Replacing LC500 torsen diff with LC500h one!
#46
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
I didn't talk about this in my review above but yes bitkahuna is right, the throttle will be a little more twitchy at slow speeds because there is more torque available. It does require some mental adjustment, which happens fairly quickly, but is not uncomfortable or a negative issue at all (to me, at least)
Last edited by breplica; 06-25-22 at 07:43 AM.
The following 3 users liked this post by breplica:
#47
Advanced
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
Then driving in Sport+ mode with this mod has got to be INSANE!
![Got NO2](https://www.clublexus.com/forums/images/smilies/nxsmile.gif)
#48
Lexus Fanatic
iTrader: (20)
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
as i said, having done this kind of mod before on a lexus v8 car (gs400), it was EXCELLENT! tempted to do this too, but probably not for a while. i also put in an upgraded torque converter too. not sure if such a thing is needed or available for the LC.
The following users liked this post:
MLMLC52K18 (06-25-22)
#49
Pit Crew
iTrader: (1)
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
I would love to do this if I know for sure that this pumpkin will fit my RCF. From what I researched, the stock 2.937 rear differential have different part numbers between the LC500 and RCF, so I guess the LCh won't fit either. I had the ring & pinion swap in my IS300 years ago and it made a big difference on how the car launched, so I've always been looking for a way to do this mod on the RCF. I don't like to do the ring/pinion swap again because it's less reliable. My drive shaft bearing went bad a couple years later. The original cost plus repair summed up to almost doing the pumpkin swap. $4000 is not bad.
#51
Instructor
iTrader: (1)
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
There’s got to be a downside. If performance can be markedly enhanced just by changing out differential, then why doesn’t Toyota just do it??? I am not a Motorhead, but from an engineering standpoint, maybe it causes some unnatural stresses to some other component in the drivetrain??? If there is any chance that it could affect vehicle warranty, then Toyota must know something. ![Uhh...](https://www.clublexus.com/forums/images/smilies/1387914497.gif)
![Uhh...](https://www.clublexus.com/forums/images/smilies/1387914497.gif)
#52
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
Anyone know if this will fit the convertible? I'm assuming it will, since I believe we have the same diff as the coupe, but I know the rear steering didn't fit, so it's worth checking.
Thanks!
Thanks!
#53
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
The rear steer module is mounted to a chassis crossbar which is in turn mounted to the differential so having rear steer does not influence the differential itself other that having one additional thing to unbolt and bolt back on during the swap
Enjoy!
#55
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
Guys, I need to make a small addendum to my earlier review of the differential swap regarding the top speed
In my original review, I mentioned the top speed would remain unchanged because the electronically limited top speed of 285km/h is reached at 6000rpm in 7th gear, which means that even with shorter gears, the car could simply rev higher (or in a higher gear) to get to that aforementioned 285km/h speed limit
Well, I was wrong
My assumption was that the 'speed limiter' in our LC500s are based on speedo readings. This is not the case!
The 'speed limit' is actually an 'rpm limit' - it simply stops producing power at 6000rpm in 7th gear onwards. On stock gearing, that is at 285km/h thereabouts. With this new differential, the speed at that gear/rpm is about 245km/h indicated. I have personally verified this at those speeds (don't ask me how I did it lol). Once you hit 6000rpm/7th gear/245km/h the car goes into a soft limiter mode where with the throttle pinned the car just maintains that rpm/speed and will not upshift. There is no sound/warning/alert from the engine, it just feels like someone turned the cruise control on at the limit rpm. In case anyone is wondering there is definitely nothing wrong with the car: I went in excess of 260km/h on it some time before I swapped out the differential
For most people I assume it wont matter. I doubt you would spend much, if any, time at those speeds, in which case then you don't have to worry about it. I'll be looking into getting myself a speed limiter removing device like the one made by Blitz or Tom's (which i suspect are the same units, just rebranded) and report back to let you guys know if it worked
285km/h - 177mph
245km/h - 152mph
for my american friends
In case anyone wants to see what the top speed limiter behaviour is like, go to 6:35 on this video:
The video cuts away abruptly just after he hits the limiter but you can see the rpm bouncing back and forth at 6000rpm (speed 285/286kmh) for a second or two before it does
In my original review, I mentioned the top speed would remain unchanged because the electronically limited top speed of 285km/h is reached at 6000rpm in 7th gear, which means that even with shorter gears, the car could simply rev higher (or in a higher gear) to get to that aforementioned 285km/h speed limit
Well, I was wrong
My assumption was that the 'speed limiter' in our LC500s are based on speedo readings. This is not the case!
The 'speed limit' is actually an 'rpm limit' - it simply stops producing power at 6000rpm in 7th gear onwards. On stock gearing, that is at 285km/h thereabouts. With this new differential, the speed at that gear/rpm is about 245km/h indicated. I have personally verified this at those speeds (don't ask me how I did it lol). Once you hit 6000rpm/7th gear/245km/h the car goes into a soft limiter mode where with the throttle pinned the car just maintains that rpm/speed and will not upshift. There is no sound/warning/alert from the engine, it just feels like someone turned the cruise control on at the limit rpm. In case anyone is wondering there is definitely nothing wrong with the car: I went in excess of 260km/h on it some time before I swapped out the differential
For most people I assume it wont matter. I doubt you would spend much, if any, time at those speeds, in which case then you don't have to worry about it. I'll be looking into getting myself a speed limiter removing device like the one made by Blitz or Tom's (which i suspect are the same units, just rebranded) and report back to let you guys know if it worked
285km/h - 177mph
245km/h - 152mph
for my american friends
In case anyone wants to see what the top speed limiter behaviour is like, go to 6:35 on this video:
Last edited by breplica; 07-08-22 at 04:36 AM.
