Mrslysly's Fuel Pump Project
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Mrslysly's Fuel Pump Project
I no longer have the original photos for this thread. I do apologize as they must have been deleted when I was doing some cleaning up of accounts and forgot this thread linked to them. I no longer have the fuel pump assembly so I cannot replace the photos.
Here is my project (in progress, will be updated as I go with more detailed information, ideas, rejects, etc) in the quest to find a solution to the fuel cutout issue.
WARNING! DISCLAIMER! THIS IS ALL INFORMATION DIRECTLY FROM MY CAR. MAZDA MAY HAVE MADE SLIGHT MODIFICATIONS AND YOUR EQUIPMENT MAY NOT LOOK EXACTLY THE SAME AS MINE.
Many people experience it at 1/4 of a tank. I don't know if they track their car or not. Personally I've experienced fuel cut outs on the stock fuel pump and stock fuel system at 2.5 gallons shy of a full fuel tank on longer left hand sweepers. The only upgrade to my car that would affect cornering performance is 245/40/18 Dunlop Direzza D1 Star Spec tires. And this cut out would only happen if under full or near full throttle. If I lifted or modulated the throttle I would lessen the severity or not experience the fuel cut out. As soon as the car exited the corner I wouldn't experience any cutouts. BUT AT 2.5 GALLONS SHY OF A FULL TANK, that was unacceptable to me.
So my first source was MazdaManiac's DIY https://www.rx8club.com/showthread.p...ight=fuel+pump . I purchased a walbro drop in pump and modified the siphon as per MM's initial directions. I enlarged the siphon ventur to 1/8 inch inner diameter. See pictures from his thread for siphon venturi location. He has since revised his directions and modifying the siphon venturi is no longer needed. READ HIS DIRECTIONS MULTIPLE TIMES BEFORE DOING ANYTHING.
I RECOMMEND PURCHASING THE TOOL FROM NAPA, OR THIS MAY HAPPEN TO YOU! (Napa part #: BK 770-8001 runs $23 bucks.) Here is what my ring looks like.
![](http://i8.photobucket.com/albums/a11/mrslysly/rx8%20fuel%20pump/IMG_1457Small.jpg)
It is hard to see it initially, but all the tabs on the right side of the ring are broken off. The result of using a hammer and brass chisel. $58 lesson (cost of a new ring) learned the hard way.
I use the tool from Napa plus another little nifty tool. A centering punch or anything else that has a tappered point that will fit into the holes in the top of the ring.
![](http://i8.photobucket.com/albums/a11/mrslysly/rx8%20fuel%20pump/IMG_1468Small.jpg)
Place the tool into one of the holes and hold it against the ring removal tool and use it as extra leverage to turn the nut. I found that the universal tool alone flexes to much and this provided the extra torque and leverage to easily remove and install the plastic nut.
While I had the fuel pump assembly out I took a picture of the bottom.
![](http://i8.photobucket.com/albums/a11/mrslysly/rx8%20fuel%20pump/IMG_1454Small.jpg)
Here you can see fuel entrance point (the red rubber cap which acts as a 1-way valve to keep fuel in the bowl but yet allow fuel to flow into the bowl when the bowl's level of fuel is below that of the fuel tank) and one of the exit points for the return from the siphon just to the right of the red cap (which is also the overflow from the Fuel Pressure Regulator). The siphon sits over a nipple in the bottom of the fuel bowl and fuel coming out of the siphon goes into three spots. First, there is a small hole in the side of siphon outlet that sits over the nipple in the fuel bowl so some fuel goes directly back into the fuel bowl. Second, some fuel is shunted out the bottom of the fuel bowl and directly back into the fuel tank. Third, some fuel is sent thru a small galley in the bottom of the fuel bowl to reduce some foaming and then that flows back into the fuel bowl.
(More detailed pictures to come next time the pump comes out, and I am working on a diagram of the fuel pump and siphon system)
![](http://i8.photobucket.com/albums/a11/mrslysly/rx8%20fuel%20pump/rx8fuelsystem-1.jpg)
As you have probably guessed that entrance point (the one and only from the fuel bowl unless fuel is running over the top lip into the fuel bowl) with the red rubber cap is not that large. Might have to look at a way to get more fuel into the bowl. Also the channels or galley in the bottom of the fuel bowl is done to reduce the amount of aeration and foaming in the fuel before it spills over the internal lip back into the fuel bowl where the fuel sock is. The sock itself, besides blocking larger chunks of debris, also acts to stop the pump from creating a vortex, which would cause any aeration in the fuel to form larger bubbles and also helps disperse the air bubbles back into the fuel and break the air bubbles up into smaller ones so there are not large bubbles flowing thru the fuel pump.
