Bought a lower plenum on eBay *Pics added* *Dyno added*

[Sentientbydesign]

Instead of enjoying Hawaii like I was supposed to, I get an email from eBay saying one of my watched items has x hours left.

The other bidder had a max bid of $50. I came in about an hour before the end time and bid $75.

Got it for $76 shipped (final bid was $51).

I was watching the auction from my cell phone while walking behind my wife in the Oaho Dole Plantation (2001 world's largest maze).

So now I'm working on polishing it. Anybody have any suggestions? I know the MREV2 has some actual aluminum cut off a couple of the intake parts, but I was wondering if anybody else had insight on what to do to improve it.

I might do a before and after dyno for the hell of it.

[kmckis1029]

you mean from an DE engine? so the "high rev" engine has a bad lower plenum?

[Tampa G35 Sedan 6MT]

Did you buy a Mrev2 or just the 03-04 plenum?

Good price tho

DJ

[Jacko3]

Nate:

Nice price. I will be looking forward to the dyno tests. Well done!

[tollboothwilley]

i believe the MREV2 is also ported somewhat, so if I were you I'd see if there was any way to make the openings of the plenum slightly larger before you get down to polishing it all.

Let us know how that goes though

[toddnos]

nice!

so you are dong your own mrev2 basically?

[Sentientbydesign]

you mean from an DE engine? so the "high rev" engine has a bad lower plenum?

There's nothing "wrong" with the rev-up lower plenum, but in order to benefit from the spacer you need the lower plenum off of a non rev-up motor or so I've read over and over (probably just Joe repeating himself lol).

The MREV2 is a modified automatic (non rev-up) plenum with shorter intake runners IIRC. They produce higher peak torque than the rev-up plenum does.

Adding a spacer to the automatic lower plenum is supposed to yield the highest gains for the rev-up engine.

I looked at some pictures of the MREV2 and it looks like they "lopped' off a small chunk from the front two intake runners (look at the pictures, the front two have grind marks on them). I assume this was done to allow even more flow to the front cylinders.

I don't see any porting or polishing for that matter done to the MREV2 (at least not from the pictures).

I'm almost half way done. I'll post up an article on it and probably do Vivek's write-up on the 350z suspension swap when I'm done.

[4drmadness]

im gona do the write up tmrw lol, so dnt worry about. u wil see it on thursday for sure k

[G_whizz]

im gona do the write up tmrw lol, so dnt worry about. u wil see it on thursday for sure k

Where have I heard that before??

[Jacko3]

Nate:

I will be waiting for the results. Can't wait to see the yields.

[Sentientbydesign]

Where have I heard that before??

Nice custom title, Sean. I was thinking something a little less mean and a little more embarassing, but that works

[Sentientbydesign]

Here are a couple of in-progress pix.

This one is a close-up of what the plenum looks like untouched



Notice the texture? The inside of the runners is a little coarser than the "smooth" parts in the picture.

Here's what I had done on Monday (didn't have any room on the camera for yesterday's results).



The top of the two front runners (The upper ones on the picture) will be cut down. The section to be cut down is approximately the same as the little rectangles seen on the right side. Those runners are the ones that get starved for air because of the sloping upper plenum.

So far, I've been using coarse sand paper and a dremel. The dremel gets most of the flat area down quickly, but once you get past the initial coarseness, those little "dents" are a PITA to get rid of.

I, stupidly, bought the 3M sanding block designed for paint removal. It works for buffing the aluminum but doesn't do much for actually removing it.

[BrandAidDesignG35]

I think it's time to bust out the power tools Keep us posted on the progress... I am fascinated with this type of work...

[Sentientbydesign]

What I really need is a medium/high powered rotary tool with a flap wheel.

The bowling proshop owner that I used to go to had these interesting fabric sanding disks that were scored to form a "flower". The were great for smoothing out holes, but I can't find them anywhere.

[Tampa G35 Sedan 6MT]

Looks like someone needs to take a trip to home depot and do some shopping!

DJ

[G_whizz]

I forgot to tell you nice score btw. Seriously...REALLY nice score!

Umm...really?? Is it mean?? I'm just having fun...

