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> The More You Know! Automotive Trivia., Mundane and Technical facts you probably never knew!
Sensation!
  Posted: Mar 30 2017, 03:15 PM


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Ever wondered why Honda's chirp their tires? Or the chemical reason for plastic headlights turning yellow? Or how the yaw control on an Evo works?
Well, this is the thread for you!

Most of us have knowledge on a variety of pretty mundane, lesser known, or even misunderstood things pertaining to our hobbies and it just so happens that a lot of these facts are actually pretty interesting.

Rather than another thread about asking questions, this thread is the for you to share and discuss whatever lesser known or misunderstood fact you know about a car, a part of a car, or anything pertaining to driving. A Perfect fit for the Technical Discussion forum!

I'll start it off.

Did you know that the S14 and S15 Silvia's share the same floor pan? A lot of people think the R&D of the S15 must be eons ahead of it's predecessor, but that isn't entirely true; certainly not for the nearly bankrupt late 90's Nissan.

As a matter of fact, the S15 chassis, with addition of a different body skin and a few bolt on body braces, is nearly identical to that of the S14, so much so that much of what fits on a S15 will also fit the S14. Case in point, the folding back seat and the entire floor carpet directly bolts into the S14, they're just made in a different color/material. Some of the biggest difference between the two cars lies in the C pillars, which the C pillars having much more reinforcement on the S15, there's also a slightly different inner A pillar reinforcement on the S15, likely for improved crash rigidity, something I assume was also implemented in the B pillars as well. As for the S15 being super high tech, there is no aluminum subframe, no carbon fiber driveshaft, no lightweight aluminum hood. So what made the S15 so much better than the S14, barring the obvious bump in power to the SR20 and a 6 speed transmission?

I believe much of it boils down to the damping between the cars, the S14 was supposed to be somewhat of a luxury coupe while the S15 was marketed with sports in mind. It's actually very likely that the S15 rode on slightly stiffer suspension, and vintage footage of both cars in their factory trim around a circuit lends some sort credibility to this case. The aforementioned body stiffening and the move to a superior helical LSD in the Spec R vs. the viscous LSD found in the S14 K's help's make the S15 a better car out of the box.

You can pretty much say that the S15 is a factory modified S14, sort of like the M3 to the S14's 335i.

Here's some photo's I nabbed off of Zilvia discussing this exact topic.

These are the additional chassis bracing found on the S15
SPOILER


Here's a the front body frame of the S14
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And here's on of the S15, albeit cut up and missing the radiator support.
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Bare floorpan of the S14
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Bare floorpan of the S15
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Rear B-C pillar of the S14
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Rear B-C pillar of the S15
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Trunk of the S14
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Trunk of the S15
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S14 engine bay
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S15 engine bay
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Meteor
Posted: Mar 31 2017, 02:43 AM


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Great idea for a thread, and a great opening post to go with it. I'd have never known any of this myself. I hope all the other extra knowledgeable car people here post some interesting facts in this thread too.

I can't say I'm one of the more knowledgeable people posting in this section, but I want to contribute to this thread as well, so I'm gonna type up a few of the things I know (even if most of you already know them anyway).

.The rumble that people associate with boxer engines isn't actually something inherent to that type of engine. The boxer engines that do rumble like that do so due to unequal header lengths, which makes the exhaust pulses travel different distances and hence creates that particular engine note.

.A common misunderstanding about differentials is that they'll always cause understeer when locked. Understeer under locking is (ignoring suspension settings) only guaranteed when coasting/slowing down, as the inside wheel won't want to spin slower than the outside wheel, and weight transfer when steering will cause the outside wheel to produce a stronger braking force, effectively trying to pull the outside of the car away from the corner. Oversteer can still be quite possible under acceleration. As with braking and steering, weight transfer will make the outside wheel produce more force, so acceleration will cause the outside wheel to rotate the car if enough weight is placed on it.

.A little known fact about tires is that their grip isn't directly proportional to the weight placed on them, due to their grip being a form of non-Newtonian friction (regular Newtonian friction being the "Friction = Weight X Coefficient" stuff that gets taught in a high school physics class). While a tire will give more grip as more weight is placed on it, it's a case of diminishing returns, and you'll see smaller and smaller increases in grip as you keep piling on the weight. This is why a higher center of gravity makes a car corner slower, since more weight shifts away from the inside wheels when cornering, but the outside wheels don't gain enough grip to compensate.
As for why tires behave like this: let's just say it's pretty complex and leave it at that. There are plenty of elastic and chemical properties at play.

