NISMO Omori Factory Chassis Refresh

So as we saw in my last post, I took the opportunity while my car was at NISMO Omori Factory to have them remove all the worn out, rusted and otherwise ugly suspension links and related parts off my car and replace with new.  Of particular interest to me was the rear suspension member - usually the bushes there harden or deteriorate with age and then the traditional easy solution is to add solid collars between the body and the member - I have not had that done yet so can't opine on whether that is the right solution, but certainly for most owners who don't want to bother removing everything to get to that rear member in order to replace the bushes, the solid mount solution is probably adequate, eliminating any weird flex.

One of my first upgrades to the car, before installing the Mine's engine, was to begin upgrading the suspension and chassis with the full Nismo suspension link set. I remember how the car immediately felt much more controllable and stable when I had the work done back in 2006 and 2007.  That means that for the past 13 years - longer than the time when the car ran on its OEM links and bushes from 1997 to 2006 (9 years) the car has been on the Nismo link set.  I don't know what the common wisdom is for when suspension link rubber bushes need to be replaced, but new ones should definitely give the car a "new car feel." I am looking forward to experiencing the brand new car feel!

Incidentally, I also have a full set of the SuperPro poly bushes, but never got around to installing them. Of course, now that I have a spare (used) set of the Nismo links...

Anyway, let's take a look underneath.

I get excited every time...

Left rear - silver is new, black is repainted

Right rear wheel - check out that beautiful "new" driveshaft!

This may be easier to see the extent of new goodness..

Of course the front is also looking great! Nice and clean...

Left front wheel 

Left front wheel, different angle - looks like I need to steam clean the oil pan!

 So a few things. One, they removed the plastic brake air guides - they were broken as the upper fin parts had snapped off.  These original Nismo ones, no longer available, cost about 19,000 yen per pair but the new dry carbon ones Nismo offers cost about ten times more! Not sure if I want to pay for parts my car probably doesn't need, given the oversize R35 brakes I now have. I guess I COULD go aftermarket here...

But damn they look good

So this adds about 150,000 yen to the price. What fool has these installed? (Thanks to Ale$$andro for the photos) 

Two, you may have noticed Omori Factory removed the Do-Luck floor support bars. The mechanics didn't really care for them not because they don't work, but because they interfere with their car lifts.  I will have to think about how to get them back on.  More importantly, I wonder how the car drives without them on. Maybe not go for them any more but look into spot welding around the door frames...They also removed, I think, the Spoon Rigid Collars (at least in the rear) - these will be an easy fix.

Three, yeah my tires are old. Will have to replace them soon.  And yes they look huge, very meaty. NISMO is pushing me to replace with the Michelin Pilot Sport 4s, but I don't know. Doesn't feel right to put on French tires on a Japanese car...And what is the current best Japanese tire out there?

Four, yes there are still many parts that need to be refreshed. Financially speaking, this is all I could afford at this time. Plus, most parts can be cleaned up or replaced at home, so I intend to do that as much as possible. To me that's part of the fun of ownership.

Fifth, I did mention in a previous post that Omori Factory did a few special extras - that's for the next post!

DTM-II Firmware "Update"

So a couple of Thursdays ago, I had some free time so I swung by Do-Luck.

The main reason was to receive an "upgraded" DTM II.

If any of you have recently bought the DTM II, don't worry - because I was one of few who had bought a very early model.  Most DTM IIs sold overseas, already incorporate the following change- if you bought yours through an authorized dealer, then you need not worry.

Ito-san told me that the change was necessary from early customer feedback. The issue specifically was that, on the racetrack during high speed cornering, the DTM II was too quick to activate and deactivate, due to the sensitivity of the onboard digital G-sensor.

So, the firmware was slightly rewritten so that the there was more of a "lag" in how the ATTESSA responded.  More accurately, it is not a "numbing" of the sensors but a reprogram whereby the unit now knows that, in certain cornering situations, to keep the torque going to the front wheels a bit longer, allowing the more average driver to better feel the ATTESSA doing its work.

