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Old 12-06-2006, 04:30 PM   #1
SloRice
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Default Buschur Racing Dual Walbro Fuel Pump Setup

A few weeks back, Tim Bailey was in town and we were tuning my car on pump gas. Right around 23-24psi, there just wasn't anymore fuel pump left in the standard Walbro. Since we were at Buschur Racing, I purchased a modified Walbro from David and installed it in his parking lot and then threw my car on the dyno. We were able to get more out of it safely with the new pump. But I have some other plans over the winter and I wanted to make sure I am good in the fuel pump department.

So I spoke with David again and he said that he was making dual fuel pump assemblies for the Evo guys and they are working out really well and he offered to make one for me. So here it is!!



It comes with high compression fuel line and high compression clamps to hold everything together.



Let me tell you...this thing is pretty slick. I've seen some other dual pump setups on here and most of them parallel the wiring of the second pump into the first pump. This is a bad idea because the stock wiring going to the fuel pump assembly isn't up to the task of running two pumps. Also there is no point to run two pumps all of the time, you just need it at WOT when you are flowing a lot of fuel.

So the way he did it is to wire the second pump directly to the battery with a fuse inline. It has a nice liquid tight fitting on the assembly plate that the wiring comes through to go to the battery.





The other nice part to the wiring is a pressure sensor relay that is also inline between the fuel pump and battery. So the 2nd pump only kicks on when the pressure sensor relay sees 16psi of boost.



The final part of the kit is a new inline fuel filter. The older WRX guys don't have to worry about this because the fuel filter is in the engine bay. But the STI and newer WRX guys have the fuel filter in the pump assembly. Well the fuel filter is now gone to make room for the "Y" pieces to connect the two pumps. So he included the inline fuel filter to put in the engine bay. It's a little bigger than I was expecting, but I have a pretty good idea what I'm going to do with it.



From talking with David, with the stock fuel lines on the car, this setup should be good for 650whp on his dyno, which is about 725-775whp on most Dynojets. On his personal Evo, David originally had the single modified Walbro and 1200cc injectors. At 590whp he was at 100% duty cycle with this setup. He installed the dual fuel pump setup and his duty cycles went to 65%. He installed 1000cc injectors and is now at 80% duty cycles. So the dual pump system obviously works.

I plan on installing it in the next few days (it's bone chilling cold outside right now) and I will be getting pictures along the way. I will then be road tuning the car with the UTEC to see how the duty cycles drop. I will be posting before and after logs of everything and more pictures as I go.

For all those that are having the same fuelling problem I am, give Buschur Racing a call and get this setup. www.buschurracing.com

Tim
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Old 12-06-2006, 04:39 PM   #2
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I cant see the pictures here at work but it sounds like a pretty sweet setup. I look foward to seeing your results with it. It is nice that there is finally a properly setup dual fuel pump setup out there.

-Matt
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Old 12-06-2006, 04:48 PM   #3
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Are those 2 Modded Buschur pumps or 1 buschur pump and 1 standard walbro?
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Old 12-06-2006, 04:53 PM   #4
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They are both standard Walbro's, just have two different socks (one for an Evo and one for a STI). Two standard walbro's are capable of making in excess of 800whp with the appropriate mods for fuel lines, etc.
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Old 12-06-2006, 04:56 PM   #5
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any idea on what this run for?
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Old 12-06-2006, 05:03 PM   #6
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Technically, I'm not allowed to post a price because i'm not a vendor and this isn't a for sale thread.

Also because I don't know what he's going to charge. Just give them a call.
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Old 12-06-2006, 05:14 PM   #7
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Tim already had two Walbro 255 pumps and asked me to just use them. The kit is pretty straight forward and easy to build on the Subaru compared to the EVO. There are parts that aren't easily found and will probably keep it from being copied part for part. On the EVO's we actually have to do quite a bit of machining to the fuel pump assembly, have a special CNC'd fitting made and it is a lot of work to build. This Subaru assembly wasn't so bad.

If you send in your fuel pump assembly to me I can build the same set up with the wiring bulk head, pressure switch, inline fuel filter (BTW, stainless steel body and 10 micron filter) two standard Walbro 255's, fuel lines with high pressure clamps etc.

If you want the two HO pumps we are using then you'd have enough fuel pump for 800+ hp. The two standard Walbros that Tim is using will actually be enough for 700+ hp.

I'd like to wait on selling anymore of them until Tim gets a chance to install this one in his car and do some testing. I did not get to test fit it in the actual car and I want to make sure it all works out O.K.

I can't put up any pricing on here as I am not a vendor. You can PM me if you like.

Thanks for posting about it Tim and thanks for interest to the rest of you.

