How The R33 GT-R Improved Upon The R32 GT-R (Part 1 - Exterior Design/Aerodynamics & the "High Traction Layout")

So although I've previously explored the differences between the R33 and R34 GT-Rs, and discovered that while the running gear basically stayed the same, with improvements to body rigidity and aerodynamics (as well as styling, of course) being the main differences, I hadn't yet really looked into the differences and improvements between the R32 and the R33 GT-Rs.

Nissan had a problem - the R32 GT-R was spectacularly successful - and its successor the R33 was bound to be in its shadow unless it was substantially better both subjectively and objectively.  While R33 haters may not like to admit it, the R33 GT-R is a technically much improved car over the R32 GT-R - so much so, if you recall the objective when designing the R34 GT-R, Nissan's goals were not to make it any faster than the R33 (it was deemed fast enough), but rather, just easier to drive for the average driver.

In any case, with all the information I found, I've split the discussion into two parts - this post, Part 1, which examines the improvements in the exterior  (design and aerodynamics) and the "High Traction Layout" (balance and body rigidity), and the next post, Part 2, which examines the Engine, ATTESA ETS PRO, and Super HICAS.

Exterior Design and Aerodynamics:

When development of the R33 (the general model, NOT the GT-R) began, it was initially conceived that the 2 door coupe would ride on a shorter wheelbase than the 4 door sedan. The coupe was to have a shorter hood as well (further, no turbo model was contemplated).  This all changed, however, when Nissan decided to put the coupe on the same wheelbase as the sedan.

We all know that the R32 GT-R excelled in the Group A racing series in Japan. However, the R33 GT-R was facing a different race series (N1 Taikyu), this one which required sustained speeds exceeding 250kph; this requires not just awesome acceleration but stable braking prowess as well.  Thus, Nissan decided to put heavy emphasis on aerodynamics during the design; and not just better aerodynamics, but balanced aerodynamics.

The R32 was developed with the “Zero Lift” concept in mind, hence it sported a large rear spoiler to help keep the car on the ground and provide stability in high speed cornering.  However, its coefficient of drag was 0.40, which was not something to brag about even back then.  Further, based on racing experience Nissan wanted the R33 GT-R to have superlative cooling and anti heat abilities, which would require large openings for the radiator and oil cooler.  The front spoiler would have to be a shape which would reduce front lift as well.

Nissan called the design theme for the R33 GT-R,  "Sophisticated Strength" -  while engineers wanted superior aerodynamics, cooling ability, and a wider tread, the designers wanted a design that suggested speed and power.

Here are some quotes on various design aspects from the chief of the GT-R’s exterior design, Hidetoshi Nishiizumi: (Source: Cartop Mook: R33 Skyline GT-R Best Album) (all Nissan Gallery photos from Wikipedia)

"The R32 had excessive front lift.  At Fuji Speedway, taking the high speed 130R corner at speed was scary, according to Kaz Mizuno (later father of the R35 GT-R). So efforts were made in the R33 to minimize front lift - and in that regard, the longer front overhang worked in our favor."

"We designed large openings in the front bumper, and made the shape spoiler-like. We experimented with various angles for the lip spoiler as well, to get the best wake separation for the air.”

“The size and height of the rear spoiler of the R32 GT-R were designed with Group A racing in mind. The regulations meant the wing could not be adjustable, so we put a big one on from the beginning.   The R33 GT-R had an adjustable one.  From the rear, you can see that it actually has a “Y” shape design.  Mizuno-san was heavily involved in the design.   Although it extends a total of 30mm on the sides, the size of the spoiler is limited.  We did experiment with a spoiler that would fit within the width of the trunk lid, but it looked unbalanced.   This is what lead to the current design with its overhang.”

“Compared to the R32 GT-R, what really gives the 33 remarkable presence is the larger spoiler on the back.  From the back, it really enhances its presence.  The reason we included an adjusting tool in the tool kit was so that the wing could be adjusted for track days – but in town, it looks best at horizontal.”

“We experimented with making the entire wing adjustable, but in the end settled only on angle adjustability and the caps on the sides, for weight purposes.  Also the reason why the rear is solid, but the front of the blade is adjustable, is just in case it became separated, it would move in the direction of generating downforce, allowing the driver to stop safely.”

The design was in a state of change until right before the car went on sale. You can see that the production car looks far more aggressive than the the prototype:
“Compared to the prototype, we widened the lower half of the body to give the appearance of a lower center of gravity.”

