How Many Revs Are You Doing At 70Mph?

[ambermarine]

Hi Rudy

Give Alan Mcewan a ring at Lexus Glasgow he is the Service Manager Tell him you are a member of the LOC and describe your problem mention the Man from Dunoon and he will be very helpful.By the way this is not Arnold Clark lexus it is the Edinburgh group.

[fred81]

I have a mini VCI interface and Techstream, I'll take a look to see if any gearbox stuff is in there and get back to you.

[Ruud]

I'm fairly sure it can read data like ATF temperature etc, just not sure about error codes.

[Ruud]

Hmm looking at this video, my revs are pretty much the same at 75

http://www.youtube.com/watch?v=hTPC1HgEJvU

[Bluesman]

Taking this one step further, have you ever checked your speed via the speedometer to what a Sat Nav (much more accurate) says you are doing.

Mine is as follows

When my speedo says we are doing 70mph the Sat Nav shows you that you are actualy doing 64/65mph

When the Sat Nav shows your doing 70mph the car speedo shows 75/76

[cruisermark]

Taking this one step further, have you ever checked your speed via the speedometer to what a Sat Nav (much more accurate) says you are doing.

Mine is as follows

When my speedo says we are doing 70mph the Sat Nav shows you that you are actualy doing 64/65mph

When the Sat Nav shows your doing 70mph the car speedo shows 75/76

is there an explanation for this?

Why is the sat nav more accurate? - is it simply because of the digital readout as apposed to anolgue neeedle?

[Foulsbane]

I have noticed that anomaly too.

Apparently all car speedo's are set about 4mph slow, for reasons better known to the Manufacturer than me !

[Bluesman]

Taking this one step further, have you ever checked your speed via the speedometer to what a Sat Nav (much more accurate) says you are doing.

Mine is as follows

When my speedo says we are doing 70mph the Sat Nav shows you that you are actualy doing 64/65mph

When the Sat Nav shows your doing 70mph the car speedo shows 75/76

is there an explanation for this?

Why is the sat nav more accurate? - is it simply because of the digital readout as apposed to anolgue neeedle?

The Sat Nav is a far more accurate instrument for measuring speed, the more you pays the more accurate they are but most are accurate down to a few metres. The Sat Nav checks with 4/5/6 different satellites every second and therefore will always be more accurate. The speedo has mechanical parts which over the years get worn and therefore can never be as accurate.

I was once told that the major manufacturers always detune their speedos to stop the possibility of you suing them for inaccurate readings which you speeding tickets.

[ManicMark]

Hmm looking at this video, my revs are pretty much the same at 75

http://www.youtube.com/watch?v=hTPC1HgEJvU

At 70 my revs are 2100 in 5th & 2800 in 4th so if its doing 2800 it is in 4th gear.

[Ruud]

Hmm looking at this video, my revs are pretty much the same at 75

http://www.youtube.com/watch?v=hTPC1HgEJvU

At 70 my revs are 2100 in 5th & 2800 in 4th so if its doing 2800 it is in 4th gear.

I'm at 2100 at well at 70mph, but selecting 4th gear manually doesn't increase revs at all :eerrrmm:

[Malc]

I just drive mine ................... someone said on another post that driving in PWR mode improves consumption, well, strangely, I think it does ( marginally ). I always now drive in PWR mode, it drives " quicker " and flies better and I think the fuel consumption is slightly improved too.

Malc

[Foulsbane]

Forgive my ignorance Malc, but what is PWR mode ?

What does PWR stand for ?

[Malc]

On the Ls400 anyway, it is a switch next to the gear knob on the console, marked PWR ECT ...... PWR is I think power mode, well that's the way it feels ........ ECT is just " ordinary " mode for the gearbox .................. don't know if it's on the Ls430 though.

I always used to think that the ECT was probably the more economic way of driving, felt like it was slipping effortlessly into overdrive or summat like that ................. no oooomph but plenty of power of course. PWR gives you everything PLUS the feeling of extra oooomph. :outforcount:

Malc

[Foulsbane]

Well, having retrieved the Drivers Handbook to remind me, the Handbook says, "For ordinary driving, Lexus reccomends that you use ECT position to improve fuel economy"

And the PWR. power position is essentially "sport"

Simples, LoL

[Malc]

But not quite so simple ....... there are other threads here about this AND a simple concensus was that PWR does seem to give slightly improved fuel economy ............ economy of course is a misnomer on a 4ltr !!!!

Malc

[Parrot of Doom]

The reason speedometers tend to overestimate speed is because regulations allow them to do so. They are not allowed to underestimate speed.

My friend had a Mitsubishi that gave a perfect reading of his speed. My TVR would tell me I was doing 70mph at 62mph...

[ambermarine]

Pwr mode is a computer setting that converts into a mechanical procedure via the solenoids that prevents the gearbox changing into a lower gear when the accelerator pedal is thrust to the floor.It is essentialy a safety device to illiminate a pause in forward motion and upward acceleration when the driver is overtaking .

[plastic orange]

Any car (including a Toyota Camry) I have hired whilst on holiday in the US has always matched my sat nav speed, so why is the Lexus so far out? My old Saab 9000 Griffin was almost spot on too.

I run 235/55 x17's and even with these it over reads by about 3 mph at a sat nav 70 increasing gradually as they wear to about 75 - worse with original fit tyres.

Pete

[Bluesman]

Any car (including a Toyota Camry) I have hired whilst on holiday in the US has always matched my sat nav speed, so why is the Lexus so far out? My old Saab 9000 Griffin was almost spot on too.

I run 235/55 x17's and even with these it over reads by about 3 mph at a sat nav 70 increasing gradually as they wear to about 75 - worse with original fit tyres.

Pete

Sometime since I drove in the States but from what I remember of the many times I have been there most speed limits are way under ours including 45mph on the Interstates and if you check 45mph over here with Sat Nav its pretty close, its not really noticeable until you get over 55mph. Mike

[plastic orange]

Speed limits are now very similar to ours, and sometimes higher. 70 on speedo is 70 on sat nav.

Pete

[Bluesman]

Speed limits are now very similar to ours, and sometimes higher. 70 on speedo is 70 on sat nav.

Pete

Not before time. They were excruciatingly painful.

[Mybikes a cx500]

In the olden days, speedos simply measured the speed of wheel rotation, with a best guess at the circumference of the tyre, so they were calibrated to be conservative. Some modern cars have the speedo linked to the GPS, and give exact readings.

Ruud, at 60(gps speed) I get 2000rpm in D and 2700rpm in 4, big difference. The speedo reads 64 mph at 60 gps speed.

Perhaps its 4th your missing, not overdrive?

[Ruud]

In the olden days, speedos simply measured the speed of wheel rotation, with a best guess at the circumference of the tyre, so they were calibrated to be conservative. Some modern cars have the speedo linked to the GPS, and give exact readings.

Ruud, at 60(gps speed) I get 2000rpm in D and 2700rpm in 4, big difference. The speedo reads 64 mph at 60 gps speed.

Perhaps its 4th your missing, not overdrive?

I was just thinking that today as well - it must be 4th gear that has gone walkies.