Monday, August 30, 2021

Pure Carbon Bling... Despite What Nismo Says...?? (*UPDATED!*)

(Updated Install Instructions, see below)

So after selling a few things on Yahoo Auctions, I realized I had saved up enough to spend some money on something which normally I would write off as complete bling. Nismo's carbon fiber airbox for the BCNR33/BNR34, originally introduced on the BNR34 Clubman Race Spec demo car back in June 2017

What a great way to make money for Nismo, right? With an eye-watering retail price of 612,150 yen including tax!

But Omori Factory claims that their airbox actually has design improvements over the OEM airbox.  For example, not only does their airbox have more volume, but it uses velocity stacks which in theory increase the air flow so much that the ECU has to be remapped! Further, their supplier is apparently a takumi who has supplied Nismo and Nissan with carbon fiber parts for their Group C and other racing cars over the past 20 other words, these are not mass produced but carefully handcrafted items by someone who probably knows what he is doing...

Of course, if you simply want the carbon look, I have seen others who have created their own carbon fiber air boxes which appear to be copies of the OEM box, just in carbon fiber and priced much less.

But as it happened I was able to get my hands on one of the Nismo ones - I figured what would I have to lose by installing one in my car? Improve the looks, at the very least right? It would be a good match for the Nismo carbon fiber air inlet pipes and the Omori Factory air inlet snorkel I recently had installed.

Ok so first thing is to open up the box. 

For those interested, here is the parts number for the 33/34

Fairly standard wrapping given the price...

Wow! Very nice. Almost blinded by this beautiful carbon fiber!

So here is the bit that costs an extra 500,000 yen...(the Nismo plaque inside!)
Actually, these are what is supposedly the technical improvement:
Exactly how? Keep reading!

Next step was to remove the OEM air box in order to do a proper side by side comparison. A few clips and bolts and don't forget the side vent, and it is a pretty easy job.  The only trick is to loosen the bands connecting to the MAFs, and remove the airbox with the MAFs still attached.

Here is photo of both airboxes in the engine bay:

If OCD like me, you can see that the carbon is different for each piece...

So here is the inward side of the airbox, after the MAFs have been removed.

Before installation of the velocity/venturi stacks

Installation of the velocity stacks is easy - you use the bolts that attach the MAFs to the airbox.

After installation - shame the velocity stacks are hidden because they are gorgeous to look at!

Close up - oops forgot to remove the tape there...

In comparison, the OEM airbox simply has these rings with the nuts for attaching the MAF bolts

Of course it was Dino who reminded me that I should weigh everything to see if there was a weight reduction benefit - after all, this IS CFRP vs. ABS plastic!

So yes, a weight savings of 197 gms!

And on the inboard side:

Ok this is strange. CFRP is heavier by 67 gms!

So a total weight savings of 130 gms! Not sure if this is really enough to write home about...

Hard to tell here, but it appears to my untrained eye that on the filter side, there seems to be slightly more volume.

You can also see that using the level, the carbon fiber box is slightly taller, thus also suggesting more volume. 

OK, so it seems like there is more volume, slightly less weight, and then possibly some increased air flow due to the velocity stacks.

Not surprisingly, installation is fairly simple, the only care point is to make sure that the MAFs are bolted on tightly to the carbon airbox and therefore also the velocity stacks inside (also watch out for the very thin O-rings on the MAFs side).

Here is how it looks with the MAFs attached. Note how one MINE'S plaque on one MAF is ready to give up (fixed up with some superglue)

I took the opportunity to check how dirty the filter is. It wasn't!

Yeah, I guess I don't drive the car much huh.

Next I turned my attention to the spot where the parts would go back in - and noticed that there was a thin layer of oil and dust so...

Of course I had to clean that all up.

Another view of the MAF side of the air filter box. You can see how the velocity stacks protrude inside.

On installation, everything was a very tight fit.  Of course had to make sure to tighten up the bands connecting the hoses to the MAFs.

Compared to the OEM box, the Nismo carbon box only uses one bolt up front to secure it (OEM used 2).

And on the other side, it initially appeared that the holes did not line up properly. (BUT SEE UPDATE BELOW PLEASE)

But this turned out to be rectified if I loosened the front side and all the clips first, and bolted down this side first. However, I also noticed something...

I found some sponge rubber with a sticky backing, and cut to size.

This way, I can bolt down and be reassured the carbon won't be scratching the engine bay paint. 

I'm pointing to this latch - tolerances are so tight here that you need to make sure the loop is already inserted towards the hook side (but not fully locked) before closing the other clips. 

OCD in action - just in case there is ANY rubbing, I taped a piece of rubber to the edge of the airbox closest to the air inlet pipe.

And here is the completed result!
See, all 3 carbon pieces look different...why...??

So will this carbon airbox actually make a difference in the car's performance? In my next blog I will reveal my findings, as I took a quick road trip down to Yokosuka to visit some old friends. Stay tuned!


