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Biggest fuel pump that doesn't overpower Vette regulator/filter

 
Old 11-27-2018, 04:26 PM
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Default Biggest fuel pump that doesn't overpower Vette regulator/filter

With a 255 lph fuel pump, I have steady 58 psi from my 99 Vette fuel filter/regulator. I have heard of pumps in the high 300s lph overpowering the regulator and causing a fuel pressure rise way above 58 psi.

What is the largest in-tank fuel pump you've used that still keeps the vette regulator/filter within control?
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Old 11-27-2018, 10:49 PM
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Post # 8

https://ls1tech.com/forums/fueling-i...bro-255-a.html

Others on this forum report the same information.

I tried the same setup - the 340 kit and c5 filter on my 98 Z28. Was getting 70 + at the rail. The pump failed at about 10 hours. Reason? Can only speculate.

The 98 bulkhead connector doesn't support enough amps for the RXP 341 (340 lph) and that it browned out. The 340 draws up to 17 amps at 13.5 volts. The 98 bulkhead connector only supports 14 amps.

The 99-2002 upgraded bulkhead connector supports up to 30 amps. They can't be installed on a 98 fuel pump module. Even so, excessive head pressure at the pump, if not controlled with an FPR, reduces the life of the pump. An FPR is the only way to go with a pump larger than a 255 lph.

Lonnies Performance essentially told me this before I installed the kit but I didn't listen. Looking back now, if the C5 filter with a Racetronix 340 or 450 could handle the volume and pressure, Racetronix and Lonnies Performance would be selling a kit. They don't however. Racetronix explains why on their site.

This is because the point of regulation is at the back of the car. The location of the FPR does not allow it compensate for line
pressure drop even though the pressure is stable at the back (regulator location). There are two options to get around this problem.
First is to convert the system to a rail mounted FRP return type (best). The second option is to install a pump booster which is
activated at the point where rail pressure starts to drop. The boost in fuel volume overwhelms the regulator / return line thereby
increasing the fuel pressure at the back of the car which translates to higher pressure at the rail. We recommend the MSD unit for
FI applications as it ramps the voltage based on manifold pressure.

Please understand that this is not an issue with the Racetronix system but rather a design limitation of the factory configuration.

Tossed it all, and started over and installed a Racetronix 510lph dual pump kit with along with their fuel rails,hose, and regulator kit.

Last edited by dlandsvZ28; 11-27-2018 at 10:52 PM. Reason: edit content
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Old 11-27-2018, 11:00 PM
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Originally Posted by dlandsvZ28 View Post
Post # 8

https://ls1tech.com/forums/fueling-i...bro-255-a.html

Others on this forum report the same information.

I tried the same setup - the 340 kit and c5 filter on my 98 Z28. Was getting 70 + at the rail. The pump failed at about 10 hours. Reason? Can only speculate.

The 98 bulkhead connector doesn't support enough amps for the RXP 341 (340 lph) and that it browned out. The 340 draws up to 17 amps at 13.5 volts. The 98 bulkhead connector only supports 14 amps.

The 99-2002 upgraded bulkhead connector supports up to 30 amps. They can't be installed on a 98 fuel pump module. Even so, excessive head pressure at the pump, if not controlled with an FPR, reduces the life of the pump. An FPR is the only way to go with a pump larger than a 255 lph.

Lonnies Performance essentially told me this before I installed the kit but I didn't listen. Looking back now, if the C5 filter with a Racetronix 340 or 450 could handle the volume and pressure, Racetronix and Lonnies Performance would be selling a kit. They don't however. Racetronix explains why on their site.

This is because the point of regulation is at the back of the car. The location of the FPR does not allow it compensate for line
pressure drop even though the pressure is stable at the back (regulator location). There are two options to get around this problem.
First is to convert the system to a rail mounted FRP return type (best). The second option is to install a pump booster which is
activated at the point where rail pressure starts to drop. The boost in fuel volume overwhelms the regulator / return line thereby
increasing the fuel pressure at the back of the car which translates to higher pressure at the rail. We recommend the MSD unit for
FI applications as it ramps the voltage based on manifold pressure.

Please understand that this is not an issue with the Racetronix system but rather a design limitation of the factory configuration.

Tossed it all, and started over and installed a Racetronix 510lph dual pump kit with along with their fuel rails,hose, and regulator kit.
Wow that is a lot of good info, thank you very much for the reply. For now I'll restrict my future power to within the 255 lph capabilities (hopefully at least 530-550 rwhp or so through a th400, pump gas, regular voltage to the pump).
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Old 11-28-2018, 06:30 AM
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I ran a 450 in tank with a hot wire kit through the stock regulator. 70 psi of pressure at the rail and was tuned for it so it ran fine no problem.
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Old 11-28-2018, 10:00 AM
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I have a Pro-M fuel pump hanger where it has a 3/8" feed and 3/8" return. So it's efficiently being returned as far as that goes but the return on the vette regulator is 5/16" I believe. I am told that the filter element becomes a restriction in bigger pumps.... but lots get away with it so combined with my 3/8" in/out fuel tank hat, I may make life easier for a higher amp pump due to the return size into the tank.
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Old 11-28-2018, 10:16 AM
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If that were true then every ls swap using the c5 reg would have an issue, and boy, are there alot if them.

Most of the kits we hear about now have 58 to 65 max pressure. We are looking at other ways to minimize any other blockage/restriction in the lines/setup also.

The issue with a bad or underperforming battery and charging system is one major issue. Some run 340+ pumps on stock regs, but sooner or later they do distort or cause issue in one way or another. That is the whole reason we engineered the kit.

As for the argument of " if it were better x place would sell it" thats not firm ground to stand on.
The c5 vette uses that setup and has 0 issue and its nearly identical to the way we make it install. Not every place will sell the same parts, or even have the same ideas for what to use or how.

I dont like hobbs switches at all. Ive had issues with them. others have not so they use and recommend them. That doesnt mean that either of us are wrong, it just means we have a different way of getting to the desired end product.

We are actively keeping track of all of the products we offer, as well as looking for better ways to design them and looking for new parts to offer at better prices while maintaining high quality.

If there are any other developments, i will let everyone know via a post on here and on the site and social media.
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Old 11-28-2018, 03:26 PM
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Originally Posted by [email protected] View Post
If that were true then every ls swap using the c5 reg would have an issue, and boy, are there alot if them.

Most of the kits we hear about now have 58 to 65 max pressure. We are looking at other ways to minimize any other blockage/restriction in the lines/setup also.

The issue with a bad or underperforming battery and charging system is one major issue. Some run 340+ pumps on stock regs, but sooner or later they do distort or cause issue in one way or another. That is the whole reason we engineered the kit.

As for the argument of " if it were better x place would sell it" thats not firm ground to stand on.
The c5 vette uses that setup and has 0 issue and its nearly identical to the way we make it install. Not every place will sell the same parts, or even have the same ideas for what to use or how.

I dont like hobbs switches at all. Ive had issues with them. others have not so they use and recommend them. That doesnt mean that either of us are wrong, it just means we have a different way of getting to the desired end product.

We are actively keeping track of all of the products we offer, as well as looking for better ways to design them and looking for new parts to offer at better prices while maintaining high quality.

If there are any other developments, i will let everyone know via a post on here and on the site and social media.
Well that's good to hear that the vette filter/regulator is better with turbo level rwhp than I thought, win win.
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Old 11-28-2018, 04:04 PM
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Originally Posted by foxsl View Post
Well that's good to hear that the vette filter/regulator is better with turbo level rwhp than I thought, win win.
If you plan to upgrade to boost and up your FWHP then I would review how to set up a FPR for boost and see what happens when there is 15 - 20 lbs of positive pressure in the manifold as a result of boost and how that affects the pressure in the lines and the injectors. And then how an FPR compensates for that. Then ask yourself if the FPR in the filter or in the tank will react the same way.

This link is pretty good.

https://www.turbosmart.com/news/how-does-an-fpr-work/

This white paper is pretty good too. Some good stuff in here. Running pumps in series vs parallel for example. Another is that Aeromotive doesn't mfg any electric single pump in it's inventory suitable for continuous duty above 70 PSI.

https://www.aeromotiveinc.com/tech-h...fi-fuel-pumps/
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Old 11-28-2018, 04:40 PM
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A rising rate fpr is better but not the end all be all for moderate boost and it doesnt change pressure in the lines only *possibly* at the injector tip.

The actual pressure measured is PSI correct? That means per square inch. How large is an injector tip? So it sees a mere fraction of that to begin with but also since the air is literally being forced in, it will carry any amount of atomized fuel directly to the back of the valve/into the chamber.

Some assumptions are only assumptions. There are so many making power on stock systems that are factory regulated and even more in swaps using the c5 filter. some of them have it plugged directly onto the rail even.

From personal and professional experience the c5 regulator will handle the same amount of fuel that the stock lines are capable of. Roughly 750ish to 800 hp in quite a few applications. Im not saying its any better than an actual external fpr but it is an affordable option used every day in boost apps.
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Old 11-28-2018, 04:45 PM
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Originally Posted by dlandsvZ28 View Post
If you plan to upgrade to boost and up your FWHP then I would review how to set up a FPR for boost and see what happens when there is 15 - 20 lbs of positive pressure in the manifold as a result of boost and how that affects the pressure in the lines and the injectors. And then how an FPR compensates for that. Then ask yourself if the FPR in the filter or in the tank will react the same way.

