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Automatic Trans Thread

AlexCim

By AlexCim,
in Four Door Family & Wagoneers

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AlexCim Grand Master

AlexCim

Posted
Posted

Ok, thought i would start a discussion on the auto trans, get a good discussion going.

Some discussion points, of which some are questions from me are

- What power is the box good for

- What upgrades can i do, apart from valve body?

- Torque converter, whats the deal? Replacing it and so on (i want to replace mine)

- Stall converter kit? Does anything exist?

- Is there any addon where i can give my car tiptronic style gear changes on my S1? Basically make it a clutchless manual style thing?

Anyone that can answer, cheers.

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https://www.sau.com.au/forums/topic/102861-automatic-trans-thread/
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CruiseLiner Mentor

CruiseLiner

Posted
Posted
Ok, thought i would start a discussion on the auto trans, get a good discussion going.

Some discussion points, of which some are questions from me are

- What power is the box good for

- What upgrades can i do, apart from valve body?

- Torque converter, whats the deal? Replacing it and so on (i want to replace mine)

- Stall converter kit? Does anything exist?

- Is there any addon where i can give my car tiptronic style gear changes on my S1? Basically make it a clutchless manual style thing?

Anyone that can answer, cheers.

so u have made up your mind or still deciding? (auto vs manual that is) :)

AlexCim Grand Master

AlexCim

Posted
  • Author
Posted

Well, ive made my mind up.

The reasons i am keeping the auto is

- I want to tow things, with the clutch i would want it wouldnt be fun!

- 7k can be spent on other mods, which i CAN remove when selling the car. Meaning i wont loose THAT much money. Meaning i get other mods sooner too.

- The money i save on the conversion, i can put towards importing something like a 7k non regoed, non complied race/drift silvia/GTST.

If i can build the auto to be quick shifting, responsive, tough, hard launching and if i can somehow get it to work tiptronically style, that would be best. All i really hate about the auto is f**king kick down.... but ill deal with it.

Many people have two cars, i am sure i can do that too...

Tangles Grand Master

Tangles

Posted
Posted

2 cars & a bike, absolute bliss. *wink*

Yeah, I too would like to 'convert' to tiptronic style. Dont know how or if it could be done, 1st thing though will be to do the actuator valve body exchange and add a big oil cooler kit.

What do torque converters do, and are they worthwhile for a 200awkw auto Stagea thats primarily a family car?

Sydneykid Grand Master

Sydneykid

Posted
Posted (edited)

I am far from an auto box expert, I leave that to the profesionals. The following assumes some level of knowledge of how an automativc geabox works. If you don't know, then this is the best thread I have seen for a while, please read it first;

http://www.ukcar.com/features/tech/gearbox/AUTO/

The auto in a Stagea is made by Jatco, and is basically the same as Z32 and R33GTST (+ a 4wd transfer case bolted on the side) and several other larger 6 cylinder Nissans, 4wd's, utes, trucks etc. So parts and knowledge are not hard to find.

If you need higher rpm for launch (so you have boost) then a high stall speed torque converter is the answer. You pick the stall rpm to suite the boost build characteristics of the turbo. The standard torque converter has around a 2,000 rpm stall speed, but as you increase the torque output from the engine the stall speed climbs a bit. At around 150 rwkw mine was at 2,250 rpm. Since you have the engine producing kinetic energy and the car going nowhere this energy has to be converted (Newtons Law, see, high school physics is sometimes usefull), in this case into heat. Think 60 or 70 of those 1 kw bar heaters, that's a lot of heat. That heat goes into the transmission fluid, hence the need for a big tranmission cooler.

An example, if you have turbo that produce boost at 3,500 rpm then you get a 3,500 rpm stall conveter. Bingo, boost at launch. The problem is (you get nothing for nothing) it is always a 3,500 rpm stall torque converter, so the car won't move until the engine is doing pretty much 3,500 rpm. That's bad for economy, emmisions etc

The Stagea auto uses a band for 2nd gear engagement, this can be upgraded with a stronger band (sometimes kevlar) which gives higher grip (to handle the extra torque) and tolerates more slip and heat.

The 3rd and 4th gears are engaged by clutches (wet clutches, like the ATTESSA), these can also be upgraded to handle the extra torque.

The bands and clutches are controlled by valves switching hydraulic pressure, so a "valve body" upgrade can be used to speed up the band/clutch engagement (sometimes called a "quick shift kit"). This lessens the wear on the bands/clutches and makes the gear change quicker/sharper. As usual you get nothing for nothing, this means slightly harsher gearchanges, not as seamless, less smoooooth. Good oil temperature control is necessary for tight gearchanges, hence the need for a big transmission cooler.

How much does it cost? Well the full upgrade (torque converter, bands, clutches and valve body) seems to be around $3,500 (excluding gearbox R&R). The first step is a big tranmission cooler (~$200), then a valve body upgrade (~$300), then its inside the gearbox time.

How much power will it handle? Damn tuff to answer as the weight of the car and its traction (Stagea = 4wd and 1700 kgs) has some bearing. It will most certainly handle as much as the standard engine internals are capable of supporting (ie; ~300 rwkw).

That's about the limit of my research so far, hope it was of some help. MV Automatics in Adelaide seem to be the Skyline auto experts. There was a valve body exchange arranged on the Group Buy section a while ago with them.

:) cheers :D

Edited by Sydneykid
  • Thanks 1
Tangles Grand Master

Tangles

Posted
Posted

Yeah, thanks heaps SK, very VERY helpful info. MV Automatics charge around that $500 mark for supply only of valve body (exchange) & big oil cooler, or around $650 fitted for me (just up the road).

Now I understand a stall converter; so you dont move until it's 'stalled up' as such. Certainly not necessary for a family-type car, for me anyways.

With the valve body upgrade, Ive been told by SA forum members who use the product that the shifts are as harsh as how far your right foot is down on the throttle. City easy driving and its not too harsh, flat stick 6000rpm change and it'll bang up into the next gear......

Thanks very much for your input SydneyKid, appreciated.

Brendan

Sydneykid Grand Master

Sydneykid

Posted
Posted
Has anyone got photos of the standard cooler vs upgraded?

I was interested in seeing the actual size difference.

It's not just size but the fluid flow though the cooler that's important.

TransCoolerComparisonSmall.jpg

I started a thread a year or so ago on transmission coolers, if you need to know

any more details this is the link;

http://www.skylinesaustralia.com/forums/in...showtopic=59399

:) cheers :)

  • 4 months later...
Fastrotor Proficient

Fastrotor

Posted
Posted

One other thing though Gary, what about the lock up clutch in the converter.... i was going to see how high Mike could make one and still keep the lock up part, so cruise and highway didnt suffer with excess slip. I really need one to help with the sprint racing.

Gary

Terminal Grand Master

Terminal

Posted
Posted

for $3500 for the upgrade, it's coming on par with my current spending for manualisation. mine will roughly come to $4000 after install (not including powerfc and hiflo turbo)

so it doesn't really matter which avenue you take, but you get a superior results afterwards.

  • 2 years later...
  • 4 years later...
  • 2 years later...
  • 1 month later...
mowgs Apprentice

mowgs

Posted
Posted

Sorry to drag up an old thread - I have searched honest!

Has anyone upgraded the belt and clutch packs? Anyone know of any decent suppliers of kevlar etc? Going to have the box out to fit a transgo kit so might as well get everything upgraded while its out.

Are the clutch packs different from different cars - I.e. would the ones from a patrol be any stronger, or are there aftermarket ones?

I'm not after mental power from the engine, would just rather do things once.

(S1 re4r01a)

Ta!

Mowgs

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