Fuel serge on track

[JB21]

Experienced it first at Oulton last month with just over 1/4 of a tank. Then again at three sisters on Sunday with over 1/2 a tank of fuel. Always on either sharp rights (Shell @ Oulton) or long sweepers (paddock bend @ 3S)

What are my options to prevent this?

[thetyrant]

Keep tank full   3 sisters is an extreme environment with its extra twisty nature but surprised you got fuel surge with over half a tank!, i ran mine at more like 1/4 at 2 sprints ive done there and never had issue, but im only on federal RSR rubber so maybe not as much grip as you and of course not slurping as much fuel in a 1zz,  are you sure its fuel surge ?

Only sure fire way if it is would be to a fuel swirl pot in the fuel line so its always pulling from a small container and hence not affected by surge, however this also means another pump inline to pump from swirl pot to rail and the tank needs to be big enough to always hold enough fuel!, space is of course an issue unless you run it inside the car but then you need an extra box etc around it for safety, tricky thing to do right and im surprised its needed in normally aspirated car like this and normally just for turbo guys needing a lot more fuel supply.

Maybe worth just opening up your tank making sure that everything is good with filter/pump and pickup teabag filter on as a first step.

[JB21]

Keep tank full   3 sisters is an extreme environment with its extra twisty nature but surprised you got fuel surge with over half a tank!, i ran mine at more like 1/4 at 2 sprints ive done there and never had issue, but im only on federal RSR rubber so maybe not as much grip as you and of course not slurping as much fuel in a 1zz,  are you sure its fuel surge ?

Only sure fire way if it is would be to a fuel swirl pot in the fuel line so its always pulling from a small container and hence not affected by surge, however this also means another pump inline to pump from swirl pot to rail and the tank needs to be big enough to always hold enough fuel!, space is of course an issue unless you run it inside the car but then you need an extra box etc around it for safety, tricky thing to do right and im surprised its needed in normally aspirated car like this and normally just for turbo guys needing a lot more fuel supply.

Maybe worth just opening up your tank making sure that everything is good with filter/pump and pickup teabag filter on as a first step.

Thanks for the reply Ian. Yeah its defo fuel surge as it only ever happens on higher g right handers, very common on the MK3 supposedly but only with around 1/4 tank. Must be a mix of pulling higher G's with my set up and the fact its a 2zz pulling in more fuel as you say.

Just been looking at a 1L & 2.5L swirl pot but as you say not lots of room to fit one, plus its looks a right faff!

I'll still have a look in the tank to make sure its all good but looks like keeping it topped up is the best option, shame as its just more weight to carry.

[JB21]

Seems fuel starvation is a real issue on track spec MK3's having read a bit more on the US forums, even some experiencing it with 1/2 a tank. Guy here with a track spec 2zzswap...

Yes,indeed.It was the first out of three laps and i pushed really hard on that right corner..Checking the lateral g force with telemetry data i saw that when the fuel cut happened lateral acceleration peaked at 1,43G...At that time i had a bit more than 1/4 of fuel in the tank.

God know what G's mine was peaking at to surge with over half a tank, 1.5G+ maybe. Seems the new set-up (upping ARB stiffness, -3.5 camber, stiffer damping) works a treat. 1.5G is getting into aero spec track car territory.

Anyway there seems to be an inexpensive and easy fix, its called a Hydramat. Pretty cool stuff!

 
PRI 2014: MUST SEE! Holley's HydraMat Just Changed The Fuel System Game In A Big Way! - BangS

[Alex Knight]

It's got nothing to do with 1ZZ, 2ZZ, NA or turbo. If there is enough lateral G to pull the fuel away from the pickup (and the level is low enough) then you will experience fuel starvation.

Only solutions are to fit a swirl pot and/or baffle the tank. I get fuel starvation (it's not surge) when just under 1/4 tank on AD08 tyres. I just fill up at lunchtime and crack on 👍🏼

[thetyrant]

AH yes i forgot about the hydramat i remember reading about it few years ago, i dont know anybody who has tried it but could be worth a go if they make one that fits in our tanks

[thetyrant]

Just looked at price of these Hydramats, wow they are not cheap for a big tebag haha... but i guess if it works and saves the engine/stops it cutting on track its worth it
 I notice Holley say normal service life 5-10 years before they start to degrade/clog and can be shorter if tank/fuel is dirty so would want to be sure tank is nice and clean before fitting one, maybe start with a new tank.

Think this is the one a guy fitted to a spyder over on SC and can be clipped to stock pump inlet but best check to be sure at that price! - https://www.fuelperformance.co.uk/index.php?route=product/product&path=635&product_id=8512

[jonbill]

I would think 1/2 litre pot would be plenty - it would give about 20 seconds protection for 4x 350cc injectors flat out. I think there's room for that, a pump and an fpr on the firewall next to the engine.
1/2 litre catch cans make good cheap swirl pots too. I modified one of these for my Datsun.

https://www.ebay.co.uk/itm/184023478790