Inspired by Captain Obvious, I thought I would go out for a last tango last night before they salt the roads.
 
As it happens less than 1.5 miles in, accelerating off a roundabout at 2.5-3k rpm, the car suddenly lost power with afr at 18+ and struggled back to idling after pulling over. I suspect the diaphragm on my good mech pump has also started to go in the same way the other one did. Last time this happened I swapped the pump on the side of the road and it’s been perfect until now.
 
I do have a NOS diaphragm, but I wonder if that will go too at some point.
 
 
So I am looking at installing a tandem electric pump or possibly just going electric full stop.
 
There are a number of options available but I’m truly confused what is best for performance and reliability.
 
Planning on staying on the SUs so I need something capable of 3.5 psi or more and a pressure regulator. Or are there self regulating pumps that stay at SU / carb safe pressures?
 
I like the idea of the K&N and it’s small foot print. What I’ve read says it’s quiet in operation too:
 
 
https://www.knfilters.co.uk/81-0401-fuel-pump

 
The NISMO was a nice option a few months ago when it was £80 on amazon but has now shot up to £180+ with import duties. So no longer as interesting.
 



Then there are NISMO “looking” ones on eBay for peanuts. I can only assume these are cheapo Chinese items that will fail quickly. Or am I being bigoted?


 
The Facet Silver top: relatively low pressure and time honoured use on Zs makes it an attractive option. I also like the Malpalsi fuel filter / regulator that would fit well where the current fuel filter resides - this eBay listing seems like a good combo - do you agree? Or shall I be going red top and pressure regulator? Wouldn’t it be a waste to have more pressure that I can’t realistically use with carbs?
 
https://www.ebay.co.uk/itm/Facet-Silver-Top-Fuel-Pump-Malpassi-Filter-King-Regulator-Kit-up-to-200bhp-/121064855696?_trksid=p2349624.m46890.l49292
 
 

 
 
Any thoughts or experiences with these or other pumps would be greatly appreciated.

3 hours ago, AK260 said:

I can only assume these are cheapo Chinese items that will fail quickly. Or am I being bigoted?

I would hazard a guess that all 4 of those pumps were made in China, the only one I wouldn't buy is the K&N, it looks like a fish tank pump.

I've got very little direct experience with the whole fuel pump thing, but since I'm planning some evil carb mods with my new motor, I'm going to have to get involved with this as well. And with that in mind, I'll be watching your progress.

So one thing to watch for is... Does the pump require some minimum amount of fuel to flow in order to keep the pump itself cool? If so, you must use a bypass style regulator and shunt excess fuel back to the tank. However, if the pump doesn't require cooling like that and is designed to be able to constantly push against a "mostly closed door", then you could get away with a dead-headed arrangement.

I've heard with my own ears two of the aftermarket pumps and they were loud. I'll see if I can figure out what they were. My buddy put one in his car and the drone made him crazy. He replaced it with another brand and it still drones, but not as bad as the first one. Maybe @GGRIII come in and tell us what brands he used.

What amazes me about many of these aftermarket pumps is how often they undershoot their rated pressure. I put a fuel pressure gauge on a 240Z with the Facet labelled version of the K&N pump. The mechanical fuel pump was bypassed. My gauge was reading about 2 PSI. (0-15 scale)

In my own experience, I had good results with a Holley Blue and a Holley 12-804 regulator, eliminating the stock rail. However, that is because I have an engine with a Maxima head that does not have the window open for the mechanical fuel pump.

 

Edited November 29, 20204 yr by SteveJ

One thing I feel like I should mention first - there is a filter IN THE FUEL TANK.  At least there was on mine (early 74)  If your inlet in the tank is restricted, you can't expect the pump to do much about that. They want to push the fuel not pull it. I had Captain obvious modify an adjustable non-bypass regulator to make it an adjustable bypass regulator. If you go that route you should eliminate the restriction orifice in the stock fuel rail. So that sums up the system as a whole.  Pump back by the fuel tank, internal filter removed from the tank, pre-filter before the pump, modified fuel rail with the restriction removed, and a bypass regulator that I keep at about 2psi. I isolated the pumps with rubber grommets and such.  The Holley Red was easily heard over an MSA twice pipes exhaust!  So I switched to a Carter P4070 better, but still loud.  Both of these pumps are overkill for a stock-ish motor IMHO.  I too am looking to get a lesser pump that isn't as freakin noisy as the two previously mentioned.  I guess on the plus side I always know if the fuel pump has power!

