missedapex

Any update on new 1/4 runs or 0-60 pulls?

anchaf3

Subjectively the car is much livelier and feels quicker. Objectively, the 60mph-100mph has improved. I was averaging 5.5-5.6 seconds now I consistently pull in the 5.2 range in the 60-100mph with my best being 5.15 seconds. As far as 0-60mph, I have had to get creative launching it because it now will break traction so bad with my pilot sport 4s tires. I can consistently pull 0-60 (with a 1 foot roll out) under 4.3 seconds now. The best time being 4.23 seconds. Before I would never break the 4.3 mark, and would usually be around 4.5, Occasionally I would have a dead hook launch with my old set up and get close to 4.3, but that very rare and under perfect conditions and having some luck. Overall it is quicker, no question.

cigadrop

Which shop did you get the job done?

anchaf3

I live in Lexington Ky. I had a local mechanic do the swap, a mechanic that specializes in Japanese imports.

flowrider

iTrader: (9)

^^^^Assuming you retained the Torsen?

Lou

anchaf3

yes. There were two options for the hybrid diff and I went with the Torsen.

pottypants

Pretty good bang for the buck !

added to my TODO list when theres a few more in salvage yard for parts

ppp

bitkahuna

iTrader: (20)

wow, didn't see this thread until now (thanks @flowrider). @anchaf3 - you da man.

must... resist...

anchaf3

This might be the best, and most expensive, mod that I did.

breplica

Not sure how many would be interested in such a mod but here goes

First, some recommended reading:

https://www.clublexus.com/forums/lc-...nion-gear.html

Summary: The LC500 rear differential has a final drive (not sure if this is the correct term, i am borrowing it from the motorcycle world) ratio of 2.94. The LC500h has a shorter final ratio, at 3.13. Why do you want a shorter ratio? Shorter gears mean more torque at every rpm, therefore more in-gear acceleration at the cost of top speed, at least in theory. There are multiple differentials that fit the LC500 including I believe some from the LS500 which all have the same exterior housings and are similarly plug and play, with different gear ratios (read the above links for more details on those).

However, to the best of my knowledge, if you wish to swap the entire differential (a much simpler and idiot proof job, as opposed to opening it up and swapping individual internal gears) and you want the Torsen LSD included, then you will need to use the one from the LC500h. Which one? Here are the part numbers:

41110-11050 - This is the entire differential from the LC500h including the Torsen LSD. This is a single self contained unit and all you need at the princely sum of about $4k USD. The drive shaft and axle seals are included with the package preinstalled but in case you need replacements, the part numbers for the seals are: 90311-47031 and 90311-47032

Installation is pretty straightforward, the exhaust muffler section comes off, the driveshaft, rear axle, and rear steer module (if you have one) is disconnected and the differential is swapped. Everything goes back in the same way it came out. The LC500h differential housing is completely identical to the LC500. The differential/torsen is completely mechanical, there are no electronic elements to worry about. No error codes, no weird behaviour from the car. Everything feels stock, and works without issue.






OK now on to my 'review':

Is it faster? Unquestionably. It is far from subtle (but I would stop short of calling it a "night and day" difference). You will notice it the moment you step on the gas pedal the first time the car starts moving: There is a noticeable increase in torque/acceleration. Something I should also make clear: It is much more than something you could ever get from an exhaust and a tune on a naturally aspirated stock engine, which could cost similar amounts of money and compromise reliability, which this mod doesn't. I was trying to think about the best way to express it and my best attempt is that it feels like someone bored out my engine by another 500-800cc, so it feels like a 5.5 or 5.8L engine now. The power increase is across the entire rev range, and the best part of it is how much nicer it pulls from below 2000-4000rpm where this engine can feel a little anemic. At higher revs the power increase is less noticeable (probably because the engine is already producing a lot of power there). The lovely part of the way it feels is not only did I get more 'power', not only did I get it 'everywhere' in the rev range, but I also got a better car for street driving at the same time, which is great. If you would like some numbers I'll quote another forum member who did the mod and took some measurements in the earlier thread:

I would like to add to his opinion that I believe the traction control systems on our LC500s are simply too invasive. I did once try to disable TC fully, with fully warm stock dunlop runflat tires on hot tarmac and was able to floor the pedal in first gear and get the car to accelerate smoothly from absolute standstill (without brake boost) with no audible loss of traction (I did not hear any tire squeal or hear the rpm spike from tire spin) even with this new differential. Unfortunately I did not have measuring equipment to measure that run. I did the exact same run next with TC enabled and it was flashing lights and cutting power everywhere so yeah, the TC sucks on our vehicles and is far too conservative

Drawbacks? First of all this is not a cheap mod, but then again this is not a cheap car, and there is no way that spending this kind of money on the car on any other mod(without forced induction) will get you this kind of improvement in performance. So from a bang for the buck perspective, it is still a good deal IMO. There are also cheaper ways to do it if you are so inclined, by swapping out internal gears. But swapping out the entire differential is also a good idea if your LC500 does not come with a Torsen LSD and you want to have one, an added bonus.

