F-Sport Supercharger?
05-27-09, 02:03 AM
#16
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Interesting how low the opinions on the manual tranny seem to be.....Having driven a plethora of manuals I think that the transmission isnt bad....well above average. (unless compared to an nsx or pretty much any honda for that matter, although smooth tranmission to engine response makes up for the somewhat arbitrary gates).
Yup, really.
EPA rates the manual IS250 at 18/26
http://www.fueleconomy.gov/feg/2008c...umn=1&id=25871
EPA rates the automatic (RWD) IS250 at 21/29
http://www.fueleconomy.gov/feg/sbs.htm
(note those are the "new" EPA ratings... the old ones had the manual at 20/28 and the automatic at 24/32).
These above are SUGGESTED ratings. Nothing more. Most of us manual drivers have experienced the disparity in fuel consumption when using lexus service cars. Anticipation of the performance of gear ratios is more responsible for the aformentioned than anything else.
Yup, really.
EPA rates the manual IS250 at 18/26
http://www.fueleconomy.gov/feg/2008c...umn=1&id=25871
EPA rates the automatic (RWD) IS250 at 21/29
http://www.fueleconomy.gov/feg/sbs.htm
(note those are the "new" EPA ratings... the old ones had the manual at 20/28 and the automatic at 24/32).
These above are SUGGESTED ratings. Nothing more. Most of us manual drivers have experienced the disparity in fuel consumption when using lexus service cars. Anticipation of the performance of gear ratios is more responsible for the aformentioned than anything else.
05-27-09, 05:51 AM
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Yup, really.
EPA rates the manual IS250 at 18/26
http://www.fueleconomy.gov/feg/2008c...umn=1&id=25871
EPA rates the automatic (RWD) IS250 at 21/29
http://www.fueleconomy.gov/feg/sbs.htm
(note those are the "new" EPA ratings... the old ones had the manual at 20/28 and the automatic at 24/32).
There's an increasing number of cars this is true for anymore, and not just from Lexus.
The Kias of the world you'll probably still see a bit better mileage with a manual for at least a few more years, since they're not putting as much modern engineering into their autos.
EPA rates the manual IS250 at 18/26
http://www.fueleconomy.gov/feg/2008c...umn=1&id=25871
EPA rates the automatic (RWD) IS250 at 21/29
http://www.fueleconomy.gov/feg/sbs.htm
(note those are the "new" EPA ratings... the old ones had the manual at 20/28 and the automatic at 24/32).
There's an increasing number of cars this is true for anymore, and not just from Lexus.
The Kias of the world you'll probably still see a bit better mileage with a manual for at least a few more years, since they're not putting as much modern engineering into their autos.
Ok wow didnt know that but I aveagre 33 highway and 25 city with my manual always have since day one. But I also do not try to beat on my car to much unless I absolutley have to like at the track. My thing is though how can a automatic car that revs higher in sixth gear then manual does sixth gear get better mileage I dont understand that I have driven both and my manual revs much lower then automatic does? I dont like fighting about it but I really would honestly like to know how that works like is there soemthing with the trannys that cause them to be more efficient event though they rev higher and suck more fuel?
Thanks,
Ryan
05-27-09, 07:18 AM
#19
Kurtz you really need to stop hating on the MT. We all get it - you don't like to shift for yourself.
Dmocchi was referring to proper gear selection to put the engine within the best part of its powerband and the anticipation of doing this as being responsible for the observed disparity in MPGs. In a nutshell, driving an automatic as you would a manual.
We all know, and it is common knowledge, that the EPA ratings are guidelines, and very few people actually exhibit the driving habits required to match their figures. My grandmother is the only person I personally know of to do so.
One thing that I myself experience daily, as do others like they have stated, and the AT owners do not, is that the manual returns better fuel economy under a wider range of driving conditions. You can quote EPA all you want but the anecdotal evidence being presented by us MT owners who actually have a basis for comparison is far more reputable in this issue just as in any other on this forum.
Dmocchi was referring to proper gear selection to put the engine within the best part of its powerband and the anticipation of doing this as being responsible for the observed disparity in MPGs. In a nutshell, driving an automatic as you would a manual.
