What kind of rear axle in the 2IS?
11-25-13, 12:21 PM
#16
A McPherson system still uses a shock and coil spring (almost always in a coilover configuration), but is definitely not more advanced than a multi-link (like in the rear) or even a dual A-arm (like in the front) of a 2IS. A McPherson system gives you little control over how the alignment (camber in particular) changes through suspension travel whereas a mult-link gives quite a-lot of control. Not to say that a McPherson system is bad, there are plenty of cars with great handling that use McPherson struts.
11-25-13, 11:31 PM
#17
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Okay, I see what you're saying. Most multi-links use separate coil spring/shock absorbers as opposed to McPherson, anyways.
When I go through the suspension forum, a lot of people are talking about switching to coilover's. What's that about? Why downgrade to lesser quality components? For ease of adjustment? I assume that there's some way to have a variable or adjustable ride hight with coil springs...
I'm also trying to figure out any info on the differential. Someone in the forum mentioned that it's open and not LSD. I also read elsewhere on the forum that the rear diff fluid shouldn't be changed because it doesn't house mechanical parts like a typical (probably not the best word, but I'm assuming the diffs in our car are more advanced?) differential does.
When I go through the suspension forum, a lot of people are talking about switching to coilover's. What's that about? Why downgrade to lesser quality components? For ease of adjustment? I assume that there's some way to have a variable or adjustable ride hight with coil springs...
I'm also trying to figure out any info on the differential. Someone in the forum mentioned that it's open and not LSD. I also read elsewhere on the forum that the rear diff fluid shouldn't be changed because it doesn't house mechanical parts like a typical (probably not the best word, but I'm assuming the diffs in our car are more advanced?) differential does.
11-26-13, 08:13 AM
#18
You (usually) aren't downgrading to lesser quality by putting in an aftermarket coilover system, it is a matter of how the nomenclature is used.
By definition a coilover is a shock (or damper if you prefer) with a coil spring over it. There is no inherent adjustment in a coilover or coil spring. The 2IS comes from the factory with dual A-arms in the front with a coilover shock, and in the back a multi-link system with a coilover shock. Here is a typical OEM coilover:
(I just pulled the image from google, it isn't from a Lexus. Based on the logo I'm guessing this is an OEM BMW front McPherson strut coilover, ignore the extra spring.)
When people talk about upgrading to coilovers they are talking about an aftermarket coil-over shock configuration where the shock body is threaded to allow changes in spring pre load and/or ride height. Most aftermarket coilovers allow choices in spring rate, provide separate ride height adjustment, pre-load adjustment, and some kind of damping adjustment, which gives you plenty of options to really screw things up!
Here is the ever popular BC coilover:
It offers separate pre-load, ride height and compression/rebound (damping) adjustment.
Here is a higher end coilover that you might find on a race car:
It has tender and main springs, a remote reservoir (to increase the volume of oil and keep the shock cooler) pre-load adjustment, rebound adjustment, low speed compression adjustment, and high speed compression adjustment.
All three of the items in those pictures can legitimately be called "coilovers", but the quality, cost, usage, and range of adjustment in them is vastly different.
As far as the differential goes it is an open differential and there is absolutely nothing special or advanced about it. It most definately DOES have mechanical components in it and people recommend against changing the fluid because Lexus doesn't recommend changing the fluid. Ever.
By definition a coilover is a shock (or damper if you prefer) with a coil spring over it. There is no inherent adjustment in a coilover or coil spring. The 2IS comes from the factory with dual A-arms in the front with a coilover shock, and in the back a multi-link system with a coilover shock. Here is a typical OEM coilover:
(I just pulled the image from google, it isn't from a Lexus. Based on the logo I'm guessing this is an OEM BMW front McPherson strut coilover, ignore the extra spring.)
When people talk about upgrading to coilovers they are talking about an aftermarket coil-over shock configuration where the shock body is threaded to allow changes in spring pre load and/or ride height. Most aftermarket coilovers allow choices in spring rate, provide separate ride height adjustment, pre-load adjustment, and some kind of damping adjustment, which gives you plenty of options to really screw things up!
Here is the ever popular BC coilover:
It offers separate pre-load, ride height and compression/rebound (damping) adjustment.
Here is a higher end coilover that you might find on a race car:
It has tender and main springs, a remote reservoir (to increase the volume of oil and keep the shock cooler) pre-load adjustment, rebound adjustment, low speed compression adjustment, and high speed compression adjustment.
