Jenvey throttle bodies on an Alfa V6 24V photos.

[STR_Strat]

More trumpet porn plus one showing where I located the filter and regulator. The first two pictures are after the conversion to Audi R8 COP's.



The two rails are effectively in series ideally there would be a "Y" piece after the filter and another after the rails before the return pipe goes into the regulator, this way both rails would be fed at the same time with an equal amount of fuel at a given flow and pressure.

Dave

[Strat Fan]

The 3 common ways I would think are firstly- the one that everyone here seems to be using (rails running in series) with the pump at the inlet to the first rail, a loop between the rails 2 & the regulator at the the end of the second rail which then returns back to the tank. See Throttle body in series fuel system.pdf

The second option would be to pre regulate the rail in much the same way as the Phase 2 Alfa's are plumbed with the pump first, then the regulator & the rails last with a bleed on the opposite end of the rails to allow them to be filled with fuel initially. This I think is the least common on an ITB set up. See Throttle body pre regulator fuel system.pdf

Finally the rails in parallel set up which David mentions where the fuel is pumped to a "Y" piece before the rails which splits the fuel to each rail & the regulator is mounted at the opposite end of the rails as per the below diagram. This I think is the most common set up for a V8 on ITB's but would obviously still work for a V6. See Throttle body fuel system.pdf

[STR_Strat]

Thanks for sketching those up Craig it makes it very clear.
Next time I would use option 3, but with a "Y" after the rails so that a single port regulator can be used. There is an option 4 where the two rails are in series but dead end and use a return regulator, this is how the Toyota OEM setup is configured I believe.

Dave

[Strat Fan]

No need for a Y piece after the rails, I'd use something like THIS where one rail connects to the LH side, the other connects to the RH side, you can fit a gauge (or pressure sender) in the front to monitor things & the return line comes off at the bottom.
All hooked up with PTFE lined hose & Black anodised fittings of course.

[ChrisC]

Ermm Chris - have you thought this through? Those pipes are running underneath moving parts (handbrake and gear change) and look to be in danger of suffering chafing in an area that you're not going to have access to once the sloping bulkhead is in. I assume that you're planning on fitting that and sealing it permanently just in case there's a high pressure fuel leak?

If the braided hoses have to remain in this area you might want to consider installing an arch over the spine/gear linkage and handbrake rods that could support the pipes on top of it?

(a concerned) Guy

I realise your chassis differs fro mine, the floorpan on mine extends right to the vertical bulkhead but I think yours only goes to the cross member for the sloping bulkhead? If that's the case have you extended the floor where the pumps are mounted to form a closed void space? I can't make it out from the pics but is there a open area on each side of the centre chassis rail there that would allow any leaked fuel to drain or vapour to vent?

Guy, this picture was taken when I initially installed the pumps and was very much a trial run and shows the basic setup. My floorpan does indeed only extend to the sloping bulkhead so the pumps sit on trays with a gap of about 50mm either end to allow the fuel to run out if something major goes wrong. The pipework now passes over the top of the gear linkage rod and sits on a metal arch so that contact with any moving parts is avoided. I have also modified my tanks to take a much larger fuel balance pipe between the two to allow for fuel movement.
I have also lined the inner face of the sloping bulkhead with fire resistant material and have installed a extinguisher nozzle connected to my Lifeline Zero 360 system. I also have a dedicated fuel pump kill switch. Hopefully this will offer enough protection if things go horribly wrong.

[Bernard]

I have also modified my tanks to take a much larger fuel balance pipe between the two to allow for fuel movement............

Not so good around long fast bends !... you could well get fuel surge from one side to the other (depending how large the pipes are of course.

Cheers

Phil

[strat24v]

The larger the pipe, the quicker the transfer to starvation. Putting flap valves in can cause a whole raft of other problems. If worried about levels not equalizing while filling up with fuel then fit a bigger vent/balance at the top and fill up slower.

[ChrisC]

Phil, My theory was by using two low pressure pumps working in tandem and plumbed to individual tanks, both feeding a fairly large swirl pot I shouldn't suffer with surge.

[john]

Is it not the case that with a large enough swirl pot you're not going to suffer from surge anyway?
I don't know. I'm just asking.....

[Bernard]

Phil, My theory was by using two low pressure pumps working in tandem and plumbed to individual tanks, both feeding a fairly large swirl pot I shouldn't suffer with surge.

Hi Chris
My concern was fuel starvation but also the transfer of weight from one side of the car to the other therefore unbalancing the car.......... but this does depend on the size of the transfer pipe used..... I remember many years ago seeing one car (can't remember who's) that had something like 1 1/2" dia transfer pipe...... so long corners would have been an issue !
Sounds like you have it sorted
Phil