Unfortunately, when I modified my siphon venture, I may have gone to far up the siphon tube withe the drill bit and damaged my siphon mechanism. My siphon now is actually a straight discharge tube and dumping fuel back into the right side saddle. Even if I completely block the outlet to the engine my pressure relief cap won't open as all the extra fuel is shunted to the right saddle.
I setup a small test with some water in some buckets to see what the fuel pump and assembly would do. Here is a video.
http://s8.photobucket.com/albums/a11/mrslysly/rx8%20fuel%20pump/?action=view¤t=MVI_1466.flv(I know its not easy to see but the outlet on the top that's suppose to run fuel to the engine is pinched off completely at the other end of the fuel hose and the siphon is running into another bucket right beside the black one. You can see the pressure relief cap never moves or opens.) I did prime the pump with fuel before it was put back into the car.
You can see bubbles coming up from the siphon pickup which means that the siphon tube on the fuel pump assembly is actually pushing fuel into the right saddle instead of drawing it into the left saddle like it was meant to do. This is immediately after hooking up the fuel pump back in the car so the siphon line still has air in it.
http://s8.photobucket.com/albums/a11/mrslysly/rx8%20fuel%20pump/?action=view¤t=MVI_1471.flv (this link takes you to the video showing the bubbles coming up)
The siphon pickup is access via the panel on the right side of the vehicle. It uses the exact same plastic lock nut (union nut as per Mazda's FSM) as the fuel pump.
![](http://i8.photobucket.com/albums/a11/mrslysly/rx8%20fuel%20pump/IMG_1455Small.jpg)
If you notice the cover for the right side saddle has the EXACT same plug port as the fuel pump assembly. Its a perfect fit for the plug on the driver side. Hmmmm.....
The siphon pickup in the right tank is simply a screen mounted to the bottom of the tank and attached to the fuel hose. There is no check valve or any other control, as evident from the air bubbles coming out of it, just a simple fuel line and debris screen.
Once open,
![](http://i8.photobucket.com/albums/a11/mrslysly/rx8%20fuel%20pump/IMG_1456Small.jpg)
it looks like a complete fuel assembly could drop right in! Easy setup for running 2 fuel pumps. Now I know how its so easy for others to do it. If you wanted to keep the fuel sender and use the stock 04-08 fuel pump assembly, the lower basket can be modified to give you clearance, and the connector for the fuel sender is the exact same as the driver side one, so it would plug directly into the lid of the fuel pump assembly and give you easy contact point for power for the pump. HMMMM! Ideas!
Pulled apart a spare siphon.
Here are the guts.
![](http://i8.photobucket.com/albums/a11/mrslysly/rx8%20fuel%20pump/DSCI0390.jpg)
Not the easiest to see but its a rubber stopper with a spring. Once pressure exceeds the springs rate, it will open to let fuel flow out the top of the siphon. WARNING! This next piece of info is NOT the correct procedure. I am leaving it in as a fair warning to others. Learn from my mistake.My solution to plugging this up was just a screw with a rubber washer in the hole that the rubber stopper sits over. Yes that means you have to cut the top of the siphon off. Just have to make sure the screw doesn't protrude into the inlet chamber, which you can check by looking into the inlet tube at the top of the siphon. End of Warning.
The piece that MazdaManiac references for melting together is the plastic disc at the top of the siphon. It holds the spring and rubber stopper in the top of the siphon. This needs to be secured so the extra pressure from the upgraded pump won't push it out of the assembly.
Here is the top view of the hole the rubber stopper sits over after I cut the top piece off the siphon.
![](http://i8.photobucket.com/albums/a11/mrslysly/rx8%20fuel%20pump/DSCI0391.jpg)
Note about fuel cell foam. Inserted 2 blocks of foam into the bridge over the drivetrain tunnel and 1 block into the driver side saddle towards the back of the bridge. Noticed right away that filling the tank takes 5x longer as the foam prevents it from entering the tank freely via the filler port and that it takes a long time to overflow into the passenger saddle. That means its working to prevent slosh. The main problem I discovered is that its almost impossible to get the foam to stay put. Every piece slipped out of place and always ended up pushing the fuel level sender down. Fuel cell foam removed until better method of securing it besides just cramming it into place is found.