We all know, and it is common knowledge, that the EPA ratings are guidelines, and very few people actually exhibit the driving habits required to match their figures. My grandmother is the only person I personally know of to do so.
One thing that I myself experience daily, as do others like they have stated, and the AT owners do not, is that the manual returns better fuel economy under a wider range of driving conditions. You can quote EPA all you want but the anecdotal evidence being presented by us MT owners who actually have a basis for comparison is far more reputable in this issue just as in any other on this forum.
05-27-09, 07:55 AM
#20
Unless you're driving both a manual and an automatic, of otherwise identical vehicles, on a daily driver basis, over the same drives, at the same times, in the same conditions, you really have no basis at all for comparison.
Which is exactly the sort of test the EPA is doing.
Now, you might get better, or worse, than the EPA ratings depending on how closely the type and conditions of your driving match theirs... but generally if one car gets singificantly better mileage than the other under a set of conditions, it's still going to get better mileage under different conditions as long as the other car is also under those conditions.
(the notable exception would be cars with regenerative braking like some hybrids where city mileage will often beat highway mileage; a condition that is unlike most straight gas cars and doesn't really apply here).
BTW, here's the gear ratios for the manual-
First Gear Ratio (:1) 3.79
Second Gear Ratio (:1) 2.28
Third Gear Ratio (:1) 1.52
Fourth Gear Ratio (:1) 1.19
Fifth Gear Ratio (:1) 1.00
Sixth Gear Ratio (:1) 0.79
Final drive- 3.73
Here's the auto in the 250-
First Gear Ratio (:1) 3.54
Second Gear Ratio (:1) 2.06
Third Gear Ratio (:1) 1.40
Fourth Gear Ratio (:1) 1.00
Fifth Gear Ratio (:1) 0.71
Sixth Gear Ratio (:1) 0.58
Final drive- 3.91
Hence 6th gear will rev significantly lower rpms on the auto than the manual. The engines are the same after all. Having 2 overdrive gears vs. only 1 in the manual helps a fair bit in better mileage.
Which is exactly the sort of test the EPA is doing.
Now, you might get better, or worse, than the EPA ratings depending on how closely the type and conditions of your driving match theirs... but generally if one car gets singificantly better mileage than the other under a set of conditions, it's still going to get better mileage under different conditions as long as the other car is also under those conditions.
(the notable exception would be cars with regenerative braking like some hybrids where city mileage will often beat highway mileage; a condition that is unlike most straight gas cars and doesn't really apply here).
BTW, here's the gear ratios for the manual-
First Gear Ratio (:1) 3.79
Second Gear Ratio (:1) 2.28
Third Gear Ratio (:1) 1.52
Fourth Gear Ratio (:1) 1.19
Fifth Gear Ratio (:1) 1.00
Sixth Gear Ratio (:1) 0.79
Final drive- 3.73
Here's the auto in the 250-
First Gear Ratio (:1) 3.54
Second Gear Ratio (:1) 2.06
Third Gear Ratio (:1) 1.40
Fourth Gear Ratio (:1) 1.00
Fifth Gear Ratio (:1) 0.71
Sixth Gear Ratio (:1) 0.58
Final drive- 3.91
Hence 6th gear will rev significantly lower rpms on the auto than the manual. The engines are the same after all. Having 2 overdrive gears vs. only 1 in the manual helps a fair bit in better mileage.
05-27-09, 09:41 AM
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Unless you're driving both a manual and an automatic, of otherwise identical vehicles, on a daily driver basis, over the same drives, at the same times, in the same conditions, you really have no basis at all for comparison.
Which is exactly the sort of test the EPA is doing.
Now, you might get better, or worse, than the EPA ratings depending on how closely the type and conditions of your driving match theirs... but generally if one car gets singificantly better mileage than the other under a set of conditions, it's still going to get better mileage under different conditions as long as the other car is also under those conditions.
(the notable exception would be cars with regenerative braking like some hybrids where city mileage will often beat highway mileage; a condition that is unlike most straight gas cars and doesn't really apply here).
