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Safest surge tank placement


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Hi,

 

Car is a 2006 NC Miata using the OEM tank. OEM tank is placed behind the driver in front of the rear axle. The trunk with the filler tube is blocked to the driver compartment with some sheet metal that is sealed with fire foam  (so if the filler tube leaks there should not be any gas flowing into the driver).

 

What would be the safest placement for a surge tank:

 

1. As close to the tank as possible almost, within the cage and above the rear axle (or maybe a little forward of rear axle). If there is leak here  the gas might flow into the driver compartment (if our firefoam is not sealing properly). This is the same as if the filler tube would leak.

 

2. A little further back in the trunk where the spare wheels is, the benefit is that this is a very shallow area so it could leak without having having much go into the driver. Eventually some of it would slosh into the driver compartment (assuming the sheet metal is not sealed properly).

This would require a little longer hoses as well (about a 1 ft).

 

I guess option 1 is better in an extreme crash, option 2 is generally better. I am not sure why anything would leak. But there are some stuff  there, surgetank, pump, FPR and maybe a filter.

 

Any thoughts?

  

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We have all of our fuel components in the trunk area for a couple reasons. First is it moves everything outside of the area of the driver. Second much easier for

service have quick easy access. We are not using the stock tank with the high pressure pump inside, again for service and a cell installation. We have a low pressure

pump to fill the surge with a filter between pick up and pump. After the surge we have a high pressure pump with a filter. This allow quick easy service of anything

and lets you visually inspect everything for leaks.

 

As for crash protection everything is mounted just about above the differential, so it would take a very hard impact to cause crash damage.

 

Haven't seen many Miata's running a surge tank with a stock tank and hope it all works for you. Are you staying with the pump in the tank?

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8 minutes ago, 55mini said:

We have all of our fuel components in the trunk area for a couple reasons. First is it moves everything outside of the area of the driver. Second much easier for

service have quick easy access. We are not using the stock tank with the high pressure pump inside, again for service and a cell installation. We have a low pressure

pump to fill the surge with a filter between pick up and pump. After the surge we have a high pressure pump with a filter. This allow quick easy service of anything

and lets you visually inspect everything for leaks.

 

As for crash protection everything is mounted just about above the differential, so it would take a very hard impact to cause crash damage.

 

Haven't seen many Miata's running a surge tank with a stock tank and hope it all works for you. Are you staying with the pump in the tank?

 

Yes, we will keep the stock thank and stock pump. The OEM fuel pressure regulator is also in the tank, will keep that as well. 

 

So we are leaving the tank untouched for now, it works well. 

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We have an e30 that I put a surge on.  I just bought a hyperfuel surge from summit for my system.  I ended up pulling the stock pump and rigging up some hydramat on the other end and put in a second similar setup on the other side saddle (e30 thing).  I put in 2 Carter low volume external pumps in the trunk, where the surge is too.  The internal pump pressure was in the 90s and my engine wouldn't keep the flame lit over 60 psi so I put in an adjustable regulator too (stock one was overwhelmed).  It is all plumbed with twist lock hoses and fittings from Summit.  I do use bulkhead fittings as well and NOTHING is in the drivers compartment.  It was an expensive setup but it works.  I no longer have to dive to the inside after exiting turn 17 at Sebring after half a tank.  Don't be afraid to skew away from the stock pump.  Most of them tend to overheat and burn out when the tank is bone dry.  The low volume Carters i have won't.  Now the high volume pump in the surge might, but we don't let it get that far down.

 

All of our fuel stuff is as close as I can fit it to the rear seat back firewall.

Edited by MPRLkld
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On 4/20/2020 at 7:38 AM, turbogrill said:

Hi,

 

Car is a 2006 NC Miata using the OEM tank. OEM tank is placed behind the driver in front of the rear axle. The trunk with the filler tube is blocked to the driver compartment with some sheet metal that is sealed with fire foam  (so if the filler tube leaks there should not be any gas flowing into the driver).

 

What would be the safest placement for a surge tank:

 

1. As close to the tank as possible almost, within the cage and above the rear axle (or maybe a little forward of rear axle). If there is leak here  the gas might flow into the driver compartment (if our firefoam is not sealing properly). This is the same as if the filler tube would leak.

 

2. A little further back in the trunk where the spare wheels is, the benefit is that this is a very shallow area so it could leak without having having much go into the driver. Eventually some of it would slosh into the driver compartment (assuming the sheet metal is not sealed properly).

This would require a little longer hoses as well (about a 1 ft).

 

I guess option 1 is better in an extreme crash, option 2 is generally better. I am not sure why anything would leak. But there are some stuff  there, surgetank, pump, FPR and maybe a filter.

 

Any thoughts?

  

 

My vote is definitely on the other side of a firewall from the driver, low enough to leak on the ground (vs in the car) if it is ruptured (like, cut a hole in the floor for it) - I am thinking on the opposite side of the driveshaft from the tank mounted with just enough ground clearance to be sure it isn't going to get a ground strike in an off. I don't own a Miata, so if I am picturing this wrong, then, never mind...

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