.The reason some drift cars use a ridiculous amount of negative camber up front is something done with steering caster in mind. These days, the caster on pretty much every car is set to increase negative camber on the outside wheel (and decrease it on the inside wheel) as more and more steering is applied. In the drift car's case, this means that when you're at full countersteer, the outside wheel will want to have positive camber (as it's technically the inside wheel in terms of steering direction) and the inside wheel will want to have negative camber, causing the front of the car to want to slide outwards. Setting lots of camber on the front wheels in advance means that the outside wheel will still have enough negative camber left to compensate.
It's still possible that some people are overdoing this though.

.The electronic throttles on most, if not all modern F1 cars are programmed to apply a small amount of throttle under braking. This is to prevent the inside rear wheel from locking up under braking, and it helps the rear tires last longer.

And that's all from me for now.
JKaiba
Posted: Mar 31 2017, 10:14 AM


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The R33 GT-R often gets a bad rap because- it's not Godzilla (has fewer spectacular motorsports winningsmanship titles in its own name); it's not as hard edged, muscular or sexy as the R32 or R34; it's heavier than the 32; it has a longer wheel base. God Foot even shit talks it saying it was a failure.

Overall however, out of the box, for the average driver, an R33 is easier to drive fast than an R32 and it has a lot to do with changes to the suspension and the engineers ability to optimize the chassis rigidity. Some of that is more efficient because the car is heavier. On traction loss, the car also had a more advanced default traction control map and an active rear differential as opposed to a 1-way plate/mechanical diff in the 32 (which as you can see in my recent photo in the track day posts works... well just ok).

That post also gives me the opportunity to dispel a myth that GT-Rs cannot be drifted consistently while under the influence of their out of the box ATTESA traction control maps. In a corner that is approached from a straight, typically all ATTESA equipped GT-Rs will enter ideally like a rear wheel drive car. If you unload the rear wheels like an FR and the car begins to slide you then have two choices- continue to scrub speed at almost neutral throttle and countersteer like an FR or counterintuitively, once your wheel is aligned straight or almost straight, feed the accelerator (don't smash it, but it's not slowly either) and watch for your car to send front wheel torque. Proceed to point and click and exit the corner like an AWD. I chose the former in the Laguna Seca incident since I noticed there was a car closely following me, I wasn't confident that my AWD would respond in time to the latter option and that it wasn't worth it to risk double KOing both cars because I wanted to exit the corner like a hero.

Having the opportunity to have driven all the models of Skyline and all the RB series cars very hard, I can say the 33 is a noticeably smoother car both to cruise in and to corner. However part of the appeal of the 32 for me personally IS that it feels like it's unhinged more so than the 33... even if you might be going slower. Modifications to improve the 32 also have more noticeable effects on the out of the box feeling but that just means the 33 is already that much better put together.

rumination begins here: information may be based on inference or hearsay
A good Nurburgring time is a great dick measuring tool, but that's all it is. While the R34 has a shorter wheelbase, is more maneouverable and stiffer there's a nasty little rumour that it scored slower than the 33 on the Nurburgring due to stability issues. Ever notice the 34 has no posted ring times.
end of rumination

This is a great GT-R Canada post about some of the differences when they went from 32 to 33: http://forums.gtrcanada.com/forum/skyline-...ssis-suspension

This post has been edited by JKaiba on Apr 3 2017, 08:36 AM
Spaz
Posted: Mar 31 2017, 08:46 PM


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I'm going to tackle a subject that everyone can benefit from: Brakes.

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I'm sure we've all heard the term "warped rotors" in our travels through the automotive world, but if you actually try to wrap your head around the idea, it actually makes less sense, and there's a good reason for that. While a lot of track guys are aware of this fact, most of your average drivers or enthusiasts are not; there is no such thing.

It doesn't matter if you're bringing your brakes up to a couple hundred degrees on the street or 1500 degrees at that track, you are not producing enough heat to physically warp that much metal. An article I read a number of years ago referenced one of the brake engineers on Ford's Le Mans engineering team that resulted in the development of the GT-40, who stated that he had never in his time as an engineer seen a rotor that had been physically warped. So if we're not warping the metal itself, what is causing that pulsation or vibration we feel under braking?

The answer is pad material. As the brake pad itself heats up, it transitions from producing abrasive friction, where the vehicle is slowed simply through the force of the pad against the rotor, into adhesive friction, where the pad material actually begins to stick to the rotor surface, producing additional force to slow the vehicle. Now, a side effect of that is that the adhesive material does not simply disappear. yes, some of it shears off into dust, but some of it also adheres to the rotor face, which is why after a set of pads has bedded to the rotor, the rotor takes on a darker coloration.

This transfer, if it happens unevenly, is the reason you get pulsation or vibration. Things like ABS causing the pad to grab and release, leaving imprints of material, a caliper-based parking brake that locks pads against the rotor, and even letting the vehicle sit stationary with too hot of pads can cause the deposits to form in an uneven manner.
xiao
Posted: Apr 1 2017, 06:48 AM


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QUOTE (Spaz @ 9 hours, 52 minutes ago)
I'm going to tackle a subject that everyone can benefit from: Brakes.

Breaks are more important than the Engine itself ... I know this because I've driven countless semi-plausible cars with ab-horrid unsafe breaks. laugh.gif

QUOTE (Spaz @ 9 hours, 52 minutes ago)
This transfer, if it happens unevenly, is the reason you get pulsation or vibration.

Some high-end rotors aren't cheap. So if I spent that much money on them, would there be a cheap cost-effective method of cleaning the pad residue from the rotor? Just curious ~ ohmy.gif
Nomake Wan
Posted: Apr 1 2017, 08:49 AM


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It's called getting the rotor turned. Essentially you grind off the upper layer of the rotor to return it to being smooth. However, if you do not re-bed it you will end up having the same problem again.

Sadly I don't have any awesome trivia to share, so this and the post above might be off-topic and better moved to a more relevant thread. Dunno.

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xiao
Posted: Apr 1 2017, 09:13 AM


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QUOTE (Nomake Wan @ 23 minutes, 26 seconds ago)
It's called getting the rotor turned. Essentially you grind off the upper layer of the rotor to return it to being smooth. However, if you do not re-bed it you will end up having the same problem again.

Typically how expensive is it though ... both the turning and re-bedding? ohmy.gif

Would I be better off just buying another rotor?
Nomake Wan
Posted: Apr 1 2017, 09:15 AM


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Turning a rotor is generally incredibly cheap to do. Rebedding is something you, the driver, do. It's a process that you perform on the car before you go using your brakes normally...so that's the low-low price of free.

If you buy a new rotor you'll have to re-bed it anyway. derp.gif
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xiao
Posted: Apr 1 2017, 10:31 AM


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QUOTE (Nomake Wan @ 1 hour, 16 minutes ago)
Turning a rotor is generally incredibly cheap to do. Rebedding is something you, the driver, do. It's a process that you perform on the car before you go using your brakes normally...so that's the low-low price of free.

If you buy a new rotor you'll have to re-bed it anyway. derp.gif

Ohh breaking them in! I thought re-bed was to coat it with some sort of ceramic layer of goo ... God sometimes my brain doesn't fire-up at all during the day. laugh.gif
The Sixth Element
Posted: Apr 1 2017, 10:58 PM


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I, myself, don't have JDM trivia but a BMW trivia.

The North American Market, in BMW's eyes. was not a good place to sell the M3 because of how the E30 M3 sold previously. Because of that, BMW initially didn't want to sell the next generation M3 in the United States. The only reason why they actually sold the E36 M3 was because the BMW CCA (Car Club of America) wrote a letter to the Headquaters in Germany to own the M3. They only got the M3 but there were differences from the European spec to the North American spec. The 3.2 liter S52 motor in the USDM E36 M3 makes only 240 bhp but the European model has an Independent Throttle Body and additional tuning that made 320 bhp. Additional things that the North American market didn't get in the M3 was the 6spd manual that Europe got. People these days just consider the E30 M3 as "The best BMW Motorsports Car in their history" rather that it was just a good handling car. The E36 M3, in my opinion, changed the M3 formula with a bigger engine and better suspension until the E92 M3 with the mighty V8 engine that revs up to 8400 RPM. (I would love to see how Takumi's 86 (Stage 2 to Final) would go against the E30 M3)
Meteor
Posted: Apr 2 2017, 09:16 AM


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And the great posts keep coming.

