crameur

I got a 1jzgte 240sx With An Lsd 4.10 Rear End ... This 4.10 rear end ratio Makes the r154 tranny Gears Very Short ... And It Really Sucks On The Highway ... Wich Rear End Could I Use To Get More Power On The Highway ??

DDSR240

Best one I can think of is the q45 diff it has the longest ratio

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crameur

Is it Bolt-on ??

g6civcx

There is so much fail in this thread.

What do you want to do? Do you want to stay with an R200? Do you want to go to an R230?

What exactly do you mean by "bolt-in"? In the end everything is nuts and bolts.

Selecting gear ratio is a function of engine torque, gearbox ratio, and application. This is more art than science.

g6civcx

Not true. R200 can be had as low as 3.133. R230 can be as low as 2.95.

4sfed180

most toyotas when equipped with the r154 had the rear end ratios in the mid 300's. the mk3 turbo supra and the soarer are like that.

automatic cars always had a higher geared diff. i have an sc300 for a daily. its a 5spd. the stock diff is a 4.08. auto diff is 4.28 and the sc400 diff is a 3.78. most people that boost the SC with a 1jzgte swap tend to go with a sc400 gearing or even lower with a GS400 gearing which is in the low low 300. i think 3.28.

other wise you run out of gear way to fast and have to work at rowing the gear box just to have a fun drive.

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joefresh

r154 with a 4.3 final drive i hear is very good for response and 5th gear 80mph on the hwy is ~3krpm. check on a supra forum but this is what i plan to run. r154 with 4.3FD. good luck man!

crameur

i need to Drop between 3.00 - 3.50 ... 240Sx Are Not A Heavy Car ... With An 1jz With Tranny In it , It's Only 150 Lbs Weighter than An Sr Setup With The Tranny , Supra Are Heavy Car And Need Higher Ratio To be Fun To drive ... 1jz Engine With the Stock Cams , The Engine Is Floating At 6000 Rpms ... My 1jz 240sx with my 4.10 Gear ratio Is Very Fast on The Start But Not Longer ... It's Reving Too Fast , So I Reach The 6000 Too fast ... Solution ?? Need To Drop The Rpm or a nice set of cams ...

g6civcx

3-3.5 is a wide range.

You didn't answer any of my questions. Do you want an R200 or an R230? Do you want to mix and match parts or do you want a straight bolt-in?

kernel

He want a straight drop-in application, he doesn't want to modify/change his axles or whatever.

I know him and I don't know if there's LSD that could give him more top-end on highway. He want to lower his LSD gear ratio, that's all.

g6civcx

If you want to keep the stock 6-bolt axles, that's going to be tough.

The final drive ratio is determined by the ring and pinion, not the LSD.


"Power" is actually the ability to accelerate the rear wheels. This is determined by torque. You want to maximize torque at the rear wheels at the speed you want.

Show me a torque curve, transmission ratios, and tyre size. Tell me if you want an R200 or R230, and 5-bolt or 6-bolt. Then tell me what speeds you want to have maximum torque and I'll tell you what diff would be the best for you.

kernel

Well, He can get 5-bolts axles, there's no problem with that. It's not rare here. I just wanted to say he doesn't want CUSTOM applications.

I know the LSD doesn't give the final ratio. I wanted to mean the whole differential...

D14

What's your rear tire and wheel size?

g6civcx

You're confusing the hell out of me. Every Nissan R200 diff can be swapped over with different axles and you can reuse the driveshaft on most diffs.

At worst, you will have to swap out the ring and pinion, and depending on the size of the pinion, you may also have to swap out the diff housing or reuse the existing housing. Sometimes you can reuse the output shaft which means you can keep your original axles.


Tell me the things I asked for above and I will tell you the best Nissan ring and pinion, and possibly entire diff if possible, for you to use.

There will be no mods. Just nuts and bolts like rebuilding a diff.

Right now you don't know what you want so nobody can help you.

D14

I think he's just trying to making highway pulls and wants longer gears so he can keep up with Supras or whatever else he's running (Vettes?).

With R154 gearing, the 240SX's stock 4.083 final drive, the 1JZ's 7000 RPM stock redline and a 265/35/18 rear tire (unlikely but for shits and giggles we'll use it) he's hitting 130ish in 4th, shifting to 5th and getting a big drop in revs. At the top of 5th he would see something like 171 mph but it's going to take a while to get there.

If he switched to the S15 ring and pinion it would drop his final drive to 3.692, he'd see a little over 140 in 4th and just under 190 mph in 5th. He's still got that drop in revs and he's still going to take a while to get there but it would put his potential top speed within range of a small single or BPU++++ MKIV Supra.

g6civcx

S15 ring bolts are 13mm while S13 and S14 ring bolts are 12mm. If you want to use an S15 ring inside an S13 or S14 diff you will have to drill out the holes on the diff to 13mm, or use some sort of centering washer.

All of your talk about top speed in 4th and 5th is great, but we don't know what his torque curve looks like. It's meaningless to talk about this without a torque curve.

D14

1JZs have torque curves?

g6civcx

I know you're joking, but you need the torque curve from a dyno plot to select gearing.