This link is pretty good.

https://www.turbosmart.com/news/how-does-an-fpr-work/

This white paper is pretty good too. Some good stuff in here. Running pumps in series vs parallel for example. Another is that Aeromotive doesn't mfg any electric single pump in it's inventory suitable for continuous duty above 70 PSI.

https://www.aeromotiveinc.com/tech-h...fi-fuel-pumps/
I've already tuned a supercharged 5.3 setup that had a vette filter/regulator, positive pressure was 8 psi and there wasn't any pressure drop. 8 psi is low though...but on a large turbo setup, 8 psi will require a lot of fuel and the pressure drop from the demand will be more significant, so I like to think in terms of fwhp and not psi.
My goal here, like many have successfully done over the years, is to retain the returnless setup with the vette filter/regulator with my low sub 600 rwhp goals. I see no need to redo my fuel system setup in terms of the returnless filter/regulator setup.
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Old 11-28-2018, 04:55 PM
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Originally Posted by [email protected] View Post
A rising rate fpr is better but not the end all be all for moderate boost and it doesnt change pressure in the lines only *possibly* at the injector tip.

The actual pressure measured is PSI correct? That means per square inch. How large is an injector tip? So it sees a mere fraction of that to begin with but also since the air is literally being forced in, it will carry any amount of atomized fuel directly to the back of the valve/into the chamber.

Some assumptions are only assumptions. There are so many making power on stock systems that are factory regulated and even more in swaps using the c5 filter. some of them have it plugged directly onto the rail even.

From personal and professional experience the c5 regulator will handle the same amount of fuel that the stock lines are capable of. Roughly 750ish to 800 hp in quite a few applications. Im not saying its any better than an actual external fpr but it is an affordable option used every day in boost apps.
740 crank hp is about 590 rwhp with a th400 auto 20% driveline loss....so it sounds like I am good for ever with my 550 rwhp street goal.
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Old 11-29-2018, 11:23 AM
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I thought my Racetronix would 255 (225 at 58 psi) would support 550 too, but was told otherwise by three vendors on this forum. So to be safe they suggested dual pumps because it was borderline and just increasing boost by 1 or 2 lbs with a pulley change would be over acceptable limits. The Racetronix 255 supports 600 FWHP. With a 15 percent drive train loss that's about 510 rwhp.

This is what Aeromotive has to say about the C5 regulator.

"One side note, the Corvette filter regulator that is so popular for EFI engine swaps is frequently used with the intent to locate the assembly at the back of the car.

Itís okay with smaller pumps of up to 190 liter per hour (lph), but that filter/regulator really begins to struggle handling higher-flow pumps in the 200-600 lph range. Itís common to see our 340 Stealth pumps damaged by these components as they seem to quickly clog the built-in filter, dead-heading and damaging the pump before thereís any real sign of a problem.

We strongly recommend Aeromotive fuel pumps be used with the recommended Aeromotive fuel filters and regulators, and that the regulator be as near the engine as is reasonably possible if engine performance is at all a focus of the build.Ē

Thatís about as concise an answer as you can expect. Clearly, thereís a benefit to placing the regulator close to the engine so it can react quickly to sudden throttle changes that will cause the fuel pressure in the fuel rail to drop. The farther the regulator is from the injectors, the longer it will take for the regulator to respond. Clowís information on fast throttle action hesitation might at least point tuners in a new direction when addressing part-throttle acceleration problems that have been difficult to overcome.

The bottom line is: Put the regulator up near the engine and your engine and EFI system will be much happier."

Racetronix essentially says the same thing on their site.

As for the FPR. At idle with a reasonably smooth and steady idle (800 to 1200 RPM) the engine has about 17 to 21 inches of vacuum. So at idle the FPR should reduce psi to about 41 if the baseline pressure is 58 psi (58-17). At WOT and at maximum boost (let's use 15 lbs) the fuel pressure should be about about 73 psi. With 15 lbs of manifold pressure, the FPR has to raise the pressure in order to maintain 58 psi (58 + 15) to compensate for the 15 psi positive pressure.

So there is a differential or swing from 41 psi at idle up to 73 psi at WOT (maximum boost). That's 32 psi. IMO that's a big swing and the function of the FPR is to attempt to manage that pressure swing.

At idle my pressure with the C5 filter and the 340 was 71+ psi. That's about 30 psi more than it should be at idle. Many others have reported 70 psi as well when running a larger pump (340 or 450).
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Old 11-29-2018, 11:31 AM
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The problem with ^ is that now you have to run a 2nd line back to the tank and defeats the purpose of basically plug and play and also adds cost. I'm sure Aeromotives message is a CYA, but plenty of other people have ran 340's or 450's with the stock and vette reg without issue. Your info is also wrong about fuel pressure idling. The stock Fbody stuff is not adjustable...its 4 bar of fuel, that's it. There's no issue with running 70 psi of base pressure as long as its tuned for it.
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Old 11-29-2018, 12:21 PM
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The stock truck regulator holds 58-60 PSI with a single 450 no problem.
With one AEM 400 I get 55-60 PSI idle pressure. With both of them on its a different story.