David Buschur
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Old 12-06-2006, 05:18 PM   #8
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That is a nifty setup there. I like the wiring move dependent on boost... great idea! I think I'll just try the single Buschur modded fuel pump if I run outta fuel though.
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Old 12-07-2006, 10:29 PM   #9
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a friend of mine and i have been running the twin walbro setup in our sti's for about a year now without any issues. i am thinking about buying your modified pumps for next year though david cause i think the walbros might not be enough.

andy
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Old 12-08-2006, 11:16 AM   #10
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Looks like my dual Walbro setup The only difference is that I use the UTEC to turn on the second fuel pump via a relay which is feed directly form the battery via a 10 guage wire
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Old 12-08-2006, 12:44 PM   #11
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Looks interesting.

I haven't looked at the internals of a fuel pump. When only one pump is on and the system is pressurized with fuel is there any way it can go through the other pump back into the tank?

Any weirdness when the second pump turns on (pressure spike).
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Old 12-08-2006, 12:48 PM   #12
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Quote:
Originally Posted by R4ND0M_AX3 View Post
Looks interesting.

I haven't looked at the internals of a fuel pump. When only one pump is on and the system is pressurized with fuel is there any way it can go through the other pump back into the tank?

Any weirdness when the second pump turns on (pressure spike).
The pumps have a none return valve so fuel cannot pass back through the pump that's not running.

I had to re-tune the map area where I have the 2nd pump turning on as the pressure does jump up. I also had to re-tune the very top of my map but that was because I was originally compensating with IDC to get the AFR's right when using a single pump
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Old 12-08-2006, 12:58 PM   #13
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Quote:
Originally Posted by mick_the_ginge View Post
Looks like my dual Walbro setup The only difference is that I use the UTEC to turn on the second fuel pump via a relay which is feed directly form the battery via a 10 guage wire
A buddy and I were actually talking about this very same thing yesterday.
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Old 12-08-2006, 02:41 PM   #14
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Quote:
Originally Posted by mick_the_ginge View Post
Looks like my dual Walbro setup The only difference is that I use the UTEC to turn on the second fuel pump via a relay which is feed directly form the battery via a 10 guage wire
Any further insight as to how that works? When do you set the 2nd pump to turn on and how via the UTEC?
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Old 12-08-2006, 04:13 PM   #15
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Easy, I just use the UTEC solenoid to trigger a relay. I have it set to turn on the 2nd pump at 10psi. The reason I use 10psi is that the UTEC also triggers my water injection primer pump at this boost level. It was easy to combine the two.

I use the UTEC spare solenoid delay feature to ensure the pump does not drop out during shifts. I have the pump stay on for 3 seconds which is easily enough time to shift.

If I was not using the UTEC spare solenoid already for the water primer pump I expect I would also setup a number of the other parameters to minimize the effect of the 2nd pump tuning on. Things like setting the boost a little higher and a min RPM for the pump enable would both have made the 2nd pump enable almost transparent.

Handy Y for connecting the 2 pumps: http://www.beveragefactory.com/draft...t/SSY-CS.shtml

I drilled a small hole in the top of the fuel pump assembly and used a industrial sealer like the one pictured in the Buschur setup above to run the wires to the second pump. Sealed fine, no smell of gas in the car.

I did not take pictures of the pump setup modification but it's just like the setup above. I hacked off the bottom of the original assembly and clamped on the two pumps with two socks.
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Old 12-08-2006, 04:18 PM   #16
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I wonder what power level a walbro + Buschur modded pump would yeild. Using the single walbro durring DD and then kicking on the Bucshur pump at 20+ psi. Dual walbros would prolly be fine for my set-up though....
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Old 12-08-2006, 04:33 PM   #17
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[off-topic]

I did dual Walbros in a friend's car years ago (image image) but I ran the wiring in parallel and made it a completely seperate fuel system (crappy welds pic, secondary fuel system pic). Worked great, actually... but the car had far too many other problems. It was eventually tweaked enough to run a 10.9, but ended up having an electrical fire thanks to a subpar installation of a standalone by a well-known shop.

[/off-topic]

Looks like a nice clean install that was done on those two pumps. That Y adapter really makes it compact.
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Old 12-11-2006, 05:31 PM   #18
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Old 12-11-2006, 05:51 PM   #19
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Default Update #2

Well, the snow God's decided to give us a break and give us 50* weather this past weekend....Stupid Ohio.

Anyways, we went ahead and installed the pump assembly, fuel filter, pressure switch and wiring.

Everything was pretty straight forward. Here's how the wiring went:

Battery-->Fuse-->Pressure Sensor-->Fuel Pump-->Ground

So basically when the pressure sensor saw 16psi, the 12Volts was allowed to go to the pump and turn on.

Here are a couple pictures of the finished product for the pressure sensor. I did have to lengthen the wire that goes between the battery and the pressure sensor. Not a big deal.





