Interesting SVX Article

[Rotorflyr]

Got this e-mail from a buddy of mine with a link to the following article
Linky

It's a pretty favorable article, thought all of you might enjoy the read









(oh yeah, WTLW, bite me )

[LarryIII]

Thanks. It was an interesting article.

[n00b on demand]

"Extending the life of your replacement transmission is relatively simple: use '3' rather than 'D' in urban driving to stop the transmission constantly shifting between its upper ratios and avoid using the 'Manual' button."....first time i have ever seen that in an article....very good read...thanks!

[GreenMarine]

Cool, it's an Aussi article

[b3lha]

Isn't that the same magazine that published the article Ianorris wrote about the UK SVX meet?

A great article and some nice photos of Jason's car, but a one interesting quote:

The full-time 4WD system starts out with a 35/65 front-to-rear torque split which moves closer to 50/50 in response to loss of front-wheel traction.

So it applies more power to the wheels which are slipping?

[Jamsvx]

I should hope it was a favourable article...I was the one who he interviewed for it!!

Unique Cars contacted me (this is during my ownership of SVX-33H) as we had the club listing in the magazine, met up with a photographer down at Sydney Harbour and got some nice photos (and some very nice ones that I will frame when I get back to Sydney!)

A lot of the stuff he had dug up from the Net but the part about the drive in 3, not D was from me...but then I got that from here so it is the Network speaking *rolls eyes into head, adopts demonic voice, twitches*..."this is Alcyone, spirit of the SVX, slayer of the 4EAT"



You would have been amazed at the number of people who came up asking what it was and when it was being released!!!!

I miss it!!!

James

[Electrophil]

Originally Posted by Jamsvx

I should hope it was a favourable article...I was the one who he interviewed for it!!

Unique Cars contacted me (this is during my ownership of SVX-33H) as we had the club listing in the magazine, met up with a photographer down at Sydney Harbour and got some nice photos (and some very nice ones that I will frame when I get back to Sydney!)

A lot of the stuff he had dug up from the Net but the part about the drive in 3, not D was from me...but then I got that from here so it is the Network speaking *rolls eyes into head, adopts demonic voice, twitches*..."this is Alcyone, spirit of the SVX, slayer of the 4EAT"



You would have been amazed at the number of people who came up asking what it was and when it was being released!!!!

I miss it!!!

James

I knew it! I could tell reading the article that someone with genuine, long term experience with the SVX helped write that article. There were too many real time facts about the car printed to be otherwise.

Excellent article. One of the best and most "dead on" I've read. Thanks for sharing!

[svxjoe]

Originally Posted by soobiesvx93

"Extending the life of your replacement transmission is relatively simple: use '3' rather than 'D' in urban driving to stop the transmission constantly shifting between its upper ratios and avoid using the 'Manual' button."

.....is this good advice from the article?

[n00b on demand]

Joe your gonna get alot of views on that subject but i have been doing this for a year now with no ill results. Keeping the tranny in 3rd while driving around the city is good because it will keep the tranny from shifting so much...as we know the shifting is what causes the heat. I will only shift up to D once i hit the highway and am going 60 MPH.

[oab_au]

Originally Posted by soobiesvx93

Joe your gonna get alot of views on that subject but i have been doing this for a year now with no ill results. Keeping the tranny in 3rd while driving around the city is good because it will keep the tranny from shifting so much...as we know the shifting is what causes the heat. I will only shift up to D once i hit the highway and am going 60 MPH.

Well I think I might have started this in the first place. The main reason is because of the very high final drive ratio, that is used. 4th gear in the US model is 2.38:1 ( 2.5:1 in the Euro), so driving around town, has the engine turning about 1500 rpm. To compensate, the torque converter works hard to lower the ratio and increase the torque. This is where the heat is produced, in the converter, not in the actual gear changing.

Of course the other benefit, is that the engine is running around 2000 rpm around town, to provide a more lively performance. The fuel consumption will stay around the same level, as it takes more throttle, to accelerate, in 4th than in 3rd. Fuel consumption is controlled by the throttle opening, not the engine rpms.

Harvey.

[Chiketkd]

Originally Posted by Rotorflyr

Got this e-mail from a buddy of mine with a link to the following article
Linky

It's a pretty favorable article, thought all of you might enjoy the read

One observation...

The UK, OZ and JDM SVXs use the 'superior' VTD trans which we keep hearing about on these boards. However, I've never seen a review on one that had a 0-60mph time of under 8 seconds (1/4 mile (400m) times are also in the 16+ second range).