More to come as the project continues.
Here is my project (in progress, will be updated as I go with more detailed information, ideas, rejects, etc) in the quest to find a solution to the fuel cutout issue.
WARNING! DISCLAIMER! THIS IS ALL INFORMATION DIRECTLY FROM MY CAR. MAZDA MAY HAVE MADE SLIGHT MODIFICATIONS AND YOUR EQUIPMENT MAY NOT LOOK EXACTLY THE SAME AS MINE.
Many people experience it at 1/4 of a tank. I don't know if they track their car or not. Personally I've experienced fuel cut outs on the stock fuel pump and stock fuel system at 2.5 gallons shy of a full fuel tank on longer left hand sweepers. The only upgrade to my car that would affect cornering performance is 245/40/18 Dunlop Direzza D1 Star Spec tires. And this cut out would only happen if under full or near full throttle. If I lifted or modulated the throttle I would lessen the severity or not experience the fuel cut out. As soon as the car exited the corner I wouldn't experience any cutouts. BUT AT 2.5 GALLONS SHY OF A FULL TANK, that was unacceptable to me.
So my first source was MazdaManiac's DIY https://www.rx8club.com/showthread.p...ight=fuel+pump . I purchased a walbro drop in pump and modified the siphon as per MM's initial directions. I enlarged the siphon ventur to 1/8 inch inner diameter. See pictures from his thread for siphon venturi location. He has since revised his directions and modifying the siphon venturi is no longer needed. READ HIS DIRECTIONS MULTIPLE TIMES BEFORE DOING ANYTHING.
I RECOMMEND PURCHASING THE TOOL FROM NAPA, OR THIS MAY HAPPEN TO YOU! (Napa part #: BK 770-8001 runs $23 bucks.) Here is what my ring looks like.
![](http://i8.photobucket.com/albums/a11/mrslysly/rx8%20fuel%20pump/IMG_1457Small.jpg)
It is hard to see it initially, but all the tabs on the right side of the ring are broken off. The result of using a hammer and brass chisel. $58 lesson (cost of a new ring) learned the hard way.
I use the tool from Napa plus another little nifty tool. A centering punch or anything else that has a tappered point that will fit into the holes in the top of the ring.
![](http://i8.photobucket.com/albums/a11/mrslysly/rx8%20fuel%20pump/IMG_1468Small.jpg)
Place the tool into one of the holes and hold it against the ring removal tool and use it as extra leverage to turn the nut. I found that the universal tool alone flexes to much and this provided the extra torque and leverage to easily remove and install the plastic nut.
While I had the fuel pump assembly out I took a picture of the bottom.
![](http://i8.photobucket.com/albums/a11/mrslysly/rx8%20fuel%20pump/IMG_1454Small.jpg)
Here you can see fuel entrance point (the red rubber cap which acts as a 1-way valve to keep fuel in the bowl but yet allow fuel to flow into the bowl when the bowl's level of fuel is below that of the fuel tank) and one of the exit points for the return from the siphon just to the right of the red cap (which is also the overflow from the Fuel Pressure Regulator). The siphon sits over a nipple in the bottom of the fuel bowl and fuel coming out of the siphon goes into three spots. First, there is a small hole in the side of siphon outlet that sits over the nipple in the fuel bowl so some fuel goes directly back into the fuel bowl. Second, some fuel is shunted out the bottom of the fuel bowl and directly back into the fuel tank. Third, some fuel is sent thru a small galley in the bottom of the fuel bowl to reduce some foaming and then that flows back into the fuel bowl.
(More detailed pictures to come next time the pump comes out, and I am working on a diagram of the fuel pump and siphon system)
![](http://i8.photobucket.com/albums/a11/mrslysly/rx8%20fuel%20pump/rx8fuelsystem-1.jpg)
As you have probably guessed that entrance point (the one and only from the fuel bowl unless fuel is running over the top lip into the fuel bowl) with the red rubber cap is not that large. Might have to look at a way to get more fuel into the bowl. Also the channels or galley in the bottom of the fuel bowl is done to reduce the amount of aeration and foaming in the fuel before it spills over the internal lip back into the fuel bowl where the fuel sock is. The sock itself, besides blocking larger chunks of debris, also acts to stop the pump from creating a vortex, which would cause any aeration in the fuel to form larger bubbles and also helps disperse the air bubbles back into the fuel and break the air bubbles up into smaller ones so there are not large bubbles flowing thru the fuel pump.