The R33 GT-R Proto - I'm not sure I see the narrower lower belt line?
Photo from http://www.gtr-world.com

You can see the solid, fixed position rear wing which has evolved from the Type M wing but is still not adjustable
Photo from http://www.gtr-world.com

Initially this rear trunk spoiler was a fixed position one, but at the very last minute a decision was made to go with the adjustable one we have now.  Incidentally, the original fixed spoiler design can now be found on the R33 GTS25t Type M.

The R33 GT-R could have had this rear spoiler design.
Courtesy: http://asteriskblog.blog90.fc2.com/blog-entry-39.html

Also, one aero design that was considered at the time, was to have a roof spoiler in addition to the rear trunk spoiler.

GT-R could have looked like this, with the roof spoiler!
From: http://infinitefocusphoto.wordpress.com/2011/12/19/hangs-muskis/

There was extensive wind tunnel and road testing of the design, with efforts made to obtain the best front-back lift balance while allowing for wide tires, blister fenders and rear spoiler.  In the end the Cd equaled 0.35 (beating the R32's 0.40), and the front /rear downforce was better balanced, with a front coefficient of lift of 0.09, and a rear downforce of 0.03 (with the spoiler at the flat position). Even with the bigger body.

For a review, see this post

The "High Traction Layout":

In addition to the aerodynamics, the High Traction Layout improved the dynamic performance of the chassis.  This is Nissan's terminology for the technical chassis design differences which were designed to improve the performance of the R33 GT-R over the R32.  In addition to the improved aerodynamics, the High Traction Layout improved the dynamic performance of the chassis.  It did this by improvements in two areas: body rigidity and weight distribution.

Body Rigidity:

With the addition of front and rear strut tower bars, as well as adding cross bars under the floor in over 30 locations, rigidity was improved – 40% increase compared to the R33 GTS, and over 150% (1.5 times) more rigid than the R32. The improvements include, front tower bar, front cross bar (which connects the sides of the transmission tunnel), floor cross bar, the seat back center (the plate behind the rear seats), rear strut bar, etc.

From: "All About the New Skyline GT-R"

Four wheel multi-link suspension: The front layout was changed.  The R32’s weak point was the use of an “I” shaped upper arm, which was susceptible to rattles.   These were changed to “A” arms, which gave 90% more lateral rigidity. 

In the rear, Nissan added the “triple cross bar” – which adds more rigidity for the suspension members (in the R34, it also provided a nice place to hang the rear carbon diffuser off of… the 33 and 34 triple cross bar is the same, incidentally).

Having increased body rigidity means, of course, that power not only gets to the ground more directly, but the suspension behaves more accurately.  To the driver, this makes the car feel more nimble and agile, with more direct feel, and thus easier to drive.

Weight Distribution:

The Problem:  The R32 GT-R was criticized as being too front heavy, which lead to strong understeer.  Additionally, the fuel tank was placed below the trunk floor, meaning that there was weight overhang in the rear as well. Not only was the weight BEHIND the rear wheels an issue, but as fuel was consumed and the rear got lighter, there was an obvious effect on the car’s performance.  Combined with a less rigid body, the R32's potential was wasted.

The Solution: With the increased wheelbase, it was now possible to improve weight distribution; the plastic fuel tank was placed below the rear seats, battery moved to the trunk, and to the extent possible, heavy things were moved towards the center of the car.  The front and rear overhang weights were lightened.

 From: "All About the New Skyline GT-R"

But improving the weight distribution wasn't just about moving things around between the wheels - it also means reducing weight in critical areas to improve the balance of the car.  The increased body rigidity didn't help - the added bracing added to the car's weight, which meant that Nissan engineers had two compelling reasons to try to figure out ways to lighten the car.

Up front, to reduce front overhang weight, the front hood and fenders were made of aluminum (as in the BNR32), the headlights were made of lightweight plastic and the intercooler was lightened, in order to lighten the front overhang, reducing inertia.  The intercoolers were changed from extruded multi hole tube to inner fin type which improved response, cooled 4% better, and was 400g lighter.

Nissan engineers also found other ways to reduce weight, even by a few grams.

This includes:

Hollowing out the side door beams.

Using high tensile steel on body panels.

Reduction in sound deadening materials.

Super HICAS becoming electric.

Hollowing out of rear stabilizer bar.

Use of high tensile springs front and rear.

Shrinking the ABS actuator.

Light aluminum wheels with higher rigidity
The front and rear axles were made of aluminum (as in the BNR32) but also so were engine mount insulators and brackets

New plastics were used for : fuel tank, head lamps, super high strength "PP" bumpers, air cleaner, changing the headlining material, changing material of rear spoiler.

So even though the R33 was heavier by 100kg, the records show that it was 30kg heavier up front, and 70 kg heavier in the rear.