So Nismo Omori Factory contacted me this morning with apologies - after viewing this blog, they realized they had neglected to inform me about one VERY IMPORTANT STEP.

Which is, to RE-USE the rubber and steel spacers on the OEM airbox:

These things

To remove - Very carefully remove these metal inserts - I used a plastic interior panel removal tool so I wouldn't scratch or tear the old rubber:

To ensure smooth OEM fit, I removed the rubber foam I had earlier attached.

Fit is 100% - and yes, this the correct positioning - I checked before removing from the OEM box, AND I contacted Nismo to verify.

Which means the side on the bottom, that touches the body are these metal washers? But doesn't it look like the top one had some kind of rubber coating from the factory?

So my solution - Tessa cloth tape!

Upon reinstall - wow this fits SO MUCH BETTER!

So of course, I complained to Nismo as well - for something costing this much, why not throw in some new rubber washers? I am ok with re-using the metal cores, but honestly how much does 3 rubber washers cost?  Their response was that this is technically NOT a Nismo part, but an Omori Factory limited production run (they apparently don't make much of a profit on these). Hence no instructions, nor the extra bits one can expect to find in an official kit. Still, I wonder...

Anyway, for anyone out there who might get this kit, I hope these FULL instructions are useful!


Anonymous said...

Could be interesting if the airbox actually does improve performance more than measuring error. My airbox has a broken mount so one of the clips falls off when you go to release it.

Tad said...

I always assumed the BNR34 airbox was exclusive to that car. Time to add this to the list then...

Anonymous said...

BTW, a long time ago you mentioned wondering why the oil coolant heat exchanger was kept in your car even though it was a street car and you had the HKS oil cooler. After driving this car and monitoring the oil/coolant temperatures I think the answer there is that most of the time that heat exchanger is actually heating up the engine oil, not cooling it down. For the first 10 minutes or so of driving these cars the engine oil is colder than the coolant. For ideal engine protection you want to get the oil to 70C on the gauge before you start to rev it to high RPM and high throttle opening. I try to stay below 3000 rpm and stay out of boost until then.

Once the engine oil is hotter than the coolant then you will start to see some cooling effect, but from what I have seen this heat exchanger is not very good at cooling the oil off, hence the need for supplemental oil cooling.

If you could do it all again, would you still have gotten the HKS oil cooler or something else? I'm thinking of putting one in as I'm taking off the plenum and throttle bodies to get access to the oil cooler and all the hoses under the plenum to prepare my car for California emissions compliance. I would probably just install the sandwich plate and all the stuff under the plenum but leave the actual cooler lines + core install for later.

マット said...

Wow! That looks amazing! Congratulations~
I want one too.

マット said...

Is there a carbon piece for the side vent? Or is the stock plastic piece reused?

Aki said...

Hey everyone, thanks for all the comments! Let me answer all of them.

1. Improving performance - stay tuned in my next post as I give my impressions.

2. Yep. Save up or bust out the credit card...

3. Wow, thanks for this, makes total sense! I think the HKS one works, as well as the Nismo one. Key is to use the space behind the bumper.. One negative of the HKS is the excessive hose length, which if installed per directions means it is visible snaking its way in front of the engine. Have to think of a way to clean that up!

4. Matt - yes they have one for the 32. Not, the stock plastic piece that goes into the fender is still used.

マット said...

Here's a neat way to organise the oil cooler hose:

Anonymous said...

JDM Masters published this interesting short, I didn't know that someone actually did a test with a production car and found the series 3 R33 to be quite impressive even without the press car modifications.

The Nismo kit looks nice but the "Nismo bumper only" requirement definitely bothers me, I don't think I want the 400R bumper.

The one thing that gives me pause for the HKS oil cooler kit is that I have a series 1 car, I'm not really sure how the intake side of things would work. It appears to me that the turn signal finisher has a grille design to it that would allow air in while catching any major rocks.

I was thinking about some way to relocate the oil filter, but so far other than the part where half the oil filter spills all over the front differential every oil change I haven't actually had issues with the placement. Obviously it will suck much more if you don't have the appropriate oil filter wrench but I haven't had big issues with it.

Re: Matt, that's a really interesting kit. A lot better than my idea of just zip-tying the oil lines lightly to guide them into less visible areas at least.

Aki said...

Matt - very nice, thanks! How do you find such cool stuff?

Anon - wow, thanks! Maybe I should offer Ken at JDM Masters an opportunity to check out my car lol. Re oil cooler, yeah at first I was more about function over form, but now I want both...

Matt said...

Congrats, it looks beautiful!

Now the question, what are you going to do with the stock air box? I’ve been trying to source one to reinstall on my s3 r33 (when I got it, it had a pod kit installed). Any suggestions??

VspecR said...

Wow thats a eye watering price for air box. Looks amazing though!