Otherwise you're just shooting in the dark.

kernel

hahaha, sorry for the confusing.

He just want to longer his gears. They're short with the final ratio he have with R154 and R200 stock diff.

He don't mind opening the diff and put a new ring and pinion. He just don't want custom applications or have to fabricate custom axles or whatever involved in installing there a diff that's not going there.

About his torque curve, I don't think he'll go soon on dyno.

Find him a ring & pinion that'll let him use his R200 diff and it'll be alright. About the axles, 5 or 6 bolts. Don't matter, but if he can keep his 6 bolts..he would be happy.

His final speed, I don't know..I'll let him answer on this one. same for torque.

g6civcx

Numerically lowest ring and pinion you can fit inside an R200 diff = 3.133. All info can be found here:

http://zilvia.net/f/s-chassis/212090...-end-help.html


Ask me if you have any specific question.

crameur

Exactly , I want To Longer The Gears , There are Too Short With This Gearing ... I got nothing on The Highway and it Suck ... 3.13 Should Be Good ! I Have Read Your Post For the Pathfinder Gearing Swap , it's Very HelpFul , Thanks !!

crameur

Here Is The Dyno Graph For a Stock 1jzgte at 13 psi

R154 Gears Ratio

• First Gear: 3.250:1
• Second Gear: 1.955:1
• Third Gear: 1.310:1
• Fourth Gear: 1.00:1
• Fifth Gear: 0.753:1

My Car Weight Is About 1300 Lbs
My rear End Ratio 4.083
Rear Tires 205/60r15 (255/45zr17 Next Summer )
280 Hp @ 6200 rpm
268 Lb/ft @ 4800 Rpm

It's not a Track Race car , It's My Summer Daily Drive , Just want To make The Car more Fun To Drive ... With This Ratio And Shitty 15 Inch Tires , I'm Running Out Of Gears Very Fast ...

Last Summer , With My Sr20det 240sx , Same Rear End Ratio , I was Able To Make Some Really Great Start , And Also To Keep Up On Corvette On THe Highway ... I would Like To Do About The Same Thing ... Wich Rear End Ratio Are You Suggest me ?? Thanks a lot !

Def

Those gears don't look that different from stock SR gears. I think a 3.1x final drive would make the car a complete dog.


...and no way your car weighs 1300 lbs... haha

g6civcx

Gear selection is dependent on torque also. He has a lot more bottom end torque than a typical SR.

That's kilograms.

crameur

Sorry Dude , My Faults , 1300 Kg

Def

I understand how it influences it, and I could see wanting a bit longer gears for a street car, but a 3.13 will still make that thing a dog. It's only a 2.5L engine off boost.

Didn't Q45's have a 3.6x? I think that'd be a lot more reasonable with how much power you're making.

MrMcgarrett

97-01 Q45's have a 3.69 vlsd that I've heard will bolt in with 5 bolt axles.

g6civcx

Alright, you've done everything I asked so I'll do my best to help you out. Keep in mind though that I am severely limited. The best way to select gear ratio is with onboard telemetry. Everything I'm doing now is just approximating and using my experience to help guide you. It's not 100% perfect but I think it's the best anyone can do for you online.

Let's start with my car as an example. I don't care about the power curve. I'm interested in the torque curve. It only revs to 5100RPM but I'm set up for low speed autocross and short roadcourse so it's perfect.



We're interested in the net torque at the driving wheels. This is on the stock 4.0833 diff. World Class T5 5-speed ratio: 2.95,1.94, 1.34, 1, .63. The wheels rotate 841 revolutions per mile.



I know this chart is strange for a lot of people. This is rear wheel torque in each gear for different wheel speeds. The horizontal axis is MPH, and the vertical axis is ft-lbs of torque. Blue = 1st gear, pink = 2nd, yellow = 3rd, baby blue = 4th, and purple = 5th.

You'll notice that the curves look a lot like the engine's torque curve. The only difference is that the curve at the rear wheels are stretched horizontally and vertically.


With this gearset, the engine revs up way too quickly. Top speeds in each gear:

1 - 29mph
2 - 44mph
3 - 64mph
4 - 85mph
5 - 135mph

The car runs out of steam too much. I'm in 1st and 2nd for less than 1 second each before the engine bumps up against the rev limiter.

g6civcx

The only change is from the stock 4.083 r&p to a Pathfinder 3.133 r&p.



If you pulled up the two charts side by side, you'll start noticing some interesing things.

Top speeds in each gear are now dramatically increased:

1 - 38mph
2 - 57mph
3 - 83mph
4 - 111mph
5 - 176mph

The more important thing is look at the speeds that you want to maximize torque to the rear wheels.

For the type of driving I do, I run max 80-85mph at most, and typically I stay in the 30-50mph range. On the old diff, I constantly have to shift between 2nd and 4th. The torque to the wheel is good but I'm wasting too much time shifting because the engine is revving up against the limter too quickly.

On the new diff, I can pretty much leave it 3rd all the time and not waste time shifting. I'm not putting down as much torque but I'm saving time shifting once or even twice.

You have to find that balance between putting down enough torque to the wheels with mechanical advantage through gearing, and wasting time shifting.

g6civcx

This is your torque curve based on the numbers you gave me: