Holley's Hydramat is now shipping - fuel starve solution?

Hotrodz · 09-06-2018, 02:25 PM

Quote:

Originally Posted by phunk

The concern with running the Z1 second pump full time is that the driver side of the fuel tank in a Z is generally empty during normal driving, if the fuel gauge is at 1/2 or below.

This is because the factory fuel pump housing has a venturi jet pump that is recovering fuel to the passenger side of the tank so that the fuel pump can pick it up and send it to the engine. The recovery of fuel is quicker than the consumption of fuel, thus if you were to pull over the average Z on the average drive with a 1/2 tank of fuel and open both sides of the tank, you will find that the driver side is empty and the passenger side is full.

The reason the Z suffers starvation is because the fuel sloshes to the driver side of the tank on hard turns, and then there is none for the fuel pump to grab. The venturi jet pump is literally "powered by" bypass fuel leaving the regulator. So when the pump starves, the jet pump dies also. This is why a real bad case of starvation can leave you on the side of the road even with a significant amount of fuel in the tank. If you slosh it bad enough, there is just none for the pump, and the jet pump is dead due to no fuel leaving the regulator.

The Z1 kit eliminates starvation by "supercharging" the recovery of fuel to the passenger side by pumping it there with an actual fuel pump. This will make the driver side of the tank far more prone to just being entirely empty when driving the car at 1/2 tank or below, especially on the street where you will rarely turn hard enough to slosh fuel back over to it.

Electronic fuel pumps dont have a great lifespan when they run dry because the gasoline is what cools and lubricates them.

So if you DO use your Z1 kit on the street, I would highly recommend you put a toggle switch on it so you can turn it off. On the track it should be fine as it will constantly get sloshed fuel. On the street, it will run dry for long period.

The CJM RRP is a surge can system that operates under an entirely different principle and it is normal and required that both pumps run all the time.

Thank you sir for the explanation as you have taught me something new and I appreciate your insight and experience.

Rusty · 09-06-2018, 03:22 PM

Quote:

Originally Posted by Hotrodz

Thank you sir for the explanation as you have taught me something new and I appreciate your insight and experience.

Don't know that about the Z1 kit.

cv129 · 09-06-2018, 05:06 PM

Wow, I was seriously considering Z1 kit for the price, but Phunk’s explanation pulls me back to the darker side lol.

Rusty · 09-06-2018, 05:26 PM

Quote:

Originally Posted by cv129

Wow, I was seriously considering Z1 kit for the price, but Phunk’s explanation pulls me back to the darker side lol.

If you are thinking about it. Get Phunk's RRP kit with the billet hat for the right side too. Then your system will be bullet proof.

zmanelite · 09-06-2018, 05:29 PM

A toggle switch could be made for Z1 and run it for track only

Or maybe just run stock pump a Y and a extra line with a Hydramat to passenger side

Hotrodz · 09-06-2018, 07:36 PM

Quote:

Originally Posted by zmanelite

A toggle switch could be made for Z1 and run it for track only

Or maybe just run stock pump a Y and a extra line with a Hydramat to passenger side

Yep, I am going to ask Seb about it this weekend as I have been running the kit for about two years without issue. I think what you are saying is reasonable fix.

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Tractionless · 09-07-2018, 08:56 AM

Quote:

Originally Posted by Hotrodz

I drive mine as a sometimes daily driver. I'm not sure what the issue is other than fuel economy which I have never been concerned with, because it is a sportscar lol. What part of not being a real fix are you speaking of. There isn't anyone in this thread that has said their issue with fuel starvation was not eliminated with the kit. You are in the track section so maybe people who don't track aren't committing because they have found a fix and moved on.

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Did you happen to read the thread I linked of my issue? I’m not sure that it’s fuel starvation to begin with. That’s just what most members default to when the engine quits on the Z.

Car sputtered to a stop 1500’ after a 500’ right turn on the street which I took moderately at best and with 7 gal. in the tank. Suitcase in the back didn’t even shift. There’s more details in the actual thread.

I came proactively seeking starvation solutions one of which is the be all end all; however, IMO overkill for a street only setup and the other while no failures in the track cars it was meant for leaves ends untied for the street.

DarkJak · 09-07-2018, 11:52 AM

The only issue i've had was user error during install from not securing a fuel line down correctly.
Otherwise, the Z1 kit works.

