mar 12, 2008 3:44 am

MrMopar64 wrote:

... long interesting post...

On a separate note, something else to think about is the pressure inside the combustion chamber. This engine is not a cummins, it has an aluminum head and its capabilities are not near as "work-horse-ish" as the cummins. If we increase the fuel delivery and the boost pressure, we will of course make more power, that is a given. However, it also means that we are going to increase the cylinder pressure by some figure. To put it in perspective, as it stands now, cylinder pressure at rated horsepower (WOT @ 3800rpm) is in the neighborhood of mid-100s bar. Obviously with an aluminum head, the limits of combustion pressure are going to be vastly different than what an iron head on something like a CUmmins can handle. If you increase power too much, the combustion pressures will no longer be within a range of values deemed "reliably safe" in terms of head life and head gasket life. Just something to think about for the long run.

Aha. This is what makes me very interested! Since my old car was accused of having a weak head gasket and head I have been concerned about head and gasket life in the KJ as a result of the aluminum part of it all

Since I'm a euro guy I know nothing of cummins - so I am pleased to learn a little thing about it. My impression from your post is that they still use cast iron heads, which are able to handler greater pressure (and deliver more power, subsequently) - most modern jap cars (well most modern diesel cars I can think of) all use aluminum heads. In a mail you once told me the head gasket can be made more flexible to keep the expanding side of aluminum vs iron in check.

But what about increased cylinder pressure?

Many people with Nissan Patrol 2.8 ('89-2000) had numerous heads and gasket replacements. After reading your post here it would seem they spent too much time at WOT compared to what Nissan spec'ed the engine for. It is not so much because of overheating, but instead because of over-WOT'ing?

It subsequently then leads me to believe that if you can stay away from WOT (assuming your cooling system is keeping everything properly cooled), your head would survive longer, right?

So my question is more regarding what kind of improvement can you do to an aluminum head to increase reliability?

Sorry to ask all these questions in a little unrelated thread, it sort of just got me going

Joe Romas · **Posted:** Wed Mar 12, 2008 6:55 am

Threeweight wrote:

Question -- how do you folks think an ECU remap like the Inmotion affects EGT's and long-term durability? They claim to simply be mapping it to "European specs," but looking over info on Jeeps sold w/ the 2.8 VM in the UK, their factory specs look the same as ours.

Keep in mind our engine is used in other NON Chrysler vehicles. Think "NON Chrysler European specs" :lol:

MrMopar64 · **Posted:** Wed Mar 12, 2008 7:40 am

The European engines have the same output as US bound engines, so mapping it to "European" specs only changes air control settings (EGR) and some timing changes for emissions standards. Anything else these engines are used in in Europe is in lower-output applications, so you'd gain nothing but a turd by using these settings.

While I can't divulge necessarily everything that I've worked on or why, I have personally done some work with increased outputs on considerably older 2.5L engines and found at some point the stock head gasket will start to seep if subjected to long-term cylinder pressures well in excess of what it was designed to handle.

If I were to desire a CP pump to make more than 1600bar (say, 1700bar), it would take nothing more than a few changes to the ECU calibration for that to happen and I'd have my increase in pressure through just a slight increase in metering unit duty cycle. You are correct in that the ECU will not give anymore than what the calibration asks for - however, if a box was to intercept the rail pressure sensor signal and thusly convert it so that it corresponds to a value some number lower than it actually is, the ECU is fooled into thinking that the rail pressure is below its set point, adjusts MeUn duty cycle to compensate, and brings it back up to what "it thinks" is the proper value. Of course, what the ECU thinks is the correct value is really some number higher, thus how you get more fuel. SO yes, the ECU doesn't think that it is exceeding it's own limits, but if the rail pressure sensor voltage were to be measured directly from the sensor and then linearized into pressure, you would find that there would be some offset as compared to the value reported by the ECU.

