1Jz 240sx Rear End Ratio Advice

[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

[crameur]

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

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]

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

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.

[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]

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

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

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.

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]

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

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.

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]

If he switched to the S15 ring and pinion it would drop his final drive to 3.692

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]

1JZs have torque curves?

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/212090-240-gearing-rear-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]

http://img.photobucket.com/albums/v605/crameur/walterE30_1JZ.jpg

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]

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.

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

no way your car weighs 1300 lbs

That's kilograms.

[crameur]

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

Sorry Dude , My Faults , 1300 Kg :Ownedd:

[Def]

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


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.

http://img92.imageshack.us/img92/8962/dynoqp3.th.jpg (http://img92.imageshack.us/my.php?image=dynoqp3.jpg)

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.

http://img116.imageshack.us/img116/8222/thruststockdiffaf9.th.jpg (http://img116.imageshack.us/my.php?image=thruststockdiffaf9.jpg)

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.

http://img522.imageshack.us/img522/2907/thrustpathfinderda9.th.jpg (http://img522.imageshack.us/my.php?image=thrustpathfinderda9.jpg)

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:

http://img247.imageshack.us/img247/2334/1jztorquedl0.th.jpg (http://img247.imageshack.us/my.php?image=1jztorquedl0.jpg)

[D14]

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

I agree with Def on all points.

Your gearing is identical to a JZA70 with the exception of final drive, the Supra's have a 4.10, you've got a 4.083. Minute difference. It's not gearing that's limiting you, it's power, revs and tire size. 95% of the "car people" I hang out with are MKIII and MKIV Supra owners, I know from first hand experience that you're not going to get very far with Supras, Vettes or whatever else on a stock twin 1JZ. Put the 17" wheels on (that will net about a 1.25" gain in tire height, slightly lengthening your ratios) and start saving for a single upgrade and supporting mods, your final drive is fine.

And don't switch to a 3.1 final drive, your car will fall flat on it's face, you don't have that kind of torque, it's a 1JZ, not an LS2. If you do decide to switch, don't go lower than 3.692.

[Def]

Exactly my point.

If you want gears that are a little longer, a J30 LSD would probably be a good compromise at a 3.9x. That plus bigger tires(which will make a big difference) will go a long way towards making your car feel like it's holding gears for longer.

[g6civcx]

This is your rear wheel curves as your car currently sits.

http://img167.imageshack.us/img167/6269/1jzthruststockcr1.th.jpg (http://img167.imageshack.us/my.php?image=1jzthruststockcr1.jpg)

Top speeds in gear:

1 - 35mph
2 - 58mph
3 - 87mph
4 - 114mph
5 - 150mph

This is what I notice. From 60 you would use 3rd gear, but 3rd gear runs out pretty quickly at 87mph. 4th gear runs out at 114mph. The car probably feels out of breath in 3rd too quickly.

[g6civcx]

This is what it looks like if you went with 3.133, which is the numerically lowest OEM gear you put into an R200.

http://img246.imageshack.us/img246/7223/1jzthrustpathfinderxl7.th.jpg (http://img246.imageshack.us/my.php?image=1jzthrustpathfinderxl7.jpg)

This is what I notice.

Top speeds

1 - 46mph
2 - 76mph
3 - 113mph
4 - 148mph
5 - 197mph

If you put this graph next to the graph on the stock diff, you'll start noticing a couple of interesting thing.

1st and 2nd gear may be way too long to be usable on the street. 3rd gear will give you a good stretch all the way up into the 110s whereas before you were running out at about 85.
4th will get you to almost 150 and I have a feeling 5th will be pretty much useless.

In my opinion, I'm not sure if this gearset is right for you unless you plan on throwing a bunch more boost at your engine to bring up your engine torque.

3.133 is actually a little too low even for my V8, but it gives me room to throw more torque at the engine and won't have to run out of gear.

Let me dig around and see if I can recommend something for you.

[Def]

This sounds like a good case to use a 275/40-17 and a slightly longer diff then.