QUOTE (JKaiba)
God Hand even shit talks it (the R33) saying it was a failure.

You mean God Foot. God Hand's too busy driving an S2000.
QUOTE (Nomake Wan)
It's a process that you perform on the car before you go using your brakes normally...so that's the low-low price of free.

And you mean a $110 inspection for the shop to say "we think your braking problem is due to some problem with the brakes", and then $660 plus parts for them to look into it tongue.gif

Anyway, thought I'd try adding to what JKaiba had to say regarding the ATTESSA-ETS. From what I've gathered from discussions on the internet, the system operates somewhat like this:
.Speed sensors in the rear wheels check for wheelspin
.Upon detection of wheelspin, power is transferred to the front axle based on wheelspin and throttle position
.The amount of power sent frontwards never exceeds the amount sent rearwards. Front power transfer on the factory ATTESSA mapping maxes out at about 25% if I remember right.

A quirk of this system is that as it's entirely dependent on wheelspin and throttle position, 4WD will only engage when both these conditions are met. If you let off the throttle while 4WD is engaged, the drivetrain will immediately reset to full RWD; and if you get on the throttle after getting into a slide off-throttle, all power will initially go to the rear wheels until the resulting wheelspin is detected and power is then sent to the front. More than one GT-R driver has been caught off-guard by this and spun out as a result, a common situation being that they let up on the throttle whilst recovering from a slide, then got on it again expecting 4WD to still be active.

And yes, this means God Foot's ability to "bypass the ATTESSA-ETS" isn't really all that special. You switch back to RWD everytime you pump the gas tongue.gif
JKaiba
Posted: Apr 3 2017, 08:49 AM


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Thanks Meteor. Post edited to reflect God Foot not Hand.

The car wants you to commit to one or the other. Letting off the throttle does have a tendency to cut off the AWD and the car is already rear happy when it cuts loose- 60/40 front to rear weight bias. Factory mapping on the ATTESA can actually go up to 50/50 and when it goes that far it has saved my ass a few times. Most of the time the car hovers around 10-25% front wheel power but it will pretty much never be on any kind of AWD mode when you're just cruising unless you're launching the car at every stop.
magiblot
Posted: Apr 3 2017, 09:05 AM


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QUOTE (Meteor @ Mar 31 2017, 02:43 AM)
A little known fact about tires is that their grip isn't directly proportional to the weight placed on them, due to their grip being a form of non-Newtonian friction (regular Newtonian friction being the "Friction = Weight X Coefficient" stuff that gets taught in a high school physics class). While a tire will give more grip as more weight is placed on it, it's a case of diminishing returns, and you'll see smaller and smaller increases in grip as you keep piling on the weight.

If you could find or draw a graph describing what you are saying, not only the pedagogical efficiency of your explanation would increase a lot, but also it would look like you are Einstein and you fucking control every force vector in the universe user posted image.
Sensation!
  Posted: Apr 3 2017, 12:20 PM


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This threads going great so far! Keep it up!

QUOTE (Nomake Wan @ Apr 1 2017, 10:15 AM)
Turning a rotor is generally incredibly cheap to do. Rebedding is something you, the driver, do. It's a process that you perform on the car before you go using your brakes normally...so that's the low-low price of free.


There actually are computer controlled machines that bed the friction layer for you, it's how racing teams get by in the 21st century. Its a service that the average daily driver doesn't really need, but for the IMSA team; its invaluable for getting the car dialed in for a race.

QUOTE (Nomake Wan)
Sadly I don't have any awesome trivia to share


I dunno man, you're a hotbed of cool info for Hondas, Mazdas, Fords, Mazda-Fords, Deloreans, Subarus...

This post has been edited by Sensation! on Apr 3 2017, 12:23 PM
Nomake Wan
Posted: Apr 3 2017, 03:36 PM


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QUOTE (Sensation! @ 2 hours, 35 minutes ago)
I dunno man, you're a hotbed of cool info for Hondas, Mazdas, Fords, Mazda-Fords, Deloreans, Subarus...