Negatives are that I do still worry about the left pump being starved and running dry outside of track days, and I always keep the tank filled when possible.
And that my fuel lights have read 1/4 tank lower than they actually are ever since the install. (maybe also user error).

CJM's product quality is worth the extra cost, though, if budget permits. More stable solution, and nicer hardware than the Z1 kit.

phunk · 09-07-2018, 12:25 PM

Quote:

Originally Posted by DarkJak

And that my fuel lights have read 1/4 tank lower than they actually are ever since the install. (maybe also user error).

This is a plague of the 370z, for the fuel level gauge to be off by around a 1/4 tank... often it will bounce between 1/4 off and correct, once or twice a tank. Or for some it just stays wrong, never reading entirely full.

Very often, it happens immediately after molesting the fuel pump housing for modifications.

I am not sure the source of the problem, I would need the car here to diagnose it. But dont feel bad, it is a common occurrence after fuel system work.

One suspicion I have, is the in-tank siphon hose slack interfering with the fuel level float arm travel. But I have in the past run into slightly worn level sensors that do not read correctly.

Hotrodz · 09-07-2018, 12:35 PM

Quote:

Originally Posted by Tractionless

Did you happen to read the thread I linked of my issue? I’m not sure that it’s fuel starvation to begin with. That’s just what most members default to when the engine quits on the Z.

Car sputtered to a stop 1500’ after a 500’ right turn on the street which I took moderately at best and with 7 gal. in the tank. Suitcase in the back didn’t even shift. There’s more details in the actual thread.

I came proactively seeking starvation solutions one of which is the be all end all; however, IMO overkill for a street only setup and the other while no failures in the track cars it was meant for leaves ends untied for the street.

I did read your thread and I apologize if I was being harsh as I was not totally grasping your situation. I get it, you don't want to spend more money than you need to resolve your issue. From all the threads I have read on this issue regardless of track or street use only it seems there is a wide range between those that have issues and those that don't. I never experienced fuel starvation before hitting the track, even after boosting. Phunk kit was the first to successfully and reliably deal with the issue then came along the hydromats. For now these are the only two good options and one is more expensive than the others and deals with the issue you brought up and I got educated on and so you just got to decide which one is best for the money or live with the issue. Many street only folks have though it was worth buying the rrp system. I just decided to go a different route because of the build I have at the time I was looking to resolve my issue.

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Tractionless · 09-09-2018, 11:23 AM

Quote:

Originally Posted by Hotrodz

I did read your thread and I apologize if I was being harsh as I was not totally grasping your situation. I get it, you don't want to spend more money than you need to resolve your issue. From all the threads I have read on this issue regardless of track or street use only it seems there is a wide range between those that have issues and those that don't. I never experienced fuel starvation before hitting the track, even after boosting. Phunk kit was the first to successfully and reliably deal with the issue then came along the hydromats. For now these are the only two good options and one is more expensive than the others and deals with the issue you brought up and I got educated on and so you just got to decide which one is best for the money or live with the issue. Many street only folks have though it was worth buying the rrp system. I just decided to go a different route because of the build I have at the time I was looking to resolve my issue.

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Thanks and no worries; I didn't feel you were being harsh.

I've decided against the pre-packaged starvation kits at the moment.

Instead I'm replacing the entire OE fuel pump assembly with a new one due to the sound of my fuel pump motor prime changing during the issue. I have a feeling the fuel pump motor is on its way out.

I'm currently debating using a Hydramat in lieu of the OE pickup sock but trying to find out the O.D. of the OE pump inlet as Holley only offers 11mm for such a configuration.

Hotrodz · 09-09-2018, 11:51 AM

Quote:

Originally Posted by Tractionless

Thanks and no worries; I didn't feel you were being harsh.

I've decided against the pre-packaged starvation kits at the moment.

Instead I'm replacing the entire OE fuel pump assembly with a new one due to the sound of my fuel pump motor prime changing during the issue. I have a feeling the fuel pump motor is on its way out.

I'm currently debating using a Hydramat in lieu of the OE pickup sock but trying to find out the O.D. of the OE pump inlet as Holley only offers 11mm for such a configuration.

Outstanding!

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Rusty · 09-09-2018, 12:25 PM

Quote:

Originally Posted by Tractionless

Thanks and no worries; I didn't feel you were being harsh.

I've decided against the pre-packaged starvation kits at the moment.