As for the Fuel Pump assembly. There were no installation issues. It fit in the tank very well and bolted down without a problem



Here is a picture with the top plate installed over the fuel pump assembly. As you can see, we drilled a hole to allow the wires for the second pump to come through.



Finally, here is the finished product. The one wire is grounded to the bracket and the 2nd wire is going up to the engine bay.



The final part of the install was installing the fuel filter. This had us a little puzzled at first because of the size of it. On the Evo's they stick them up next to the gas tank because there is some rubber lines there. Not the case with our cars, all hard lines. So I took a look at the rubber lines between the hard lines on the strut tower and the Perrin distribution block. Looks like it will fit there. There is normally a bracket that holds the lines in place. This bracket was making things a pain in my @$$. So I removed it and the install went much better.

Here is a picture with the bracket in place.



Here is a picture with the bracket removed and the new fuel filter installed. Windshield washer resevoir also fits back in without any problems.




Now on to the results!

I don't have any datalogs right now because I don't have my LM-1 installed, I just have a NGK AFX installed which doesn't integrate into the UTEC log. So we just watched the gauge to see what would happen.

With the fuse pulled for the 2nd pump so it can't run, my AFR's were in the 11.6 area through out the entire RPM band. Installed the fuse and my AFR's dropped to 11.3 throughout the entire RPM band.

So it's obviously working and showing that even at 22-23psi and pump gas, a single Walbro isn't quite up to the task of my setup. If it was, my AFR's wouldn't have changed at all.

Talking with David, race gas and high boost is really going to show the difference between the two as at higher horsepower levels the single pump just can't keep up with the demand for fuel. Unfortunately, my clutch is baked and I can't do pulls with race gas anymore and my motor is going to be coming out soon.
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Old 12-11-2006, 07:07 PM   #20
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Actually, With the fuse in I remember seeing 11.3 throughout the midrange and 11 flat at the topend. We will need to confirm that hopefully after PRI, if the weather cooperates.


Eric
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Old 12-14-2006, 11:53 AM   #21
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Wow, big demand for these, it was surprising. I don't get many PM's on here and my box was swamped after this post.

The thing to remember with the double pumper is if your single pump is up to the job of supply enough volume the second pump coming on will have little or not effect on AFR's. So in this case, as Slorice said, not a huge effect at 22-23 psi as the single pump was not being run out of fuel. When his car is turned up to where it was making 500+ whp on our dyno we should see a fairly drastic change in AFR's compared to what they were.

Mick the ginge,

I saw the post you made awhile back about your dual pumps and checked out that link to the beverage part then. No offense meant by this at all but personally I didn't like the way it was designed. It just isn't going to flow as well as it should. We are using a very high grade SS "Y" connector on our double pumpers, both for the Subaru's and EVO's. The fuel is going to try to be forced into the second pump with the fitting you are using more so than with a proper "Y" connector. We are also using an approved fuel cell wiring harness/bulk head connector. Pretty cool stuff, it's sealed with orings and special sleeve internally for the wiring. I am sure yours works, just making some observations, hope I'm not ticking you off.

Last edited by David Buschur; 12-14-2006 at 12:49 PM.
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Old 12-14-2006, 12:46 PM   #22
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.....pm sent
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Old 12-14-2006, 01:02 PM   #23
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Quote:
Originally Posted by David Buschur View Post
Wow, big demand for these, it was surprising. I don't get many PM's on here and my box was swamped after this post.

The thing to remember with the double pumper is if your single pump is up to the job of supply enough volume the second pump coming on will have little or not effect on AFR's. So in this case, as Slorice said, not a huge effect at 22-23 psi as the single pump was not being run out of fuel. When his car is turned up to where it was making 500+ whp on our dyno we should see a fairly drastic change in AFR's compared to what they were.

Mick the ginge,

I saw the post you made awhile back about your dual pumps and checked out that link to the beverage part then. No offense meant by this at all but personally I didn't like the way it was designed. It just isn't going to flow as well as it should. We are using a very high grade SS "Y" connector on our double pumpers, both for the Subaru's and EVO's. The fuel is going to try to be forced into the second pump with the fitting you are using more so than with a proper "Y" connector. We are also using an approved fuel cell wiring harness/bulk head connector. Pretty cool stuff, it's sealed with orings and special sleeve internally for the wiring. I am sure yours works, just making some observations, hope I'm not ticking you off.
Do you guys sell just the "Y" peice, wiring harness/ connector and pressure switch seperatley? If so, what are the prices?
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Old 12-14-2006, 02:38 PM   #24
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No I do not sell those parts seperately, sorry.
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Old 12-14-2006, 03:13 PM   #25
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Quote:
Originally Posted by David Buschur View Post
No I do not sell those parts seperately, sorry.
then what do you sell? what makes it a kit? 2 walbros and these parts?
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