[Sentientbydesign]

I would have done something like "I hump tailpipes" or "I drive mommy's mini-van"

[Jacko3]

Nate:

I think we are on the threshold of something big here. If this works out, this would be a big improvement and a very interesting technical piece to send to Nissan to consider in future Nissan vehicles. Keep us posted. Well done!

[4drmadness]

[BrandAidDesignG35]

So????? What's going on with this beast now? Any luck grinding that Bi#$^ down?

Do you think this is something I could tackle over the next few months? I love working on my cars, but in the winter I can't because it gets to cold, this would be something I could work on in the basement or something Please keep us posted with the progress, really interested, oh, and a dyno would be nice to back it up

[zozoka1212]

Once you smoothing it you should send give it to somebody who can electro polish. It would make it even better. We making some parts for Toledo and some required high gloss finish and smoothness. We have a surface roughness at 30 and after electropolish it drops down to 7. That is pretty damn good.

zozo

Also there is a polishing compound you can use when you are buffing it. It is like a bar of soap and it is blue. I think we have some of those buffing wheels left in the shop. I'll check it out next week.

[Sentientbydesign]

So????? What's going on with this beast now? Any luck grinding that Bi#$^ down?

Do you think this is something I could tackle over the next few months? I love working on my cars, but in the winter I can't because it gets to cold, this would be something I could work on in the basement or something Please keep us posted with the progress, really interested, oh, and a dyno would be nice to back it up

Sorry, not much progress. Last night I did a grounding kit install on a soon-to-be member (he can't seem to register) and it took longer than expected because it's the middle of Fall and the sun goes down quickly. Normally I think about stuff like this, but it's been so hot here that I forgot what time of year it is.

With the right tools and time, I don't think this mod would be too hard for anyone. I wish I had a grinder to lop off the top of those two front runners...wait...I think I do have one hehe. It's got the wrong attachment, but it's basically an angle grinder.

Right now, I have the sunken in area sanded to about 220 grit and I'm almost done with 1 runner (at 80 grit). I'm going to take the dremel to the other side to sand off all of the coarse texture then start working on the sunken area and the rest of the runners.

I need to have this done by weekend after next for the dyno day I signed up for. 2 before runs and 2 after runs for $40.

Zozo,

I might look into polishing it. I just don't want to buy a bunch of tools I won't be using again for a long time. Maybe I can rig up a flexible shaft with a wool attachment at the end and some rubbing compound?

[4drmadness]

damn u got 4 runs. im just waiting for my work schedule. hopefully i dont work saturday or else i might not go for it. wat time r u goin?

[Sentientbydesign]

damn u got 4 runs. im just waiting for my work schedule. hopefully i dont work saturday or else i might not go for it. wat time r u goin?

12:40 and 5:00. I want to have plenty of time to swap plenums.

[BrandAidDesignG35]

Hey SBD... got a quick question.. see pic below

[BrandAidDesignG35]

Are those areas highlighted in red the areas you're trying to shave? I'm just wondering

[Sentientbydesign]

I did some poking around on another forum. Seems like I'm not the only one who's tried to make my own MREV2. Although, honestly, I'm not and just so Tony over there knows, I'm not going to try to capitalize on this either.

The front two (top of the picture) need to be cut down. All of the coarse texture needs to be removed as well. I'm not sure if there is any additional work that needs to be done. My research is still pending.

[zozoka1212]

Zozo,

I might look into polishing it. I just don't want to buy a bunch of tools I won't be using again for a long time. Maybe I can rig up a flexible shaft with a wool attachment at the end and some rubbing compound?

Do you have any tools. Grinder, car polisher, drill? With a little magic you can use those or others for polishing.

zozo

[toddnos]

im sure that porting is all you need to do. there are schools of thought against polishing anything on the intake side of the head.

[Sentientbydesign]

The intake on the G is interesting. There's the throttle connected to the upper half of the plenum, connected to the lower half of the plenum (includes intake runners), then there is another piece that sits between the heads and plenum.

If the need for atomization really exists (still don't completely believe it), then the section between the heads and plenum should take care of that.

If not, then I always have a backup plenum hehehe.