Uffe, you have to remember that the engine was of course to operate around certain constraints with max cylinder pressure being one of them. The engine in your KJ you could hold at WOT for over 1000hrs and it'd still be fine. Of course an engine that is not abused will last longer, but if a stock engine operating within the stock limits to ensure xxx,xxx miles/km of longevity was worked hard all the time there'd be no problem. It's when an engine is asked to give more than what it was designed for that longevity and durability are compromised. IN the case of the Nissan engines, I would guess that a sub-standard cooling system would be at the heart of it followed by a design with a less-than desirable margin of safety. The concern of overheating comes from two dissimilar metals being clamped together because they will distort differently with temperature and at some point a high enough temperature will cause a distortion that the head gasket cannot compensate for. The only way to improve reliability is to not subject the system to extreme swings in temperature and to not overheat the system. Keep those two in check and you'll be more than fine for multiples of years of service.

Uffe · **Posted:** Wed Mar 12, 2008 1:51 pm

MrMopar64 wrote:

Uffe, you have to remember that the engine was of course to operate around certain constraints with max cylinder pressure being one of them. The engine in your KJ you could hold at WOT for over 1000hrs and it'd still be fine. Of course an engine that is not abused will last longer, but if a stock engine operating within the stock limits to ensure xxx,xxx miles/km of longevity was worked hard all the time there'd be no problem. It's when an engine is asked to give more than what it was designed for that longevity and durability are compromised. IN the case of the Nissan engines, I would guess that a sub-standard cooling system would be at the heart of it followed by a design with a less-than desirable margin of safety. The concern of overheating comes from two dissimilar metals being clamped together because they will distort differently with temperature and at some point a high enough temperature will cause a distortion that the head gasket cannot compensate for. The only way to improve reliability is to not subject the system to extreme swings in temperature and to not overheat the system. Keep those two in check and you'll be more than fine for multiples of years of service.

There was a few guys on a forum who took the head off the Patrol 2.8 and discovered that some of the water channels in the head around the 6th cylinder was "shorted", meaning there would not be any flow of signifigance around the particular cylinder no matter the rpm of the water pump.

Threeweight · **Joined:** Mon May 14, 2007 5:57 pm **Posts:** 679

MrMopar64 wrote:

The European engines have the same output as US bound engines, so mapping it to "European" specs only changes air control settings (EGR) and some timing changes for emissions standards. Anything else these engines are used in in Europe is in lower-output applications, so you'd gain nothing but a turd by using these settings.

Based on my understanding of VW TDI performance tuning (which generally involves fuel boosting, different nozzles, exhaust, etc...), I've always thought the Inmotion tune was likely just a ECU reprogram to boost rail pressure.

warp2diesel · **Posted:** Wed Mar 12, 2008 4:23 pm

After reading the posting from GMCTD last night, I put together what the absolute limitations of a Common Rail type system are. Before I purchased my CRD a little over a year ago I researched as much as I could on the Common Rail system and in doing so obtained a lot of development information. One of the early problems with development of the first Generation of the Common Rail system was small cracks caused by metal fatigue. At that time engineers thought the absolute limit would be 26,000 PSI, engineering and technology have put these past worries to rest.
GMCTD and MrMopar have a lot of company direct, hands on information they have passed on for which they should be commended, I hope this small contribution can connect the rest of the dots to make a more complete picture.

