I'm going to get my Zed (auto) and I've got a daft question to ask, well its not daft really as I don't know the answer.....

 

What does overdrive do? and while i'm making a pratt out of myself how does the power button and hold work on the auto box, sorry for sounding such a div, but if I don't ask i'll never know...

 

 

One holds the Rev's longer and the other is a petrol saver'ish not holdng the gears as long.

 

Overdrive on = Not holding Rev's as long. (normal driving)

 

Overdrive off = Holding Rev's longer.

 

Now I've said that someone will say m button is back to font.....LMAO

 

Matty.

 

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Bounce...Bounce...Bounce...Bounce...Bounce...Bounce...Bounce... (sorry no sound!) LOL

Here's something I poached from a website ages ago :-

 

Nissan researched the precision and ease of movement of sports car gear shifts, with the result that the manual transmission was fitted with double cone synchronisers on second and third gears to reduce the gear changing effort, as it was considered drivers would make more shifts to these gears. A new lever linkage was also designed, and (on the turbo) servo assistance provided for the clutch. The same gearbox is fitted to all models.

 

The 4 speed automatic transmission is a lockup type. When in drive mode, gears change 1-2-3 then 3 lockup, giving the effect of 4 gears. When overdrive (4th) is switched in, the change goes 1-2-3-4 then 4 lockup, giving the effect of 5 forward gears. There is a communications link between the automatic transmission control computer and the engine management computer, and this amongst other things, allows the engine computer to retard ignition, thus momentarily reducing engine power, during auto gear changes. Auto gear changes therefore are very smooth. The automatic transmission fitted to the turbo model is stronger than the one installed in the non turbo. Although the gear ratios are almost identical, there are many minor differences between the two transmissions.

 

The Japanese automatic transmission has many more features than the export models. A "power", "normal" and "hold" switch is fitted to modify transmission shift points. The effect of the "power" setting is to delay upshifting, but does not alter the maximum RPM that change occurs. In order to change at the red line or rev limiter speed, one must operate the shifter manually. The hold setting allows holding prevents downshift into second when the shifter is set to "D", and prevents downshift into first when the shifter is in "2". Another curious feature with the Japanese version is that lock up is also available in second gear.

 

Power is transmitted to the viscous coupling limited-slip differential via a 2 section propeller shaft. A centre bearing is located at the junction of the 2 sections, and is located above the main catalytic converter assembly.

Gear ratios are: 1st 3.21, 2nd 1.93, 3rd 1.30, 4th 1.00, 5th 0.75 for the manual.

 

With standard tyres -245/45ZR16 on 8.5J X 16 rims, the manual twin turbo (final drive ratio 3.69:1) the turbo achieves the following speeds:

Gear MPH RPM

1st 43 7200

2nd 72 7200

3rd 107 7200

4th 139 7200

5th 155 6000 with speed limiter

5th 165 6400 without speed limiter

5th 186 7200 intermittent theoretical, rev limited

 

 

The automatic ratios are: 1st 2.78, 2nd 1.54, 3rd 1.00, 4th 0.69, so results for the turbo are

(Maximum, as actual speeds will depend on torque converter slip):

Gear MPH RPM

1st 48 7200 Held in first

2nd 87 7200 Held in second

3rd 139 7200 Held in 3rd, overdrive off

4th 155 5500 with speed limiter

4th 178 6400 without speed limiter, not attainable by stock TT

4th 201 7200 intermittent theoretical, rev limited

 

Can't remember where to give credit though ...

Actually, this raises an interesting point. Did the manuals get tested in 4th on the RR day ? I know my auto was done in 3rd.

Andy you need to put that on the Duffman Muffman Hoffman Bullshitman thread .

 

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