Dynosty presents Walbro 485, E85 fuel pump
04-19-2012, 06:50 AM
#1
Dynosty presents Walbro 485, E85 fuel pump
We are very excited to announce the new Walbro 485 fuel pump, which is a true E85 compatible fuel pump. This pump flows more than the others on the market including the 255 and 400, and features sealed connectors. We estimate this pump should be capable of over 850whp on gasoline, and over 600whp on E85 and we intend to test the limits soon. The first order is on the way, so call now to order! Pricing is $220 shipped
Modifications will be required to a 350Z / G35 fuel pump basket, similar to the Walbro 400. For those not comfortable modifying their hanger, you can mail to us and we can perform the upgrade install with same-day turnaround if required.
Modifications will be required to a 350Z / G35 fuel pump basket, similar to the Walbro 400. For those not comfortable modifying their hanger, you can mail to us and we can perform the upgrade install with same-day turnaround if required.
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04-25-2012, 08:22 AM
#9
I do believe that we can replace the secondary pump in our twin with a Walbro 400 or 485, if we leave the primary pump as a 255. So you would be looking at 655lph or 740lph... which is a TON of fuel. We need someone to be the guinea pig since I sold my 350z and my 370z is running an Aeromotive 340 as my daily driver.
I will explain the situation....
The CJM twin pump uses a special model of the walbro 255 that has venturis built in to them. The purpose of this was to eliminate operating the venturis on the return side like the stock assembly does. The venturis are very small openings that all the return fuel has to pass through, and they become too restrictive for huge/multi pumps and the regulator can no longer control fuel pressure at idle, etc where the return volume is very high. You can open these venturis to flow better and eliminate the fuel pressure spike at idle... but then once you open them up, you will find that they are no longer very effective when the engine is consuming high quantities of fuel when cruising and under power. The overtank siphon becomes irradically weak and you run into fuel starvation issues.
APS tried to reengineer a return side venturi with their twin pump hanger, and it had problems for some people, and they had to update it, which created a new set of problems. Basically they started large on the venturis so that fuel pressure was in check, but then some people were suffering fuel starvation from a weak siphon leaving too much fuel on the drivers side of the tank. Then they updated it to smaller, which in turn caused uncontrollably high fuel pressure at idle. We decided to skip that all together and do it off the pressure side / integrated into the pumps, which is how domestic cars handle their venturi needs.
The CJM twin pump uses one pumps venturi to handle the over-tank siphon so that you can access all the fuel in the tank. The other pumps siphon is simply used to help fuel enter the bottom of the little fuel canister to help keep it full at lower tank levels.
We consider the pump that handles the over-tank siphoning the "Primary" pump and explain that when staging our twin pump, to use the primary as the full time pump, and the other pump can kick in later. This was after extensive testing in my own 350z making sure that the fuel pump system worked just fine with only the primary pump running full time.
If we replace the secondary pump with a Walbro 400/485, we will loose the siphon that pulls more fuel into the can. At higher tank levels, it couldnt even matter because fuel will simply flow over the top of the can to fill it anyway. At lower tank levels, I have a MINOR concern of the pumps sucking fuel out of the canister, faster than fuel can re-enter the canister. I say minor because we already have some extra holes in the can to help with that in-case the secondary siphon wasnt enough. Where the secondary siphon would normally be, will now be an additional hole under the can, so it should be fine anyway. If there was STILL a problem, at that point, holes could just be punched in the canister to eliminate any remaining blockage, but I dont expect that to be needed. The more of the canister that can remain intact, the more function the canister retains, and the less likely the car will be to suffer starvation in hard turns / road racing (and the higher the tank level, the less likely to encounter).
Worst case scenario, the canister ends up completely ineffective, and you simply have pumps hanging in the tank... similiar to how the discontinued SP triple pump hanger was. In that case, I would recommend not using the fuel pumps for what they are worth below a half tank or coming out of hard right turns.
I will explain the situation....
