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have to start calling you VL400 - BigData

On my EVO they have only a 2.5mm return inside the tank. It creates a venturi effect to draw fuel from the LH side of the tank. I fitted a Walbro 255 and had problems only to find out that the venturi hole needed to be drilled out to 3.5mm. I did some before and after fuel pressure tests on both the supply and return line and found it was around 15 psi in the return line and now is around 4. Car is now running as it should.

Spare tank now has an access hole Looks like the venturi is only 2mm, well that sucks! Certainly sounds like similar issues in the Evo Charlescrown.

Some pics...

Would a fuel tank from a later model Commodore possibly have a larger venturi on the return?

Just add a 2nd bleed in the line to relieve pressure but still allow the stock venturi to work.

Alternatively, turn a new larger one up out of SS or if you can, drill that one out larger.

The new fuel setup with the return in to the swirl pot seems to be holding up ok so far. Think it will stay for now. And with the rewired fuel pump now only seeing about 1-2PSI off target at around 230LPH of fuel flow, this is an internal 340LPH pump.

The cooler that was replaced earlier in the year performs better in terms of pressure drop but as expected the tube and fin design is slightly less efficient compared to the old bar and plate. But overall happy with the systems as a whole, total ratio of 1.3 for exhaust back pressure to inlet pressure is reasonable. Dropping 2 PSI at 10.5 PSI inlet manifold pressure, it was dropping around 4 PSI and climbing for 8 PSI manifold pressure on the old cooler with the same 70% wastegate DC.
Added a switch for manual/auto control, so the above pull was in 2nd gear. Works like a charm using the manual input pin D10 (on a '424 PCM) and the following settings and applying battery volts to get manual mode. No kickdown control in manual mode so never kicks back, just follows whatever position the shifter is in.
Have had issues with wheel spin, once boost starts in first it never ends. Some may not see that as a problem So have added a number of correction tables for what was the flex output but is now tailored more for wastegate control.
This was a test to see what would happen on the 1-2 shift with only the shift boost reduction table in play (time since last shift multiplier table), so have cleared the table that reduces duty cycle in first gear. It starts to spin at around 50KPH, and then on the 1-2 shift the gate duty cycle drops to 0 which reduces wheel spin massively from what it was. Still heaps of spin but the VSS and actual road speed are probably only 30odd KPH different for a second or so instead of at least double that for much much longer.

you could try one of these units. G has one on his race car with E85 and it's been flawless. Neat and easy setup to install.

I have looked at the same unit for my next VP, depending if I can clear the gap between the floor and tank. You can space the tank out a bit if needed.

https://www.aeromotiveinc.com/product/phantom-flex/

https://www.aeromotiveinc.com/wp-conten ... -0revA.pdf


You can get a dual pump version as well for more power potential.

Yeah, been really good, as long as you can swallow the costs. Has copped a fair beating and really been trouble free

I love this thread, I go back over it when ever i need inspiration Kinda like project binky just in pictures

Yeah those intank setups from Aeromotive are sweet, certainly on the upgrade list. Circle track is a good test for fuel slosh!

I also like the idea of this product ... https://www.holley.com/products/fuel_sy ... hydramats/
Just needs an inspection hatch cut on the top of the tank and can use most the factory setup still.

Biggvl wrote:Kinda like project binky just in pictures

haha, about the only similarity is that my pictures are also in colour

Awesome car now. What is the exh ratio your logging?