Longer Gears - Page 2 - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

kodyo · 02-03-2015, 08:54 PM

Quote:

Originally Posted by trsiidno

I dont get how any of this works but i have a guy that sells the diff for that car do i just say i need the m85 differntial and thats it?

M85 is a sticker that should be on the diff itself. If it has fallen off, you can still tell if it's an LSD based on the door jam tag. M98 will also work, but has a higher gear ratio than the M85. See my pic below.

From an IS300 forum:
"How to tell if my IS300 has LSD?
Look at the sticker on your driver door sill/jamb, look for the area that reads "A/TM"
You'll see numbers such as B02A, B02B, B02C
A=no LSD
B,C = LSD"

Here's a great DIY on how to swap it yourself.
http://www.ft86club.com/forums/showthread.php?t=54054

It's a pretty easy swap. I got so good at rebuilding it I could do the whole job in my parking lot in 2 hours (including jacking up the car). But that's after doing it at least 4 times.

I recommend replacing the axle seals when you swap, it can be done without much pain and cost about $10 for the seals (save yourself the headache of a diff leak). Make sure you put multi purpose grease on the axle seals too before install.

Dipstik-sportech · 02-03-2015, 08:57 PM

U can also weigh it, non lsds only weigh 50ish pounds, while the LSD onesr over 90

xwd · 02-04-2015, 09:41 AM

Is there anything special about the non LSD vs the LSD one if you are going to install an aftermarket LSD? I plan on using an OS Giken LSD.

Dipstik-sportech · 02-04-2015, 06:58 PM

You'd be better off going with the open diff then because you'll be paying more for something you aren't going to use. As far as I know there is zero difference between the two other than the LSD itself.

Poodles · 02-04-2015, 11:32 PM

How do you correct the speedo after doing this swap? Just trying to put this info away for future upgrades.

Dipstik-sportech · 02-05-2015, 06:36 AM

The speedo stayed the same, it takes it's reading from the abs sensors not in the trans like most older cars so the gear ratio doesn't affect it.

UtahSleeper · 02-05-2015, 02:07 PM

Pardon my noobness. How much would this slow down a stock car? I am not a fan of the gearing of the trans for my commuting and wondering if getting this diff would yield better MPG's.

I know most people are out for power, but I have other cars for that lol.

Dipstik-sportech · 02-05-2015, 04:27 PM

It might work for a stock car but you might be to low in the rpm band for a stock engine.

UtahSleeper · 02-06-2015, 02:55 PM

Quote:

Originally Posted by Dipstik-sportech

It might work for a stock car but you might be to low in the rpm band for a stock engine.

I guess I would need to figure out what power levels would be needed to make it all feel good. Down the road I plan for the simple EL headers and exhaust, tune and drop in filter with maybe the power blocks. I just hate being at 70 mph and sitting at 3k when just cruising.

AVodka14 · 02-06-2015, 03:06 PM

I feel ya @UtahSleeper. I am going to do the swap simply because of that reason. Needs a lower cruising RPM in 6th gear at 80 mph. I would like to see 2,500 RPM at 80 mph.

slicktop · 02-07-2015, 10:02 AM

Lower RPM doesn't always equal better fuel economy. Your powerband also plays into fuel economy.

If the lower RPM band requires more load on the engine (more throttle = more fuel) to maintain speed, you will lose fuel economy. If your RPM band is slightly higher than that, but reduces that engine load requirement, your fuel economy increases.

Sure higher RPM will have more combustion, however, notice how at lower RPM you have to really floor it compared to the higher RPM (powerband).

If you're going for economy only, keep your FD in there. I'm 100% positive that the engineers designed it properly in that way. I mean, I had mid-30 MPG on a 1500 mile road trip in mine. That's calculated by fuel receipts, not the gauge.

Muaddib · 02-07-2015, 11:13 AM

I usually cruise at around 3k rpm in 6th and i can barely get 30mpg.