Instead I'm replacing the entire OE fuel pump assembly with a new one due to the sound of my fuel pump motor prime changing during the issue. I have a feeling the fuel pump motor is on its way out.

I'm currently debating using a Hydramat in lieu of the OE pickup sock but trying to find out the O.D. of the OE pump inlet as Holley only offers 11mm for such a configuration.

If you re replace the whole assembly. Get phunk's billet top hat for it. Then you don't have to worry about it breaking.

phunk · 09-09-2018, 02:44 PM

Later this evening or tomorrow I can give you the part number for the hydramat that will best fit the bottom of th stock pump.

I’m not sure if you have looked at the fuel pump housing yet, but if not... putting a hydramat on there isn’t going to be so simple as just attaching it to the pump. You will need to cut away quite a bit of the bucket for the hydramat to spread out. It also isn’t going to reach to the driver side of the tank so it will only contribute a small bit to reducing starvation tendency because the only benefit will be collection of fuel outside the bucket, but still passenger side of tank only.

phunk · 09-09-2018, 02:45 PM

Quote:

Originally Posted by Rusty

If you re replace the whole assembly. Get phunk's billet top hat for it. Then you don't have to worry about it breaking.

Many people who’s top hat is already broken reported a change in the fuel pump sound when it must have occured. With his last post mentioning a change in sound, he might already need the top hat.

09-06-2018, 05:06 PM	#63 (permalink)
cv129 A True Z Fanatic Join Date: Jul 2011 Location: Dallas, TX Posts: 3,270 Drives: 09 Nismo, 16 Nismo Rep Power: 163996	Wow, I was seriously considering Z1 kit for the price, but Phunk’s explanation pulls me back to the darker side lol. __________________ Setrab \| RE-71 \| SPL \| JRZ \| Nismo \| ARK \| Whiteline \| RacingBrake \| CJM Oil Pan \| Ti shield

09-06-2018, 05:29 PM	#65 (permalink)
zmanelite Track Member Join Date: Nov 2013 Location: Anaheim Posts: 753 Drives: 370 Z Nismo Rep Power: 37	A toggle switch could be made for Z1 and run it for track only Or maybe just run stock pump a Y and a extra line with a Hydramat to passenger side __________________ Instagram @zmanscm

09-07-2018, 11:52 AM	#68 (permalink)
DarkJak A True Z Fanatic Join Date: Jun 2011 Location: Madison, WI Posts: 1,397 Drives: 2009 370Z Rep Power: 16805	The only issue i've had was user error during install from not securing a fuel line down correctly. Otherwise, the Z1 kit works. Negatives are that I do still worry about the left pump being starved and running dry outside of track days, and I always keep the tank filled when possible. And that my fuel lights have read 1/4 tank lower than they actually are ever since the install. (maybe also user error). CJM's product quality is worth the extra cost, though, if budget permits. More stable solution, and nicer hardware than the Z1 kit. __________________ @stupidtoycars \| My track vids 09 7AT\|MCS 2WNR\|Topgunz Rotrex\|Ecutek (Eugene)\|Maxxis RC1\|Titan-7 TS-5\|OSG LSD\|Rear Mount Derale Oil Cooler (WIP)+25 Trans Cooler\|Fismo\|G-LOC R12/R10\|Zeta III L\|NLR Wing and Splitter\|CJM Pan and Fuel Hat\|Radium Surge Tank\|AP Racing CP9668

09-09-2018, 02:44 PM	#74 (permalink)
phunk A True Z Fanatic Join Date: Mar 2009 Location: Chicago Posts: 3,669 Drives: 370 Rep Power: 974724	Later this evening or tomorrow I can give you the part number for the hydramat that will best fit the bottom of th stock pump. I’m not sure if you have looked at the fuel pump housing yet, but if not... putting a hydramat on there isn’t going to be so simple as just attaching it to the pump. You will need to cut away quite a bit of the bucket for the hydramat to spread out. It also isn’t going to reach to the driver side of the tank so it will only contribute a small bit to reducing starvation tendency because the only benefit will be collection of fuel outside the bucket, but still passenger side of tank only. Rusty and Hotrodz like this. __________________ Charles @ CJ Motorsports : Website \| Facebook \| Instagram \| YouTube Home of the 9 second, stock longblock, stock drivetrain 6MT 370z. 9.91 @ 142mph

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