Agreed. all I was pointing out here was that when going from driving an is 250 manual to an automatic (service car) and driven by the same driver, under the same conditions, same monotonous routes, and appreciable diffence in consumption is notes. Let me preempt same of your rebbutals. Yes, they will be different cars, with diffent mileage, not being driven under the exact same condition.
BTW, here's the gear ratios for the manual-
First Gear Ratio (:1) 3.79
Second Gear Ratio (:1) 2.28
Third Gear Ratio (:1) 1.52
Fourth Gear Ratio (:1) 1.19
Fifth Gear Ratio (:1) 1.00
Sixth Gear Ratio (:1) 0.79
Final drive- 3.73
Here's the auto in the 250-
First Gear Ratio (:1) 3.54
Second Gear Ratio (:1) 2.06
Third Gear Ratio (:1) 1.40
Fourth Gear Ratio (:1) 1.00
Fifth Gear Ratio (:1) 0.71
Sixth Gear Ratio (:1) 0.58
Final drive- 3.91
Hence 6th gear will rev significantly lower rpms on the auto than the manual. The engines are the same after all. Having 2 overdrive gears vs. only 1 in the manual helps a fair bit in better mileage.
Which is exactly the sort of test the EPA is doing.
Now, you might get better, or worse, than the EPA ratings depending on how closely the type and conditions of your driving match theirs... but generally if one car gets singificantly better mileage than the other under a set of conditions, it's still going to get better mileage under different conditions as long as the other car is also under those conditions.
(the notable exception would be cars with regenerative braking like some hybrids where city mileage will often beat highway mileage; a condition that is unlike most straight gas cars and doesn't really apply here).
Agreed. all I was pointing out here was that when going from driving an is 250 manual to an automatic (service car) and driven by the same driver, under the same conditions, same monotonous routes, and appreciable diffence in consumption is notes. Let me preempt same of your rebbutals. Yes, they will be different cars, with diffent mileage, not being driven under the exact same condition.
BTW, here's the gear ratios for the manual-
First Gear Ratio (:1) 3.79
Second Gear Ratio (:1) 2.28
Third Gear Ratio (:1) 1.52
Fourth Gear Ratio (:1) 1.19
Fifth Gear Ratio (:1) 1.00
Sixth Gear Ratio (:1) 0.79
Final drive- 3.73
Here's the auto in the 250-
First Gear Ratio (:1) 3.54
Second Gear Ratio (:1) 2.06
Third Gear Ratio (:1) 1.40
Fourth Gear Ratio (:1) 1.00
Fifth Gear Ratio (:1) 0.71
Sixth Gear Ratio (:1) 0.58
Final drive- 3.91
Hence 6th gear will rev significantly lower rpms on the auto than the manual. The engines are the same after all. Having 2 overdrive gears vs. only 1 in the manual helps a fair bit in better mileage.
The ratios are indeed similar in both manual and automatic. Only manual cars are shifted by people.
I empathize with your crux here but Id like to point out in my earlier post I wasnt debating the merits of the transmissions (ie which is better) only that the manuals give u achoice when and how to shift thus allowing most capable drivers of achieving much better mileage than otherwise suggested.
05-27-09, 09:47 AM
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Unless you're driving both a manual and an automatic, of otherwise identical vehicles, on a daily driver basis, over the same drives, at the same times, in the same conditions, you really have no basis at all for comparison.
Which is exactly the sort of test the EPA is doing.
Now, you might get better, or worse, than the EPA ratings depending on how closely the type and conditions of your driving match theirs... but generally if one car gets singificantly better mileage than the other under a set of conditions, it's still going to get better mileage under different conditions as long as the other car is also under those conditions.
(the notable exception would be cars with regenerative braking like some hybrids where city mileage will often beat highway mileage; a condition that is unlike most straight gas cars and doesn't really apply here).
