Someone had to start this thread, so i thought I would, and wait for the real experts to help me and everyone else.

I am running the HKS FCON VPro, AAM Return Fuel system, Walbro 255 fuel pump and 1000cc injectors. According to the shop and Walbro, at maximum fuel pump efficiency, given the injectors, I can achieve 500 whp. For those of us who want to exceed the 500 whp horsepower mark, what is the fuel pump solution?

What is everyone with high hp goals planning to do on this issue? Auxillary pump? Dual in tank pump? Does anyone think the Walbro can flow more than 500 whp?

 

Alot of the supra guys used to run dual walbro 255 intank pumps.

 

I have a walbro in my car as well. Walbros do not have a rep as the best fuel pump on the market... and I would not trust one for much more than 500rwhp.

The most difficult part about designing a custom intank solution for the 350z is that fact that the gas tank is divided into 2 for the most part. Siphoning from the other side of the tank is the part to work out.

For example, you could put a pump on each side and everything seems like it would be OK at first... but then you have to consider your return line... if you return to the passenger side then that side will have more fuel than the drivers side and soon the drivers side pump will run dry.

Figureing out the best solution is something that is constantly in the back of my head, and when I finally decide on it we plan to manufacture the solution. I have resources for plastic injection molding and CNC mold making and when I figure it out I want to test it out on our car for a while and if it works then put it into production.

 

Wanna hide a race fuel tank in there that can be activated by a switch? How cool would that be?

 

I have been having a discussions with George (crew chief for Performance Motorsports) and Motec tuner extraordinaire about creating a tuner version of a fuel system for those guys that are simply out of capacity..maybe a package that has a base program for you to play with. Stay tuned for more in the near future.

 

Hey I know where you got that idea. hehe

 

Hmm...many Supras, Evo's, and 350Z's are running well into the 550-650range with a single Walbro 255. 255 liters per gallon is an enormous amount of fuel. Granted, the people I reference are running 650-750cc injectors.

 

Also worth thinking about the injector spray pattern not only the size............do you have an injector designed for a 4 valve head..........an injector with the correct delta angle and spray pattern, if not this can lead to other engine/valve problems in the future.

Peter

APS

 

Ive wanted one since adding the SC. No one ever listens to me thats all.

 

Peter, good point, and I must admit, one I did not address. I chose the Bosch injectors which I believe are not designed for a 4 valve head. I know Phunk is running the HKS injectors, and I believe they are designed for a 4 valve head.

Can anyone confirm or deny this on both of these injectors? Might as well add the RC Enginneering injectors to the list since they are on the GB right now.

 

Man, thats news to me. Can you tell us more about what could happen to our valves w/o the proper delta angle and spray pattern.

 

Fuel cell!

 

For all practical purposes...nothing. The fuel will be better dispersed with the proper angle....but usually, the drawback is a slightly rougher idle, and possibly, a slighty lower power output.

Again...we are probably splitting hairs at this point. Plenty of guys have used the larger RC injectors to push this car into the mid 600whp range....no problems.

 

Peter, care to chime in?

 

Not wanting to upset anyone else on this issue though I believe that the correct delta angle is critical to both piston and valve life over the long term, why else do you think that injector manufactures go to all of the trouble to get the right injector spray angles?

I know that the correct spray pattern is very important for both engine emissions and fuel consumption though there are also other considerations in terms of injector operation.

No doubt that injectors designed for a 2 valve head can work/operate in a 4 valve head though it's certainly less than an optimum solution.

I would much prefer to utilise the correct delta angle/design of injector in a 4 valve engine, each to their own of course.

Thanks

Peter

 

Nicely put Peter...you are very diplomatic.

Just as a note..RC Engineering uses several different bodies and injector styles...and can usually match them up pretty close to optimal. I like the RC's primarily becuase they are half the price of the PE injectors. If cost is no object, I would certainly prefer the PE's becuase these seems to be better designed for our motor.