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  #91  
Old 05-09-2017, 08:31 AM
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Not with e85!
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  #92  
Old 05-09-2017, 10:43 AM
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Might be a little laggy on a 2.0. On my 2.5 it was fully boosted at 3.6k. On a 2L that would be getting into the 4ks before anything atarts happening. Also depending on avcs aswell as displacement. My dom has the 3" inlet which i think really helps with spool.

The dom 1.5 and 2.5 have the same compressor. Its just the 1.5 has a smaller turbine which helps vring it on faster. At the expense of a little topend when compared to the 2.5.
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  #93  
Old 05-09-2017, 01:21 PM
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Thanks again guys for all the input and involvement.

Yeah definitely don't want a turbo that starts kicking only after 4,000rpm, had that before with my GT3071R just don't like it and defeats the purpose on what I'm using it for.

I know I'll be up for a retune again but it's gonna be later on down the track and unfortunately as I mention just really can't spend that sort of money at the moment, sucks not being single hahaha, I mean the money's there and still more than enough buffer even after spending on Dom but she still says no Grrrr... funny thing is I earn twice more than her so the savings are largely due to my contribution.... shouldn't have agreed that she will be the one managing the finance when we got married hahahha

Anyway I am keen to know more about the Surge Tank, I need to get out of it in the most cost effective way just to stop the surging coz my day involves going around town from meeting to meeting and I am not always in the position to be able to find BP and fill her up, so this is quite important for me.

Strangely I would've thought the surge happens because the injectors are running so close to the maximum duty cycle (97%) and once I do the top feed it would be gone but hey I'm a noob which is why I rely on everyone's experience

Any brand that you guys can recommend for the Surge Tank? are they all universal or specific for each cars like injectors?

Thanks again guys
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  #94  
Old 05-09-2017, 05:27 PM
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Fuel surge is when at low levels of fuel. The fuel sloshs around in the tank and the pump pickup is exposed to air instead of fuel. So you get a momentary gulp pf air/lack of fuel doen the fuel lines.

In subarus there is another factor involved. The fuel tank is kinda divided into 2 halves. This is because the driveline must transmit power to the rear anf goes under the middle of the tank. The tank is what is sometimes called a saddle bag. Think of a saddle on a horse with 2 pouches on either side. And a big fat horse inbetween. Well its the same thing.

The fuel pump is on one side of the tank and it pumps to the rails. The return from the rails is cleverely used by subaru to drive a siphon thqt actually sucks fuel from the other side of the tank and pumps it to the side with the pump. But at low fuel levels and hard driving, fuel ends up on the far side of the pump. And you experience fuel surge.

Subaru tried an upgraded pickup/baffle contraption on the spec C pump cradles. But these are still pretty in effective.

The best way is to have a surge tank. The intank pump pumps into a small external tank. In the bottom of the tank is your main fuel pump. (Or external if your using the old bosch motorsport pumps) the setup is designed in such a way that there will always be fuel available for the main pump (unless the car is upside down.) And any air that goes to the surge tank from the main fuel tank surging, is quickly bypassed back to the tank. Meaning there is always fuel available. Its more of a motorsport thing. But itcan be doneon street orientated cars if surge is a problem.
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  #95  
Old 05-09-2017, 05:59 PM
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Id be surprised if it is fuel surge at 1/4 to 1/2 tank, street use, with only around 250hp? I'd be thinking if less than 1/4 tank, and when heavy on the gas for prolonged periods??
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  #96  
Old 05-09-2017, 06:09 PM
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Quote:
Originally Posted by matto20v View Post
Id be surprised if it is fuel surge at 1/4 to 1/2 tank, street use, with only around 250hp? I'd be thinking if less than 1/4 tank, and when heavy on the gas for prolonged periods??
I used to get fuel surge at as low as 2/3rds to almost 3/4s FULL in my forester. And that was with an upgraded Hyperflow intank baffle/pickup bucket thing over the pump pickup.

Granted, not on the street. That was for skidpans and RAC etc. But its possible. Definitely possible at more than 1/2 load of fuel.
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  #97  
Old 05-09-2017, 06:10 PM
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Originally Posted by matto20v View Post
Id be surprised if it is fuel surge at 1/4 to 1/2 tank, street use, with only around 250hp? I'd be thinking if less than 1/4 tank, and when heavy on the gas for prolonged periods??
If it doesnt happen to you, then it just means your driving like a pussy.
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  #98  
Old 05-09-2017, 06:51 PM
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And its more in cornering, not acceleration.
Used to get it in my old shitbox VS ute when being too aggressive on a roundabout.
that was no where near 250hp.
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  #99  
Old 08-09-2017, 10:54 AM
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Thanks guys for the input and many thanks Bram for the very thorough explanation.

I've done a fair bit more research into this and found that there are actually many different types and brands.

Would there be any difference in terms of reliability over brand? I mean on Ebay there were a lot generic unknown brand for quite cheap but then again I've been caught up before with buying cheap JECS injectors from ebay who claims they are ASNU Tested but didn't spray properly when Justin tuned it. But at the same time I don't want to go overboard and pay a lot of money just for street use.

Also are there any pros and cons running the surge tank inside the boot or under car? I have a small single subwoofer box and 2 small amps in the boot which might be a bit challenging but easy enough to move to one side if need be, some one was telling me to have it on the tyre well.

Any thoughts guys? what would work well with Subaru?

Thanks again for your help guys
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  #100  
Old 08-09-2017, 12:44 PM
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Quote:
Originally Posted by Ben628 View Post
Thanks guys for the input and many thanks Bram for the very thorough explanation.

I've done a fair bit more research into this and found that there are actually many different types and brands.

Would there be any difference in terms of reliability over brand? I mean on Ebay there were a lot generic unknown brand for quite cheap but then again I've been caught up before with buying cheap JECS injectors from ebay who claims they are ASNU Tested but didn't spray properly when Justin tuned it. But at the same time I don't want to go overboard and pay a lot of money just for street use.

Also are there any pros and cons running the surge tank inside the boot or under car? I have a small single subwoofer box and 2 small amps in the boot which might be a bit challenging but easy enough to move to one side if need be, some one was telling me to have it on the tyre well.

Any thoughts guys? what would work well with Subaru?

Thanks again for your help guys
If your asking for the surge tank, then yes you can use the cheaper tanks. They can work very well and do exactly what you need them to.

The thing with using the cheap surge tanks is they are mostly all designed as a simple tank, which then feeds to a external pump (or 2). Usually the Bosch motorsport units. There is nothing wrong with this. Its been done successfully for years and years. The thing is now a days, its not the best way of doing things. (Imho) Now a days its common to have surge tanks with internal pumps. Usually a walbro 450 (or 2 in big builds.) The thing with the walbro 450/460s is each one flows about 1.5 times what a bosch motorsport pump does. And they do it with a twin turbine styles pump mechanism as opposed older rotary vane positive displacement design of the bosch. Which works fine. But is very noisy.

Internal pump surge tanks are more complicated and expensive to produce. They need the pump hanger and plumbing. Aswell as a way of getting electrical energy into the tank. And they also need a sealed opening so you can install/replace the pumps. So they cost more. External pump tanks dont need any of this. Bit they do need more plumbing external to the tank.

So when you look at surge tanks, you need to conside what you want from it. How many pumps will you need. And where its gonna fit on your car.

I have a radium tank on my car. Ive mounted it down the left side of the gearbox. Basically where the dump pipe woulld be if it was on the left side instead of the right.
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Last edited by Bram; 08-09-2017 at 12:57 PM.
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