Well...okay. I suppose I could go with a few random anecdotes. I'm not sure they'll be as impressive or interesting as what's been presented so far, but let's start with one that was brought up in the first post and not addressed, shall we?
QUOTE (Sensation! @ Mar 30 2017, 03:15 PM)
Ever wondered why Honda's chirp their tires?

I knew of this meme way back when I was first starting to get into cars and always just thought it was people making fun of Honda drivers for not knowing how to drive. I mean, growing up in upstate NY in the height of the F&F craze, you saw a lot of dumbass Honda drivers. I always use this video as a reference:

YOUTUBE ( https://www.youtube.com/watch?v=y9hSDWvoZjk#t=59s )


However, after buying my first old Honda and experiencing this hilarious tendency to wheel-hop first hand, I now actually know why it happens. At least as far as my Integra goes, I have no less than five engine mounts. There are the two main side mounts, a main lower rear mount, and two lower front torque mounts. It's actually these front torque mounts that are to blame for the infamous wheel hop. These mounts are designed to absorb some of the vibration the naturally unbalanced engine makes so that the vehicle is incredibly comfortable and quiet to drive. However, these squishy mounts also don't do a particularly good job of holding torque (despite their names!) and as such sudden application of torque by demanding the car accelerate quickly can cause the entire drivetrain to twist. When this happens, it means that some of your engine's torque is actually being lost into the drivetrain motion, which is then overcome by the main engine mounts, which is then again brought back by the weak torque mounts...until eventually you reach an equilibrium point where you can no longer out-torque the torque mounts.

This back-and-forth of the drivetrain is what causes the front wheels to 'hop' or 'chirp' during sudden acceleration, especially from a dead stop. The solution is to solidify the engine and torque mounts to reduce that back-and-forth motion. While this absolutely does work to minimize or eliminate wheel hop, it also re-introduces that vibration into the frame of the vehicle and thus, into the passenger compartment where you'll feel it in your hands and butt. It's a trade-off; would you rather have wheel-hop and your engine flopping back and forth on its axis, or would you rather have your car vibrate from idle all the way to redline?

Me personally, I already ordered new more solid torque and engine mounts, so I'll let you guess which way I went.

Tune in next time for exciting trivia about the Subaru SVX!
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Meteor
Posted: Apr 4 2017, 04:45 AM


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QUOTE (magiblot)
If you could find or draw a graph describing what you are saying, not only the pedagogical efficiency of your explanation would increase a lot, but also it would look like you are Einstein and you fucking control every force vector in the universe user posted image.

Dug up a few graphs for you after seeing that the tire physics papers I've got downloaded don't seem to have this stuff neatly plotted out.

Here's one from a site called Racing Car Dynamics.
user posted image
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And here are two more graphs that apparently come from the book Chassis Engineering by Herb Adams.
user posted image
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user posted image
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The first and third of these images show how G-force ultimately goes down as vertical load goes up, because the tire's grip increases by a smaller percentage than the weight acting on it does. The second image directly illustrates this by plotting cornering force against vertical load - the curve becomes less steep as weight goes up, and each increase in grip gets smaller than the last.

EDIT: Also, this particular characteristic of tires is known as tire load sensitivity. Now you know what to call it/search for info on.


As for Hondas chirping their tires, can't say I ever knew it as either a meme or an actual phenomenon. I did know something about how the stock engine mounts on Honda FWDs cause traction loss on drag launches, but I didn't know this went as far as being noticeable in everyday driving too.
Anyway, having personally gotten some SVX trivia from you before, I am definitely looking forward to your next post. I know it'll be even better than this one was.

This post has been edited by Meteor on Apr 4 2017, 04:50 AM
kyonpalm
Posted: Apr 4 2017, 05:59 AM


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I wondered why my Accord tended to hop sometimes even without full throttle. Cool tidbit.
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Nomake Wan
Posted: Apr 5 2017, 10:30 AM


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Neat to see that the wheel hop info seems to have gone over well. I suppose that means it's time for the next anecdote from good ol' Nomake Wan. Next on the agenda is a car I grew to love and hate and love again, my second car and second Subaru--the Subaru SVX.