Unfortunately, when I modified my siphon venture, I may have gone to far up the siphon tube withe the drill bit and damaged my siphon mechanism. My siphon now is actually a straight discharge tube and dumping fuel back into the right side saddle. Even if I completely block the outlet to the engine my pressure relief cap won't open as all the extra fuel is shunted to the right saddle.
I setup a small test with some water in some buckets to see what the fuel pump and assembly would do. Here is a video.
http://s8.photobucket.com/albums/a11/mrslysly/rx8%20fuel%20pump/?action=view¤t=MVI_1466.flv(I know its not easy to see but the outlet on the top that's suppose to run fuel to the engine is pinched off completely at the other end of the fuel hose and the siphon is running into another bucket right beside the black one. You can see the pressure relief cap never moves or opens.) I did prime the pump with fuel before it was put back into the car.
You can see bubbles coming up from the siphon pickup which means that the siphon tube on the fuel pump assembly is actually pushing fuel into the right saddle instead of drawing it into the left saddle like it was meant to do. This is immediately after hooking up the fuel pump back in the car so the siphon line still has air in it.
http://s8.photobucket.com/albums/a11/mrslysly/rx8%20fuel%20pump/?action=view¤t=MVI_1471.flv (this link takes you to the video showing the bubbles coming up)
The siphon pickup is access via the panel on the right side of the vehicle. It uses the exact same plastic lock nut (union nut as per Mazda's FSM) as the fuel pump.
![](http://i8.photobucket.com/albums/a11/mrslysly/rx8%20fuel%20pump/IMG_1455Small.jpg)
If you notice the cover for the right side saddle has the EXACT same plug port as the fuel pump assembly. Its a perfect fit for the plug on the driver side. Hmmmm.....
The siphon pickup in the right tank is simply a screen mounted to the bottom of the tank and attached to the fuel hose. There is no check valve or any other control, as evident from the air bubbles coming out of it, just a simple fuel line and debris screen.
Once open,
![](http://i8.photobucket.com/albums/a11/mrslysly/rx8%20fuel%20pump/IMG_1456Small.jpg)
it looks like a complete fuel assembly could drop right in! Easy setup for running 2 fuel pumps. Now I know how its so easy for others to do it. If you wanted to keep the fuel sender and use the stock 04-08 fuel pump assembly, the lower basket can be modified to give you clearance, and the connector for the fuel sender is the exact same as the driver side one, so it would plug directly into the lid of the fuel pump assembly and give you easy contact point for power for the pump. HMMMM! Ideas!
Pulled apart a spare siphon.
Here are the guts.
![](http://i8.photobucket.com/albums/a11/mrslysly/rx8%20fuel%20pump/DSCI0390.jpg)
Not the easiest to see but its a rubber stopper with a spring. Once pressure exceeds the springs rate, it will open to let fuel flow out the top of the siphon. WARNING! This next piece of info is NOT the correct procedure. I am leaving it in as a fair warning to others. Learn from my mistake.My solution to plugging this up was just a screw with a rubber washer in the hole that the rubber stopper sits over. Yes that means you have to cut the top of the siphon off. Just have to make sure the screw doesn't protrude into the inlet chamber, which you can check by looking into the inlet tube at the top of the siphon. End of Warning.
The piece that MazdaManiac references for melting together is the plastic disc at the top of the siphon. It holds the spring and rubber stopper in the top of the siphon. This needs to be secured so the extra pressure from the upgraded pump won't push it out of the assembly.
Here is the top view of the hole the rubber stopper sits over after I cut the top piece off the siphon.
![](http://i8.photobucket.com/albums/a11/mrslysly/rx8%20fuel%20pump/DSCI0391.jpg)
Note about fuel cell foam. Inserted 2 blocks of foam into the bridge over the drivetrain tunnel and 1 block into the driver side saddle towards the back of the bridge. Noticed right away that filling the tank takes 5x longer as the foam prevents it from entering the tank freely via the filler port and that it takes a long time to overflow into the passenger saddle. That means its working to prevent slosh. The main problem I discovered is that its almost impossible to get the foam to stay put. Every piece slipped out of place and always ended up pushing the fuel level sender down. Fuel cell foam removed until better method of securing it besides just cramming it into place is found.
More to come as the project continues.
