Why is the IS300 AWD detuned from the IS350?
07-11-22, 08:27 AM
#16
Intermediate
In my experience, all IS's will short shift a bit unless I use manual mode... except perhaps the IS 500. I pinned it in that car, and it went all the way to about 7000 in first gear.
However, yeah, the power difference between the 300 AWD and 350 is in the top of the powerband. Peak power is still over 6000 RPM in both cars, but the torque gets cut pretty hard just before 4500 RPM in the 300, and it never really gets back up to that level again. The 350 is allowed to continue building until it reaches peak torque around 4800-5000 RPM. If I am looking for it, I can feel that torque dip in the 300 as well as the peak in the 350 - in fact, that peak is one of my favorite things about my 350, like a reward for finding the opportunity to reach said RPM. As you said, it's a subtle difference, to the point where someone would probably say they feel the same, that is, until you get into higher gears and spend more time in that high-RPM range.
However, yeah, the power difference between the 300 AWD and 350 is in the top of the powerband. Peak power is still over 6000 RPM in both cars, but the torque gets cut pretty hard just before 4500 RPM in the 300, and it never really gets back up to that level again. The 350 is allowed to continue building until it reaches peak torque around 4800-5000 RPM. If I am looking for it, I can feel that torque dip in the 300 as well as the peak in the 350 - in fact, that peak is one of my favorite things about my 350, like a reward for finding the opportunity to reach said RPM. As you said, it's a subtle difference, to the point where someone would probably say they feel the same, that is, until you get into higher gears and spend more time in that high-RPM range.
The same thing also happens if I'm making a turn, hit the left paddle to go into D1 (to force it to stay in first gear, otherwise it would upshift to second and will not downshift to first unless I'm going 34 kmh or slower). 1st goes all the way to redline, then I hit the right paddle twice to go to D3 (because I want to limit the shift range to 3rd and I'm letting the car decide when to shift out of 2nd) and that's when I notice that 2nd gear goes a bit further and longer than it usually does.
All of this is somewhat irrelevant anyway, if I'm driving for fun, I usually go into manual mode so the inconsistencies I encounter in auto mode are a moot point.
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arentz07 (07-11-22)
07-11-22, 08:33 AM
#17
drives cars
I got back from a 4 hour drive from up north, with plenty of time to play around on some back roads, and my IS doesn't seem to short shift - at least, while it is in Sport S+ mode, and if I pin the gas pedal (ie. foot right to the floor with a lot of conviction) from a dead stop all the way to the top end of 3rd. I can hear the V6 pitch change until it sounds very urgent and shrill, and it keeps going beyond when I normally expect it to shift. This is clearly the peak you're talking about, and I don't often get the chance to reach for it (until yesterday anyway, so much fun!). I don't know how else to explain it other than I get the impression that the ECU is finally letting the reins go and the V6 can go to its full (safe) potential.
The same thing also happens if I'm making a turn, hit the left paddle to go into D1 (to force it to stay in first gear, otherwise it would upshift to second and will not downshift to first unless I'm going 34 kmh or slower). 1st goes all the way to redline, then I hit the right paddle twice to go to D3 (because I want to limit the shift range to 3rd and I'm letting the car decide when to shift out of 2nd) and that's when I notice that 2nd gear goes a bit further and longer than it usually does.
All of this is somewhat irrelevant anyway, if I'm driving for fun, I usually go into manual mode so the inconsistencies I encounter in auto mode are a moot point.
The same thing also happens if I'm making a turn, hit the left paddle to go into D1 (to force it to stay in first gear, otherwise it would upshift to second and will not downshift to first unless I'm going 34 kmh or slower). 1st goes all the way to redline, then I hit the right paddle twice to go to D3 (because I want to limit the shift range to 3rd and I'm letting the car decide when to shift out of 2nd) and that's when I notice that 2nd gear goes a bit further and longer than it usually does.
All of this is somewhat irrelevant anyway, if I'm driving for fun, I usually go into manual mode so the inconsistencies I encounter in auto mode are a moot point.
In the 350, I kinda feel something waking up at about 5000 RPM, and that's true in the 300 AWD as well, but it seems to die off a little in the 300 AWD before redline, where the 350 seems to pull strong all the way up. Very intentional on Lexus's part.
07-11-22, 09:52 PM
#18
yeah, good point.
Just checked and it looks like is350 awd does come with the very same awd 6 speeder.
Yeah, could be just a tier-adherence for the is300 model, then....
Just checked and it looks like is350 awd does come with the very same awd 6 speeder.
Yeah, could be just a tier-adherence for the is300 model, then....
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arentz07 (07-12-22),
Deepverses (10-01-22)
07-12-22, 08:28 AM
#19
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Rhydg1 (07-14-22)
07-13-23, 08:20 PM
#20
Because they need a entry level AWD option to compete with MB/BMW/Audi; and it's cheaper to detune the drive train they already have, rather than develop a whole new AWD 2.0T powertrain. MB did more or less the same thing with the last generation C300/C350. As well instead of having 20 different flavors of the 350, with the 21+ the 300 is positioned as the 'luxury' entry level, while the '350 FS' is the sport entry level.
I have a IS300FS with the RR racing tune & a 'stock 350 tune'; and I borrowed the the 21 250FS for about a month this year. The stock 300 and the 350 feel identical power wise around town. On the highway though, the stock 300 dies at ~4K RPM while the 350 or tuned 300 keep on pulling till redline. It's definitely noticeable but not world changing. It felt a little faster with the tune on, but I really felt the difference driving around with the 'stock 350' tune for a few months then switching back the stock 300 tune.
I have a IS300FS with the RR racing tune & a 'stock 350 tune'; and I borrowed the the 21 250FS for about a month this year. The stock 300 and the 350 feel identical power wise around town. On the highway though, the stock 300 dies at ~4K RPM while the 350 or tuned 300 keep on pulling till redline. It's definitely noticeable but not world changing. It felt a little faster with the tune on, but I really felt the difference driving around with the 'stock 350' tune for a few months then switching back the stock 300 tune.
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