Now, there are lots of things one could talk about with the SVX. You could harp on the windows, like the half-myth that they were designed to allow the driver to have the window open in the rain without getting wet (they weren't, but in light precipitation you can indeed lower the window and not get wet). You could talk about their legendary glass transmissions (which aren't; the most common issue to crop up on these transmissions is a 'bad Solenoid A', which 90% of the time is actually because a ceramic resistor located behind the battery has failed and is causing that error code rather than actual transmission failure but causes the transmission to enter limp mode and feel like it's broken). Instead, I've decided to bring up a few things about this oddball car that perhaps not everyone knows. For the rest, you could always watch Regular's review of it. wink2.gif

In truth, most of the nitty-gritty stuff that mostly only hardcore SVX fans know is actually related in some way to the transmission, though not relating to how 'delicate' they are. I'll start with differences between the SVX we got here in the US versus those that were available overseas. Here in the USA, the SVX was introduced with a 4-speed automatic transmission that was essentially a FWD at cruise with a 90/10 front/rear torque split but which could lock up to 50/50 as the situation required. This was the same 4EAT transmission found in the Subaru Legacy which was introduced in 1990, just two years prior. As such, the SVX here in the USA handled like a heavier Legacy with more power. It was impressive for the time, but it was not particularly exciting. To make matters worse, as a 'cost-cutting' measure there were two later years (1994-1995) of the US SVX which got the low-end FWD 4EAT transmission that were even more of a dog.

In Japan, however, the Alcyone SVX (Subaru's high-end brand which never made it to the US) was introduced as an incredibly different beast. While the body, engine and computer systems were fundamentally the same as the US model, the transmission and to a small extent the suspension were incredibly different. Designed to be a luxury grand tourer to compete with the Skyline--which was not available in the US market and thus not a threat--the SVX in Japan featured Subaru's latest AWD technology. Dubbed Variable Torque Distribution or VTD, this was a modified 4EAT which had a standing torque ratio of 30/70 front/rear up to a 50/50 split, much closer to the ATTESA system that Nissan had introduced (The ETS of which, found on the Skyline 4WD and GT-R, could go from 0/100 to 50/50). This standing nature of rear torque bias meant the car handled much more sportily when thrown into a corner, and on the high-end CXD model this was further enhanced by the addition of electronic 4-wheel-steering, again copying Nissan's Super HICAS found on the GT-R (among other Nissans). Here in the US we never got a Subaru with 4WS, and VTD only made it onto our shores nearly a decade later in the 2001 WRX.

In addition, Japanese vehicles came with an additional switch on the shift selector not found on US vehicles. On a US vehicle, the shift selector has a 'MANUAL' switch (which forces the transmission to stick to a gear all the way to redline, with some caveats) and an emergency release button (in case the safety lockout failed and you needed to shift the car into gear). A picture of the US shifter is here:

user posted image

See the little empty cover on the bottom? Let's fill that in when we switch to the Japanese model, shall we?

user posted image

So, on the Japanese model you have a 'POWER' switch. What this did was initiate a special transmission mode that increased pressure to the solenoids to harden the shifts and held back shifting until higher RPMs. It was essentially a performance mode for the transmission. On US models, if you mash the gas pedal you could enable this mode for passing purposes, but the lag between hitting wide-open-throttle and the mode enabling just made people think it was a passing-use-only thing for shifting at redline. In fact, this mode is much more useful at lower RPMs and partial throttle, making the car feel much less 'slushbox' than it does otherwise. Thanks to a brilliant SVX fan in the UK who disassembled the computer code, we now know that the US and Japanese computers are in fact very similar, and the code for this switch is in the US computer even though the switch is not present. As such, if you wire a switch to the empty pin on the back of the transmission computer (or just jam a ground into it like I did, since I never turned the mode off after using it the first time), even US cars can access this mode. As it stands, any SVX owner in the US who wants a free instant performance upgrade they can actually feel can perform this modification and enjoy.

In case you're curious about the other switch in that photo of the Japanese shifter, that's the rear deck ionizer. Japanese people in the 90s were big on that 'air quality' thing, so high-end models had an interior fan with an ionizer installed. Imagine that!