BTW, here's the gear ratios for the manual-
First Gear Ratio (:1) 3.79
Second Gear Ratio (:1) 2.28
Third Gear Ratio (:1) 1.52
Fourth Gear Ratio (:1) 1.19
Fifth Gear Ratio (:1) 1.00
Sixth Gear Ratio (:1) 0.79
Final drive- 3.73
Here's the auto in the 250-
First Gear Ratio (:1) 3.54
Second Gear Ratio (:1) 2.06
Third Gear Ratio (:1) 1.40
Fourth Gear Ratio (:1) 1.00
Fifth Gear Ratio (:1) 0.71
Sixth Gear Ratio (:1) 0.58
Final drive- 3.91
Hence 6th gear will rev significantly lower rpms on the auto than the manual. The engines are the same after all. Having 2 overdrive gears vs. only 1 in the manual helps a fair bit in better mileage.
Which is exactly the sort of test the EPA is doing.
Now, you might get better, or worse, than the EPA ratings depending on how closely the type and conditions of your driving match theirs... but generally if one car gets singificantly better mileage than the other under a set of conditions, it's still going to get better mileage under different conditions as long as the other car is also under those conditions.
(the notable exception would be cars with regenerative braking like some hybrids where city mileage will often beat highway mileage; a condition that is unlike most straight gas cars and doesn't really apply here).
BTW, here's the gear ratios for the manual-
First Gear Ratio (:1) 3.79
Second Gear Ratio (:1) 2.28
Third Gear Ratio (:1) 1.52
Fourth Gear Ratio (:1) 1.19
Fifth Gear Ratio (:1) 1.00
Sixth Gear Ratio (:1) 0.79
Final drive- 3.73
Here's the auto in the 250-
First Gear Ratio (:1) 3.54
Second Gear Ratio (:1) 2.06
Third Gear Ratio (:1) 1.40
Fourth Gear Ratio (:1) 1.00
Fifth Gear Ratio (:1) 0.71
Sixth Gear Ratio (:1) 0.58
Final drive- 3.91
Hence 6th gear will rev significantly lower rpms on the auto than the manual. The engines are the same after all. Having 2 overdrive gears vs. only 1 in the manual helps a fair bit in better mileage.
Hmmm idk then cause what you show makes very good sense and you have proven that you must be right but my thing is my car still revs lower then a is250 rwd suto period. I mean both my freinds car and the one I test drove revs were much higher then mine? I cant figure out maybe something is different in my rear end or soemthing idk just know that it does rev lower for some weird reason.
05-27-09, 09:48 AM
#24
You can't view the EPA tests as infallible. It is a set of tests under specifics conditions to serve as a guideline and should not be viewed as deterministic. The EPA itself recognizes this with a disclaimer attached to the results.
We are comparing two different systems. There does not have a be a linear trend, or even an easily modeled trend, between driving habit and fuel economy. This is before we even consider that manufacturers can write code for the ECU to optimize certain behaviors for testing conditions that may or may not be applicable to both models.
Example - the 6th gear in the AT is so low and the engine produces so little torque at low rpms that it is not useful for accelerating, and can not easily maintain speed uphill. At higher speeds it may have issues just overcoming the force of drag. But it works great at a 60mph EPA test.
Driving a MT I can choose to stay in 6th gear all the time, eliminating gas wasting downshifts, and having more avilable power at lower highway speeds, allowing me to deal with slow traffic.
Now, depending on how YOU drive, one of those options will be better, while for how someone ELSE drives it may be the other.
My point is not that one is better than the other but that they each have strengths. I am not sure why you are so resistant to the idea that the MT might use less gas under certain conditions, and driving habits might adjust to do so.
We are comparing two different systems. There does not have a be a linear trend, or even an easily modeled trend, between driving habit and fuel economy. This is before we even consider that manufacturers can write code for the ECU to optimize certain behaviors for testing conditions that may or may not be applicable to both models.
Example - the 6th gear in the AT is so low and the engine produces so little torque at low rpms that it is not useful for accelerating, and can not easily maintain speed uphill. At higher speeds it may have issues just overcoming the force of drag. But it works great at a 60mph EPA test.
Driving a MT I can choose to stay in 6th gear all the time, eliminating gas wasting downshifts, and having more avilable power at lower highway speeds, allowing me to deal with slow traffic.
Now, depending on how YOU drive, one of those options will be better, while for how someone ELSE drives it may be the other.