Last edited by mrslysly; 02-16-2015 at 11:51 PM.
#3
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Others have done the secondary pump mod as well...almost all of the Koni 8's had some sort of secondary pump system at work. Speedsource even did a full fuel tank conversion but it also had a secondary pump.
From what, I've heard so far about the 09 pumps...they seem to remedy the fuel cut issue. Seems like a cheaper mod than adding more to the existing unit.
From what, I've heard so far about the 09 pumps...they seem to remedy the fuel cut issue. Seems like a cheaper mod than adding more to the existing unit.
#4
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I can only find the '09 units for about $350 new. It would be really interesting to see some nice detailed pics of the '09 units to compare to an '04-'08 unit.
I am looking at maybe putting a second pump in that I can manually turn on just for track time. I need spare parts first. PM me if anyone has spare fuel system parts.
Adding diagram and more info to OP.
Adding diagram and more info to OP.
Last edited by mrslysly; 09-20-2009 at 06:07 PM.
#5
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I've done the dual-pump setup (the source of CW's input).
It isn't necessary, but it can be done.
If you have a pump motor installed that ALWAYS keeps the regulator open, the cross-siphon action actually works really well, negating the need for a second pump.
You will need to rework the connector to handle the power to the second motor and deal with the unused cross-siphon input on that side.
The siphon input on the standard pump position is not designed for receiving pressurized fuel, so the result can be "interesting" (read: stalling the pump and "running out of fuel" with a seemingly full tank).
It isn't necessary, but it can be done.
If you have a pump motor installed that ALWAYS keeps the regulator open, the cross-siphon action actually works really well, negating the need for a second pump.
You will need to rework the connector to handle the power to the second motor and deal with the unused cross-siphon input on that side.
The siphon input on the standard pump position is not designed for receiving pressurized fuel, so the result can be "interesting" (read: stalling the pump and "running out of fuel" with a seemingly full tank).
#6
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I've done the dual-pump setup (the source of CW's input).
It isn't necessary, but it can be done.
If you have a pump motor installed that ALWAYS keeps the regulator open, the cross-siphon action actually works really well, negating the need for a second pump.
You will need to rework the connector to handle the power to the second motor and deal with the unused cross-siphon input on that side.
The siphon input on the standard pump position is not designed for receiving pressurized fuel, so the result can be "interesting" (read: stalling the pump and "running out of fuel" with a seemingly full tank).
It isn't necessary, but it can be done.
If you have a pump motor installed that ALWAYS keeps the regulator open, the cross-siphon action actually works really well, negating the need for a second pump.
You will need to rework the connector to handle the power to the second motor and deal with the unused cross-siphon input on that side.
The siphon input on the standard pump position is not designed for receiving pressurized fuel, so the result can be "interesting" (read: stalling the pump and "running out of fuel" with a seemingly full tank).
How does the siphon handle the full flow of the walbro without the enlarged venturi and the sealed off pressure relief cap? Does yours still siphon properly or does yours push fuel back into the right saddle?
Last edited by mrslysly; 09-20-2009 at 06:29 PM.
#10
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Thanks! Coming from you thats greatly appreciated.
It only took 45 edits and revisions to catch all the vague info and errors. And I'm still not satisfied with it.
Let me know when you can send me a siphon. I will toss you some $$ for shipping and the part.
It only took 45 edits and revisions to catch all the vague info and errors. And I'm still not satisfied with it.
Let me know when you can send me a siphon. I will toss you some $$ for shipping and the part.
#11
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It looks like they changed the passenger side pickup from the 04's...mine has a different pickup in the passenger tank
Good description and write up...you are right about the passenger pump fitting....it is an easy drop in
You can leave the siphon assembly intact and plumb the 2 pump back into the cup on the drivers side...
Good description and write up...you are right about the passenger pump fitting....it is an easy drop in
You can leave the siphon assembly intact and plumb the 2 pump back into the cup on the drivers side...
#14
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I ran separate power wire to both pumps from the battery..used the OEM power wire to trigger the relays....this makes the safety shutdowns on the PCM still effective
I wired the passenger pump to a manual switch...so far...thinking about using a reed switch of some sort to shut it off
Main pump siphon is left intact..I just zip tied the pickup to the passenger pump
Siphon from the passenger pump is just blocked off.
