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Improved Fuel Economy After Spacer Install?

180 wanabe
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180 wanabe Proficient

180 wanabe

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Posted

I was wondering if anyone had noticed any improvment in their fuel economy after installing the plenum spacer mod?

I know that the main reason for the install is to gain power but im sure i remember reading somewhere that it is supposed to improve MPG and wanted to know of this was BS or something real

Cheers

VE35GT Apprentice

VE35GT

Posted
Posted
I was wondering if anyone had noticed any improvment in their fuel economy after installing the plenum spacer mod?

I know that the main reason for the install is to gain power but im sure i remember reading somewhere that it is supposed to improve MPG and wanted to know of this was BS or something real

Cheers

Didn't notice a real difference (well that was once I got over 'testing' whether it really did breath better near the redline... I think we all know what happens to the VQ's fuel consumption figures when the needle is making frequent trips to the Right Hand Side of the tacho)

Kam-80 Enthusiast

Kam-80

Posted
Posted

Also didn't notice a difference either way, but thinking about it I'm not sure how it would improve fuel economy? The spacer allows the plenum to flow more air and more air equals more fuel? I did read somewhere that the two cylinders at the end of each bank closest to the front of the car can go a bit lean from the stock plenum design, so with a spacer you could get a safer, leaner tune, which would save fuel, but that's a bit of a stretch.

scathing Grand Master

scathing

Posted
Posted
I did read somewhere that the two cylinders at the end of each bank closest to the front of the car can go a bit lean from the stock plenum design

They run rich compared to the other cylinders.

The "280ps" lower intake runners are longer than the "300ps" runners, and with the way the upper plenum slopes down (and the fact that the air comes from the back of the engine bay) it means they get strangled.

The spacer gives more room for air to make it to the front of the plenum.

I doubt you'd save any noticable amount of fuel. They don't run that rich in terms of what comes out the exhaust pipes, or otherwise they'd fail emissions. Assuming the car's running perfectly in every other cylinder you're only running a little rich in 1/3 of your combustion volume. 1/3 of f**k all is still f**k all.

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