Sunday, June 30, 2013

BNR34 Rear Diffuser Project, Part 3: How to Get the Diffuser to the Shop

Or more accurately, how to get a BNR34 rear diffuser to the shop when you don’t have the proper brackets in place?

I’m not especially proud of this, but basically what I did was to attach the front of the diffuser using the RB Motorsport supplied bolts, which surprisingly alone was able to keep the diffuser off the ground.  However, the diffuser did not neatly fit around the Tomei muffler (so there will have to be some cutting), resulting in a diffuser unbalanced left and right. 

Just to be on the safe side, of course, I decided to do what I can to control movement in the unattached back, so I ended up passing twine through the two bracket hole, and then running the string around the license plate frame. Meanwhile, I also used some packing tape between the diffuser and the bumper, to lessen the load on the twine.

The end result was ugly (some would say "ghetto"), and looked like this:

But I WAS able to get to BeAmbitious safely, and so I left my car with Ninomiya-san with great anticipation.

Next:  How it all turned out!

Wednesday, June 26, 2013

BNR34 Rear Diffuser Project, Part 2: Fitment (Attempt)

So after the diffuser was cleaned up and to some extent restored, the next step was to fit it to the car.  As I alluded in my intro post, the easiest way to do this, is to have the BNR34 V-spec triple cross bar installed (some people chose to have the bolts welded on the R33 triple cross bar instead).

Truth be told, this I had done by Ninomiya-san way back after I first got these pieces, right about the time Igot my personalized number plate

But obviously, I have been too busy to work on this diffuser project since then.

Anyway, the triple cross bar takes care of the front half of the diffuser. In the picture below, the front of the diffuser would be facing left, and the rear to the right.

Again thanks to

The front of the diffuser attaches to the left most double hole bracket by way of two metal brackets (like the one on the left in the photo below).  The holes in the middle, take a single bolt, the corresponding hole which is in the diffuser itself.

The rear of the diffuser is attached to the body by way of the side brackets (on the center and right), as well as a center bracket.  The side brackets attach permanently to the diffuser, while the center bracket is normally permanently attached to the car. The diffuser side is the left side with the cutout, the side that connects to the body are the two "fingers" with one hole each.

Unfortunately, the side brackets do not fit directly on the R33 – and that is because the R34 bumper is a bit wider in this area, allowing clearance to the body, which in turn has pre-welded stays for the diffuser to bolt onto. On the R33, the attachment point to the body is where the bumper is (the bumper covers it). Hence, the side brackets either end up attached to the body underneath the bumper – like this (with access holes cut out to access the bolts attaching the bracket to the body):

Or, get tucked in underneath, like this, with cutouts in the rear bumper or spats to allow bolt access.

Then, there is the rear center bracket. It normally looks like this.
While the RB kit DID come with a replacement piece in stainless, unfortunately its dimensions were off:
Look closely, and you can see that the left side bent piece extends from the 0mm mark to the 125mm mark.  The right side extends from the 300mm mark to the 415mm mark - thus a difference of 10mm! So the left and right sides are not perfectly mirrored, and the angle of the bent pieces are also different. I can't use this!!
Finally, there was the question of re-installing the fins. As seen in my previous post, the stock ones were essentially destroyed, and so of course I sought improvement. I looked at the Nismo ones made of carbon fiber, but not only are they made to order and cost 42,000 yen for the set, their tallness compared to stock is an invitation to getting damaged or snapping off in a parking maneuver. So I settled on these carbon ones from Wisteria Sports, in the same dimensions as the stock ones and for half the price of the Nismo.
So the fact that I did not want to arbitrarily/sloppily drill holes in my car for the rear center bracket, which was off to begin with, as well as coming up with a solution for the side brackets, meant that I would be taking my car to BeAmbitious for the final fitting.

And because of that, I chose not to install the carbon fins myself, but to have Ninomiya-san do it when the car was at his shop.

Stay tuned as I next show you how I got the diffuser to his shop!

Sunday, June 23, 2013

BNR34 Rear Diffuser Project, Part 1: Restoring the Diffuser

So given the condition the OEM BNR34 diffuser that I got on Yahoo Auctions (for relatively cheap) was in, it needed to be freshened up.  This meant removal of as many rusted or bent, broken parts, and replacing with new or refurbished.   Also, it meant that the carbon itself would have to be sanded down and a clear coat applied, where applicable.
Bent fins, scraped up carbon fiber, rusty bolts and rusted leading edge plate
As you can see clearly here, the leading edge of the diffuser is rusted.

This shows clearly how the supports for the fins are rusted as well

Left rear bracket is rusted and bent

Right rear bracket is in much better shape, although there still is some rust.

I guess this happens a lot, but check out the condition of the fins, as well as the rusted bolts, for example.
These side guard things are scratched up, the bolts rusted and the fins bent!
So I removed everything that I could easily. That included the side guard things (as above), the front brackets (thing on left in photo below), the side brackets (one was severely bent up), and the fins. 

With the fins, you can see how much dust was trapped underneath each one! 
excuse the mess in the
Also, the side guard things (made of ABS plastic) were scuffed up, and in some places, damaged, so they needed to be repaired. The best I could do, of course, was to sand down the rough spots, and then spray on the spray rubber (Plasti-Dip).

Came out OK though. I mean, you really can't see them, so as long as they are looking shiny and newly protected, I'm happy. 

