TC and LSD questions
Thread Starter
Joined: May 2002
Posts: 81,941
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From: Lovely OC
Re: Re: Tom:
Originally posted by DaveGS4
I drove my GS without the LSD but WITH TC for almost two years, then added the LSD. The answer to your question is "it depends"
.
Most of the time you'll get the benefit of the TC without the LSD. Definitely quicker off the line, but you can experience wheel spin (aka burnouts) depending on a number of variables including:
- grip of your tires (remaining tread, softness of tire compound, heated, etc)
- road surface (including hard straigh-line launch, dips in road, angle of launch uphill)
- other variables that impact the power output of your car (my GS runs much stronger in the cool weather, for example)
I would not hesitate to recommend getting the TC installed without an LSD. IMO it's by far the biggest bang-for-buck performance mod you can make to your GS. However, if I had the opportunity and means to do them both at the same time I would certainly go ahead and do it.
I honestly did not feel the need to get an LSD until I went to a quarter mile track with my GS. The track surface was less-than-ideal with lots of rubber and some fluid, and I had severe traction problems. Although I put on a good show for the crowd by lighting up our tires in a HUGE cloud of smoke, leaving burnt rubber all over the back underside of our cars
, it didn't leave me with the good ETs I hoped for. I went looking for options for better traction immediately after that event and added the LSD and new wheels.
I drove my GS without the LSD but WITH TC for almost two years, then added the LSD. The answer to your question is "it depends"
.Most of the time you'll get the benefit of the TC without the LSD. Definitely quicker off the line, but you can experience wheel spin (aka burnouts) depending on a number of variables including:
- grip of your tires (remaining tread, softness of tire compound, heated, etc)
- road surface (including hard straigh-line launch, dips in road, angle of launch uphill)
- other variables that impact the power output of your car (my GS runs much stronger in the cool weather, for example)
I would not hesitate to recommend getting the TC installed without an LSD. IMO it's by far the biggest bang-for-buck performance mod you can make to your GS. However, if I had the opportunity and means to do them both at the same time I would certainly go ahead and do it.
I honestly did not feel the need to get an LSD until I went to a quarter mile track with my GS. The track surface was less-than-ideal with lots of rubber and some fluid, and I had severe traction problems. Although I put on a good show for the crowd by lighting up our tires in a HUGE cloud of smoke, leaving burnt rubber all over the back underside of our cars
, it didn't leave me with the good ETs I hoped for. I went looking for options for better traction immediately after that event and added the LSD and new wheels.
this thread is soooo informative, i can't spend that much time now but tonight i am going to read everything over again to make sure i learn every single thing. you gotta love the technical aspect of CL
I have the TC installed and no LSD. I can attest that I can light up my rear 275s now where I couldn't before!! 
It's a hoot.
I also have a TRD LSD sitting in my basement waiting for me to find someone who can install it!
It's a hoot.I also have a TRD LSD sitting in my basement waiting for me to find someone who can install it!
Instructor
Joined: Apr 2002
Posts: 957
Likes: 13
From: Texas
Originally posted by bitkahuna
I have the TC installed and no LSD. I can attest that I can light up my rear 275s now where I couldn't before!! It's a hoot.
I also have a TRD LSD sitting in my basement waiting for me to find someone who can install it!
I have the TC installed and no LSD. I can attest that I can light up my rear 275s now where I couldn't before!!
It's a hoot.I also have a TRD LSD sitting in my basement waiting for me to find someone who can install it!
Last edited by UTGS400; Jan 6, 2003 at 10:28 PM.
Originally posted by UTGS400
I have a TC and LSD and I can not light up my 265's without power-breaking. If I simply slam the gas down, the tires will squeal for about 1 second then catch.
I have a TC and LSD and I can not light up my 265's without power-breaking. If I simply slam the gas down, the tires will squeal for about 1 second then catch.
Joined: Feb 2001
Posts: 31,944
Likes: 2,739
From: North Carolina
Re: Re: Re: Tom:
Originally posted by rominl
so dave, after you got the lsd, did you immediately feel better "grip" and power transfer to the wheels
so dave, after you got the lsd, did you immediately feel better "grip" and power transfer to the wheels
Originally posted by bitkahuna
I don't see how an LSD can help in a straight line.
I don't see how an LSD can help in a straight line.
UT - with my new larger wheels/tire contact patch and LSD I now have exactly the same traction experience. Every now and then I''ll catch a good one and light em up, but most often it's a little squeak and I'm off.
Lexus Champion
Joined: Nov 2001
Posts: 3,085
Likes: 1
From: Florida
Re: Re: Re: Re: Tom:
Originally posted by DaveGS4
Yes. I would not necessarily call it grip, but a more even launch force as the torque builds at launch.
You can still break one wheel loose in a straight line and smoke the tires with an open diff. A prime example is what happened to me at the drag strip (straight line) which caused me to get the LSD.