Naturally, I asked Ito-san about future upgrades. He told me that, so long as you buy a DTM II from an authorized dealer, then the upgrades such as this one, which "refine" the product, will be free.  Any big changes to the programming - for example "maps" appropriate for certain racetracks, for example, may or may not be at nominal cost, however.

I don't have any pictures of the upgrade, which was literally a replacing of the circuit board on board my DTM II control box, for a new one.

The swap was done in literally five minutes - just access, then unhook the leads, pry off the old one, replace the circuit board, and tape it back into place.  Then teach the unit the closed and open throttle positions, and that was it!

Ito-san and I then popped open the hood (bonnet) of my car, and spotted some things that needed improvement...so we agreed that in the near future we'd have some work to do.

As for the improved DTM II - I really have to take the car to a track soon, or on the twisties, but I have at minimum 2 more mods I want to do before that...stay tuned!

Do-Luck's DTM-II, Part 3: Some More Info and preliminary Driving Impressions

So I had a few minutes today to take the car out for a spin. Unfortunately, most of it was in stop-and-go traffic, so I was unable to fully explore what the DTM-II could do. I plan to take the car out for a spin in the mountains or track soon, after which I promise to provide a full report on the driving experience.

However, I was able to shift between the various settings, G-1, G-2, G-3 and A-1, A-2... and yes there IS  a difference, EVEN in city traffic. There is a marked delay in how quickly the ATTESA sends torque to the front wheels, for the G settings versus the aggressive A settings. Even amongst the G settings, I noticed that G-2 (Tarzan G-box) appeared to react the quickest.  However, it was in A mode where I saw the front torque gauge meter needle shoot up to the max of 50kg...in the other modes I saw the needle go up to 10kg consistently, which Ito-san had told me is about 30% power to the front.

Now, an addendum to my previous posts and the instructions.  While driving I realized that, perhaps hiding this device in the center console may be a waste for those of us who like to have interesting info displayed.  In fact, I am almost tempted to put this up on the right corner of my dash, next to the heads up display (I needed something to read speed above 180kph as I didn't want to change the speedometer).  This is because the device displays peak G forces, front, left, right and rear (and the right side of the two vertical bar chart), AND, on the left side of the two vertical bar chart, the real-time longitudinal Gs (as indicated by the "V") and side Gs (as indicated by the "H"):

Very entertaining to see what kind of Gs you can generate while driving...

So my next task is 1) to take the car on a fast drive, and 2) to play around with the driver programmable settings.  Apologies for the relative lack of information in this post, but schedule permitting I hope to be able to at least do one track day before year's end.

Do-Luck's DTM-II, Part 2 - Initial Set-Up and the Settings, Explained

Once installed, the first thing you will need to do is ensure the DTM-II unit "learns" the voltage outputs for closed and open throttle positions on your particular car.

Here is a video clip where Ito-san and I demonstrate how this is done.

This shows that in my car, the voltage ranged from 0.4V at close to 4.1V at full open throttle. This is consistent with what's to be expected, as shown here:

Ok so now we're ready to roll... except you'll need to figure out which setting you want!

There are 7 settings for the DTM II: 4 in "G" mode (displayed as G1, G2, G3, and G4), and 3 in "ARX" mode (displayed as A1, A2, and A3).

Here is a video I shot (at night, sorry it's blurry - the actual device is super crisp and clear) that shows how to switch between the various settings.

Before I describe each of these settings, we first need to review what the DTM II device is doing. Recall that the ATTESA ECU bases its decision making on various inputs, 3 of which are, the car's longitudinal and lateral G forces (from the onboard G-sensor), and throttle position.

Here is a diagram showing the ATTESA map in 3D, showing just how G forces affect ATTESA output. The right axis is lateral acceleration, the left axis is longitudinal acceleration, and the vertical is amount of power going to front wheels.

Taken from the 1997 R33 GT-R catalog

The impetus of Do-Luck to develop its original Digital G-sensor was that due to age, the OEM G-sensors, which are analog devices (basically a pendulum in oil), were degrading to the point where the signals being sent to the ATTESA computer were inconsistent, slow, weak or non-existent, thus preventing the ATTESA from performing as it should.  And an OEM replacement cost somewhere around 130,000 yen and were still analog.  Digital G sensors are now commonplace (most smartphones have them), are inexpensive, ultra accurate, and fast. So it was only natural that the Digital G-sensor was developed.