There were a few drawbacks to the High Traction Layout, however - although these were deemed worthy sacrifices to get better performance:

1) With the battery moved to the back, as well as the rear strut bar, trunk space and volume is smaller on the R33 vs the R32.
2)  Additionally, the fuel tank shrank from 72 liters to 65 liters… resulting in a lower range.

In any case, I think they did a great job on both the looks, aero and chassis development.  It is ironic that people criticize the longer wheelbase without understanding how Nissan engineers actually used that to the car's advantage from a dynamic technical standpoint - the longer wheel base is not just stability at speed in a straight line, but also with the High Traction Layout in corners too!

Next: Engine, ATTESA E-TS PRO, and SUPER HICAS

Sources:
1) Cartop Mook: R33 Skyline GT-R Best Album
2) Neko Mook: I Love R33 Skyline GT-R
3) Motorfan: 新型スカイラインGT-Rのすべて("All About the new Skyline GT-R")

Mini Aero Project - OK So That Didn't Work... What Was I Thinking?

So in my quest to modernize the car, in addition to mechanical and electrical items, I stumbled upon this:

Courtesy: http://parisworkingforart.wordpress.com/2010/06/06/lexus-lfa/

This is the driver side rear view mirror from the Lexus LFA - note it has the horizontal strakes built in, presumably to better manage airflow going around the car.  So I began to wonder if there might not be an easy to way to replicate this on one's existing mirror?

I found this:

From the manufacturer's description, this appears to be just what I was looking for!

Apparently, with the strategic application of these double stick tape rubber pieces, you can straighten out the flow of air around your car, and in the process, reduce wind noise!

For less than US$8.50 (JPY 830), this was too good not to try.

So while June is rainy season in Japan, on a sunny day I broke out the can of KR4 spray paint (which I still have left over from the fluidic nozzle mod) and spray painted the two pieces for the mirror in the hopes that they would blend in fairly decently.

Then on a trip to Chiba prefecture just today (to implement Step 1 of my long awaited audio upgrade... stay tuned, pun intended) I had the opportunity to try these pieces out.  Mounting was as simple of finding a place to put them, peeling off the double stick tape, and sticking them on:

On the B Pillar

This was the only place this piece would stick on the door sail

You can see the knob sticking out off the bottom of the mirror

And then it was a matter of driving to see what the difference was.

The verdict?

Uh... well... I could NOT tell the difference - not because these don't work - maybe they do - but because the road noise and engine noise coming in from the firewall area, plus the sound of the exhaust, basically made it too loud for me to hear any wind noise. For my audio upgrade, while I did lay down sound deadening as well as undercoating looks like I will have to do the firewall...

I even drove (a bit ?? lol) over the speed limit, in the hopes that at really fast speed wind noise would be more apparent - but no difference.  The only thing I DID notice, however, was that my BNR34 rear diffuser was working quite nicely - sending up a rooster tail of water at speed (it was raining quite hard by the time I was driving back home today).

Thankfully, again this aero mod cost me less than 850 yen to try.... maybe I can find a Prius to try it out on...

BNR34 Rear Diffuser Project, Part 5: Done!

While taking photos of the various pieces that had to be fitted to make the diffuser fit, I realized from the following photo, the rust on the leading metal edge of the diffuser really bothered me.

That, and I also realized that I was simply ignoring another problem, the rust on the inside fin mounts:

So off to the hardware store I went, searching for the Japanese equivalent of Rust-Oleum StopsRust, the paint that you spray on and which slows down the progression of rust (it was too much work to actually strip down all the rust and then respray). I couldn’t find a spray product, but did find something in a can that’s used for black iron fences, etc.

So, I took off the diffuser, and painted all rusted surfaces with this anti-rust paint in the hope that this would at least slow down the spread of the rust that’s already there. If of course it’s too late, well at least I have the stainless brackets and other parts from the RB Motorsports kit that can probably be used in their place.

Looks much better, right?

And, since I had the diffuser off, I decided to see if I could do one more mod.  I remember reading in GTR Magazine about a shop that installed a red F1 style rear LED in the center bracket, and found two examples on Minkara.  (Here's the other).

But, I’m not about to spend 34,000 yen (plus that was a limited edition run of 10 plus units) on this! So I searched on Rakuten and first found this:

Not bad at 900 yen, but the reviews were mostly all bad....

But given that the dimensions I could work with were:  about 6cm for the space between the body of the car and the diffuser, and about 3cm between the leading edge of the diffuser and the bumper, I found instead a rectangular one with better dimensions: 

Once ordered it quickly arrived - and though I'm sure it probably costs less than $5 in the US (and even less than that in China), unfortunately it was a bit more than that here...

