6-speed with KA-T?

[Edub1]

The stock 240 in the US has a 4.083 rear end.

[Chezedik]

I thought it was 4.086, but that is just splitting hairs. I thought I was told at some point that a sixth gear can be added. Maybe I will call a trans shop now while mine is out. I have a few bucks to spend if it will get me a sixth gear.

[TheOne]

49/12 = 4.083636 (stock ratio) <<from ka24development.com(orion)

as for addin a 6th gear to the stock trans, wouldn't that be the same as the S15 trans?(they added a gear to a stock 5 sp, thus makin the other gears weaker because of makin'em smaller)

any of ya looked @ OS GIKEN, might be expensive but they have some stuff for the sr20 trans which i believe is the same as the ka.

[Edub1]

Anyone know of a formula or calculator that can determine acceleration for different gearing? I'm sure it can be calculated if one were to take the time.

Anyway, many cars in the range of 300HP use taller final drives. Sure, you will lose some torque in the low RPM range but you will also prolong your shift a little bit, thus getting it back up top.

Consider that with a Q45 rear (+15%), our 1st gear would streatch from about 25MPH to about 29MPH and would give the turbo a bit longer to do its thing.

For spirited around town driving, I'm betting you'll have more torque (and more fun) being in the top of first than in the bottom of second. Or, the top of 2nd Vs. the bottom of 3rd, etc...

If I had a Q45 rear end lying arround I would not hesitate to slap it on and try it.

[Chezedik]

Plus, in theory, you are talking about an automatic 15% increase in mileage (of course, reality is a mother ****er).

[hannibal]

Greg currently has a 4.36 rear, so the J30 is 10% taller. The stock 4.083 is 6% taller than his 4.36...

[hannibal]

There are two common types of T56's (Cobras might use a thrid type)...

Viper/94+ F-body T56 (rated at 450lbs-ft)1st: 2.66:1 2nd: 1.78:1 3rd: 1.30:1 4th: 1.00:1 5th: 0.74:1 6th: 0.50:1

93 Camaro (M29) and C5 Z06 T56 (rated at 400lbs-ft)1st: 2.97:1 2nd: 2.07:1 3rd: 1.43:1 4th: 1.00:1 5th: 0.80:1 6th: 0.62:1

The 93 Camaro (M28) had a 3.36 1st and 1.35 3rd gear. All other ratios are the same as the M29 transmission. But these rare M28's are only rated at 360lbs-ft of torque, though all these T56's seem quite underrated. The C5 Z06 made nearly 400lbs-ft stock I think and the trannys have survived in modified Z06.

Ive read about a company called D&D Performance in a few Mustang magazines. They make T56's to adapt to earlier Mustangs. They might be able to build you a T56 bellhousing to bolt up to the KA.

[nismofly]

any of ya looked @ OS GIKEN, might be expensive but they have some stuff for the sr20 trans which i believe is the same as the ka.

those are close ratio road racing gears, that would make his problem even worse

but it sure would haul with them

[PapaSmurf2k3]

Plus, in theory, you are talking about an automatic 15% increase in mileage (of course, reality is a mother ****er).

Thats not true, just because you are taching higher doesnt mean you are burning that much more fuel (linearly anyway). Fuel economy is based on power output, efficiency, and forces acting on the car. your power output (based on throttle position and RPMs, higher throttle/ lower rpms, and lower throttle/ higher rpms net the same power) and forces acting on the car will be the same (uniform linear motion... ie, forces cancel out= no accel) so the only thing effecting it would be the efficiency... which is probably the smallest factor (yes it is slightly more efficient at lower RPMs, but not much)

actual fuel savings are probably in the 1-5 % range

[Chezedik]

Good contribution, I should've thought a little more.

[Redline240]

I dunno how big it is but what about the 350z and g35 transmission? i mean there's a lot of 6spd trannys out there, find one with the gearing you desire and get an adapter plate and start making it work, lol...

[Edub1]

I smell a group buy on the horrizon.

Perhaps a NICO member is a machinist and can make an adapter.

First, we need a good trans to start with. Is there a 6 speed tarns that can be had at a reasonable price?