Both this Digital G-sensor and the Tarzan G-Box, however, do not simply send back the actual raw G force data to the ATTESA ECU.  Both devices actually modify the signal being sent by multiplying the actual raw G reading by a pre-set variable (or set of variables, in the case of the Tarzan G-Box), which, as can be seen from the map above, means that the ATTESA is engaging faster than before because it believes that the car is experiencing higher Gs than it really is. As an example, if the car is actually experiencing an acceleration of 0.3Gs, but the Digital G-Sensor multiplies that number by a pre-set number, say 1.5, so the ATTESA thinks the car is accelerating at 0.3x1.5=0.45Gs.

In "G" mode, the DTM II is acting as a standalone G-sensor.  Specifically, in G1 mode, the DTM-II unit is outputting the same modified G signals as the Do-Luck Digital G-Sensor; in G2 mode, the unit is outputting the same modified G signals as the Tarzan G-BOX; however in G3 mode, the unit is outputting what the OEM unit would have put out when new (i.e., a "pure" unadulterated G signal).

G4 mode is user programmable - that is, the user can choose by what percentage each of the 4 (front, rear, left, right) G forces should be multiplied by, as sent to the ATTESA ECU. The user can choose an amplification between 0% to 200% for front, left and right G forces, but for the rear G force (i.e. braking), the amplification range is between 100% and 115%.

Here is a video where I demonstrate the G4 mode:

So what is ARX mode? Remember with the G mode settings, the raw G-force signal was amplified by a set variable.  In ARX mode, the throttle position comes into play along with the G-forces (however there must still be enough G-forces first, as throttle position alone won't activate ATTESA).  Further, unlike in the G modes where the raw G-force signal is essentially only "multiplied" by a set variable, in the ARX modes both the throttle signals and G-force signals are outputted according to a unique "map" (still based on the original ATTESA ECU map).  Ito-san explained that, rather than a linear output (where all the incoming data is mutliplied by the same variable), in ARX mode each data point is specifically associated with a specifically amplified (or de-amplified) data point which is then sent to the ATTESA ECU.

Ito-san calls A1 mode the "street" mode, and the A2 mode the "circuit" mode.  A3 mode is again a "pure" signal mode for both G forces and throttle position.

Speaking of throttle position, the user can also adjust the throttle position signal being sent to the ATTESA unit, as I show in this next video clip.

Note that I was getting tired and lost my train of thought at about the 2 minute mark, and mistakenly said that at 100%, I would get the "maximum of the ATTESA working to pull me out of the curve." Note this is only true if there are G forces in play as well, as noted earlier.

Also during the video at around the 3 minute mark, I referred to the Optional Map Edit, which refers to one of the two leads which the DTM II has.  Originally, the OPT lead (as shown below) was designed to hook up to the AYC in the Lancer Evolution cars (this unit works with them as well); however as I mentioned in my previous post Ito-san is working on using this to control the Active  LSD found in V-Spec 33 and 34 GT-Rs.

So that's pretty much it for now. I apologize if I left anything out or was unclear.

Finally, in response to a few questions that I have already gotten:

1) No, this unit will NOT allow you to switch to a pure rear wheel drive (FR) car.  Remember in 33s and 34s, there is always some power going to the front, so the only way to get around that is to essentially have a separate switch that cuts power to the ATTESA ECU. (but then you'll get warning lamps). Although I wonder what would happen if you set the front G force setting to "0" in G4 mode...(theoretically, that would mean no signal gets sent to the ATTESA unit, no? Maybe someone will tinker and find out!)

2) The difference between the DTM-II and something like the below, is that traditional ATTESA controllers only amplify the signal from the G-sensor. The DTM-II has its own G-sensor, and further allows for manipulation of the throttle signal.