A 3.91 J30 diff is about 4.4% longer, and a 275/40-17 is 4.0% larger than your current tire.

So that would give you 8.5% longer gears total with those two changes.

Giving you speeds of:

1 - 38 mph
2 - 63
3 - 94
4 - 124
5 - 163

Doesn't sound like bad gearing to me. Hell, sounds better than the long gears you get with a 4.08 on an SR box. You'd also have some tire to put down some speed. Don't go with a 255/45-17, the sidewall would look absolutely ridiculous. Even Mustang guys don't use that much sidewall on a 17" wheel.

[g6civcx]

These are possible candidates for ring and pinion into an R200 diff available from Nissan dealers:

3.357 from 05-07 Pathfinder 4WD, and 08 Pathfinder 4WD, but be careful because the 08 4WD also comes with R230 diff

3.357 from 350Z autos

3.538 from 350Z manuals


Other than these, you can find an S15 diff, or look towards Infiniti. You can also find some ring and pinions on ebay from old stock for 280Z and 300ZX.

[D14]

Or he could keep the 4.083, raise the limiter to 8,000 RPM (On your 255/45/17):

1st - 46 mph
2nd - 77
3rd - 115
4th - 151
5th - 201

3.91 might still be a little tall.

EDIT - Forgot to reset the calculator :squint:[/quote]

But now that I think about it, unless he's running some monster single that takes forever to spool he's not making much power at 7 or 8,000 RPM anyhow. He'd probably be better off with the 3.91 than trying to hit 8,000 RPM in 3rd with a 4.083. :rofl: Me = FAIL.

Yeah, give the 3.91 a shot. Should give you what you're looking for and keep you in your power band.

[g6civcx]

This sounds like a good case to use a 275/40-17 and a slightly longer diff then.

A 3.91 J30 diff is about 4.4% longer, and a 275/40-17 is 4.0% larger than your current tire.

So that would give you 8.5% longer gears total with those two changes.

Giving you speeds of:

1 - 38 mph
2 - 63
3 - 94
4 - 124
5 - 163

Doesn't sound like bad gearing to me. Hell, sounds better than the long gears you get with a 4.08 on an SR box. You'd also have some tire to put down some speed. Don't go with a 255/45-17, the sidewall would look absolutely ridiculous. Even Mustang guys don't use that much sidewall on a 17" wheel.

I tend to agree. Make one change at a time. Pick your rubber first then look at how the car responds.

I wouldn't go much lower than a 3.5-3.6 at most for your current setup.

[crameur]

Ok !! I will Switch The Tires First To see How the car will Respond ... I Think i will install a new set Of Cams Too , Maybe Usdm 2jz Cams Modded To Fit 1jz ... This Will Help My powerband Too !!! 14 Psi Of boost And I will see After If it's Good Or Not ! I would Like To Thanks EveryBody Who Take Time To Help Me , It's very Appreciated !!!

[D14]

My not-so-expert opinion:

Keep your final drive stock for right now, get rid of the 15s, put the 17s with 255/45/17s on and when you upgrade to a single turbo, look at doing the J30 diff with the 3.91.

[crameur]

I want To Keep The Stocks TwinsThings i Will Do This Winter

- Put The 17 Inch On the Car
- Upgrading Injectors For jdm 2jz 440cc
- Upgrading Cams For Usdm 2jz Cams
- Map-Ecu Fuel Management
- 80 Or 100 Shots Of Nitrous
- 14 - 16 Psi Of Boost

it Should Be Good , I'll See How the Car Will respond and Get a New Diff If I got the same Problem ...

[czarboo]

Hi there,

Sorry about the weird thread revival, but this seemed like a good place to post my questions.

Do any of you have any experience regarding the torque capacity of the standard 6-bolt axles? Specifically, are any of you running over 500ft/lb through them? How much are you guys running through them, before they become broken bits?

Also, are there different versions of these, that may have different capacities for acceptable torque loads?

Thanks!