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I supported Toymods
Location:
Perth
Registered:
May 2002
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 Which Diff Ratio is better?
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Fri, 25 October 2002 12:04
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Ok guys, I've been thinking, I would've thought a 4.1 diff would be suited to a 1GGTE with a W58 manual box giving good acceleration through the gears and still a nice overdriven 5th with the W58.
Whats peoples opinions, what would be better?
 A 4.1 from an auto
A 3.9 from a manual
A 3.7 from an import Supra
or even go the other extreme
A 4.3 from a LiteAce
Which one do you guys think would suit this engine/gearbox combination better?
Thanks,
Nathan
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Banned member
Location:
Brisbane
Registered:
May 2002
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Re: Which Diff Ratio is better?
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Fri, 25 October 2002 12:18
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3.9 id say if it was hell worked maybe 4.3 but thats just my opinion depends if you want off the start go or hell top speed
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Location:
Brisbane
Registered:
May 2002
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Re: Which Diff Ratio is better?
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Fri, 25 October 2002 12:22
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A 4.1 seemed to work nicely with my 6M... a 1G is going to be more rev-happy and with less bottom-end response, so I wouldn't go any taller than that.
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Re: Which Diff Ratio is better?
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Fri, 25 October 2002 12:29
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By taller you mean not going to something like a 3.9? Sorry, I'm in dumb mode 
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Location:
c'town, NSW
Registered:
May 2002
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Re: Which Diff Ratio is better?
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Fri, 25 October 2002 12:58
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3.9
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Re: Which Diff Ratio is better?
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Sat, 26 October 2002 01:37
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*Bump*
Looking for a bigger sample 
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Location:
Perth WA
Registered:
May 2002
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Re: Which Diff Ratio is better?
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Sat, 26 October 2002 10:01
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I'll go for a 4.3... but that's just my 2 cents.... 
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Re: Which Diff Ratio is better?
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Sat, 26 October 2002 12:49
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Saw your car again at the Auto Salon, looking good dude
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Location:
Perth WA
Registered:
May 2002
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Re: Which Diff Ratio is better?
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Mon, 28 October 2002 10:45
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Thanks Nathan. Have I actually met you in person? Don't think I have...
Have you sorta decided on what you are after? 3.9? I reckon get the one that is easiest to get....
Cheers.
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Location:
Sydney
Registered:
May 2002
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Re: Which Diff Ratio is better?
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Mon, 28 October 2002 11:06
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3.9 gives you a top speed of about 240ish with a w58.. hitting the rev limiter in 5th.. just my 2 cents.
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Location:
Sydney
Registered:
May 2002
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Re: Which Diff Ratio is better?
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Mon, 28 October 2002 11:49
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The way I like to think of ratios is this..
First look at your powerband and torque curve, the wider your powerband and curve is then the taller gearing you can go without it driving like crap, but if your car has a very narrow powerband then you want to go as short gearing as posible, but not so short that you are doing 200km/hr in 5th @ 7000rpm.
Have a look at the compound ratios between different diff ratios and see how far they are apart...from my memory the W58 has very wide spread ratios so a taller diff would be pretty crappy to drive around town even with a 1GGTE in it...its only a 2L motor...not a V8...with 300+Nm @ 2000rpm
Id honestly say to stick with a 4.1, but a 3.9would be nicer to cruise on the highway with, just slurp more fuel around town...
And remember the taller the overall gearing then the more load you are placing on the driveline components, just a thought.
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Re: Which Diff Ratio is better?
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Mon, 28 October 2002 11:49
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Nah, I haven't met you in person, I make a point of going and looking at your car every time there is an Auto Salon or something. You had the same dyno graph you did last time didn't you?
As for the diff, I'm undecided. kevz0r has his 5MGTE Supra, that was originally an auto, hence 4.1 diff. He is unhappy with the revs it pulls on the freeway (he has W57) so hes got a 3.7 diff from an import wreck that he's going to put into his car. I was thinking about grabbing his 4.1, thought it would match the 1G pretty well.
As for the 240kph, I dont think there is anywhere I will really use that so...
Just read your message Mike, the W58 has fairly tight spacing between the gears, just a nice overdriven 5th. Its not going to bother me if the car sits near 3000rpm on the freeway, my Celica does this anyway with its W57 and 3.9 combo. Its not as if its a V8 so its not going to be be bad on fuel like that
[Updated on: Mon, 28 October 2002 11:51]
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Location:
newcastle
Registered:
June 2002
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Re: Which Diff Ratio is better?
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Mon, 28 October 2002 12:57
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The choice of diff ratio is an important one but you cant even begin the ratio decision without first looking at tyre size.this can make as much effect on the final drive ratio as a diff change itself .
comparing a 3.9 and a 4.11 is a MINOR comparison and VERY LITTLE difference will be noitced .wihtout knowing the charactarisitics of the Engine first it is Impossible to say that for example 4.11 is better .at 5000 rpm there will only be a difference of 4 kph in second gear.(i believe that peak torque is around 4800 rpm)
Often turbo engine's respond well to load so a ratio such as 3.9 can be beneficial .however if acceleraton is the name of the game and having driven a 1ggte and felt the peaky power a 4.11 or 4.3 may be a clear choice .Depending on car weight and tyre size
Having said that all turbo cars love autos .the stall in an auto reduces lag and torque is ultilised more effeciently .An auto will be prove quicker ( as it does with 1jzgte) BUT a diff ratio
assuming say 215/50/16 tyres would be best around 3.7 i believe a 3.8 hiace LSD is available
EVEN with 4.11 gears my 1ggze auto was as quick as other manual 1ggze with same power .2nd gear was WAAAYYYYY to long and 3.77 is the factory diff ratio .The only thing that saved the ze was the instant blower power .
The auto was fitted with the 1ggte auto torque converter that had a 2000 rpm stall .MAUNALS feel quicker
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Re: Which Diff Ratio is better?
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Mon, 28 October 2002 13:05
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I love my manual too much Its going to initially have 15" x 6.5" Rays Engineering rims with 215/60R15 tyres.
Later on it will have Speedy Holotype R's in 16" x 7" with 225/45 or 50R16 tyres.
The car is a 1981 Celica XX (Mk2 Supra) and the goal weight is about 1250kg once I've finished.
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Location:
Finland
Registered:
June 2002
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Re: Which Diff Ratio is better?
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Mon, 28 October 2002 22:22
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How about 'all out acceleration' with really long overdrive?
That would mean rally car like gear ratios from 1st through to 4th gear. 5th gear would be for highway only, just like stock.
Take a really high rear ratio, between 4,5 to 5,0 . Go to Bill Sherwood's homepages and have a look at gearbox modding guidelines. Strip your tranny, have input/lay shaft gearing machined to different ratio. This will net you almost rally car like close ratio transmission from 1st to 4th gear. 5th gear automatically moves way up. From top of my head, something like 25% altered ratio would do the job.
I reckon it would be quite enough if your 4th gear top speed would be around 150-160kmh. Not that many traffic light grand prix go beyond those speeds.
Only handicap this mod has is the gap in ratios between 4th and 5th gears. So we'd suffer greatly in acceleration between 150 to 200kmh area. Who has points left in their driving licence to go that fast anyways?
-A.
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Re: Which Diff Ratio is better?
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Tue, 29 October 2002 08:23
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Thanks for the replies. I think the 4.1 diff and the W58 would be a nice match for the revvy nature of the 1GGTE in my car
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