UT - with my new larger wheels/tire contact patch and LSD I now have exactly the same traction experience. Every now and then I''ll catch a good one and light em up, but most often it's a little squeak and I'm off.
Yes. I would not necessarily call it grip, but a more even launch force as the torque builds at launch.
You can still break one wheel loose in a straight line and smoke the tires with an open diff. A prime example is what happened to me at the drag strip (straight line) which caused me to get the LSD.
UT - with my new larger wheels/tire contact patch and LSD I now have exactly the same traction experience. Every now and then I''ll catch a good one and light em up, but most often it's a little squeak and I'm off.
I know your TC is that Steel Cockatiel.....
Instructor
Joined: Apr 2002
Posts: 957
Likes: 13
From: Texas
Originally posted by bitkahuna
I don't see how an LSD can help in a straight line.
I don't see how an LSD can help in a straight line.
Lexus Test Driver
Joined: Mar 2001
Posts: 1,202
Likes: 0
From: ATL
rominl,
Just as an FYI, the two readily available LSD's are the RMM, and the TRD. The difference between them is twofold;
1) RMM has lower gearing than the TRD, ie; it take a "lower" number of revolutions of the drive shaft to rotate the axle one full revolution. This equates to slightly better off the line performance, an a slight loss in top end speed. I say slight, because the difference in the gear ratio between the two is not that great.
2) This is the biggie in my book. The RMM is the entire rear differential housing whereas the TRD is just the internals. What this means is that virtually any competant mechanic can install the RMM while the TRD is best left to real transmission experts. They will have to be intimately familiar with using shims and spacers to get everything lined up perfectly, otherwise the LSD will meltdown to an $800 - $900 pile of pot metal.
Both Bitkahuna and myself still have our TRD's sitting in the box due to the difficulty of finding someone competant enough to install them. If you have known high-end tuners in your area, you should be o.k. with the TRD, if not, I'd recommend going with the RMM.
Hope this helps!
Just as an FYI, the two readily available LSD's are the RMM, and the TRD. The difference between them is twofold;
1) RMM has lower gearing than the TRD, ie; it take a "lower" number of revolutions of the drive shaft to rotate the axle one full revolution. This equates to slightly better off the line performance, an a slight loss in top end speed. I say slight, because the difference in the gear ratio between the two is not that great.
2) This is the biggie in my book. The RMM is the entire rear differential housing whereas the TRD is just the internals. What this means is that virtually any competant mechanic can install the RMM while the TRD is best left to real transmission experts. They will have to be intimately familiar with using shims and spacers to get everything lined up perfectly, otherwise the LSD will meltdown to an $800 - $900 pile of pot metal.
Both Bitkahuna and myself still have our TRD's sitting in the box due to the difficulty of finding someone competant enough to install them. If you have known high-end tuners in your area, you should be o.k. with the TRD, if not, I'd recommend going with the RMM.
Hope this helps!
Last edited by mumbles; Jan 7, 2003 at 02:15 PM.
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Lexus Test Driver
Joined: Mar 2001
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From: ATL
Originally posted by bitkahuna
I don't see how an LSD can help in a straight line.
I don't see how an LSD can help in a straight line.
The LSD sends power to the wheel with the most traction, so say you take off from a light doing a burnout (not that you would ever do such a thing), and your right wheel is on a better portion of pavement traction-wise then the left wheel, it will get the majority of the power. But, say your right wheel hits a puddle or patch of ice and starts to spin, the LSD will transfer the power to the left wheel thereby "limiting" the slipping and maximizing power tranfer. But, like I said, since you never do any burnouts, you should probably just sell your LSD to rominl...
Joined: Feb 2001
Posts: 31,944
Likes: 2,739
From: North Carolina
Originally posted by mumbles
Just as an FYI, the two readily available LSD's are the RMM, and the TRD.
Just as an FYI, the two readily available LSD's are the RMM, and the TRD.
There are a number of other threads on CL debating the differences/merits between the two if folks are deciding which to buy (use search
).
Originally posted by mumbles
Both Bitkahuna and myself still have our TRD's sitting in the box due to the difficulty of finding someone competant enough to install them.
Both Bitkahuna and myself still have our TRD's sitting in the box due to the difficulty of finding someone competant enough to install them.
Lexus Test Driver
Joined: Mar 2001
Posts: 1,202
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From: ATL
Originally posted by DaveGS4
Eric - I've corresponded w/ Bit on the install here in Charlotte and placed another call to Hendrick today. Maybe we can work out a two-fer with them once I confirm the mechanic.
Eric - I've corresponded w/ Bit on the install here in Charlotte and placed another call to Hendrick today. Maybe we can work out a two-fer with them once I confirm the mechanic.