My point is not that one is better than the other but that they each have strengths. I am not sure why you are so resistant to the idea that the MT might use less gas under certain conditions, and driving habits might adjust to do so.
05-27-09, 10:11 AM
#25
While it's true you can put the manual into 6th sooner you'd be bogging the car to do so... the auto gets into 6th well below any highway speeds... and thanks to having 2 overdrive gears it can downshift to 5th if you put strain on it at cruise and -still- be revving similarly to the manual when in 6th.
The new EPA tests aren't the same old "drive at 60 with the AC off" either... and they still show the auto beating the manual by several mpg both city and highway.
It's certainly -possible- you could find some weird condition under which the manual produces better mileage, but you can't really argue with the math and the gearing such that those conditions will be few, far between, and not resemble how just about anyone ever drives the car.
As to rscott, unless there's a significant difference in tire size between the cars what you describe simply isn't possible. An auto IS250 in 6th gear will turn lower rpms than a manual in 6th gear at the same speed. You can put the numbers into any rpm calculator on the net yourself to see em. (plug in the transmission gearing I listed, tire size, and the target speed, and it'll tell you the rpms the car will turn)
For example with 255/40-18 wheels at 70 miles per hour an IS250 automatic will be revving at 2051 rpms. Same tires, same speed, IS250 manual, will be 2666 rpms.
http://www.westerndiff.com/rpm.html
Use the bottom section... ring/pinion would be 3.73 or 3.91 and then transmission ratio is the ratio of whatever gear you're in (.79 vs. .58 for 6th for example)
The new EPA tests aren't the same old "drive at 60 with the AC off" either... and they still show the auto beating the manual by several mpg both city and highway.
It's certainly -possible- you could find some weird condition under which the manual produces better mileage, but you can't really argue with the math and the gearing such that those conditions will be few, far between, and not resemble how just about anyone ever drives the car.
As to rscott, unless there's a significant difference in tire size between the cars what you describe simply isn't possible. An auto IS250 in 6th gear will turn lower rpms than a manual in 6th gear at the same speed. You can put the numbers into any rpm calculator on the net yourself to see em. (plug in the transmission gearing I listed, tire size, and the target speed, and it'll tell you the rpms the car will turn)
For example with 255/40-18 wheels at 70 miles per hour an IS250 automatic will be revving at 2051 rpms. Same tires, same speed, IS250 manual, will be 2666 rpms.
http://www.westerndiff.com/rpm.html
Use the bottom section... ring/pinion would be 3.73 or 3.91 and then transmission ratio is the ratio of whatever gear you're in (.79 vs. .58 for 6th for example)
05-27-09, 10:55 AM
#26
Lexus Test Driver
You really need to ask yourself what your attempting to do...
Do I love this particular car because of emotional value?
Do I just want raw power?
Do I want to be the first one with a boosted IS250 becuase it's different?
If your looknig to be different, this is a cool project...you will need very deep pockets and probably even deeper resorces once you get to the ECU, but If it's power your after this is not the one...I would think a 2JZ swap would be a more affordable option...( not that it wil be cheap) but those engines are proven to laydown some power and someone has already dropped one in a 2IS. I think it was a drift car.
But I still think the AWD IS would be a cool car to pump power into if it could handle it, but again it's a big undertaking developing the first parts to with stand any real power.
Do I love this particular car because of emotional value?
Do I just want raw power?
Do I want to be the first one with a boosted IS250 becuase it's different?
If your looknig to be different, this is a cool project...you will need very deep pockets and probably even deeper resorces once you get to the ECU, but If it's power your after this is not the one...I would think a 2JZ swap would be a more affordable option...( not that it wil be cheap) but those engines are proven to laydown some power and someone has already dropped one in a 2IS. I think it was a drift car.
But I still think the AWD IS would be a cool car to pump power into if it could handle it, but again it's a big undertaking developing the first parts to with stand any real power.
05-27-09, 10:59 AM
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You really need to ask yourself what your attempting to do...
Do I love this particular car because of emotional value?
Do I just want raw power?
Do I want to be the first one with a boosted IS250 becuase it's different?