European models, however, had a radically different setup. Here's a photo of their shift selector:

user posted image

This image is in fact labeled incorrectly--letting out the button on the shifter puts it into 'normal' mode, not 'power' mode. Economy mode shifts much earlier than normal in order to hold higher gears. Normal mode is just like the normal mode on US and Japanese cars. However, because these cars have an Economy selector that is wired the same way as a Power switch, European cars do not have code for a 'power mode' switch in their computers. You can swap computers with a USDM or JDM model, or if you are savvy you can program a new ROM to switch the function yourself (again, thanks to the work of that awesome guy in the UK). European models also featured manually-leveled headlights, and models designed for German road compliance also had all-glass headlights rather than plastic like everywhere else in the world. Fancy~!

I've got one more tidbit about the SVX to share, but I think this post has gone on long enough and the next topic really deserves its own post, so I'll hold off. For now, enjoy!

This post has been edited by Nomake Wan on Apr 5 2017, 10:33 AM
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kyonpalm
Posted: Apr 5 2017, 12:17 PM


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Some more Skyline trivia, though I'm sure a lot of you may already be familiar with this. Nomake Wan and I came across this one day a while ago and it just came back in my mind.

Officially speaking, the R32 GT-R first went into production in May 1989 and 5035 units were produced. The chassis numbers produced in that year were 000054-005082 and 100001-100006. Odd, though, that the first BNR32 would have a chassis number starting at 000054. The answer? They actually started in 1988. The first 53 units were made and subsequently tested for fine tuning. Rather than set them aside, Nissan actually counted them in the production numbers. Here's a rare shot of one of those test units at Nürburgring in 1988:

user posted image
Image size reduced, original size: 972 x 655. Click here to view the image in its original dimension.
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Nomake Wan
Posted: Apr 6 2017, 02:15 PM


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I think that's an excellent segue into the next and final post about the Subaru SVX. Let's talk about the prototype stage of that vehicle for a moment.

Subaru wanted to build a car that was so unbelievably futuristic that it would be their halo car and set them apart from everyone else. They invested in Giorgetto Giugiaro of ItalDesign to help turn their vision into reality, and his influence can easily be seen in the car's distinctive windows. However, that sort of thing is something someone reading Wikipedia or listening to RCR could know, so let's move on to some more interesting facets of the prototype stage of the car.

For starters, Subaru actually toyed with several possible designs for the car's drivetrain. The first experiment was in the power department. They knew they wanted at least a 3-liter engine, but when it came time to actually making one their six-cylinder engine ended up a 3.3L. I'll get to that in a bit, but once they had an engine they did experiment with making it turbocharged. In fact, in these photos from a Car Styling magazine in 1991, you can see an early prototype of the car marked as such:

user posted image
user posted image

In fact, the early prototypes even had a voice-controlled navigation system! However, while the navigation system was scrapped for simplification and cost (though the car did still have an automatic climate control), the turbo was supposedly scrapped because Subaru wanted the car to keep the smooth power of the naturally-aspirated engine rather than the 'violent' power of the turbo. However, while that is the official story from Subaru's press materials, I don't think I buy it. In the many years since the SVX has been available to the public, after all, we've come to learn that its one-off powerplant has a fatal flaw...one that started whent he engine was first created, and yet one that managed to make it all the way through the car's development stages without being remedied.

When I bought my SVX, it was in rough shape. I had managed to repair it into pretty decent shape, and yet when I took it for serious drives it seemed to have an issue with overheating. Driving normally, most of the time it was totally fine. If I took the car up into the canyons and forced it to drive hard, however, it would overheat without fail. I was sure that it must be head gaskets or some other weird issue, but no matter what repairs I made the car kept overheating anyway. In the end, I sold the car without knowing the problem. Years later an irrigation system engineer who happened to be an SVX owner had a theory about this overheating behavior and created a test rig of the engine to see what would happen. Sure enough, he found the cause...and the solution! I wish I had the photos he took handy, but sadly I don't.

The short version is, after a certain RPM (around 4000), the water pump on the SVX starts to cavitate. It gets worse as RPMs increase, and the more you go the more uneven the cooling circuit gets. Eventually not only does the pump cavitate but only half of the engine gets coolant circulating through it! This causes the engine to, obviously, overheat. The solution for the cavitation issue is to enlarge the water pump outlet from 30mm to 42mm inner diameter and match it to the radiator correctly, thankfully an easy fix. Fixing the uneven flow rates for the two banks of the engine is more difficult, but can be done. So, why is such a 'simple' problem, one that any fluid dynamics engineer would have noticed early on, present in a production vehicle?

