Modyfying a Walbro.....
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Modyfying a Walbro.....
I get alot of people who ask me how to modify a walbro fuel pump to hold pressure. There are alot of guys now that are running their dual pumps past 75psi since they are running 40+psi of boost. Well heres the story on how I accidently found out how the modified ones work.
Back last year when I sent our Dual Pump setup in to RC ENG to get flowed, I got the flow chart back and it said on the bottom of the page that the "Bypass Valve opens at 75 psi" When I saw that I was like wtf!! So I went and found the flow chart for the "Modified Walbro" and what do ya know.. at 70-75 psi the modified walbro kicks the non modified's ***. At that point I knew that the bypass was the only reason why the modified walbros outflowed the non, but i never got around to messing wit it.
Then, about 6 months ago I got in a shipment of walbros and 2 of them were damaged and UPS was being ****** about it so I just decided to keep it incase i needed them to mock up any new projects. Well.. today i was at work and just just got done wrapping up a customers car and had some free time to play with the pumps. Here is what I found.. I suck at explaining things so Ill let the pictures help.
WARNING!! I DO NOT RECOMMEND THIS MOD, WALBRO WILL VOID THE WARRANTY OF YOUR PUMP FOR SURE IF YOU DO THIS TO THE PUMP. THERE IS A REASON WHY WALBRO CHOSE TO PUT IN A RELIEF VALVE. PLEASE DO THIS AT YOUR OWN RISK
Here is a ghetto drawing of a non modified walbro ( i know i spelled hole wrong)
Heres the pump all take apart
Here is a shot of the bottom of the bypass valve
Heres a shot of the top
Befor we go on please be careful and wear goggles and a pair of gloves. You might want to have a friend help you.
Take a punch, I forgot the size of the punch but just size one up that fits and line it up and give it a few good wacks jk all you need to do is tap it a few times until it bottoms out.
BAM!!! Thats it youre all done, now go have a and paypal donations to Fullblown@tmail.com
Here is a drawing of the modified walbro and befor and after pics of the plug
Before
After
Back last year when I sent our Dual Pump setup in to RC ENG to get flowed, I got the flow chart back and it said on the bottom of the page that the "Bypass Valve opens at 75 psi" When I saw that I was like wtf!! So I went and found the flow chart for the "Modified Walbro" and what do ya know.. at 70-75 psi the modified walbro kicks the non modified's ***. At that point I knew that the bypass was the only reason why the modified walbros outflowed the non, but i never got around to messing wit it.
Then, about 6 months ago I got in a shipment of walbros and 2 of them were damaged and UPS was being ****** about it so I just decided to keep it incase i needed them to mock up any new projects. Well.. today i was at work and just just got done wrapping up a customers car and had some free time to play with the pumps. Here is what I found.. I suck at explaining things so Ill let the pictures help.
WARNING!! I DO NOT RECOMMEND THIS MOD, WALBRO WILL VOID THE WARRANTY OF YOUR PUMP FOR SURE IF YOU DO THIS TO THE PUMP. THERE IS A REASON WHY WALBRO CHOSE TO PUT IN A RELIEF VALVE. PLEASE DO THIS AT YOUR OWN RISK
Here is a ghetto drawing of a non modified walbro ( i know i spelled hole wrong)
Heres the pump all take apart
Here is a shot of the bottom of the bypass valve
Heres a shot of the top
Befor we go on please be careful and wear goggles and a pair of gloves. You might want to have a friend help you.
Take a punch, I forgot the size of the punch but just size one up that fits and line it up and give it a few good wacks jk all you need to do is tap it a few times until it bottoms out.
BAM!!! Thats it youre all done, now go have a and paypal donations to Fullblown@tmail.com
Here is a drawing of the modified walbro and befor and after pics of the plug
Before
After
Last edited by CharlesJ; Aug 20, 2007 at 07:27 AM.
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#12
I can only speak for my set-up. It may be different for yours.
I've been running the modified pump since last year.
On E85 with PTE 1200 injectors, I can run 30 lbs of boost. That is pushing it!
This is with a stock block, stock cams and a 35R kit.
I've been running the modified pump since last year.
On E85 with PTE 1200 injectors, I can run 30 lbs of boost. That is pushing it!
This is with a stock block, stock cams and a 35R kit.