Besides the structural limitations of the components such as the CP3 pump, the true limiting factor on rail pressure is the factor of fatigue and shear strength of the weakest material used to carry the rail pressure. Stronger alloys with more fatigue resistance will enable higher rail pressures to be used and then the limiting factor will be the pressure and temperature where the fuel starts to form unwanted molecular bonds and formation of longer carbon chains and a more viscous fuel with undesirable burning characteristics.
One positive aspect of the common rail injection system is due to the pilot actuated injectors that use a pilot to open the main injector valve and reduce the shock loads and material fatigue on the injection system. Pizeo injectors have a higher and quicker build up of the electromagnetic flux allowing an even smaller pilot to make faster multiple firings of the injector. By reducing the hydraulic shock loads the rail pressure can be increased to higher pressures being only limited by the absolute limiting factors of structural strength of the components, material shear strength, material fatigue, and unwanted molecular bonds and formation of longer carbon chains in the fuel.
One of the reasons Bosch set the rail pressure limit of the Generation II at 23,200 PSI is due to the use of the electromechanical injectors and the hydraulic shock loads they generate on the system. Pizeo injectors used on Generation III produce lower hydraulic shock loads allowing the maximum pressure to be increased to 30,000 PSI.
Adding a performance module that increases rail pressure making the common rail system work harder, can raise the fuel temperature and make the use of a fuel cooler a necessity to prevent the ECM from cutting back on power out put.

Steve

gmctd · **Posted:** Wed Mar 12, 2008 9:15 pm

I've lost it, but if found will post it - someone sent me a link to a patent awarded to Robert Bosch GMBH covering a new technique for creating a hi-pressure rail by eliminating the sharp edges that turn into stress risers, then cracks, allowing potential pressures to 30kpsi

Also, for comparison, we have the Edge Trail module, always in the tow-mode position #2 - monitoring with SGII and AE enhanced scantool, WOT rail pressures never made it to 23206psi, Bosch published max for the system - for any with similar module and similar monitoring capability, post your findings in all of the switchable modes - I'll have to get back with you later on position #3, if I ever see ours again

MrMopar64 · **Posted:** Thu Mar 13, 2008 12:03 am

You have to remember that the rail pressure that you are seeing from the scan tool is that which the ECU "thinks" is the correct rail pressure. However, the only true way to measure the actual rail pressure would be in tap into the wiring coming directly off the sensor and data log the voltage there while you drive. This voltage can then be linearized into the actual rail pressure which can then be compared to that which you are measuring from the ECU side.

As for the Bosch patent on techniques, I believe that this is the new process of laser-welding on the rail they are using. If you were to compare a 5.9 CR Cummins and the new 6.7 Cummins, the rail on the 5.9 is a rough forged piece which looks like that which is on the KJ. The rail on the 6.7L appears smooth and shiney from the outside, and if you look closely around where the tube connections are, you can see how it is laser welded togther. These rails are much stronger that previous ones and are part of new packages used on higher-pressure systems.

gmctd · **Posted:** Thu Mar 13, 2008 11:12 am

Agreed on the scan view vs actual RP, and I had posted that at an earlier juncture when doing the runs - would like some comparitive figures from the various boxes as installed, tho it would be more effective if compared on the same vehicle

The patented rail method involved a cross-boring technique, rather than boring one wall for the ports, such that further steps could involve deburring the holes and relieving the edges - required thicker-wall rail tubing due to 12 opposing holes instead of the previous six - I haven't seen a practical representative of that, but seems as though it would present an ideal method of tapping the rail for auxiliary pressure guage, with an electronic strain-guage transmitter and meter - most automotive guage vendors now offer those for ~250bucks.

I really appreciate your input from "inside" - this stuff is extremely difficult to come by, even on the 'net, prolly due to the EPA restrictions on modification - most of this CRD stuff I pick up on the various forums by noting the complaint, then analyzing the results of various suggested fixes, workable or not, then determining how the failure resulted the various reported symptoms - sort of back-engineering by failure analysis, probably the easiest way to learn, for me - it can leave some unanswered questions, but then later another complaint will add another bit of data, and another, then the answer is clearer - noting repeated complaints of CP3 seal leakage by the members with 45psi lift pumps is revealing (to me, but not to them) - noting the mechanical modifications to the CP3 to obtain greater volume and pressure output is also informative - prolly also helps to have a background in flow measurement and process control - these EFI systems are just mini-microcosms of the large petro-chemical systems I worked with

The sky is falling! The sky is falling!

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