Long time my friend! Bit and I managed to get some possible connections here in ATL from the Supra guys... have to see how they pan out. Not that a "leisurely" jaunt to Charlotte and a visit to Dave and his Somniplex wouldn't be enjoyable!
Guest
Posts: n/a
Here are the differences between Torsen style RMM LSD and clutch type TRD LSD.
Torsen style is gear driven torque bias differential while the TRD unit is clutch driven full lock bi-directional differential. Torsen style will send power to different rear wheel proportional to the traction while the clutch type is either fully locked or fully un-locked. The TRD unit can handle higher HP than the Torsen type.
The TRD unit is a well desiged directly drop in piece. No shim is needed while doing the swapping. My tech. was surpirsed to see the unit fit perfectly into the pumpkin without any shiming. Just remember to use the LSD diff. oil. I've had the TRD LSD installed for 2 years w/o any problems.
Torsen style is gear driven torque bias differential while the TRD unit is clutch driven full lock bi-directional differential. Torsen style will send power to different rear wheel proportional to the traction while the clutch type is either fully locked or fully un-locked. The TRD unit can handle higher HP than the Torsen type.
The TRD unit is a well desiged directly drop in piece. No shim is needed while doing the swapping. My tech. was surpirsed to see the unit fit perfectly into the pumpkin without any shiming. Just remember to use the LSD diff. oil. I've had the TRD LSD installed for 2 years w/o any problems.
Thread Starter
Joined: May 2002
Posts: 81,941
Likes: 527
From: Lovely OC
Originally posted by mumbles
rominl,
Just as an FYI, the two readily available LSD's are the RMM, and the TRD. The difference between them is twofold;
1) RMM has lower gearing than the TRD, ie; it take a "lower" number of revolutions of the drive shaft to rotate the axle one full revolution. This equates to slightly better off the line performance, an a slight loss in top end speed. I say slight, because the difference in the gear ratio between the two is not that great.
2) This is the biggie in my book. The RMM is the entire rear differential housing whereas the TRD is just the internals. What this means is that virtually any competant mechanic can install the RMM while the TRD is best left to real transmission experts. They will have to be intimately familiar with using shims and spacers to get everything lined up perfectly, otherwise the LSD will meltdown to an $800 - $900 pile of pot metal.
Both Bitkahuna and myself still have our TRD's sitting in the box due to the difficulty of finding someone competant enough to install them. If you have known high-end tuners in your area, you should be o.k. with the TRD, if not, I'd recommend going with the RMM.
Hope this helps!
rominl,
Just as an FYI, the two readily available LSD's are the RMM, and the TRD. The difference between them is twofold;
1) RMM has lower gearing than the TRD, ie; it take a "lower" number of revolutions of the drive shaft to rotate the axle one full revolution. This equates to slightly better off the line performance, an a slight loss in top end speed. I say slight, because the difference in the gear ratio between the two is not that great.
2) This is the biggie in my book. The RMM is the entire rear differential housing whereas the TRD is just the internals. What this means is that virtually any competant mechanic can install the RMM while the TRD is best left to real transmission experts. They will have to be intimately familiar with using shims and spacers to get everything lined up perfectly, otherwise the LSD will meltdown to an $800 - $900 pile of pot metal.
Both Bitkahuna and myself still have our TRD's sitting in the box due to the difficulty of finding someone competant enough to install them. If you have known high-end tuners in your area, you should be o.k. with the TRD, if not, I'd recommend going with the RMM.
Hope this helps!
man, there are just so much i have to learn on this
Thread Starter
Joined: May 2002
Posts: 81,941
Likes: 527
From: Lovely OC
Originally posted by JacobT
Here are the differences between Torsen style RMM LSD and clutch type TRD LSD.
Torsen style is gear driven torque bias differential while the TRD unit is clutch driven full lock bi-directional differential. Torsen style will send power to different rear wheel proportional to the traction while the clutch type is either fully locked or fully un-locked. The TRD unit can handle higher HP than the Torsen type.
The TRD unit is a well desiged directly drop in piece. No shim is needed while doing the swapping. My tech. was surpirsed to see the unit fit perfectly into the pumpkin without any shiming. Just remember to use the LSD diff. oil. I've had the TRD LSD installed for 2 years w/o any problems.
Here are the differences between Torsen style RMM LSD and clutch type TRD LSD.
Torsen style is gear driven torque bias differential while the TRD unit is clutch driven full lock bi-directional differential. Torsen style will send power to different rear wheel proportional to the traction while the clutch type is either fully locked or fully un-locked. The TRD unit can handle higher HP than the Torsen type.
The TRD unit is a well desiged directly drop in piece. No shim is needed while doing the swapping. My tech. was surpirsed to see the unit fit perfectly into the pumpkin without any shiming. Just remember to use the LSD diff. oil. I've had the TRD LSD installed for 2 years w/o any problems.