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I am currently in the middle of a valve cover gasket replacement on my 2003 Nissan 350z and just got to the lower plenum. However I have seen videos of pictures of what to expect....
when i opened my plenum I had no scopes on the lower plenum. There are tons of scratches marks/chips around the where the scoops should be.
Prior to taking off the plenum the engine ran fine for like 200 miles that I have owned it. Other than the valve gaskets spilling oil of course.
I am curious as I have looked to see maybe this is a power modification I didn’t know of but cannot seem to find this on google/YouTube/other forums.
Does anyone know why someone would do this?
is this safe?
I have tried to attach an image to show the “work” Lower plenum no scoops
LMAO, never seen that before, safety wise i don't see it being a problem. If you so want a OEM bottom I have a entire wrinkle black manifold with spacer I can sell. Just shoot me a PM if interested.
Makes me wonder if the previous owner was running some kind of FI.
Did the previous owner think he was going to get 50whp by doing this mod?! .... Hell, now I am actually curious as to what the difference was in power. Either Gained 1hp or lost a few.
So I have like no info from previous owner. He bought it from someone else with the purpose to learn manual and didn’t enjoy himself.
he claimed he bought it from an MIT student who had started to take the interior apart because he wanted to “see how far parts fit together”. He had like 0 information.
This student had removed a ton of the interior parts and even the a pillar plastic so I wondered if that was true or maybe he was trying to make a drag car (I am in Arizona and drag racing is huge here due to that is the main track in Phoenix that has weeklies)
DO NOT RUN THAT PLENUM! You will loose power, you need those scoops to create velocity. Even with the gained air flow you it is a very fine line between Air Flow and Velocity. you need both and you only have half of the equation looing power.
I'd swap it back to stock or an MREV2 if you're looking to start modifying. Unless the car has been tuned with that modified plenum I'm guessing every characteristic is worse than stock.
So I got a OEM lower plenum off eBay (ended up not as pictured and covered in RTV gasket, I spent quite a few hours cleaning that up). I just got it installed and ran the 350z around the block and the butt dyno feels wayyyyyy better. Feels like 15+ new hp added.
Lower plenum scoops look cut off (new owner)
