T4styPh0

iTrader: (2)

I tried searching but couldn't find the answers to the gearing on these cars. On my 250, cruising about 80mph on the freeway. When on 6th gear, the car's rpm is just about 2300rpm. But now that I have the 350, it's revving at 2500rpm and was just wondering if that's normal. BTW, the car has about 340 miles on it if that has something to do with it.

lobuxracer

iTrader: (2)

The IS350 should be at 2472 rpm at 80 mph with the stock tires. The IS250 RWD with 18" wheels should be at 2366 rpm at the same speed. The gearboxes have the same ratios but the final drive ratio is slightly higher in the 250.

PhilipMSPT

iTrader: (5)

According to CarAndDriver.com:


IS250 Automatic RWD Gear Ratios:

First Gear Ratio (:1)3.54
Second Gear Ratio (:1)2.06
Third Gear Ratio (:1)1.40
Fourth Gear Rato (:1)1.00
Fifth Gear Ratio (:1)0.71
Sixth Gear Ratio (:1)0.58

IS350 Gear Ratios:

First Gear Ratio (:1)3.52
Second Gear Ratio (:1)2.04
Third Gear Ratio (:1)1.40
Fourth Gear Rato (:1)1.00
Fifth Gear Ratio (:1)0.72
Sixth Gear Ratio (:1)0.59



Yup, they're slightly different, but insignificantly.

lobuxracer

iTrader: (2)

Car and Driver is wrong (it wouldn't be the first time.) I got the info direct from TIS. The gearbox ratios are identical, only the final drive is different.

PhilipMSPT

iTrader: (5)

^^^That's why I said it was insignificant...

T4styPh0

iTrader: (2)

Thanks for the info guys! Just what I was looking for.

tfz_hebe89

iTrader: (1)

from your attachment, I see that IS350's engine is lighter than 250s. Is it really true although 350s has bigger displacement?

as3.0cl

iTrader: (2)

my awd sits at like 2700rpm doing 80 on the highway...no wonder my gas millage is just ok.... i didn't realize how much lower 350's and rwd 250's rev at 80 in 6th gear.

kickingras

I was thinking about this thread yesterday while I was on the highway and thought I would note the RPM's
I have an '08 250 6MT. At 80 MPH I am at 3100 rpm and 2400 rpm at 60 mph on a level stretch of road.
YES I am sure I was in 6th gear. How the HELL are you getting mid 2k's at 80 mph?

Carl

lobuxracer

iTrader: (2)

MT gearing is completely different than the auto's gearing.

Jeff Lange

iTrader: (1)

I know this is an old thread, I just stumbled across it, but that information from TIS is actually not entirely correct either.

The ratios shown are correct for the A760E and A760H, however there are actually 4 transmissions used in the 2IS, and they depend on AWD/RWD as well as MT/AT. The IS350 RWD uses the A760E while the IS250/350 AWD uses the A760H; these two share the same transmission ratios. That said the IS250 RWD 6AT uses the A960E and it does not share the same ratios.

ISx50 AWD (A760H) / IS350 RWD (A760E) Ratios:
1st: 3.520
2nd: 2.042
3rd: 1.400
4th: 1.000
5th: 0.716
6th: 0.586
Rev: 3.224
Final: 4.100 (ISx50 AWD) / 4.083 (IS350 RWD)

IS250 RWD 6AT (A960E) Ratios:
1st: 3.538
2nd: 2.060
3rd: 1.404
4th: 1.000
5th: 0.713
6th: 0.582
Rev: 3.168
Final: 3.909

IS250 RWD 6MT (RA62) Ratios:
1st: 3.791
2nd: 2.275
3rd: 1.524
4th: 1.185
5th: 1.000
6th: 0.786
Rev: 3.466
Final: 3.727

What I was referring to earlier with what the NCF has wrong is that they consistently list a Torsen as optional for the IS250 in the 2006 NCF book, but Lexus never actually built one with a Torsen in any market. It was likely planned at an earlier stage and then killed. Later books no longer list it, but it was even in some of the earlier owner's manuals too.

Jeff

MikeFig82

iTrader: (13)

Talk about bring this back to life again.

My question is this for the IS250 AWD. Is that both differentials front and rear are 4.100 gear ratios?

That being said I'm planning to get my mechanic uncle to install the FRS 4.10 differential. So this wouldn't affect the gears up front? His concern was that the gear ratios must match. My bad was thinking the gear ratios where 3.72 both front and rear.

Jeff Lange

iTrader: (1)

IS250 AWD is 4.10:1 front and rear. They need to match.

Jeff

MikeFig82

iTrader: (13)

Now I can get'er done!