Carb to EFI
#22
My dyno partner Norm did all the TB work, it was also quite surprising how close the Modded 90 mm tb flowed to a slightly modded 102 mm TB without the volute, within 40 cfm of each other If I recall correctly. Then with volute the 102 went up 200+ cfm more then the 90 mm gained with it. It shows us that what gets bolted on front of it is critical. Several of the cone filters I bought to try with this on the dyno even with a attempt by manufacturer to create a sorta volute in the cones filter still killed flow, none of them were blended real great, Smitty
#24
Im getting close to dtnoing a 4th one soon and otsered this:
https://www.ebay.com/itm/33487813144...mis&media=COPY
to use, it appears to be same one
#25
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Joined: Nov 2022
Posts: 27
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From: Tennessee
I will definitely get one of those air filters on the way to try. Going to start working on getting the volute to fit the throttle body. May have to mill down the outer lip of it to slide up on to the throttle bod.
#26
yes, it will take work to get the volute to fit over it, I cut one down w die grinder to get it to fit, the most recent one rookie posted pics of we used mill and rotary table to cut lip down and bored the volute
#29
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Joined: Sep 2022
Posts: 77
Likes: 11
From: Europe

Was browsing and saw this 2023 merc 565, i like this plenum did a bit more searching and found the parts diagram. Do you see like me ? It’s like a 525 plenum with 2 TB on the surface instead on the side. Which I think it makes more sense if you are not planning for force induction.

Someone knows the size of these TB merc 565 is using ?
#30
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Joined: Nov 2022
Posts: 27
Likes: 24
From: Tennessee
I have noticed that as wee on the 565. Looks like two of the mercury 520 throttle bodies on the top. I believe Eddie young did some plenum modifications to 500efi intakes at one time adding a second throttle body and moving them to the top of the plenum as well.



