CJM Billet Dual Pump Hanger (pics)
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Joined: Jun 2007
Posts: 10
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From: Tempe
Originally Posted by George@GTM
I am glad your coming close to the release date! Another thing I liked about this fuel pump assembly was how light it was. Can't wait to get mine!
-George
GT Motorsports
-George
GT Motorsports
I don't get the "light" definition. It will be heavier than the stock one.
Vendor - Former Vendor
Joined: Sep 2005
Posts: 69
Likes: 0
From: lombard IL
Originally Posted by old school 280
I don't get the "light" definition. It will be heavier than the stock one.
Great work-Ive been waiting patiently for this. As soon as I (and I know many others) get their hands on this, power levels in the Z community will start going up. Thanks for the pics/write up.
Joined: Dec 2005
Posts: 10,740
Likes: 25
From: On a forum dedicated to Boost
Originally Posted by old school 280
I don't get the "light" definition. It will be heavier than the stock one.
price please!!! When are you guys scheduled for production?
Originally Posted by phunk
There were a lot of obsticles to overcome in the development of this product. Aside from my personal problem of finishing what I start, and Brandon's very difficult schedule making it hard for us to coordinate development time, there were many design hurdles.
The top billet piece required constant adjustments to get everything aligned so that the assembly would all fit inside the can. Every little part was drawn in the CAD so that orientation could be perfected. We are so picky and we wanted the 3 fittings to form a perfect triangle so even that was a task in getting everything to properly fit and be symetrical.
The first major hurdle was finding a cost effective electrical bulkhead that is compatable with gasoline. There are many options if you dont mind spending $200+ each, but that wasn't within the budget. We needed something a fraction of a fraction of that, and Brandon was able to find them and I managed to get our hands on them.
The top billet piece had to incorperate a venturi siphon powered by the return fuel to transfer the drivers side fuel to the passenger side of the tank where the pump sits. This required reverse engineering of the factory siphon, and then some playing around on a test bench we made to figure out how to balance the siphon to work with the massive return flow of twin pumps at idle. This is the final part undergoing testing for consistency right now. The siphon is a very difficult balance, involving a compromise between adjustability of fuel pressure and strength of the siphon. If we forced everyone to use the same fuel pressure, then it would have been a lot easier. But we wanted one of the advantages of our system to be maintaining adjustable fuel pressure to help tuners do their thing.
The white part holding the pumps together is now a seperate product of ours. its made of a special plastic and each side has 2 viton orings that VERY securely hold the pumps in place and isolate vibration to keep the operation smooth and quiet, and also increase reliability of the pumps.
The lower billet piece has gone thru changes as well. Our goal was to keep full function of an intank surge can like the stock unit. We wanted as little way for the fuel to escape the can as possible, this meant limiting any openings in the can other than at the top of course, to maintain as much control over the fuel as possible. This increases pressure stability at lower tank levels around turns and high acceleration. Notice how one of the pumps has a port going thru the bottom. This is a special pump from walbro that I learned about when I was building Vipers. It has a transfer siphon to move fuel from outside the surge can to inside the surge can. Its suction to the pump is still located inside the can thru its little filter. The other pump is your standard GSS342 that uses your stock pickup filter from your OEM assembly.
Not installed on the unit in the photos is a filter that goes on the bottom of the assemble to keep debris from entering the primary transfer siphon.
Also not shown in the pictures is a diffuser tube on the return fuel, because 1000hp worth of return fuel at idle blasting into the can was causing cavitation and pressure stability issues at idle on previous prototypes.
Then we also have to CNC 2 individual pieces for the level sensor mount so that it can snap into place like stock and be removeable without having to drill in any holes in it or cause other damage to it making it so that it could not be reinstalled to the factory assembly should you ever wish to go back.
