Fuel Surge

[Noddy]

Fuel surge is some thing most of us never realy concider... untill it is too late.

Surge is a particular problem in drift because the cars spend so much time sliding with lateral G loads pushing the fuel in ur tank to 1 side or the other. The fuel pump pick up is usualy positioned so it will pick up fuel pretty much all the time under normal driving conditions. When the tank is getting low, some times going around a corner you might get a small cough out of the engine. The petrol has run over to the other side of the tank away from the pick up and the pump sucked air for a moment or 2. The pocket of air runs down the line and to the injectors. bop bop bop doesn't make a nice mixture for the engine to run smooth for an instant, It leaned out.

On the track drifting or racing, pushing the car and engine hard, the same thing happens, only under load the lean out is more sevear. A longer starvation occurs, more Oxygen less fuel = more heat = detonation = dead engine. Don't get me wrong here, it's a pantine thing, it wont happen straight away...but...it will happen.

The answer is to run a serge tank which is always full so you dont get surge untill the tank is ptrtty much totaly empty. The normal pump lifts fuel from the main tank into a smaller tank that is usualy tall and skinny that holds about 1.5L. At the base there is a fitting that you connect you hi-pressure pump to the engine which feeds the injectors or carby. the pressure regulator maintains the pressure for the injectors to work properly and retuns the excess fuel to the surge tank. Having the 2 feeds in to the surge tank, (return fro eng and fill from main tank) keeps it full just about all the time. Excess fuel in the small surge tank come out a overflow and falls back into the main tank.

I had 1 made to my own specifications. Cost a few $$$ but it is exactly how I wanted it. Most surge tanks will have normal barb fittings, I needed something more purpouseful.

This 1 is about 3.5-4L with a bosh Intank 600hp motorsport pumpin it. There is a return from the engine and return to the main tank up hi. The fill from the main tank is down low and the feed to the engine comes out of the inturnal pump out the top. The fill from the main tank is drawn from the bottom of the main tank where the fuel should be coolest. it is fed in to the surge tank down low so the hi pressure pump picks up the cool fuel first. The return from the engine goes back in on the same side as the main feed which creates a swirl. This and a horizontal baffel lowin the tank helps keep the fuel stable in the tank. The return is on the opposite side at the top working with the swirl, returning hot fuel to the main tank where it has a chance to rest and cool down. Just some ideas.

pm me if your interested in costing something like this or need something custom made.

[Duncan]

sounds and looks good.

might be worth running a fuel cooler as well with a surge tank since you dont have a whole tank full of fuel to share the temp with

[Gts-t]

this is my latest effort pretty much done

thanks to wrxhoon for the battery, and femno for the surgetank/fittings

[giant]

very nice set ups!!

[Noddy]

I'm actually looking at changing mine slightly to run twin 044 or 040 pumps... i forget which is the good out of tank ones atm... so the thirsty beast doesn't run close to its limit on the long straights at Queensland Raceway. dual feed to the rail and central regulator return. I'm in the middle of up grading injectors and turbo setup. It will be drinking more juice so i don't want it to run beyond the capabilities of the 1 in tank pump.

over kill?

Edited October 6, 2007 by Noddy

[R31Nismoid]

Well depends on how thirsty really?

350rwkw track GTR's here just have a good ole in-tank upgraded one.

And they never have fuelling issues

[Gts-t]

i run a 040 intank, and the 044 externally. Only finished the setup today, so far so good tho

Bit noisy but no fuel smell..... yet

[Gts-t]

Well depends on how thirsty really?

350rwkw track GTR's here just have a good ole in-tank upgraded one.

And they never have fuelling issues

Dont gtr's have a half decent anti surge arrangement standard? Enabling them to bandaid the situation somewhat?

I think old mate has a silvia or gtst so hes not as lucky?

[Duncan]

well yes ash, but they aren't running 1/4 tank fuel or less are they - keep the tank above that and you will always be fine.

we are doing the 1hr endurance race at oran park in 3 weeks and this is a major concern or us. the long, high g left hander off the bridge leads to fuel surge, and by 55min into the hr we are having trouble every lap - need to drive carefully and remember everytime to make sure we dont lean it out. Would love to run a surge tank but regs do not allow it...we can do a fuel cell so might go that way

[giant]

hey dunc are you allowed to run a fuel tail in the tank??

[Duncan]

whats a fuel tail? extend the input to the tank?

anyway no, full system must be standard unless you put a fuel cell in, in which case you need to put the stock pump into the fuel cell

[giant]

it's where you extend the pick up in the tank with a hose and weight it so when you go around a corner the hose goes to same side the fuel is getting pushed to by the g forces and it stays with the fuel

russ

[R31Nismoid]

well yes ash, but they aren't running 1/4 tank fuel or less are they - keep the tank above that and you will always be fine.

we are doing the 1hr endurance race at oran park in 3 weeks and this is a major concern or us. the long, high g left hander off the bridge leads to fuel surge, and by 55min into the hr we are having trouble every lap - need to drive carefully and remember everytime to make sure we dont lean it out. Would love to run a surge tank but regs do not allow it...we can do a fuel cell so might go that way

Well yeah indeed

Gotta remember though he is drifting, he isnt out there for enduro's... and nor is are club track-day GTR's out there for more than 20mins

So no massive fuel requirements. Twin pumps you gotta be cranking some overtly major horsepower IMO.

[Gts-t]

twin pumps is just a lesson in doing it properly Its not about massive fuel requirements, its about quality of supply.

and as far as saying he is just drifting? thats going to throw the fuel around alot more than circuit racing which should be relatively smooth in comparison. well unless you are in giants gtr, hehe.

this is the point where u tell me giant runs one pump in tank with no mods to any thing else and i lose :]

Edited October 6, 2007 by 2630GTS

[giant]

three pumps.

cant remember size dash at supply and return i think, dont quote me though.

russ

[Noddy]

Dont gtr's have a half decent anti surge arrangement standard? Enabling them to bandaid the situation somewhat?

I think old mate has a silvia or gtst so hes not as lucky?

If I am old mate, it is an r33 GTST logbooked as a 2A Sports Car. It is still powered by and RB25 with good head work, matched custom grind cams and plenty of other goodness. On a mild tune running 1 bar it is happily punching 300 rwkw. It has won its class at every meeting Ive taken it to this year bar 2. I had fuel issues at QR round and ran 2nd to a GTR at the Grafton round of the NSW hill climb champ round. I plan to run the QLD state sports car series next year so it has to perform and be bullett proof reliable.

[Noddy]

drift has been a lot of fun and still is, but this car has verymuch outgrown drift. As said above the focus with this car is firmly on curcit racing.

[giant]

it looks the goods noddy!!

[FATGTS-R]

As someone said its not just about volume of supply but quality of supply.

A friend has a serious HP car and like giant runs three pumps. One of the three pumps can supply enough fuel to keep the rail happy but he runs three. The other two pumps are just plumbed in for insurance allowing for a failure of one ...or two of them.

[Duncan]

great to hear, I didn't realise a gtst fit within 2A rules, they are very long cars.....but at least you will be allowed to do some decent mods and run good tyres under those rules.