Top speed!
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Joined: May 2003
Posts: 742
Likes: 210
From: Florida
Too late - you’ve revived an oldie but a goodie 
I believe 286 kph = 177.717 mph
4 questions:
1) Does anyone know why it says the car has 477 hp instead of the usual rating of 471 hp we get in the USA?
2) Were there any mods done to the car?
3) Given that almost all cars read several mph too fast - how much speedometer error is built into the LC500? I’m gonna guess the car was doing about 170 mph in reality which is still impressive.
4) Has anyone seen a top speed run without the computerized governor limiting power above 6K rpm in 7th gear? I’m guessing a coupe could go a genuine 185 mph if ungoverned.
Heres another vid where it looks like the same tester hit 281 kph / 174.605 mph in a convertible.
I believe 286 kph = 177.717 mph
4 questions:
1) Does anyone know why it says the car has 477 hp instead of the usual rating of 471 hp we get in the USA?
2) Were there any mods done to the car?
3) Given that almost all cars read several mph too fast - how much speedometer error is built into the LC500? I’m gonna guess the car was doing about 170 mph in reality which is still impressive.
4) Has anyone seen a top speed run without the computerized governor limiting power above 6K rpm in 7th gear? I’m guessing a coupe could go a genuine 185 mph if ungoverned.
Heres another vid where it looks like the same tester hit 281 kph / 174.605 mph in a convertible.
Last edited by GatorGreg; Dec 2, 2023 at 04:07 AM.
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Joined: Jul 2021
Posts: 36
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From: FIN
In case of LC500 German official number is 464 which isn't in line with US 471. There has to be some difference between models or German number is not correct. Possibly 464 is old value from first LC500's and German imported just haven't updated it.
4) Has anyone seen a top speed run without the computerized governor limiting power above 6K rpm in 7th gear? I’m guessing a coupe could go a genuine 185 mph if ungoverned.
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Joined: Feb 2023
Posts: 37
Likes: 10
From: UK
The 477 is PS, the European measurement.
US cars don’t have the EU-mandated gas particulate filter which knocks engine bhp down from 471 to 464. This filter came in in the UK in 2018 so some of our early 2017/18 UK cars get the same 471 bhp as the US, then later cars are all 464 bhp.
The gas particulate filter (GPF) also negatively affects the exhaust note. Removing it throws engine fault lights and means the car won’t pass annual safety/emissions/condition tests.. unless you know a friendly tester.
The farcical emissions bobbins is mostly why the LC is being discontinued in the EU/UK as of the last couple of weeks. RIP.
This car is heeeavy and a little light on torque so I’d guess that’s why it’ll ‘only’ hit 175-ish.
US cars don’t have the EU-mandated gas particulate filter which knocks engine bhp down from 471 to 464. This filter came in in the UK in 2018 so some of our early 2017/18 UK cars get the same 471 bhp as the US, then later cars are all 464 bhp.
The gas particulate filter (GPF) also negatively affects the exhaust note. Removing it throws engine fault lights and means the car won’t pass annual safety/emissions/condition tests.. unless you know a friendly tester.
The farcical emissions bobbins is mostly why the LC is being discontinued in the EU/UK as of the last couple of weeks. RIP.
This car is heeeavy and a little light on torque so I’d guess that’s why it’ll ‘only’ hit 175-ish.
Racer
Joined: Sep 2003
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From: El Paso, TX
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Joined: May 2003
Posts: 742
Likes: 210
From: Florida
I don't think it's governed; it's just can't go any faster. And I'm surprised it can actually do an actual 170 (or thereabouts); it's a whale of a car, and with a substantial frontal area. And yes, we don't know if the car had any mods (including different tires, and tire pressures), plus altitude, ambient temperature, road inclination, wind speed/direction, etc. All of that affects how fast the car can go too. But to be honest, I probably wouldn't feel like doing anything above 150 on a car like that, but that's just me.
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Last edited by GatorGreg; Dec 8, 2023 at 02:19 PM.
Racer
Joined: Sep 2003
Posts: 1,477
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From: El Paso, TX
Even if it is, it'd only be a few mph, if at all. It's pretty much maxed out at that speed. Even a new M3 ungoverned tops out at 172 (real speed), and it's a smaller and lighter car, with about the same power. Can't defy physics.
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Joined: May 2003
Posts: 742
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From: Florida
Heres the post by breplica from the other thread:
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
Last edited by GatorGreg; Dec 8, 2023 at 02:53 PM.
Pit Crew
Joined: Feb 2023
Posts: 139
Likes: 80
From: VT
At the Loring (Maine) speed trials on July 16, two GPS systems in my LC showed a speed of 170.9 mph just before we hit the 1.5 mile electronic timers. The speed limiter then activated, slowing us to 168.239 mph., the official top speed. The governor works. Damn.