I then sanded down the carbon fiber in places where it was rough (as well as gently all over), then applied a clear coat, just in case. (Note that the carbon fiber itself is a dry weave and probably doesn't need a clearcoat, if in new condition...)
Nice and Shiny!
After I was happy with how this turned out, I used a rivet gun to reattach the side pieces, this time with stainless steel rivets:

The end result being this - note that I did not attach the fins back on.  Also note that I replaced the front brackets with stainless ones from the RB Motorsport kit (one on the left attached here):

So in Part 2, I'll review how I was able to attach it to the car.

Tuesday, June 18, 2013

BNR34 Rear Diffuser Project, Intro

So I’m not sure why this mod is not more popular overseas, I've seen a couple on R33s at the SSCT gatherings, and even on the Minkara car blog here in Japan, there are several examples of people who have installed the R34 V-spec rear diffuser onto their R33s.

In my study of the R33 GT-R vs. the R34 GT-R, one obvious engineering difference, if not THE difference, was the aerodynamics that the R34 had. And, the most obvious piece was the rear diffuser. Thus, I’ve been wanting to do this mod for quite some time now.  So I did some research, learned that it basically bolts on, but first I wanted to confirm this so and then found and bought a used BNR34 diffuser on Yahoo Auctions.  This was over two years ago! (so yes, it sat there collecting dust all that time...)

It turns out however the tricky part was, despite its “bolt-on” nature, figuring out exactly how the diffuser would be attached to an R33.  Luckily, all that is really needed is to either weld on the necessary nuts onto the existing “triple cross bar” or to replace the R33’s triple cross bar with the R34 V-spec’s triple cross bar, which happens to be identical except for having the necessary brackets already welded on.  The triple cross bar is three pieces of pipe in the rear that extends from side to side in a rough “U” shape - here is what a standard R33 “triple cross bar” set looks like (bottom piece is towards rear, top is in front of the rear wheels) :

And here is the R34 one, with the differences (that is, where the diffuser is bolted onto towards the front), highlighted:
So I first had to find a used 34 V-spec triple cross bar. This I did by contacting a dismantler.  Then, it turns out that the used diffuser wasn't in the best condition, either missing some brackets, or the existing ones were extremely rusted and bent out of shape, so I had to find a tuner that could supply me with replacement brackets.  
Yeah, this isn't going to work...maybe stainless steel is a good idea, given the location?
I searched for a while in Japan and found one place that was prohibitively expensive – however Allen at Tomei Powered introduced me to RB Motorsports in the UK, who had a bracket kit of stainless steel brackets, bolts and rivets, just for this purpose!  

Unfortunately, as I found out later, this solution was not a complete one.

So after collecting the diffuser, the triple cross bar, and a set of bolts and brackets, it looked like I was good to go. I now had everything I needed to do the install. So this project was essentially broken down into the following steps: 1) restoring the carbon diffuser and then 2) ensuring the diffuser could be attached to the R33, 3) temporarily attaching the diffuser to get it to my tuners shop and then finally 4) full installation, including getting custom brackets made in order to make it work for the R33.  In order to make this easy reading, I’ve broken up the posts into 4 sections. 

Meanwhile, here are some links to Minkara posts showing other R33s with the BNR34 diffuser mod:

A nice LeMans

Black V-Spec

Silver Tommy Kaira tuned

White Race Spec

Midnight Purple Autech 4 Door GT-R

R33 GTS25T Type M

Midnight Purple 2.8L (with decent photo instructions)

Stay tuned for Part 1, next!

Saturday, June 15, 2013

Finally....A Rear Diffuser!

Details to follow in a multi-part post!

Friday, June 7, 2013

oops that didn't work... Rear Aero Wiper Mod

So obviously, not every mod I do goes well.  Here is a prime example.

After upgrading the front windshield wipers with the awesome Bosch Aerotwin wipers, people reminded me that I hadn't done the same to the rears.

Unfortunately, I haven't found a model from Bosch that works for the rear window yet, as the air is coming in the opposite direction than for the windshield. So I suspect to have an aero effect, the shape of the aero blade would have to be reversed.

I did stumble upon, however, an "aero" blade on Rakuten here in Japan, for a very cheap price - around 1000 yen! Recalling that when I measured the OEM rear wiper, it was 450mm, I ordered it, figuring it would be an easy mod to do (and a way to complete the Bosch wiper blades post).

It arrived quickly (the green is a clear plastic cover protecting the rubber blade):

 But I immediately noticed that there was a difference:

The clip area on the Bosch wiper is much nicer - no weird holes, and enclosed. I guess this is why the non-Bosch ones are "universal"?  But "who cares" I thought, these will be in the back, no one will notice. 

Comparing with the OEM rears, the length looks pretty good!

Now to check to see how they fit.  Good news was, they fit on the "J hook" perfectly, without drama. The BAD NEWS was - after the J hook fit into the universal clip - the wiper itself was too long!
The OEM wiper is a comfortable 2cm away from the spray nozzle.  This photo shows the new aero blade just grazing the spray nozzle, but in actuality the blade would rest on top of the nozzle a bit more. So even though the blade LENGTH is the same, the location of where the arm meets the blade is different.  If I were to order another of the same series, to be safe I would order the shorter 400mm.

But there MUST be a Bosch for the rear, and this mistake only cost me 1000 yen, so I will keep looking...  oh and as for the rear nozzle, it appears to be stuck somehow to the glass, so I'm not going to mess with it. Stay tuned!