Several mags in the USA, were able to run low to mid 7 sec times with the transfer clutch awd system in our 4EATs with 1/4 miles times in the 15's.

What gives? Is the VTD equipped trans heavier, or is there a greater power loss to the wheels in that trans?

-Chike

[Weebitob]

That is also something I have been thinking for some time ever since reading specs on SVX in the UK, which are probably JDM ones that were imported. I always assumed that a VTD system would weigh less, even though I have very limited knowledge on this. But perhaps the 0-60 times are lower as well because not only would the center diff in a VTD system be larger but since it uses torque converters to send power to both wheels while the US ones use a system that still has a more direct way to send power to the front, (I do not completely know what it is or what I am pretty much guestimating so could be nice if someone can help fill me in on this one.) So I am guessing that because of that perhaps the is not as much whp or torque initially generated at the front wheels, which might account for more balanced handling, perhaps more capable of going at slightly higher speeds (I still want to know if a governorless US SVX can reach 175mph , just curious) and less wear on the transmission itself. Of course I am pretty much guess this, so can someone please link an article or type something up on how the VTD system works and perhaps even looks because I can't find article on it.

So please help someone who wants to know why but is clueless to exactle how?

[oab_au]

Originally Posted by Weebitob

That is also something I have been thinking for some time ever since reading specs on SVX in the UK, which are probably JDM ones that were imported. I always assumed that a VTD system would weigh less, even though I have very limited knowledge on this. But perhaps the 0-60 times are lower as well because not only would the center diff in a VTD system be larger but since it uses torque converters to send power to both wheels while the US ones use a system that still has a more direct way to send power to the front, (I do not completely know what it is or what I am pretty much guestimating so could be nice if someone can help fill me in on this one.) So I am guessing that because of that perhaps the is not as much whp or torque initially generated at the front wheels, which might account for more balanced handling, perhaps more capable of going at slightly higher speeds (I still want to know if a governorless US SVX can reach 175mph , just curious) and less wear on the transmission itself. Of course I am pretty much guess this, so can someone please link an article or type something up on how the VTD system works and perhaps even looks because I can't find article on it.

So please help someone who wants to know why but is clueless to exactle how?

These are a couple of drawings that I did, to show the difference in the two types of AWD.

The Transfer type, is a front wheel drive box, with a TCU operated clutch to drive the rear wheels.

The VTD uses a compound planetary gear set, that uses different size sun and planet gears, to divide the torque, in the ratio set by the gear sizes. It uses an TCU operated clutch as a Limited Slip unit, that prevents either front or rear wheel spin.

The drive comes in the front sun gear, to drive the compound planet gears. The planet gears are mounted on the carrier that drives the front wheels through the transfer gears. The rear sun gear is driven by the other half of the compound planet gears, to drive the rear wheels. The Limited Slip clutch is connected between the carrier and the rear sun gear. Any difference in wheel speed over 20%, is detected as wheel spin, so the TCU applies the clutch to move more torque to the other wheels.

Under normal driving conditions, the whole gear set revolves together, as a solid unit, the gears don't rotate against each other. The only time that they rotate, is when there is wheel spin.

Now the hard part. Although the gears don't rotate, with each other, they still divide the torque. A set of gears, are only a set of revolving levers, so even though they don't revolve, they still divide the torque by the differential leverage, of their diameter.

Harvey.

[Chiketkd]

Harv,

Great diagrams. One question though, do you see any reason why the VTD equipped SVXs had 0-60mph results in the 8 second range while the US transfer clutch equipped SVXs got results in the 7's???

Do the extra sun gears in the VTD box cause higher drivetrain losses?

-Chike

[oab_au]

Originally Posted by Chiketkd

Harv,

Great diagrams. One question though, do you see any reason why the VTD equipped SVXs had 0-60mph results in the 8 second range while the US transfer clutch equipped SVXs got results in the 7's???

Do the extra sun gears in the VTD box cause higher drivetrain losses?

-Chike

No idea Chike, don't know where the numbers came from. I doubt that the Euro would be slower that the US version, for a couple of reasons. The ECU does not have the leaner mapping of the more stringent pollution, US model, no lag. It also runs. the lower 3.7 diffs. I'll be going down to my sons place soon, so I'll do some G-Tec Pro runs to see what it does.

No as I stated the whole set-up revolves as a solid unit, would be the same as the Transfer system. The two systems would be no different on straight line acceleration.

Harvey.