3) Is it possible for the user to have another channel to self-program? No, however Ito-san has indicated that select dealers will be given the ability to change the programming found in A3 and G3 modes, giving users even more choices (e.g. a setting specific to a certain circuit?)

4) Is it possible to change the ATTESA "map"? No, because that map is onboard the ATTESA ECU.  However given the ability to send different and amplified G and throttle position inputs, it is possible to use only certain sections of that base map (e.g. the most aggressive portions), or distort the map so that the ATTESA unit's lowest/highest thresholds are raised, lowered or both.

In my next blog post, I'll post my driving impressions, as well as address anything else I left out! Leave a comment or question if you have one, thanks!

Do-Luck's DTM II, Part 1 - The Installation

Courtesy of the Do-Luck Website: http://www.do-luck.co.jp/product/1452

In perhaps another world's first, I was given the honor of being one of the first R33 GT-Rs on the road to be fitted with the DTM II - Do-Luck's even more advanced G-sensor - now with throttle position input and being driver and tuner programmable as well.  (I am certainly the first to do a full write up in English, so I hope I get this all correct!)

To review, the Do-Luck digital G-sensor devices (both the Digital G-Sensor model and the Tarzan GBOX) replace only the OEM G-sensor, located under the center console in the RB26 GT-Rs.

The Do-Luck Digital G-Sensor

The TARZAN GBOX

The DTM II adds not only 7 different settings, (1 of which is user programmable and 2 others which are programmable by select tuners; and the user also is able to modify all the maps simultaneously) but also an organic EL display unit with 5 input keys and compact enough to be mounted almost anywhere in the car.  Installation is straightforward, but since a picture is worth a thousand words:

The very plain box the DTM II comes in

The contents of the box

 The first step is to remove the shift knob, shift knob surround, and ashtray, and then undo the screws holding in the center console, in order to access the G-sensor installation location.  In my case, in my effort to keep my car looking as stock as possible, I chose to install the EL display unit inside the console box (and thus chose to give up the ability to be able to read the real time G readings displayed by the unit).

Fits very well indeed.

Of course this means having to drill a hole for the wiring...

Once the console box is removed, step back and review the scene: In my case, as I had previously installed Do-Luck's Digital G-Sensor, the gold OEM analog box was no longer there.

The Red Arrow on the Digital G Sensor shows the direction it should be installed

A closer look

 Remove the old G-sensor. With my car, installation was easier than usual because I had already removed the OEM G sensor. (click on this link for my blog post showing how to).

Removing the Digital G-Sensor

And here is how the DTM II looks, installed

So slightly larger than the Digital G Sensor

 The next step is to wire in the throttle position sensor leads. The instruction manual simply said to "splice in" but when I asked Ito-san about this, he clarified that you cut a particular wire coming out of the ECU loom, and then one wire from the DTM II is connected to one cut side, and the other wire to the other cut side.

Found on gtr.co.uk...Refer to the Instructions... they will say "Throttle Output Signal" which is Pin 56 ( I think this is common to the BNR32, BCNR33, and BNR34, but please verify).

Once that's done, all you have to do is thread the lead under the carpet so it ends up under the main unit. 

So this lead connects to the DTM II main box...

Like so.

Wait? What's this? Two EXTRA leads? 

 That's right. Two outputs. There are three input/output leads, one of which connects to the lead coming from the throttle position. The others are labelled "OPT" and "LOG." The "OPT" one, Ito-san tells me, will soon allow control of the A-LSD (active LSD) found in the V-Spec models (he's working on how it can be done).  The "LOG" lead is for those who like to datalog what is going on in the car.  The unit produces variable voltage according to the front/back and left/right G-forces, and so if you can record that, then you can log this data.

Install finished! Quite easy. No messing around with anything that will get your hands dirty (i.e. perfect for me).  In my next posts, I will go into HOW the DTM II works, how it can be programmed and other details NOT mentioned in the install manual (that I've seen) and yes, my driving impressions (in a word, AWESOME).

Preview: the Do-Luck DTMII

My quest to modernize my car continues...

Trying out "live blogging"... Check back later tonight as I report on the install and my driving impressions of Do-Luck's latest electronic wonder!