[Chezedik]

I would think Camaro SS is going to be easiest to find. There have to be hundreds of punk kids who have wrecked those by now, but then again, the Z has been popular...

[Tulsa_S-13]

Anyone know of a formula or calculator that can determine acceleration for different gearing? I'm sure it can be calculated if one were to take the time.

Anyway, many cars in the range of 300HP use taller final drives. Sure, you will lose some torque in the low RPM range but you will also prolong your shift a little bit, thus getting it back up top.

Consider that with a Q45 rear (+15%), our 1st gear would streatch from about 25MPH to about 29MPH and would give the turbo a bit longer to do its thing.

For spirited around town driving, I'm betting you'll have more torque (and more fun) being in the top of first than in the bottom of second. Or, the top of 2nd Vs. the bottom of 3rd, etc...

If I had a Q45 rear end lying arround I would not hesitate to slap it on and try it.

This is for a 240sx 5spd with 15inch wheel, 205mm 50 series with the stock 4.08 final drive with a redline of 6500rpm

1st: 32.93mph2nd: 57.49mph3rd: 83.69mph4th: 109.35mph5th: 144.07mph

S13 4.36 final drive (180sx), 205/50/15 tire

1st: 30.81mph2nd: 53.80mph3rd: 78.23mph4th: 102.32mph5th: 134.81mph

S13 3.916 final drive (J30), 205/50/15

1st: 34.30mph2nd: 59.90mph3rd: 87.10mph4th: 113.93mph5th: 150.10mph

Dang, ok well I just realized that when tried to find my radius of my tire I accidentally took 205 and divided it by .50 instead on my actual tire series (.60) so oh well. These should be close enough numbers.

I actually posted this awhile back....and you have to keep in mind this just gives you an idea of what to expect, its certainly not perfect..

Hmmmm..... Ok keep in mind you need to know that Circumference is C=2piRadius And to get your sidewall height its simply your tire width times tire series (Ex. 215mm*60% or .60)

RL:Redline rpmFD:Final DriveTG:Transmission gearingTW:Tire Width<---- millimeters You convert this in the formula using 25.4TS: Tire SeriesR:Rim radius (Ex. 15inch rim, 7.5" radius)<-----InchesWRPM: Wheel Rotations per minute

So, RL/FD/TG=WRPM then,WRPM*2pi(((TWxTS)/25.4)+R)=_ _ _ _ _ in/min so to convert that to mph you take your _ _ _ _ _ in/min. x 60 is _ _ _ _ _ _ _ in./hour divided by 12 is _ _ _ _ _ _ ft/hr divided by 5280 converts that to MPH

[Edub1]

Thanks for taking the time to post all that.

I'm wondering about how this would affect acceleration, not max speed. So, the answer would be in meters per second squared.

The idea would be to come up with an equation where X = torque and Y = RPM and then plot a graph using each rear end ratio for comparison. This could even be done for each of the 5 gears.

An extra cool feature would be to see all 5 gears on 1 graph to see where the torque curvs cross.

Perhaps someone wants to work on such a project. In fact, I'm going to start a new post.

[C-Kwik]

its actually http://www.quaife.co.uk/catalogue/page55.htm

and with dog engagement type transmissions, expect a really harsh engagement and lots of noise.

But, you'ld have clutchless shifting! weeee!

[GlacierFreeze]

Tweak your lower rpm fuel and timing maps for better fuel mileage.

edit... I've read on another forum that certain SR guys, with tuned ECUs, getting 30+ MPG.

[tryiian]

SR20 = 2.0KA24 = 2.4

That ain`t helpin, y` know.

[xekushnr]

i may be wrong, and it could have even been mentioned before, but i think any 6-speed options you have will require you to swap bellhousings or fab up your own to mount the transmission.

[Chezedik]

Yes, that was posted.

[GlacierFreeze]

SR20 = 2.0KA24 = 2.4

That ain`t helpin, y` know.

Just means you need a bigger turbo so you won't see spool so early hahaha.

[Edub1]

Taller 5th gear - here you go.

http://www.nismoparts.com/catalog/?section=241

[sultan]

that's shorter, not taller.

[sxseguy]

http://home.comcast.net/~amyers35/GearRatios.xls

[Edub1]

I began to question that after posting. Oh well.