Malt · 02-07-2015, 11:24 AM

Quote:

Originally Posted by Muaddib

I usually cruise at around 3k rpm in 6th and i can barely get 30mpg.

How you drive while you are not cruising has just as much effect on total MPG. Air resistance increases at the square of speed so traveling faster nets increasingly lower MPG. Jack rabbiting starts and stops also kills mpg.

Muaddib · 02-07-2015, 11:59 AM

My commute is 220km. I just set it on cruise control. So i am not flooring it like a retard.

02-03-2015, 08:57 PM	#16
Dipstik-sportech Senior Member Join Date: Oct 2012 Drives: 2013 BRZ satin white pearl sportech Location: Thunder Bay Ontario Canada Posts: 1,813 Thanks: 842 Thanked 911 Times in 576 Posts Mentioned: 43 Post(s)	U can also weigh it, non lsds only weigh 50ish pounds, while the LSD onesr over 90 __________________ 2013 SWP BRZ sportech. 11.11sec@129.01mph, 511whp on e70. FullBlown base kit, FullBlown built 9.5:1 engine, GTX3076R GEN2 turbo, 1700cc Bosch injectors, FullBlown flex fuel kit, FullBlown radiator and oil cooler, FullBlown custom 3" dual exit exhaust, act xtreme clutch, whiteline diff and subframe inserts, BC Racing coilovers, hotchkiss 18mm rear sway, is300 3.73 differential ... Never finished

02-04-2015, 06:58 PM	#18
Dipstik-sportech Senior Member Join Date: Oct 2012 Drives: 2013 BRZ satin white pearl sportech Location: Thunder Bay Ontario Canada Posts: 1,813 Thanks: 842 Thanked 911 Times in 576 Posts Mentioned: 43 Post(s)	You'd be better off going with the open diff then because you'll be paying more for something you aren't going to use. As far as I know there is zero difference between the two other than the LSD itself. __________________ 2013 SWP BRZ sportech. 11.11sec@129.01mph, 511whp on e70. FullBlown base kit, FullBlown built 9.5:1 engine, GTX3076R GEN2 turbo, 1700cc Bosch injectors, FullBlown flex fuel kit, FullBlown radiator and oil cooler, FullBlown custom 3" dual exit exhaust, act xtreme clutch, whiteline diff and subframe inserts, BC Racing coilovers, hotchkiss 18mm rear sway, is300 3.73 differential ... Never finished

02-05-2015, 06:36 AM	#20
Dipstik-sportech Senior Member Join Date: Oct 2012 Drives: 2013 BRZ satin white pearl sportech Location: Thunder Bay Ontario Canada Posts: 1,813 Thanks: 842 Thanked 911 Times in 576 Posts Mentioned: 43 Post(s)	The speedo stayed the same, it takes it's reading from the abs sensors not in the trans like most older cars so the gear ratio doesn't affect it. __________________ 2013 SWP BRZ sportech. 11.11sec@129.01mph, 511whp on e70. FullBlown base kit, FullBlown built 9.5:1 engine, GTX3076R GEN2 turbo, 1700cc Bosch injectors, FullBlown flex fuel kit, FullBlown radiator and oil cooler, FullBlown custom 3" dual exit exhaust, act xtreme clutch, whiteline diff and subframe inserts, BC Racing coilovers, hotchkiss 18mm rear sway, is300 3.73 differential ... Never finished

02-05-2015, 04:27 PM	#22
Dipstik-sportech Senior Member Join Date: Oct 2012 Drives: 2013 BRZ satin white pearl sportech Location: Thunder Bay Ontario Canada Posts: 1,813 Thanks: 842 Thanked 911 Times in 576 Posts Mentioned: 43 Post(s)	It might work for a stock car but you might be to low in the rpm band for a stock engine. __________________ 2013 SWP BRZ sportech. 11.11sec@129.01mph, 511whp on e70. FullBlown base kit, FullBlown built 9.5:1 engine, GTX3076R GEN2 turbo, 1700cc Bosch injectors, FullBlown flex fuel kit, FullBlown radiator and oil cooler, FullBlown custom 3" dual exit exhaust, act xtreme clutch, whiteline diff and subframe inserts, BC Racing coilovers, hotchkiss 18mm rear sway, is300 3.73 differential ... Never finished

