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Location: Casino
Registered: August 2004
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1JZ-GTE R154 Diff Ratio
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Tue, 18 January 2005 10:00
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Hi Guys,
I am in the process of putting a 1JZ and R154 into my VL Commodore, as I am having the diff reco'd to turbo spec I have the option of picking the diff ratio.
what would be best for a daily driver that see a fair bit of highway driving?
Std VL diff 3.45:1
I belive the standard 1jz Soarer manual is 4.11:1 ??
Can anyone help me out?
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Location: Sydney
Registered: May 2002
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Re: 1JZ-GTE R154 Diff Ratio
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Tue, 18 January 2005 10:41
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The Soarer 1JZ factory R154 diff ratio is 4.083:1 for a 1600kg car and revs at 2500rpm in 5th for 100km/hr.
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Location: Brisbane
Registered: May 2002
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Re: 1JZ-GTE R154 Diff Ratio
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Tue, 18 January 2005 11:19
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I reckon around 3.5:1 would work pretty well. The Soarer has a pretty low ratio but it's also a lot heavier than a VL. If you do a lot of highway driving you'll want reasonably tall gearing.
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Location: Montrose, VIC
Registered: May 2002
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Re: 1JZ-GTE R154 Diff Ratio
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Tue, 18 January 2005 13:15
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Well, you could probably pick either the 3.7 or 3.889 bogwarmer diff gears, just remember that especially the 3.889's seem to be pretty prone to being noisy...
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Location: tas
Registered: June 2002
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Location: Brisbane
Registered: July 2002
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Location: Newcastle, NSW, Australia
Registered: May 2002
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Location: Canberra
Registered: June 2003
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Re: 1JZ-GTE R154 Diff Ratio
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Wed, 19 January 2005 03:15
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The JZA70 diff (same diff) i have in the GT8 is a 3.7:1. It was behind a R154 so should be reasonably well matched ratio wise.
If anything it's a bit too short for the GT4 but it only weighs 1380kg. Plus i have A LOT of torque.
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Registered: June 2002
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Re: 1JZ-GTE R154 Diff Ratio
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Wed, 19 January 2005 05:05
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I had a 3.46 behind my W58 (similar 5th ratio) and it was good, pulled well sat at ~2400rpm @ 100km.
I now have a 3.91 and it is too short, the engine doesn't need to work very hard and doesn't make use of the 1JZ torque, sits at ~2700@100 (but ~3k @ 120, a bit buzzy.)
Mind you a E30 BMW only weighs just over 1100kg wet.
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Location: Sydney
Registered: March 2003
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Location: Brisbane
Registered: July 2002
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Re: 1JZ-GTE R154 Diff Ratio
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Wed, 19 January 2005 05:28
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E30-323ti wrote on Wed, 19 January 2005 16:05 | I had a 3.46 behind my W58 (similar 5th ratio) and it was good, pulled well sat at ~2400rpm @ 100km.
I now have a 3.91 and it is too short, the engine doesn't need to work very hard and doesn't make use of the 1JZ torque, sits at ~2700@100 (but ~3k @ 120, a bit buzzy.)
Mind you a E30 BMW only weighs just over 1100kg wet.
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jesus, they are that light?.. thats bloody awesome
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Location: Casino
Registered: August 2004
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Re: 1JZ-GTE R154 Diff Ratio
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Wed, 19 January 2005 10:51
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Thanks grant for that spread sheet.
I made some modifications so that I can show the differences between both doff ratios and the different gear ratio from the MX5 VL 5 speed and the R154.
I've looked at many of everyone suggestion this is what I came up with
3.2:1 100kph @ 2000 rpm
1st @6000 rpm 70 kph
2nd @ 6000rpm 100kph
3.5:1 100kph @2300rpm
1st @6000 rpm 63 kph
2nd @ 6000rpm 105 kph
3.7:1 100kph @2400rpm
1st @6000 rpm 59 kph
2nd @ 6000rpm 99 kph
3.889:1 100kph @2500rpm
1st @6000 rpm 57 kph
2nd @ 6000rpm 94 kph
Purely going of these figure I would lean towards 3.5 or 3.7 ratio. What would be like to drive? would I still get good take off? would the engine make boost at a reasonable speed?
feedback please guys
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Location: Casino
Registered: August 2004
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Re: 1JZ-GTE R154 Diff Ratio
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Sun, 23 January 2005 12:06
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Bump
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Registered: June 2002
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Location: Kelmscott, Perth, W.A
Registered: March 2004
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Re: 1JZ-GTE R154 Diff Ratio
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Tue, 09 August 2005 15:37
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Stenno wrote on Wed, 19 January 2005 13:25 | JZA70's ran a rear end ratio of 4.100 - there were no other ratios offered by Toyota.
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auto jza70's equipped with a torsen recieved a 3.91 ratio.
...cant let a thread be burried with false information now can we?
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Location: Melbourne
Registered: October 2003
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Re: 1JZ-GTE R154 Diff Ratio
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Tue, 09 August 2005 18:06
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I'd actually stick with the 3.45's, or if it costs no more 3.55. I guess the question is what do you want out of the 'daily driver' part of it. I'm biased towards pulling long torquey gears, (once owning a 360cu/R154/2.78 diff - The available borg warner ratio's would prob be a choice of:
2.77, 2.92, 3.08, 3.23, 3.45, 3.55, 3.7, 3.9, 4.1, 4.3's
Quite literally somewhere in the middle at 3.45/3.55 I would choose. Any variation lower or higher from there will be how biased you are towards performance/economy. Having a first gear that can allow the engine to load enough to produce boost is what I like, but if you want to zip thru gears in traffic maybe 3.9/4.1?
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