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James Millers SRD PT6262 8 Speed Build


Lee P
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Looks awesome :cool:

 

What diff are you using? And any idea what the theoretical top speed is with the gearing? This could potentially be a bit of a game changer - much quicker through the gears than a 6 speed or tiptronic, and better motorway fuel economy.

 

We chose to put a 6 speed diff in this as its closer to the ISF ratio

 

The ISF ratio is 2.94

Auto diff is 3.769

6 speed is 3.266

 

The ISF owners talk about changing to a 3.266 as they feel that the higher gears are just for cruising so that ratio should suit pretty well.

 

Will give great acceleration but as you say cruising on the motor way will be good fuel economy as rpm will be low.

 

I have a chart of the speed per gear on the ISF, will post it in a sec

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Looks awesome :cool:

 

What diff are you using? And any idea what the theoretical top speed is with the gearing? This could potentially be a bit of a game changer - much quicker through the gears than a 6 speed or tiptronic, and better motorway fuel economy.

It is win win for everyone I think.

From what I've read, the AA80E box can change gears pretty quickly. 0.1s on upshift and 0.3 downshift, that was on the Lexus ECU. I suspect the Syvecs can speed that up.

 

Pretty epic really.

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why does is over rev when changing is the lower gears ?

I take it thats because you still have your foot on the throttle and as the gear changes Ie clutch engaged the revs rise as would in a manual car if changing gears with out moving the throttle ?

 

I assume thats down to it not been mapped fully yet?

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Just worked out the gearing - and made the following assumptions.

 

Final Drive: TT JSpec 6spd Facelift

Tyre Width: 275

Aspect Ratio: 35

Rim Size: 18

 

Speeds at 7000rpm are:

1st: 36.5

2nd: 61.6

3rd: 90.0

4th: 114.5

5th: 136.2

6th: 167.7

7th: 203.5

8th: 244.8

 

 

80mph would be:

3rd: 6500rpm

4th: 5000rpm

5th: 4250rpm

6th: 3400rpm

7th: 2850rpm

8th: 2350rpm

 

Not too bad at all.

 

Moving to a Auto Diff:

1st: 30.7

2nd: 51.9

3rd: 75.8

4th: 96.5

5th: 114.8

6th: 141.3

7th: 171.4

8th: 206.2

 

80mph: would be:

4th: 5700rpm

5th: 4900rpm

6th: 4000rpm

7th: 3300rpm

8th: 2700rpm

 

I think the Auto Diff would suit it best.

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Will it have an auto mode as well? I could see myself getting a little bit irritated having to constantly change gears (being 8 speed).

 

Yes of course full auto mode :)

 

Manual mode and a sport mode.

 

why does is over rev when changing is the lower gears ?

I take it thats because you still have your foot on the throttle and as the gear changes Ie clutch engaged the revs rise as would in a manual car if changing gears with out moving the throttle ?

 

As said this is just purely a base calibration just to get the car driving but think it's more the Rev counter.

Edited by Lee P (see edit history)
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Just worked out the gearing - and made the following assumptions.

 

Final Drive: TT JSpec 6spd Facelift

Tyre Width: 275

Aspect Ratio: 35

Rim Size: 18

 

Speeds at 7000rpm are:

1st: 36.5

2nd: 61.6

3rd: 90.0

4th: 114.5

5th: 136.2

6th: 167.7

7th: 203.5

8th: 244.8

 

 

80mph would be:

3rd: 6500rpm

4th: 5000rpm

5th: 4250rpm

6th: 3400rpm

7th: 2850rpm

8th: 2350rpm

 

Not too bad at all.

 

Moving to a Auto Diff:

1st: 30.7

2nd: 51.9

3rd: 75.8

4th: 96.5

5th: 114.8

6th: 141.3

7th: 171.4

8th: 206.2

 

80mph: would be:

4th: 5700rpm

5th: 4900rpm

6th: 4000rpm

7th: 3300rpm

8th: 2700rpm

 

I think the Auto Diff would suit it best.

 

We drove it with the auto diff and first gear especially felt very short

 

Feels much better on the 6 speed diff

 

Will see how it is when mapped and may try an auto diff as well

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