The CJM twin pump uses a special model of the walbro 255 that has venturis built in to them. The purpose of this was to eliminate operating the venturis on the return side like the stock assembly does. The venturis are very small openings that all the return fuel has to pass through, and they become too restrictive for huge/multi pumps and the regulator can no longer control fuel pressure at idle, etc where the return volume is very high. You can open these venturis to flow better and eliminate the fuel pressure spike at idle... but then once you open them up, you will find that they are no longer very effective when the engine is consuming high quantities of fuel when cruising and under power. The overtank siphon becomes irradically weak and you run into fuel starvation issues.
APS tried to reengineer a return side venturi with their twin pump hanger, and it had problems for some people, and they had to update it, which created a new set of problems. Basically they started large on the venturis so that fuel pressure was in check, but then some people were suffering fuel starvation from a weak siphon leaving too much fuel on the drivers side of the tank. Then they updated it to smaller, which in turn caused uncontrollably high fuel pressure at idle. We decided to skip that all together and do it off the pressure side / integrated into the pumps, which is how domestic cars handle their venturi needs.
The CJM twin pump uses one pumps venturi to handle the over-tank siphon so that you can access all the fuel in the tank. The other pumps siphon is simply used to help fuel enter the bottom of the little fuel canister to help keep it full at lower tank levels.
We consider the pump that handles the over-tank siphoning the "Primary" pump and explain that when staging our twin pump, to use the primary as the full time pump, and the other pump can kick in later. This was after extensive testing in my own 350z making sure that the fuel pump system worked just fine with only the primary pump running full time.
If we replace the secondary pump with a Walbro 400/485, we will loose the siphon that pulls more fuel into the can. At higher tank levels, it couldnt even matter because fuel will simply flow over the top of the can to fill it anyway. At lower tank levels, I have a MINOR concern of the pumps sucking fuel out of the canister, faster than fuel can re-enter the canister. I say minor because we already have some extra holes in the can to help with that in-case the secondary siphon wasnt enough. Where the secondary siphon would normally be, will now be an additional hole under the can, so it should be fine anyway. If there was STILL a problem, at that point, holes could just be punched in the canister to eliminate any remaining blockage, but I dont expect that to be needed. The more of the canister that can remain intact, the more function the canister retains, and the less likely the car will be to suffer starvation in hard turns / road racing (and the higher the tank level, the less likely to encounter).
Worst case scenario, the canister ends up completely ineffective, and you simply have pumps hanging in the tank... similiar to how the discontinued SP triple pump hanger was. In that case, I would recommend not using the fuel pumps for what they are worth below a half tank or coming out of hard right turns.
05-30-2012, 01:50 PM
#10
I just finished building a custom twin pump assembly with one walbro 255 and one walbro 485. Its headed out to someone who is going to be testing it in a high power car that is converting to E85 i believe.
Should be interesting to see how all this pans out. It was a nightmare for me to assemble (will get better with practice im sure).
Should be interesting to see how all this pans out. It was a nightmare for me to assemble (will get better with practice im sure).
honestly i cannot see ever running out of fuel with mine, if i where do do e85 would mayby have to upgrade the intake but the dual bosch 044's should be fine.
I saw the thread on NAGTROC.
06-07-2012, 03:47 PM
#17
Ive wanted to do a fuel pump solution for the GTR for a while now... Ive got some great ideas for it and also heard many complaints of the current existing options. I see plenty of room for improvement, unfortunately I have no GTR and thats too expensive of a car to buy simply for the purpose of building fuel system parts. If someone wants to lend me one for a couple weeks, free stuff for you!
06-11-2012, 06:16 AM
#20
So in a single pump configuration at 18v, I'm thinking this pump will hit the sweet spot of most all builds, even on e85. We shall see how well this does on a CJM stage 2, running a KB BAP at 18v above 4 psi. I think 1000cc injectors will be the limiting factor, not pump.
Any thoughts on use as a single pump, re: starvation or driveability with stock basket use?
Any thoughts on use as a single pump, re: starvation or driveability with stock basket use?
Last edited by rcdash; 06-11-2012 at 06:17 AM.
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