1J, Big Single, What gears to use??

[Jayhall]

So, ive just got my car back and running. I got in on the Kaaz gb, but im wondering what everyones opinions are on the differant gearing avalable. I want to choose the right gears before i put my 2way together.

My set up is a 1JZ-GTE with a SP67GT running an 4.30 LSD. What gears do you like and why? Also, what kind of driving do you mostly do, city, highway? Are you finding that with a taller gear your hitting your max boost quicker than with a shorter? Any and all input is apriciated

 

[suprahero]

I had 3.73 in my car originally, but I switched to the 3.91 because the 1jz loved to rev so much. I think it ran better with this gear over the 3.73's, but I don't have anything to prove it other than my best with the 3.73's was a 8.37 and my best eigth mile time with the 3.91's was a 8.24.......I'm not thinking about going back to the 3.73 because of gas priceing and I also have the 2jz block now. I think if you're used to the 4.3's you'll love the 3.91. Good luck.

 

[tissimo]

3.73s.. with my single 1jz, it went through the gears fast all ready, I couldn't imagine anything less (was reving to 7600 rpm too)

 

[86_sports_1jz]

i'm at about 400 whp on the 4.30 lsd, my gears seem really short and i hit 5th gear in no time. with the 4.30 on 19 psi i hit full boost around 5k, i think with a longer lsd i would see full spool earlier. i want a 3.73 or 3.91 because i want more power so i have better top end and so each individual gear don't seem so short. i would say from my experience if you are around 4-500 whp i would go with a 3.91 but if you are 600+ i would go with the 3.73, as for my daily driving i think i would like the 4.30 better than the 3.91 or 3.73 because my car has no low end

 

[becauseican]

Daryl, I liked the 3.90 gears the best, I have the 3.73 now, and its great on the freeway but I liked the 3.90's better, esspecially at the track. I was road tuning on the hwy tonight and did 220 KMH in 4th gear with another 1000 rpm to go.......I think I may be able to hit 300 kmh!!!!..... Anyways, Your 4.30's are to short for your setup....you will probably see an inprovement in spool with the taller gears as it loads the car more. Next spring i will be installing some 4.10's that i got from my 1jz clip, it should be the perfect ratio from drag racing.

Randy

 

[OneJSupra]

I will say it again if you want to go fast from the start 4.30 will get you there. If you do a lot of highway driving I will get a 3.73. Personally, I like my 4.30. With my T61 turbo I can really punch it like mad max ... :naughty:

 

[annoyingrob]

My 4.3s sure do make my 1.5JZ accelerate pretty damn fast, but if I'm not running my slicks, all I get is wheelspin under 60mph. I bet I would actually be faster on the street with 3.90 gears just due to the traction.

The 4.3 is poo on the highway. I'm always above 3000rpm. I mean, the gas mileage isn't bad, and it's instant power when I hit the gas, but I want it lower just so I'm not tempted to step in it, and start going crazy fast.

 

[viperkillertt]

Thanks for the insight guys!
I am running 3.73 on the 1j. I have been very interested in what it feels like with the 4.3, because it is the stock diff for the 1jz supra.

 

[tissimo]

Thanks for the insight guys!
I am running 3.73 on the 1j. I have been very interested in what it feels like with the 4.3. That is the stock diff for the 1j.

Stock diff is a 4.10 on a jza70 car.

Theres nothing like going 115mph in 3rd gear though, or dropping it in 2nd gear while cruising at 70mph :evil2:

 

[jz*supra]

I would avoid the 4.10 JZA70 LSD. The gears have a huge tendency to go flying through rear casing. They Simply are not good for launching. you want a clutch style LSD if you plan on drag racing. I blew my 4.10 up after 2 passes at the track. Launching from 4000 rpm on street tires.

My 4.3 LSD gained me 0.5 in the 1/4 mile over the 3.71. The 4.3 will give you amazing throttle response. My car does 118 MPH trap speed at about 6300rpm in 4th (275/40/17 tires).

A 4.3 WILL accelerate faster than a 4.1, 3.9, or 3.73. Assuming your car hooks up but thats a totaly different issue then.

Also don't get fooled by "hitting max boost quicker". You hit max boost quicker because you are not accelerating. It's the same reason a big turbo car does not see full boost in first gear. You must remember boost does NOT mean more power. Boost is the inefficency of your motor to use the turbos air. I'm not the guy to be explaining this, so to justify myself http://www.supramania.com/forums/showpost.php?p=1049464&postcount=22,
If simply swapping a LSD makes you acheive boost at lower rpm it is because you have reduced the overall efficency of the car.

 

[Blind Drifter]

my 4.30 1j is fun but it sucks on the high way. anything above 65 and its singing....

Anybody up for an even trade on diffs?

 

[OneJSupra]

my 4.30 1j is fun but it sucks on the high way. anything above 65 and its singing....

Anybody up for an even trade on diffs?

nah it ain't that bad ... lol

 

[Dylan JZ]

nah it ain't that bad ... lol

it helps to get that slow car moving.. :biglaugh:

 

[Bigzavs]

Ive had a 4.30 lsd and a 3.73 lsd on a 61mm setup, there was a huge difference between the two, 4.30s burned the tires into 4th but the 3.73s seemed a lil slower, but the gears lasted much longer

ive got a 72mm now and i doubt i could make any useable boost in 1st on it. id say 3.73s or 3.91s on any big single setup

 

[JustinGotA1j]

I have a JZA70 and blew my 4.10 rear end the first time at the track. I'll admit it was sweet but still pissed me off. I have since swapped in a 3.73 and a 3.91 and have to say the 3.9 is by far my favorite. And I'm not shifting right before the end of the quarter either.

 

[Gritz]

430's seems like a lot...but i guess if you are heavy than it helps..you guys must be turning 4 grands going 60mph with 430's..

 

[86_sports_1jz]

going 60 mph i'm around 2200 rpms with the 4.30 lsd. hey guys, what is the top speed with the 3.91 lsd? 170 mph mayb? i'm thinking about changing to the 3.91 or 3.73 but i didn't decide which one yet so just wondering cuz with the 4.30 i top out around 155 mph and i don't like that

 

[albert74]

What do 89 AT turbo 7m cars come with? I have no idea what i'm running.

 

[viperkillertt]

What do 89 AT turbo 7m cars come with? I have no idea what i'm running.

You can read the inner door pannel on the drivers side door. It tells you everything. There is a code reader somewhere online that tells you what the codes mean. It tells you the original engine, tranny, diff, color and other things. Also, i am guessing it will be a 3.73 like mine. Mine was originally a at turbo.

 

[albert74]

You can read the inner door pannel on the drivers side door. It tells you everything. There is a code reader somewhere online that tells you what the codes mean. It tells you the original engine, tranny, diff, color and other things. Also, i am guessing it will be a 3.73 like mine. Mine was originally a at turbo.

Cool thanks for the info, i'll check on that today.