There is more going on, but I have already said enough. We used to hold back on giving people any details about it, but now that we know first hand what a pain in the *** it is to build this thing that is comprised of about 50 individual parts (doesnt look like much, but trust me its there)... we just arent worried about anyone trying to copy it. Its hardly worth it. For the CNC time and assembly and packaging time for this product, we really arent going to be making any money, this is just about supporting our customers who have used our existing products, and trying to help them move on as their needs grow. Sorry its been taking us so long guys. and by the way, it still aint cheap
pricing coming soon.
The top billet piece required constant adjustments to get everything aligned so that the assembly would all fit inside the can. Every little part was drawn in the CAD so that orientation could be perfected. We are so picky and we wanted the 3 fittings to form a perfect triangle so even that was a task in getting everything to properly fit and be symetrical.
The first major hurdle was finding a cost effective electrical bulkhead that is compatable with gasoline. There are many options if you dont mind spending $200+ each, but that wasn't within the budget. We needed something a fraction of a fraction of that, and Brandon was able to find them and I managed to get our hands on them.
The top billet piece had to incorperate a venturi siphon powered by the return fuel to transfer the drivers side fuel to the passenger side of the tank where the pump sits. This required reverse engineering of the factory siphon, and then some playing around on a test bench we made to figure out how to balance the siphon to work with the massive return flow of twin pumps at idle. This is the final part undergoing testing for consistency right now. The siphon is a very difficult balance, involving a compromise between adjustability of fuel pressure and strength of the siphon. If we forced everyone to use the same fuel pressure, then it would have been a lot easier. But we wanted one of the advantages of our system to be maintaining adjustable fuel pressure to help tuners do their thing.
The white part holding the pumps together is now a seperate product of ours. its made of a special plastic and each side has 2 viton orings that VERY securely hold the pumps in place and isolate vibration to keep the operation smooth and quiet, and also increase reliability of the pumps.
The lower billet piece has gone thru changes as well. Our goal was to keep full function of an intank surge can like the stock unit. We wanted as little way for the fuel to escape the can as possible, this meant limiting any openings in the can other than at the top of course, to maintain as much control over the fuel as possible. This increases pressure stability at lower tank levels around turns and high acceleration. Notice how one of the pumps has a port going thru the bottom. This is a special pump from walbro that I learned about when I was building Vipers. It has a transfer siphon to move fuel from outside the surge can to inside the surge can. Its suction to the pump is still located inside the can thru its little filter. The other pump is your standard GSS342 that uses your stock pickup filter from your OEM assembly.
Not installed on the unit in the photos is a filter that goes on the bottom of the assemble to keep debris from entering the primary transfer siphon.
Also not shown in the pictures is a diffuser tube on the return fuel, because 1000hp worth of return fuel at idle blasting into the can was causing cavitation and pressure stability issues at idle on previous prototypes.
Then we also have to CNC 2 individual pieces for the level sensor mount so that it can snap into place like stock and be removeable without having to drill in any holes in it or cause other damage to it making it so that it could not be reinstalled to the factory assembly should you ever wish to go back.
There is more going on, but I have already said enough. We used to hold back on giving people any details about it, but now that we know first hand what a pain in the *** it is to build this thing that is comprised of about 50 individual parts (doesnt look like much, but trust me its there)... we just arent worried about anyone trying to copy it. Its hardly worth it. For the CNC time and assembly and packaging time for this product, we really arent going to be making any money, this is just about supporting our customers who have used our existing products, and trying to help them move on as their needs grow. Sorry its been taking us so long guys. and by the way, it still aint cheap
pricing coming soon. Charlie .. Yes I'm still here and yes I'm still working on my car 
And thanks Chris for posting such a nice work of art.Az
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Joined: Jun 2007
Posts: 10
Likes: 0
From: Tempe
Originally Posted by oorx7
I think the APS assembly is made out of stainless or polished steel. Sam @ GT has held both assemblies. Ours uses aluminum, plastic and stainless hardware. So ours will fall in between the APS and stock in weight.
the plug does not match, there are 6 pins in our plug where the stock is 5. For our assembly, each pump gets its own power and ground wire to make sure each pump can run in its optimum state. The other 2 pins are used for the level sensor, and the fuel temp switch is eliminated.