If your looknig to be different, this is a cool project...you will need very deep pockets and probably even deeper resorces once you get to the ECU, but If it's power your after this is not the one...I would think a 2JZ swap would be a more affordable option...( not that it wil be cheap) but those engines are proven to laydown some power and someone has already dropped one in a 2IS. I think it was a drift car.
But I still think the AWD IS would be a cool car to pump power into if it could handle it, but again it's a big undertaking developing the first parts to with stand any real power.
Do I love this particular car because of emotional value?
Do I just want raw power?
Do I want to be the first one with a boosted IS250 becuase it's different?
If your looknig to be different, this is a cool project...you will need very deep pockets and probably even deeper resorces once you get to the ECU, but If it's power your after this is not the one...I would think a 2JZ swap would be a more affordable option...( not that it wil be cheap) but those engines are proven to laydown some power and someone has already dropped one in a 2IS. I think it was a drift car.
But I still think the AWD IS would be a cool car to pump power into if it could handle it, but again it's a big undertaking developing the first parts to with stand any real power.
and you dont have to tell me about the power a 2JZ makes I have one of those to 
single turbo and all very much fun but they have some of there own little quirks but nothing like th IS does. I just wanted to be different and boost in my comfortable daily driver EVO and STI are way to stiff and rigid for me to buy one of those if thats what people are thinking I should have bought if i wanted boost.
05-27-09, 11:15 AM
#28
While it's true you can put the manual into 6th sooner you'd be bogging the car to do so... the auto gets into 6th well below any highway speeds... and thanks to having 2 overdrive gears it can downshift to 5th if you put strain on it at cruise and -still- be revving similarly to the manual when in 6th.
The new EPA tests aren't the same old "drive at 60 with the AC off" either... and they still show the auto beating the manual by several mpg both city and highway.
The new EPA tests aren't the same old "drive at 60 with the AC off" either... and they still show the auto beating the manual by several mpg both city and highway.
The new EPA tests consist of things such as letting the car sit in 95 degree heat for 10 minutes and then driving with the A/C on. The final number is still a weighted average of various tests.
if I wanted better city mileage I could skip 1st, 2nd, or 3rd gears, or even 2 of the three. Skipping 1 of them is fairly common for me. This is similar to the AT, I believe it starts in 2nd gear. If this was done in the EPA tests I'm sure the results would be near identical for city mileage.
as for the comment about the IS350, it is a technological feat and while similar, the two engines contrast in more areas than just displacement. Probably the biggest difference is that the 350 has direct *and* port injection and will vary the two based on throttle load and engine speed.
05-27-09, 11:17 AM
#29
You really need to ask yourself what your attempting to do...
Do I love this particular car because of emotional value?
Do I just want raw power?
Do I want to be the first one with a boosted IS250 becuase it's different?
If your looknig to be different, this is a cool project...you will need very deep pockets and probably even deeper resorces once you get to the ECU, but If it's power your after this is not the one...I would think a 2JZ swap would be a more affordable option...( not that it wil be cheap) but those engines are proven to laydown some power and someone has already dropped one in a 2IS. I think it was a drift car.
But I still think the AWD IS would be a cool car to pump power into if it could handle it, but again it's a big undertaking developing the first parts to with stand any real power.
Do I love this particular car because of emotional value?
Do I just want raw power?
Do I want to be the first one with a boosted IS250 becuase it's different?
If your looknig to be different, this is a cool project...you will need very deep pockets and probably even deeper resorces once you get to the ECU, but If it's power your after this is not the one...I would think a 2JZ swap would be a more affordable option...( not that it wil be cheap) but those engines are proven to laydown some power and someone has already dropped one in a 2IS. I think it was a drift car.
But I still think the AWD IS would be a cool car to pump power into if it could handle it, but again it's a big undertaking developing the first parts to with stand any real power.
Falken put a 2JZ in an IS350... but nothing else in the car worked (well, none of the original stuff anyway).
AFAIK nobody has gotten a 2JZ to work in a 2IS while retaining all the factory features (ie making the dash work, making memory seats work, making VDIM/VSC work, etc, etc...).
Supposedly at least two folks have tried, putting over 50k into each project (on top of the vehicle cost) without a working car.
