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300zxt fuel pump...fuel rails?


Guest DATTO

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Guest DATTO

hey guys

im new at this turbo stuff. wanting to learn as much as possible. well for starters, is the 300zxt (z31) fuel pumps good for building a 270hp motor or are there any stock fuel pumps i can get from other cars..supra, rx7,...etc? and about fuel rails, id like to make a custom one but dont know how to go about it...any site out there with any step by step instructions and what i need to drill or what not. thanks all

 

oh yeah one more thing..i have an l28 with e31 head but plannig to switch over to turbo with p90 head. i have a european distributor with electronic ignition and crane amplifier. will i need to change my distributor to the turbo one or can i use my existing distributor? i would think the only diff. between 240z distributors are not electronic and 280zx's were...im getting an extra distributor from a turbo car just in case i have to change over...just dont see why im gonna have to use it..thanks all

 

[ July 16, 2001: Message edited by: DATTO ]

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i think holley makes one for imports, just tell them its for a 300zx 84-89 turbo or something,or maybe any of the earlyz turbo gen2 rx7, supras, or use the stock 280zx turbo fuel pump, for 270hp it will flow, i dont know if it is in tank or not, if it is you are even more in there because you can go to a junkyard and yank a gas tank, you will probably need a gastank because youre injected right?

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On the fuel pump -

 

270hp is going to require a pump capable of about 155 lb/hr of fuel flow (I assumed a .5 BSFC, and 15% safety margin).

 

It's very important to know what operating pressures you will need to run. 270hp should put you in the neighborhood of 10psi of boost. This means that your pump will need to produce 10psi over the baseline fuel pressure, assuming that you are using properly sized injectors. So, if you are running 35psi baseline fuel pressure, your pump will need to supply 155lb/hr, at 45psi.

 

If you are using stock injectors and a rising rate FPR, you will need that same 155 lb/hr at even higher fuel pressures. As I recall, the stock fuel injectors are good for 19 lb/hr at 45psi. So to make them flow enough fuel to make 270hp, you will need to run in the neighborhood of 75psi at the pump. So in this case your fuel pump will need to flow 155lb/hr at 75psi.

 

This is a huge difference in requirements for the pump. In general, a fuel pump's output flow drops dramatically as it's output pressure rises.

 

In the end, these are the requirements that you will need to specify, NOT how much horsepower the pump is capable of. There are lots of pumps out there that will flow 155lb/hr at 6psi, or even at 45psi, but there are considerably fewer that will do the same at 75psi (or that can make 75psi at all, for that matter).

 

On the distributor -

 

You can use the Euro distributor, provided you can add some sort of method of retarding the timing as boost rises. Does the ignition you are using have an option of adding something similar to the MSD Boost Timing Master? If so, then you should be okay. Otherwise, maybe you should consider changing the electronics over to MSD, or similar, with this capability.

 

[ July 17, 2001: Message edited by: TimZ ]

 

[ July 17, 2001: Message edited by: TimZ ]

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Guest DATTO

thanks tim

helps me a lot, i dont know much about this stuff but the learning experience is fun. ill be looking at fuel pumps at the specs you wrote and check if my distributor is capable of timing retard at high boost. well if i can get at 250hp with stock injectors and turbo ill be cool. thanks again, ill be posting questions as i go along the turbo project. see yah

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