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overdeveloped beater
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Yep....that's the one I used. I didn't mount it inside the tank because:
1. I wasn't sure it if's supposed to be submerged.
2. I didn't have a good idea of how to securely mount it.
3. I didn't want to drill into the tank cover to run the wires and then figure out how to safely seal it.

4. It works fine when mounted outside the tank.
rob said:
This is a really good thread. Thanks Storm for the details. Since my engine swap, I have been having fuel cutouts during rallyx sessions and it is costing me finish positions! I am glad I found this info.

One thing I am not clear on is the secondary pump that you added. I assume that this one would suffice:
http://store.summitracing.com/partd...836965+4294891680+4294891681+115&autoview=sku

Where did you mount yours? Is there any reason why it can't be mounted in tank with the main pump?

Thanks,
Rob
I mounted ours under the car near the rear subframe (on the drivers side) and routed the hose from the secondary pickup to the pump and then over to the 3rd inlet pipe on the main pump assembly. The car used to have an amp (and then a battery) in the trunk, so I kept the power wire and wired a 30A relay for the second pump. It's triggered by tapping the main pump power wire (since the relay only draws a fraction of the current) which closes the circuit for main battery power to the second pump.

When set up like this, both pumps run whenever the main pump runs. No extra switch to turn it on or off, you hear it prime for 2 sec. on ignition and you hear it turn off when you shut the car off. You hear it because it's LOUD. It sounds like a tatoo gun left on the hood of a car....but it provides about 15psi of fuel directed right at the main pump inlet when running. If if cavitates, the sound changes....and it might even damage the second pump.....but it's cheap to replace.
 

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Hi Jay,

1) I am waiting for a response from Mr. Gasket
2) Wouldn't the hoses and a zip tie keep it secured to the pump assembly?
3) Why not just tap into the main FP wiring at the pump? It is supposed to be low current draw and I can imagine with no real pressure to pump into it would be near it's minimum.
4) I think it would be easier and eliminate most of the noise problem?

Has this mod eliminated your starvation problems?

-Rob
 

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overdeveloped beater
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rob said:
Hi Jay,

1) I am waiting for a response from Mr. Gasket
2) Wouldn't the hoses and a zip tie keep it secured to the pump assembly?
3) Why not just tap into the main FP wiring at the pump? It is supposed to be low current draw and I can imagine with no real pressure to pump into it would be near it's minimum.
4) I think it would be easier and eliminate most of the noise problem?

Has this mod eliminated your starvation problems?

-Rob
1. Cool, shouldn't be too big a deal unless the pump simply won't stand up to it.

2. It's not a smooth operating piece like an inline pump. It oscillates back and forth....might cause issues in the long term. Also, it's feeding from the drivers side. Not much in there to secure it to (on that side) and the access hole isn't all that big.

3. I did tap the main FP harness to trigger the relay. I didn't want to take any current from the main pump.

4. Give it a go and post the results. I think I was under the gun in leaving for an event when I decided to do ours.....I had to get it working first and foremost before deciding if it needed any better "packaging". I was happy with the way it came out in our case.

I still need to make another surgetank with less holes in it. It's draining too fast but it is an improvement. I have some ideas about making 1way flapper valves but haven't dug back into the car in a long time.
 

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Yeah I gotcha. Is there a reason you don't think it can be mounted on the crossover pipe exit right next to the main pump? That's where I was thinking about mounting. Connect it right to the end of the crossover pipe and a hose from the pump outlet right to the surge box.

Also, what about moving all the holes to the right hand side of the box? The theory being, under right handers, the fuel in the surge tank would push up against the left wall and only new fuel could slosh in from the right; a poor man's 1 way flapper. With the return and secondary pump dumping right into the box, that should improve the situation greatly.

I doubt that I can get something up before my next event, but probably before the last one in October.

I would never have known what this was except I had logged the run with my Defi gauges. I could see my FP drop from a 40psi (differential pressure) down to 20 and sputter around for about 3-4 seconds. This was at WOT and full boost! Thankfully the gauge alarm started screaming and I got off of it. I think rallyx presents a particularly bad scenario because through most 180+deg sweepers one is usually full on the power to rotate around. That leaves very little fuel to return and hence, little help to the venturi pump.

-Rob
 

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overdeveloped beater
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I put on the drivers side to make it a bit easier to find a spot and also to keep the feed line as short as possible. I'd rather push the fuel than pull it.

Having all the holes on one side is a great idea that I never though of.....try it and find out!

With rallyx being much rougher than autox, I would see an even greater need for this. You might want to look at bypassing the rollover valve while you're at it....or at least repositioning it to let you go a bit further before it engages.....
 

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Meany Head
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Hey, instead of that Mr Gasket pump, what about using a fuel pump from something like a Goldwing or a YZF600? They are small in size, and all over EBay for $10ish. I don't know what their flow rates are, but I'll bet it's more than enough to feed from the drivers pickup to the surge tank? And they might be of better quality (oem) than the less expensive aftermarket ones.
 

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99 RS, 01 RS, 01 Forester S
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Discussion Starter · #69 ·
let us knows how it goes. I still have issues with my white RS, but again its swapped and sucks some major gas.

I recently had fuel cut with my new to me black RS. I was below a quarter of a tank though and it was ralllyxing not autoxing.

Storm I think autoxing is harder on the fuel starve than rallyxing. More g's on the ashault.

Check out the antenna! I guess theres a some little g's in the dirt.
 

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I actually think Rallyx is a worse case scenario because you can have very long sweepers where you can stay heavy on the gas. This means the lateral force is applied for a longer period at the same time as high consumption out of the rail.

I have run into the problem at 1/2 tank. I have solved this in the short term by filling up before the events. Baffle box is in the works for the long term fix.

-Rob
 

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overdeveloped beater
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"Solved" may be subjective. How much fuel do you want to run?

I've done a fuelpump change on my chevy truck and found that they use a pretty good setup for keeping fuel right at the inlet.


Of course, this won't fit our tanks, but the canister idea can be adapted to work well. It's got flapper valves, an inlet sock filter and the return line routes directly into it.
 

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1998 2.5 RS
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Since I was changing the pump during my swap I decided to try this too.

First trial. Couldn't get in the tank at all (should have looked at the pictures)


Next revision. Got into tank but hit the front of the tank and would not seat.


Final revision. Still hard to get into the tank, but made it in there. Pickup is basically at the back of the RC tank.


Thanks for the idea guys.
 

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overdeveloped beater
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Lets see, what's an STi tank cost (roughly)? I know the pump assembly is nowhere near cheap. The labor to install it is just as bad....you better hope you can DIY since the whole rear drive assembly has to come down somewhat. I can see a shop charging nearly $700 if you supply the parts.

This way works arguably as well for less than 1/10 the cost.
 

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Meany Head
2000 RSC
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I have had 4 AutoX races since putting in my anti-slosh tank. And.. all 4 races have been left-hand-turns. So... I still can't confirm if I can run at less than 3/4 tank on right hand turns. I can confirm to running 1/4 on lefts though! But, that was never an issue.

Anyway... I thought I'd at least share my "Stom Inspired" tank rig also.
http://www.ludicrous-speed.com/wiki/index.php?title=Shanes_impreza_fuel_slosh_mod


 
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