Saturday, February 17, 2018

GT-R Magazine Article: Using Bolt On BNR34 Body Reinforcement Parts for the BCNR33

As some friends from the ClubR33 Facebook owner's group had given me a heads up that this month's GT-R Magazine (#139, 2018/Mar)...

...had an interesting article featuring how a Japanese tuning shop, Garage Yoshida, had developed a menu of BNR34 bolt on parts in an effort to improve the BCNR33's body rigidity, I went out and bought this issue in the hopes that the content would be worth sharing here.  I was pleasantly surprised!

As I had learned in my research on the objective differences between the BCNR33 and the BNR34, Nissan put lots of effort into improving body rigidity (along with aerodynamics, of course) in the BNR34.  This month's article provided even more insight, as follows.

1) The BCNR33 and the BNR34 are, save for the extended chassis, basically the same mechanically.  Nissan developed bolt on parts to improve body rigidity of the BCNR33 over the base R33 chassis based on the input of Nissan's top test driver, Hiroyoshi Kato, during the development of the BCNR33.  It turns out that the locations of these bolt on parts are essentially the same for the BCNR33 and the BNR34, and that for the BNR34, these parts were revamped for even better body rigidity.  So, Garage Yoshida decided to offer an "R34 Body Reinforcement Plan."

2)  Some of the parts may require a bit of extra work to fit.  The basic difference in parts are increases in the size/area of the part bit that is attached to the body, and reinforcement of the part itself. For example the diameter of a tube may be similar but the BNR34 part has extra ribbing on the base, or the base has dual layers, in other words changes that are cheap (for Nissan) to implement. 

3) As these parts were developed by Nissan, unlike some aftermarket parts from various tuners, you can be assured that the parts were subjected to R&D and thoroughly tested.

So, what are these parts?

As you can see from above (and my summary below):
Starting from, left top to bottom:
A) Trunk Bar.  I installed the S15 trunk bar on my car, but the 34 one is installed differently. First, the trunk floor needs to be prepped as there is a base that needs to be welded to the floor and then painted. The trunk bar attaches to that base.

B) Front Tower Bar.  I have the NISMO titanium one, but when comparing the OEM BCNR33 and BNR34 front tower bars, you can see that, although the diameter of the bar itself is the same, again the base mount area is different. For the R33, the base bracket is simply welded on, but in the 34, in addition to the welding, the shape of this bracket is different and has ribs.

C) Center Plate.  These center plates are attached at the base of the B pillar area for additional rigidity.  For installation in the 33, the floor side is bolted on, but the pillar side apparently requires a gusset, to which the center plate can be attached. I will have to look into this, although after having the Do-Luck Floor Support Bar bracing installed I am not sure there is much to be gained in my car.

D) Upper Plate.  These connect the body and the rear upper (coilover) mount areas, resulting not in body rigidity but more vibration suppression.  All it takes to install in the 2 door coupes are drilling 2 extra holes.  I am DEFINITELY going to install these, someday.

E) Steering Member.  The BNR34 version has larger diameter piping in some areas and gussets added to the attachment points, presumably to increase steering response. However this requires removal of the dashboard and so for me, having just had my dashboard replaced, a lost opportunity. Although most people who have driven my car have praised the steering so not too worried...

Right top - F) Rear Strut Tower Board.  This is the bolt on part that results in the biggest improvement. The BNR34 board is dual layered, and so its overall rigidity has increased.  For the BCNR33, the lower part of the panel was separate, and in the BNR34 this section has become unified with the main part.  For Series 3 kohki cars, this BNR34 part is an easy bolt on, but for Series 1 zenki and 2 chuki cars, some work is required as the floor shape is slightly different and so some heating and painting are needed.  Another part I definitely want to get installed.

Right middle - G) Front Cross Bar.  The BCNR33 part has a diameter of  25.4mm, while the BNR34 part is 32mm. Additionally, the gusset and ribs are thicker, with more surface area attaching to the body.  I have installed the NISMO Underfloor Front Brace, which replaces this OEM part for both the 33 and 34. I will have to check to see if the 33 and 34 NISMO parts are the same (the parts number is different but I don't know if the dimensions are) but I doubt I will change as the NISMO part seems to be designed to improve even the OEM 34 part, and so if the 33 NISMO part is shaped the same, then I suspect the NISMO part has better results than the OEM 34 part. 

So friends, this gives me some other stuff to think about and possibly install this year, in addition to my continuing interior modernization saga! Comments always welcome and thanks for reading!

UPDATE: I just called Nissan Prince Tokyo Motorsports, and this is what they told me:

That Nissan Prince Tokyo Motorsports is where GT-R Magazine shote the photos used in the article, using the magazine's own R33 GT-R. AND, truth be told, the usage of some of those parts are questionable in the opinion of the top mechanic there.

For example, the Rear Strut Tower Board - even the the article claims it is "bolt-on" for Series 3 kohki R33 GT-R, the mechanic is claiming that isn't exactly true.  Some minor mods are probably needed to make it work properly.

The Center Plate, as well - see how, in the photo, the right side of the piece rises up towards the B pillar? This means that the rear seat cushion now won't lay flat, as you will have to literally cut out a section of the rear seat to make it fit properly again.