We have a theory. The Boxer engine that set Subaru apart was the EJ22, created for the 1989 Legacy. In creating the engine for the SVX, Subaru added two additional cylinders--1.1L--for a total of 3.3L. However, by looking at the engine castings, it becomes clear that Subaru either was not aware that increasing the volume would affect fluid dynamics or chose on purpose to ignore that fact. The cooling and oil passages for the EG33 are mirror copies of the EJ22 (albeit extended by two cylinders), and therein lies the problem. You cannot add volume to a system like that without accounting for the additional distance traveled by the fluid. It is for this reason that the cooling is uneven and the pump cavitates, and is also responsible for oil starvation to the rear cylinders under extremely hard cornering (as experienced by those who tried to race the SVX on professional courses). When you look at a later-generation 6-cylinder Subaru engine, such as the EZ30R, you find that the cooling and oil passage designs are completely different from the EJ22 and EG33, suggesting that they took the time to learn from and fix their mistake.

Further reinforcing this theory is the fact that every single SVX was shipped with an automatic transmission standard with absolutely no option for a manual shift. While there are rumors abound that this was done 'because no manual transmission could take the strain', this is easily dismissed by looking at the design of the Legacy RS and the Impreza around the same time which had gearboxes more than capable of holding the horsepower and torque that an EG33 engine produces stock. So, if it isn't the durability of the transmission at fault, why only offer an automatic? Well, for one, the automatic transmission tries very hard to have the engine live life under 4000 RPMs as long as it can. So by using an automatic, they can be sure that in the majority of real-life driving, drivers will not exceed 4000 RPMs for extended periods of time. That is, until a certain someone messed around with the transmission computer and decided to take it into the canyons to race uphill. whistling.gif

As my last little Subaru SVX tidbits, it turns out that in the prototype testing stages Subaru created both FWD and RWD versions of the SVX to compare against their new VTD-4WD system. If they could create a car that could perform just as well as much less cost and weight by using FWD or RWD, they would. Subaru was not new to FWD vehicles, and while a RWD would be relatively new the basic concept was not dissimilar from how they constructed their AWD transaxle. However, testing showed that especially in wet conditions the VTD-4WD was far superior to either single-axle drivetrain, so their halo car remained staunchly AWD. But hey, that means that at least at one point, Subaru did produce a RWD coupe! laugh2.gif

For all the SVX's quirks, I still love the thing. I wish the US had gotten all the lovely features found in the vehicle in other parts of the world, but that's where this year comes in. Starting in 2017, Model Year 1992 vehicles can be legally imported into the USA, which means the very first SVXes are now becoming legal on our shores. So... I guess it's time to save up and get myself a new one! cool.gif

Tune in next time for the love affair between Ford and Mazda, and why the winner in that affair is no one.

This post has been edited by Nomake Wan on Apr 6 2017, 02:15 PM
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Sensation!
  Posted: Apr 6 2017, 03:34 PM


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A neat bit of trivia: it's our very own Nomake Wan who figured out how to get the sport mode to work on North American SVX's!
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Posted: Apr 6 2017, 08:06 PM


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QUOTE (Sensation! @ 4 hours, 32 minutes ago)
A neat bit of trivia: it's our very own Nomake Wan who figured out how to get the sport mode to work on North American SVX's!

Hahaha, I wasn't going to say anything, mostly because I only helped. It was b3lha in the UK who looked at the TCU code I sent him and went, "Huh, this code looks the same, do you have anything plugged into pin A4 on the TCU?" So I asked where pin A4 was, and when I saw that nothing was plugged in I was just brave/stupid enough to jam a wire in there and see what would happen. Luckily what happened was Power Mode turned on (and not me frying the TCU on my only car). laugh2.gif

So I can't take all the credit. I sent the code for analysis, I tested it out, and I figured out an efficient way to wire it all up (since on the SVX, there is a diagnostic cable in the driver's kick panel which is really just a ground, and the TCU is right above that panel). It was b3lha who analyzed the TCU code and figured out that the mode existed in the first place, so I give him the credit for the discovery. Not to mention he's the one who created the PC interface circuitry and interface program I used to dump the code in the first place!

For more information on the software side of SVXes, check out b3lha's website here: http://www.alcyone.org.uk/ssm/index.html
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