So as you can see it had this clip attached to it. Initially I was not going to use this clip, but then decided that, instead of making my own brackets, it might be better to figure out a way to attach it using this clip – either to the car body or to the diffuser itself.

After some thought, I realized that to attach this LED to the car body would require new holes to be drilled, or the diffuser stays would have to be modifed.  It would probably be easier to attach to the LED light to the diffuser itself, so that's what I decided to do.

I found a stainless steel (so it wouldn't rust) bracket with holes, which bolted on nicely to the end bolts of the rear-most bolts of the two inside fins (which are spaced apart exactly 46 cm!) on the inside top surface of the diffuser (you can also see the formerly rusted inside fin mounts now painted black here too):

Then, using the clip that came with the LED light, I was able to test fit it by slipping it (temporarily) on like this:

I was envisioning I would be able to attach it all so it would be like this:

But I then realized that I had to do something to prevent the LED lamp and its clip from slipping off the stainless bracket - so I decided to use a "V" shaped rubber piece with adhesive on both inside surfaces between which I sandwiched the stainless bracket.  The two bolts shown here were then used to center the LED clip on the stainless bracket:  

So it ended up looking like this:

And then to prevent the whole contraption from slipping around and thus possibly falling off, used some silicon adhesive on the side that would contact the diffuser:

After I bolted this whole contraption onto the diffuser (again using the two rear-most bolts of the inside fins), I temporarily re-attached the diffuser to see how it would fit.

Looks pretty good, huh!

Now all that was left was to wire it up to the lights. This I'll cover in a future post, because it took some time to get right.   In any case - finally - here is the finished result, in day light! Comments, critiques, and questions most welcomed!

BNR34 Rear Diffuser Project, Part 4: Putting it All Together!

So when I went to pick up my car from BeAmbitious, I was happy with  the seamless job Ninomiya-san had done.

Taken at 7pm in the evening, hence a bit unclear... sorry!

First, instead of a four sided rear center bracket, Ninomiya-san simply used two hangar type brackets. 

Simplicity at work here - only time will tell if this is enough.

Second, the carbon was cut in order for the Tomei muffler to peacefully coexist. I couldn't tell how it was cut, it was only apparently after I took the diffuser off for another upcoming project! (Stay tuned!)

Some smooth cutting there, no rough edges.

Third, the entire diffuser was dropped a few millimeters in order for the exhaust pipe to have a bit more leeway on the front side of the diffuser.

For those of you with R34s, you should be aware that Tomei has apparently been sending out a retrofit kit similar to these spacers, in order to prevent the leading edge of the diffuser from pressing into the ExPreme titanium exhaust.

Fourth, the metal jack-up point was moved a few cm forward, and an alumite "gap filler" attached, in order to ensure the jack up point is not only flush with the diff, but also far in front of the Greddy extra capacity diff cover (wouldn't want to jack it up on that)!

But the piece de resistance was the way he used the RB Motorsport side brackets:

Note how, instead of attaching them to the car directly, he chose to attach them by way of hard rubber bushings, in order to prevent any metallurgical issues to the body of the car, as well as considering the vibration the diffuser will generate, and tucked the side brackets up under the rear bumper. This means however that I cannot remove the diffuser with the brackets still attached to the diffuser, as one might do normally.

Rather, I have to undo the bolts for the two outer most fins, plus two additional bolts on the side protectors,  which then separates the diffuser from the side brackets, which remain attached to the car.

And this is why the side brackets and the diffuser's side protectors are not riveted together :

Pointing to where normally there would be a rivet holding the diffuser's plastic side piece to the side bracket 

So neither rivet is there now.

And the effect? Well, that will have to wait, at normal expressway speeds I haven't noticed much of a difference to be honest. Oh and when backing up, now have to be careful not to scratch the fins.
But next track day, let's see what speeds north of 200kph will do!

Finally - I realize I have yet to provide a nice photo that clearly shows the diffuser, in daylight. Patience my friends, I have ONE MORE diffuser related mod before I show the final, final result! 

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!

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 http://minkara.carview.co.jp/en/userid/301215/car/194604/415795/note.aspx

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.

http://minkara.carview.co.jp/en/userid/301215/car/194604/415795/note.aspx

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):

http://www.wind.sannet.ne.jp/quess/diy/ex-9.htm

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

http://minkara.carview.co.jp/en/userid/301215/car/194604/415795/note.aspx

Then, there is the rear center bracket. It normally looks like this.

http://www.wind.sannet.ne.jp/quess/diy/ex-9.htm

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.

From: http://minkara.carview.co.jp/en/userid/705558/car/601264/1470770/note.aspx

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!