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02-04-2015, 09:41 AM	#17
xwd Senior Member Join Date: Feb 2012 Drives: 2013 DGM Subaru BRZ (Subie #9) Location: ATL, US Posts: 2,667 Thanks: 123 Thanked 861 Times in 552 Posts Mentioned: 32 Post(s)	Is there anything special about the non LSD vs the LSD one if you are going to install an aftermarket LSD? I plan on using an OS Giken LSD.

02-04-2015, 11:32 PM	#19
Poodles Senior Member Join Date: Oct 2013 Drives: 2015 Series.Blue Location: Fort Worth, TX Posts: 1,781 Thanks: 88 Thanked 781 Times in 481 Posts Mentioned: 16 Post(s)	How do you correct the speedo after doing this swap? Just trying to put this info away for future upgrades.

02-05-2015, 02:07 PM	#21
UtahSleeper Senior Member Join Date: Sep 2014 Drives: 80 Corolla 88 Celica Alltrac 13 FRS Location: Magna, UT USA Posts: 120 Thanks: 82 Thanked 53 Times in 33 Posts Mentioned: 3 Post(s)	Pardon my noobness. How much would this slow down a stock car? I am not a fan of the gearing of the trans for my commuting and wondering if getting this diff would yield better MPG's. I know most people are out for power, but I have other cars for that lol.

02-06-2015, 03:06 PM	#24
AVodka14 Senior Member Join Date: Aug 2012 Drives: 2013 Raven FRS MT Location: KY Posts: 857 Thanks: 351 Thanked 302 Times in 185 Posts Mentioned: 4 Post(s)	I feel ya @UtahSleeper. I am going to do the swap simply because of that reason. Needs a lower cruising RPM in 6th gear at 80 mph. I would like to see 2,500 RPM at 80 mph.

02-07-2015, 10:02 AM	#25
slicktop Senior Member Join Date: Mar 2013 Drives: 2013 Raven FRS 2JZ-GTE/V160 swapped Location: Hampton, VA Posts: 960 Thanks: 376 Thanked 623 Times in 315 Posts Mentioned: 18 Post(s)	Lower RPM doesn't always equal better fuel economy. Your powerband also plays into fuel economy. If the lower RPM band requires more load on the engine (more throttle = more fuel) to maintain speed, you will lose fuel economy. If your RPM band is slightly higher than that, but reduces that engine load requirement, your fuel economy increases. Sure higher RPM will have more combustion, however, notice how at lower RPM you have to really floor it compared to the higher RPM (powerband). If you're going for economy only, keep your FD in there. I'm 100% positive that the engineers designed it properly in that way. I mean, I had mid-30 MPG on a 1500 mile road trip in mine. That's calculated by fuel receipts, not the gauge.

02-07-2015, 11:13 AM	#26
Muaddib Mentat Join Date: Jun 2013 Drives: 2013 Scion FRS 6MT Location: Vancouver Posts: 542 Thanks: 666 Thanked 358 Times in 198 Posts Mentioned: 4 Post(s)	I usually cruise at around 3k rpm in 6th and i can barely get 30mpg.

02-07-2015, 11:59 AM	#28
Muaddib Mentat Join Date: Jun 2013 Drives: 2013 Scion FRS 6MT Location: Vancouver Posts: 542 Thanks: 666 Thanked 358 Times in 198 Posts Mentioned: 4 Post(s)	My commute is 220km. I just set it on cruise control. So i am not flooring it like a retard.

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