Of the 3 parts I was interested in (the aforementioned 2 plus the Upper Plate), I would probably only install only the Upper Plates.  Except that since it's quite tight back there and holes need to be drilled, I would likely do so only in the event I have to replace the rear window.  Luckily, I was told there are plenty of these Upper Plate pieces in stock, AND they only cost 960 yen each.

So, I guess this won't be happening anytime soon... On the other hand, looks like I've got the other areas covered already. So, time to focus on other stuff...

Saturday, February 3, 2018

Yes, I Actually Had a Subwoofer Installed (For a While...)

Friends, some of you may have been surprised in reading my latest Speedhunters post that I had actually had a subwoofer, amp and custom made enclosure, which ended up getting thrown out by Nakamura-san at Worx AutoAlarm. Putting my feelings on that aside, I'd like to bring you all up to speed as to what I was doing in the audio department.

Long story short, yes I was working on a set up, but I wasn't ready to publish here on this blog until it was all done. And I had so many ideas that I was sure was going to make this the mother of all subwoofer enclosures!  But now that the cat's out of the bag... I won't spill all of my secrets and ideas, so this can be considered to be Version 1. Hopefully soon I can replicate and improve upon this idea.

Anyway - a few years ago I embarked on a DIY sound insulation project and actually while doing that, laid the plans for a subwoofer system. Because I had lost the use of the temp tire that is normally kept in the trunk due to the R35 calipers and rotors now on my car, the wheelwell was empty. Additionally, my research for how the R33 improved upon the R32 showed that weight distribution in the rear was important, and now my car was lighter in the back without the spare temp wheel!

So, installing a subwoofer would accomplish two tasks - it would restore or even improve the weight distribution of the car in the rear (assuming a subwoofer, amp and box would weigh more than the spare tire), AND if possible, I could utilize otherwise dead space where the spare used to be.

The first task of course was to get educated on car audio, specifically regarding how to build a subwoofer enclosure.  I quickly learned that each subwoofer has a recommended, ideal cubic volume for enclosure space, at which it sounds the best. I also learned that several well known manufacturers were producing "shallow mount" subwoofers - subwoofers designed to not require as much space but reducing the size of the magnet, etc.

Then after a lot of research on subwoofers, I chose the Alpine SWR-T10 10 inch shallow subwoofer as the best possible candidate for the job.
Not only was it compact so it would fit within the relatively short trunk in a flat position, it also appeared to have the lowest cubic volume requirements. This was important because, ideally I did not want to build more than I had to vertically above the wheel well, because I was envisioning the enclosure to extend all the way across the trunk area, forming a new floor. And I wanted to keep the floor as low as possible to save as much trunk volume.

Ideally, this new trunk floor would be level with the S15 trunk bar that I had also installed previously, so that I would have a perfectly flat floor all the way across.

With the Alpine subwoofer, I chose to match it with Alpine's PDX-M6 600W mono amp. Figured there would be no compatibility issues, at the very least.

So now, I had to figure out how to construct the enclosure.
As you can see, not exactly the cleanest space down there
The first trick of course was to find someone talented enough for the challenge - both to make a custom enclosure as well as to put up with my ideas. Through a friend I was introduced to a free-lance carpenter in Chiba.  He had no problems agreeing to the task, and so the first task was to lay out  some wood long enough to span the width of the trunk.  This wood was then made into a frame upon which we planned to hang the fiberglass mold from, and then cover up to provide a flat floor. And of course allow the subwoofer itself to be mounted flush.

I can't seem to find all the photos but will update when I do!

Anyway, once the ladder type frame was put together, using water and some garbage bags to verify the volume, we laid out fiberglass to create the unseen side of the enclosure, making sure it fit into the spare tirewell.
Hard to tell but the inside of the fiberglass provides ideal volume for the Alpine subwoofer.
I had actually asked another friend of mine (Alex) for advice on car stereo wiring, long before I started this project.  He swore by Monster, but since it was sourced in the USA it wasn't that expensive.

Love it or hate it, these worked well for me.
Alex (as well as the DIYMobile crowd) all recommended a fuse in line to the amp, just in case.
Another Monster product, ordered at the same time as the cable.
The biggest pain for me of course was to run the wiring connecting the amp to the back of my old head unit. You can make out the double bluish grey cabling on the lower left of the following photo.

Then it was just hooking up the Amp to the battery and the subwoofer.
Meanwhile, we checked the placement of the subwoofer and found some polyurethane foam.
Here is the speaker installed, with the grill on.
Speaker installed with the grill on. The surrounding polyurethane foam formed a flat floor on top of the box.

close up, you can see the Alpine R logo.
A shame I don't have a daylight photo of the whole set up. But, you can see the glowing blue Alpine amp to the left of the speaker.

I had planned some storage pods to try to use all available space as efficiently as possible. I never got around to doing that, however I can tell you that, even in conjunction with the cheapish Pioneer components in the car, the subwoofer really provided a much needed low frequency OOMPH to really give life to the music. Also, maybe because the amp was a source of clean power, compared to the current system (where due to lack of the subwoofer I have to really crank up the volume) which actually has more sound leakage at the levels where you can really hear the details in the music.

Anyway - looks like I will have to go back and figure out how to do this again. Maybe with the same components, but at the very least the search is on for a car audio shop that can do a great job with a custom subwoofer enclosure.  As usual, I will keep all of you posted!