#15
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I pretty much came to the same conclusion. Another full pump assembly could drop right in as long as the siphon pickup screen was moved and resecured so that 2nd pump would only need to be run in high demand situation and wired to a manual switch. You would remove the siphon from the 2nd pump and put the fuel pump outlet via fuel hose directly into the fuel bowl of the main pump.
Or use the 2nd pump as a full time transfer pump with a reed switch or "wet sensor" as a automatic cut out when fuel levels were to low in the right saddle. Without the need for the siphon on the 2nd pump you can remove the filter and FPR and siphon and use the extra space for the fuel level cut out switch.
It would be easy to wire the second pump so it can be controlled via the ECU for obvious "safety" cutouts. The passenger fuel sender wiring harness in the car has the 4 pin plug, all you would need for power is to put your own pins into the plug (as they aren't installed, only the ones for the fuel sender unit).
Or use the 2nd pump as a full time transfer pump with a reed switch or "wet sensor" as a automatic cut out when fuel levels were to low in the right saddle. Without the need for the siphon on the 2nd pump you can remove the filter and FPR and siphon and use the extra space for the fuel level cut out switch.
It would be easy to wire the second pump so it can be controlled via the ECU for obvious "safety" cutouts. The passenger fuel sender wiring harness in the car has the 4 pin plug, all you would need for power is to put your own pins into the plug (as they aren't installed, only the ones for the fuel sender unit).
Last edited by mrslysly; 09-20-2009 at 08:39 PM.
#19
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great write up. you put a lot of thought into this--had the wife helping too?!
https://www.rx8club.com/attachment.p...7&d=1234653861
heres one picture of the 09 pump versus the earlier model.
Soon I will be trying the kenne Bell boost a pump
Olddragger
https://www.rx8club.com/attachment.p...7&d=1234653861
heres one picture of the 09 pump versus the earlier model.
Soon I will be trying the kenne Bell boost a pump
Olddragger
#20
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When I upgraded to the Supra Denso pump I removed the passenger pump...because I thought that it would be a better solution...and it worked great NA...when I went Turbo..the problem came back....so the passenger pump went back in again...and I went to a return type system with larger fuel lines
So far so good......
I think the upgraded wiring is important if you go to a higher flow pump...the stock wiring is not that great....and I hate the stupid resistor. It was easy for me to run the pump wiring to the battery...it is in the trunk
![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
#21
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The OE wiring will support (easily) 15 amps. Its fused for 20A.
The Walbro pulls about 7 under nominal load and a full 14v.
I wouldn't use a "Boost-a-Pump", especially in this application.
The over-voltage limit on the OE-style pumps is only 17v or so and you won't see nearly as much of a flow increase as you will going to a gerotor pump over the Wesco. At the cost of the KB, you could upgrade 3 pumps.
The Walbro pulls about 7 under nominal load and a full 14v.
I wouldn't use a "Boost-a-Pump", especially in this application.
The over-voltage limit on the OE-style pumps is only 17v or so and you won't see nearly as much of a flow increase as you will going to a gerotor pump over the Wesco. At the cost of the KB, you could upgrade 3 pumps.
#22
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great write up. you put a lot of thought into this--had the wife helping too?!
https://www.rx8club.com/attachment.p...7&d=1234653861
heres one picture of the 09 pump versus the earlier model.
Soon I will be trying the kenne Bell boost a pump
Olddragger
https://www.rx8club.com/attachment.p...7&d=1234653861
heres one picture of the 09 pump versus the earlier model.
Soon I will be trying the kenne Bell boost a pump
Olddragger
Do you have any more pictures of the '09 disassembled? Be interesting to see how that one is setup. Although I already have a few good guesses just from that picture.
Last edited by mrslysly; 09-20-2009 at 10:38 PM.
#24
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got a couple more
understand the overvoltage thing--but only plan to use 15 --maybe less volts. The KB is also a voltage regulator for the pump. 2 more volts can make a big difference--still that bigger pump upgrade does keep it more simple.
OD
https://www.rx8club.com/attachment.p...8&d=1234653949
https://www.rx8club.com/attachment.p...9&d=1234654113
understand the overvoltage thing--but only plan to use 15 --maybe less volts. The KB is also a voltage regulator for the pump. 2 more volts can make a big difference--still that bigger pump upgrade does keep it more simple.
OD
https://www.rx8club.com/attachment.p...8&d=1234653949
https://www.rx8club.com/attachment.p...9&d=1234654113
Last edited by olddragger; 09-21-2009 at 10:54 AM.