Author Topic: 6G75 Variable Intake - The Piston Eater  (Read 8685 times)

ChargerX3

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Re: 6G75 Variable Intake - The Piston Eater
« Reply #15 on: November 15, 2017, 04:55:53 PM »
ChargerX3, I tried that, but Lisin is protective of his IP in these things. He's a nice guy and has a family, ever bit of scratch comes in handy in Russia.

Ordering info is coming soon!
Not a problem. He could save himself the hassle and sell the licensing to each customer who would want to print their own.

OKTIREFRYER

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Re: 6G75 Variable Intake - The Piston Eater
« Reply #16 on: March 14, 2018, 07:08:01 AM »
Kevin, any updates on this project?  I'd like to order a set.

CharlieN

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  • Collector of Mitsubishi vehicles dating back to 71
Re: 6G75 Variable Intake - The Piston Eater
« Reply #17 on: March 14, 2018, 08:13:06 AM »
Many years ago I did start to build a new mid intake manifold for my SR. A big block of phenolic to machine which would eliminate the long low speed intake tract.
The second SR I bought came to me with a brand new intake on it and at that time I swapped it onto my driver.
After a few days of driving with the system functioning I just unplugged the vacuum hose so the butterflies will not close, all they do is kill the mid range power. I do not recall just what rpm the butterflies open on the G74 but it was way higher than torque peak.
I do recall the same thing on the 12V motor in my Diamante wagon, the engine was dead till 3500 and then suddenly came to life.
I eliminated the butterflies and saw a 2mp improvement with the added power.
A year later I swapped in a G72 DOHC with 5 speed from a 3KGT into my wagon. That engine was dead to 4500RPM and then came to life. Again I deleted the vacuum system so the valves were open. An instant 4 MPG from the increase of mid range power.

So no, I have not made the custom manifold for the 6G74, I just deleted the vacuum actuator so the butterflies close. This way they never see the large pulses which fatigue all the small parts in the intake, very little chance of failure run this way.

FWIW the 6G72 DOHC in my wagon has 280K miles on it with the original intake valves with no issue. Had I not run some cheap synthetic oil for too long I would happily be driving that car but I stupidly let it spin a rod bearing.

So my opinion, if you have a set of butterlies that clatter, pull the valves and shaft out of the intake. Seal the open end where the shaft came though and run it.
If the intake is not clattering, delete the vacuum actuator and run it open, on my 3.8L DOHC engine I think it was 1 or 2 mpg improvement, about what delectable hubs up front offer.
Regards, Charlie N

CharlieN

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Re: 6G75 Variable Intake - The Piston Eater
« Reply #18 on: March 14, 2018, 08:41:39 AM »
To add another thing, if you are looking to 3D print the bushings for the intake I would consider filament from, https://www.igus.eu/wpck/10783/3Dprinting
Regards, Charlie N