Swirl Pot Advice

[Guest david_l_perry]

Since having the Jag Engine conversion up and working, I have found a few times on hard cornering when tank is fairly low, that I have experienced slight fuel starvation until I am straightened up again....

 

I was not really expecting this unless I was really low on fuel, or constant fast turns, but either way I am pretty sure a swirl pot is the answer.

 

Its fine on full tank, its just when it gets to 1/4 full and on sharp right hand bends that I am getting the symptom, and this would be as the fuel swashes over the left away from the outlet.

 

 

Currently I have my tank outlet into a fuel filter, into the high pressure pump all right next to the tank outlet, and a single feed straight into the injectors via an injection fuel filter, and then return via the fuel regulator back into the tank.

 

 

Does the swirl pot require a secondary pump on an injection system and how is it all plumbed in ??

 

Dave

[theduck]

You would have a low pressure pump into the swirl pot and then the high pressure out of the swirl pot.

[Guest whiz]

I have just done this mod this week on my zero. As like you when nearly empty the car would splutter around corners. Been out for a long run today and ran it nearly to empty. Transformed the car. Due to having a high pressure pump in between the tank and the fuel rail already I plumbed this one to the swirl pot And just added another high pressure pump after the swirl pot, to the fuel rail and took the return back to the swirl pot, then back to the tank.

[Guest david_l_perry]

Cheers, found a few links showing the same online.

 

Most said no need to use a high pressure into the swirl pot.

 

Dont really want to have to spend a lot on a second pump if I can re-use my original pump from the carb settup

I assume the original low pressure pump that ran my pinto bike carbs would be ok to use for this purpose then ??

 

Any particular problems with one type or another swirl pot, is bigger better......

[Bob Tucker]

Taller is better

[Guest whiz]

I used another high pressure pump due to way my car is plumbed already. It was easier to do.

[Guest david_l_perry]

Cant even think how much work removing the tank would be on the 2B.....I think it would be all rear body panels off.

 

To be fair, as far as I understood it, the original fitted tank does have baffles and a small swirl pot fitted - just going off what Mitch said about it. It does have a small pot noted under the tank where the fuel take off pipe is located, and this made me think I should be fine without, but clearly driving round sharp right hand bends on low fuel tells a different story.

 

 

I would actually love to have a much larger tank for touring, but think the work to remove the tank would be excessive

[Guest whiz]

It cost me approx £150 for everything but £45 of that was the HP fuel pump 2litre swirl pot was OBP £50

[Snapperpaul]

You just use your existing high pressure supply and return from the swirl pot instead of the tank and run a low pressure pump from tank to swirl pot then overflow from swirl pot to tank

I also plumbed a breather with roll over valve to the fuel filler

[Guest david_l_perry]

Cheers guys. It's all making more sense. Is the low pressure fuel pump used on the original bike carbs going to be ok, (as I still have it) or is this too low a pressure pump ?? I know bike carbs didn't like higher pressure pumps.....failing that, and as I don't know the age of this original pump, what sort of pump would people typically go for as the lift pump if I decided to buy a fresh one.

Edited September 21, 2015 by david_l_perry

[Guest shaggy]

Dave pop round and see my set up, works well, is simple to install, and does not require tank removal. Be quick though as car is going on the bay today............I may also have a serviceable swirl tank and HP pump.

Si

[Andi]

As far as I can see, I have a low pressure pump, tall swirl pot and high pressure pump

 

Andi

[Guest 2b cruising]

Whatever system you use, the lpp should be mounted bellow or at least as low to the bottom of the tank.

Otherwise to much lift head ruins the output of the pump. Easy enough to mount and if you were running bike carbs successfully, that pump would be fine for the purpose.

Edited September 21, 2015 by 2b cruising

[Bob Tucker]

You need to make sure the LPP delivers at least the same volume of fuel as your engine consumes at WOT.

We recently did this calculation for Rays Vette.

The following seems to be the formula to follow.....DONT use the GPH

as it refers to US gallons. Stick to litres.

 

There’s a simple formula to calculate GPH or LPH (liters per hour), but there are some variables to this formula, depending on your application. Norm Koval, a team leader in the Summit Racing technical department, typically follows this formula as laid out by the air/fuel experts at Holley:

Optimal GPH = (Max. HP x BSFC) / 6

Optimal LPH = (Max. HP x BSFC) / 1.585

In order to make the proper calculation, you need to determine your variables for this equation, starting with your vehicle’s maximum horsepower (Max. HP). You can determine this by having your vehicle dyno tested or by making a reasonable horsepower estimate based on the manufacturer’s advertised horsepower plus a conservative estimate of power gains made by aftermarket modifications.

The second variable in the equation is BSFC, or brake-specific fuel consumption. BSFC is a measurement of the amount of fuel consumed per unit of power produced. According to Holley, an engine typically requires .5 pounds of fuel per horsepower every hour at wide open throttle.

For the more scientifically minded try this...

https://en.wikipedia.org/wiki/Brake_specific_fuel_consumption

HTH Bob

Edited September 21, 2015 by Bob Tucker

[Guest david_l_perry]

Thanks for that. It's a completely different engine than the one I was running carbs on (2.1l pinto, now a 3.0l v6 injection) so it's not a straightforward assumption that the old pump will work.

 

Simon, will try and Bob up to yours this week. Appreciate the offer !