Its a shame the stock truck rail mounted regulator does so much better of a job being a regulator than the Corvette one does.
I've never look inside of one. Does the return fuel get filtered before being sent back or does it bypass the filter?
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Old 11-29-2018, 12:35 PM
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[img][/img]

[img][/img]

It appears the return fuel is filtered. That would explain SOME of the restriction in the return.
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Old 11-29-2018, 12:58 PM
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Excessive fuel pressure due to a restrictive return system translates to high pump head pressures and poor regulation.
Pressure will vary greatly with pump voltage, fuel temps and engine demand.
High pump head pressure translates to excessive power demands, fuel heating and reduced pump life.

- Upgrade wiring
- Upgrade plumbing
- Front/remote mount a regulator
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Old 11-29-2018, 01:15 PM
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Originally Posted by ddnspider View Post
The problem with ^ is that now you have to run a 2nd line back to the tank and defeats the purpose of basically plug and play and also adds cost. I'm sure Aeromotives message is a CYA, but plenty of other people have ran 340's or 450's with the stock and vette reg without issue. Your info is also wrong about fuel pressure idling. The stock Fbody stuff is not adjustable...its 4 bar of fuel, that's it. There's no issue with running 70 psi of base pressure as long as its tuned for it.
The point I was attempting to make is that the C5 regulator is not adjustable in post 2, 8 and my last. And then for anyone reading the white papers in the links to compare the C5 regulator to the way a rail mounted FPR works and is adjusted and then make a choice. Aeormotive, Raceronix, and others point it out as well. Every source used plus the tuner and a 20 year or more drag racer agreed on how to set up an FPR. They also point out the fuel pressure differential at idle and at WOT (with boost).

Whether anyone wants to agree to disagree - or believe it not believe it - not my call.

As for me I own the first choice I made - I' m not blaming anyone. I think my second choice is the better one because I don't want to destroy a $12k engine. Again readers can agree or disagree on that too.

As for GM - suspect your are right. Since the intank or C5 regulator isn't adjustable, they compensated for the pressure swing from idle to WOT in the stock tune.

I didn't mention it previously, but at 75 mph per hour and at 15 miles to the gallon, a 450lph pump will completely cycle the fuel in a Camaro fbody about 6 - 7 times in an hour. It's overkill IMO 90 + percent of the time. It was pointed out to me, that the 255/225 is adequate most of the time, but when I need the additional volume a secondary pump of the same size comes on to meet the additional fuel and pressure requirements ( at max boost as pressure requirements increase - pump volume decreases).
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Old 11-29-2018, 01:31 PM
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To answer the original question, I have an aeromotive stealth in mine. I think its a 315lph. non return type system. Keeping up fine on 10psi boost right now. Its about 58-50 at idle whicj is in range. works fine. My buddy has the same pump in the same car and been in there for about two years. no problems.
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Old 11-29-2018, 08:30 PM
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71psi - 58psi is not 30psi.

And like i just said most plug it directly onto the rail. It had nothing to do with putting it at the back of the car at all.
The C5 vettes drop 255+ pumps in all the time from lingenfelter and racetronix on the stock filter/reg with no issue.

Of course aeromotive is going to recommend you buy their stuff. They also DONT tell you you need a hotwire kit for any of their pumps nor do they sell one. And their 340 kits lack alot to be desired as far as that goes. Cheap install kit with rubber hose.

That regulator works with many many higher hp setups than you apparently know.

The main reason higher pressure was reported was due to faulty filters which we fixed. Since then the highest ive ever heard was 65 and it dropped aftetlr that they told me also. Some people create extra pressure/restriction in the system due to the liberties they take in installing the kit and quite a few were due to kinked lines either from the pump to the module or the nylon return line we include.

I will be doing a before and aftet test soon to show exactly the differences and the right way to install the filter kit. With pictures.

Why would 70psi be an issue anyway? You want higher fuel pressure under boost which is mostly what you are arguing about so why is it bad? Its already compensated for 12lbs then roughly. It also artificially makes even the stock fuel injectors flow more lb/hr. I realize it should not be that high theoretically but its not bad that it is.
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Old 11-29-2018, 08:35 PM
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Also there is no pressure swing from wot to idle for the in tank or c5 regulator. If you saw how most stock tunes were "compensated" at wot ie the PE tables youd shake your head.

Is it THE BEST to use? Obviously not. Does it work? Yes. Is it much more affordable? Of course. Is it better than the regulator in the tank? Yes, for many reasons.
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