The following 3 users liked this post by breplica:
#56
Lexus Fanatic
iTrader: (20)
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
awesome info/reporting/feedback, thank you breplica.
and yeah 152mph would be plenty for me.![Big Grin](https://www.clublexus.com/forums/images/smilies/biggrin.gif)
and yeah 152mph would be plenty for me.
![Big Grin](https://www.clublexus.com/forums/images/smilies/biggrin.gif)
The following 2 users liked this post by bitkahuna:
breplica (07-08-22),
MLMLC52K18 (07-09-22)
#57
Pit Crew
Thread Starter
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
Guys, I need to make a small addendum to my earlier review of the differential swap regarding the top speed
In my original review, I mentioned the top speed would remain unchanged because the electronically limited top speed of 285km/h is reached at 6000rpm in 7th gear, which means that even with shorter gears, the car could simply rev higher (or in a higher gear) to get to that aforementioned 285km/h speed limit
Well, I was wrong
My assumption was that the 'speed limiter' in our LC500s are based on speedo readings. This is not the case!
The 'speed limit' is actually an 'rpm limit' - it simply stops producing power at 6000rpm in 7th gear onwards. On stock gearing, that is at 285km/h thereabouts. With this new differential, the speed at that gear/rpm is about 245km/h indicated. I have personally verified this at those speeds (don't ask me how I did it lol). Once you hit 6000rpm/7th gear/245km/h the car goes into a soft limiter mode where with the throttle pinned the car just maintains that rpm/speed and will not upshift. There is no sound/warning/alert from the engine, it just feels like someone turned the cruise control on at the limit rpm. In case anyone is wondering there is definitely nothing wrong with the car: I went in excess of 260km/h on it some time before I swapped out the differential
For most people I assume it wont matter. I doubt you would spend much, if any, time at those speeds, in which case then you don't have to worry about it. I'll be looking into getting myself a speed limiter removing device like the one made by Blitz or Tom's (which i suspect are the same units, just rebranded) and report back to let you guys know if it worked
285km/h - 177mph
245km/h - 152mph
for my american friends
In case anyone wants to see what the top speed limiter behaviour is like, go to 6:35 on this video: https://www.youtube.com/watch?v=Q3Ka...nnel=AutoTopNL The video cuts away abruptly just after he hits the limiter but you can see the rpm bouncing back and forth at 6000rpm (speed 285/286kmh) for a second or two before it does
In my original review, I mentioned the top speed would remain unchanged because the electronically limited top speed of 285km/h is reached at 6000rpm in 7th gear, which means that even with shorter gears, the car could simply rev higher (or in a higher gear) to get to that aforementioned 285km/h speed limit
Well, I was wrong
My assumption was that the 'speed limiter' in our LC500s are based on speedo readings. This is not the case!
The 'speed limit' is actually an 'rpm limit' - it simply stops producing power at 6000rpm in 7th gear onwards. On stock gearing, that is at 285km/h thereabouts. With this new differential, the speed at that gear/rpm is about 245km/h indicated. I have personally verified this at those speeds (don't ask me how I did it lol). Once you hit 6000rpm/7th gear/245km/h the car goes into a soft limiter mode where with the throttle pinned the car just maintains that rpm/speed and will not upshift. There is no sound/warning/alert from the engine, it just feels like someone turned the cruise control on at the limit rpm. In case anyone is wondering there is definitely nothing wrong with the car: I went in excess of 260km/h on it some time before I swapped out the differential
For most people I assume it wont matter. I doubt you would spend much, if any, time at those speeds, in which case then you don't have to worry about it. I'll be looking into getting myself a speed limiter removing device like the one made by Blitz or Tom's (which i suspect are the same units, just rebranded) and report back to let you guys know if it worked
285km/h - 177mph
245km/h - 152mph
for my american friends
In case anyone wants to see what the top speed limiter behaviour is like, go to 6:35 on this video: https://www.youtube.com/watch?v=Q3Ka...nnel=AutoTopNL The video cuts away abruptly just after he hits the limiter but you can see the rpm bouncing back and forth at 6000rpm (speed 285/286kmh) for a second or two before it does
The following users liked this post:
breplica (07-09-22)
#58
Advanced
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
breplica---Who is this Daredevil driving the LC like a ‘bat out of hell’! And where is he driving? Is this on the Autoban? I hope so! I like to drive ‘pedal to the metal’ but it looks a lil fast even for me!
![Yikes!](https://www.clublexus.com/forums/images/smilies/yikes.gif)
#59
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
I had the Blitz speed cut. On the US market car it seems to do nothing. I had the car on the dyno a few times, and like you, I experienced a "soft" limit when going WOT. I cannot remember the exact speed, as this was over two years ago. I think the product is used for the JDM cars that have a much lower speed limit.
#60
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
![Smilie](https://www.clublexus.com/forums/images/smilies/smile.gif)
Last edited by breplica; 07-09-22 at 06:11 AM.
The following 2 users liked this post by breplica:
Charedj (07-27-23),
MLMLC52K18 (07-09-22)