Other drawbacks besides cost are a small but noticeable increase in engine braking off throttle, whether or not this will annoy you is highly subjective but not everyone will like it (it annoyed me slightly at first but I adapted after a while and it just feels normal to me now). The issue is slightly exacerbated by the fact that when coasting to a stop, the downshifts on the 10 speed are not the smoothest in the world, you get small changes in the rate of deceleration as you drop down the gears and the increased engine braking does accentuate this a little

Fuel consumption: Doing a 100% apples to apples comparison is difficult. When i first had the differential swapped, my fuel consumption skyrocketed because i was flooring it all over the place lol. Now that things have settled down a bit and I am back to my regular driving style, i would say fuel consumption has gone up by about 5-8%, for the same style of driving

How about top speed? Well on some other cars, you might lose a little, on this car, you lose nothing. The car is limited to 285km/h and the 10 speed is geared to reach that speed in 7th gear (at about 6000rpm). the only difference with this mod is that you will hit 285km/h at a slight higher rpm in 7th gear compared to before. In fact, with the improvement to in-gear acceleration, you will probably hit top speed a lot sooner compared to stock. You do lose a little 'top speed' in each gear due to the shorter gear but if anything it makes the car more fun to drive, especially in manual mode, because you're banging up and down that lovely gearbox even more. (Edit: I was wrong, limited top speed drops to 245km/h. Please read my post below to find out why)

Overall great mod, really happy with it. If you're ok with the cost, and can deal with a little more engine braking (Edit: or you actually spend time driving between 245 and 285km/h)...there really is no reason not to do it

Hope someone finds this useful, shoot me a question if I missed something and I'll try to answer if I can

NiceCars

Very cool, shorter final drives always equal more street fun. I like the idea of adding lsd if one doesn’t already have it

Where was this work done? Looks like a Lexus dealership from the pics, if so how did you arrange this?

So you are another confirming the downshifts aren’t that great for the 10 speed, wonder why more here haven’t experienced this?

breplica

No it was just a regular workshop that specialises in Lexus vehicles lol, not the dealership

My car is a 2022 so it has the supposed improved shifting behaviour and truthfully most of the time it is excellent but IMO the coasting-to-a-stop downshifting still isn't the smoothest. It's not so much the downshift itself, which is fine, but rather the change in deceleration rate as you coast to a stop.

For example, coasting down from 5th to 4th there is a noticable increase in engine braking as it enters 4th gear, then a split second later the transmission disconnects and the car starts rolling forward again with almost no engine braking down through 3rd and 2nd and then a slight increase in engine braking as the car enters 1st (probably because 1st gear is pretty short compared to other cars so you will notice the engine braking here a little more). this behaviour is 100% consistent and repeatable and occurs every single time as long as you are off the throttle and coasting or braking down through the gears to a stop.It happens before and after the differential swap but you will notice it a little more with the shorter final drive on the LC500h differential.

Truthfully, perhaps others do not mention it because I am making it sound worse than it actually is, I would not be surprised at all if other people don't even realise this is happening and I've more or less gotten used to it as of some time ago, its a little frustrating because this is something easily fixable electronically...but lexus as yet has not been able to do so, and to my knowledge, no one has been able to unlock the stock ECU so we go in and alter the shift logic for ourselves

jonez

Great write up! Thank you for providing so much detail. This is something I may try later this year or next year. One question about downshifts, any specific noticeable changes? As an example, with stock differential manually downshifting through most gears is pretty smooth but around 2500-3000 RPM downshifting 4->3 or 3->2 are very aggressive downshifts. I have the Armytrix exhaust and those downshifts sound amazing (almost guaranteed a loud pop every time and it puts a smile on my face).

breplica

Thank you! Other than the slightly increased engine braking, the actual shifting behaviour has not changed at all. So you dont get the hyper aggressive blip downshifts in places where they did not occur before, and vice versa. To my knowledge you only enter 'full attack' downshift mode (with the blips) when in manual mode or under very heavy braking in Auto with Sport or Sport + mode. The behaviour seems identical to me both pre and post differential swap. I am on the stock exhaust though (with exhaust valves open) so I probably wont get aggressive sounds from downshifts in normal shifting modes like you probably do with the armytrix which has an incredible sound. Hope this helps

NiceCars

Does the mode have any affect on it make it better/worse, and are you a frequent user of the paddles?

Is your warranty now toast? Be a real shame if it is especially on a 22