 

Up until I swapped to EFI last year, I was using a BMW diesel 4 bar pump and an Aeromotive bypass regulator. Now I'm on EFI, I'm using a BMW diesel 4 bar pump and an Aeromotive bypass regulator 🙂

The fuel pump has done about 200,000 miles, so I think it's good on the reliability front. 

When I was looking at high pressure pump options I found that older Ford trucks used two pumps.  One to pull from the tanks and one to pressurize the EFI system.  The high pressure pump was mounted up under the driver's side firewall, and the supply pump was in the tank I think, or close to it.  I don't know the specs on the supply pump but I'd assume it would be low pressure.  Might be worth digging in to.

2 hours ago, GGRIII said:

One thing I feel like I should mention first - there is a filter IN THE FUEL TANK.  At least there was on mine (early 74)  If your inlet in the tank is restricted, you can't expect the pump to do much about that. They want to push the fuel not pull it. I had Captain obvious modify an adjustable non-bypass regulator to make it an adjustable bypass regulator. If you go that route you should eliminate the restriction orifice in the stock fuel rail. So that sums up the system as a whole.  Pump back by the fuel tank, internal filter removed from the tank, pre-filter before the pump, modified fuel rail with the restriction removed, and a bypass regulator that I keep at about 2psi. I isolated the pumps with rubber grommets and such.  The Holley Red was easily heard over an MSA twice pipes exhaust!  So I switched to a Carter P4070 better, but still loud.  Both of these pumps are overkill for a stock-ish motor IMHO.  I too am looking to get a lesser pump that isn't as freakin noisy as the two previously mentioned.  I guess on the plus side I always know if the fuel pump has power!

 

I don't think that was a stock fuel filter in the tank. I can't find any mention of it in the parts manual or FSM.

It sticks in my mind that people also have used an RX7 electric fuel pump on a 240Z with good results, that may be worth searching and reading about unless anyone here has first hand experience.

I own a 1st gen. RX7. The elec. pump in it is virtually silent. Many z owners over the years have reported using the 1st gen. RX7 pumps (not sure about later gens) with satisfactory results.

Why would anyone not use it?  Seems to meet the needs, and there are options.

https://www.rockauto.com/en/catalog/mazda,1979,rx-7,1.1l+r2,1192227,fuel+&+air,fuel+pump,6256

It's weird that there is no option for an electric pump around the internet even though the 240Z's are wired for it.  It's a market that needs to be addressed.  Opportunity missed.

https://www.rockauto.com/en/catalog/nissan,1973,240z,2.4l+l6,1209170,fuel+&+air,fuel+pump,6256

Thank you all for giving me lots to absorb and think about!

One of my main requirements is a quiet pump - can’t stand the loud buzzing on some classics I’ve seen / heard running elec pumps!

Interesting also that the K&N one appears under different brands - good to know it worked well.

There is made in China and made in China - I guess the difference is quality control by certain brands and what can come out of the side of the factory without oversight. I received some AirPods I hadn’t ordered (long story), the box said price was $25 they were utterly identical to Apple ones - worked great for 12 hours!!!

The BMW / RX7 pumps I like the idea of and will defo research more.

I had no idea there was a fuel filter in the tank!! Being a ‘77 I’m not sure if mine has one or not. How on earth did CO remove it? When I put a camera into my tank this summer, I saw that the intake on mine was behind the baffle - did you take the tank apart?

I was planning on leaving the fuel rail alone and setting the regulator to c. 2-3 bar to allow headroom for any pressure creep. Is that a bad idea?

As for the facet pump and Malpassi regulator combo I found on eBay, Demon Tweaks in the UK is doing both for 1/3 less.

It is perplexing why two pumps would fail in less than 500 miles of each other. I am wondering if the lining inside the tank is coming off and causing an intermittent blockage? Will take filter and one of the pumps apart this week and have a closer look. I worry that if this is the case, it will also cause issues with an electric pump. [emoji848]

I would avoid the `carter p4070` model in particular if you like to not hear the pump. I think anything in a similar style will give you the same problem I have, which is LOADS of cabin noise, i cant figure out how to dampen it. However I've used it since i got the car, never had an issue with it, so its reliability is nice.

I like the Facet one, I would opt for that for easier install with the OEM bracket for the electronic fuel pumps.

Iif that is also noisy then something like the Rx7 one you posted should work, my buddy uses one similar in his classic mini and his buyeye sprite, I never notice the noise they make.