All three of the items in those pictures can legitimately be called "coilovers", but the quality, cost, usage, and range of adjustment in them is vastly different.
As far as the differential goes it is an open differential and there is absolutely nothing special or advanced about it. It most definately DOES have mechanical components in it and people recommend against changing the fluid because Lexus doesn't recommend changing the fluid. Ever.
11-27-13, 01:52 PM
#19
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Thanks for the detailed breakdown of the coilovers. I think I've got what I need to know now.
Is there any reason why Lexus doesn't recommend changing the fluid? Its just unnecessary to a car under normal driving circumstances? I've heard that if you take your car to the track, that changing rear diff fluid is something that you do in preparation for each track day since a lot of heat is generated under all that stress.
Is there any reason why Lexus doesn't recommend changing the fluid? Its just unnecessary to a car under normal driving circumstances? I've heard that if you take your car to the track, that changing rear diff fluid is something that you do in preparation for each track day since a lot of heat is generated under all that stress.
11-27-13, 06:03 PM
#20
^Well, 99% of Lexus drivers really don't test the performance limits of their vehicles; thus the reason Lexus says there's no reason to change it. But if you're like me and you actual "DRIVE" your vehicle on a daily basis, I'd recommend a flush every 60k. I'll be doing a diff flush coming up next year, perhaps before summer.
Well, on a true racecar, I can see the diff fluids being flushed regularly. Here are the reasons why :
*Like you stated, they create TEMENDOUS heat and are the fluids CAN breakdown during extended durations
*Most racecars will be using an LSD of some sort, and to extend the LSD's life, it is just a smart thing to do.
*More than likely, the racecar's diff clearances are looser than OEM spec, thus leading to more movement equaling more foreign material in the fluid (aka metal particles).
Just a few I can think of off the top of my head; 2 of the 3 above are reasons why I regularly changed the fluid in my LSD trans in my Honda Civic back when. Though I shimmed my Quaife LSD closer to OEM spec, I still changed the ~1.9 qts of fluid every oil change.
Well, on a true racecar, I can see the diff fluids being flushed regularly. Here are the reasons why :
*Like you stated, they create TEMENDOUS heat and are the fluids CAN breakdown during extended durations
*Most racecars will be using an LSD of some sort, and to extend the LSD's life, it is just a smart thing to do.
*More than likely, the racecar's diff clearances are looser than OEM spec, thus leading to more movement equaling more foreign material in the fluid (aka metal particles).
Just a few I can think of off the top of my head; 2 of the 3 above are reasons why I regularly changed the fluid in my LSD trans in my Honda Civic back when. Though I shimmed my Quaife LSD closer to OEM spec, I still changed the ~1.9 qts of fluid every oil change.
11-27-13, 07:29 PM
#21
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I don't think I push it too hard, but the pedal reaches the floor at least twice a week and I just hit 83k on it. The previous 17k being all me, and everything before, I think the car was babied.
If its never been changed, I'd like to do it at some point as well.
What about transmission fluid change?
If its never been changed, I'd like to do it at some point as well.
What about transmission fluid change?
11-28-13, 08:55 AM
#22
^LOL, only twice a week? Mine hits the floor about every other light! Some folks like me "drive" the car, while other let the car drive them. In my case I'd recommend a fluid flush routine. But in your case (as you described), I getting don't see the need for it. But for a peace-of-mind thing, there's no harm.
Trans fluid is another "lifetime" fluid; but others say they've had there's done. But the problem with our transmissions is that they're a totally sealed case. No fluid input or drain plug. The ONLY way to exchange or drain trans fluid is to hook it up to a fluid exchanger via the trans cooler lines. And even then, there are estimates that only 25-40% of the old fluid is removed and replaced with new.
Trans fluid is another "lifetime" fluid; but others say they've had there's done. But the problem with our transmissions is that they're a totally sealed case. No fluid input or drain plug. The ONLY way to exchange or drain trans fluid is to hook it up to a fluid exchanger via the trans cooler lines. And even then, there are estimates that only 25-40% of the old fluid is removed and replaced with new.
11-28-13, 11:23 AM
#23
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Haha. Well I have an aftermarket warranty good for another year and a half, so maybe I should push it hard while I can. My car before this was a 5.0 Mustang and I still regret not having as much fun with it as I could've.
What are the limits of these cars? How do you know which sort of abuse the car can handle and which it cant?
What are the limits of these cars? How do you know which sort of abuse the car can handle and which it cant?
11-28-13, 05:36 PM
#24
Yes, you should! 
What fun did you have in the 5.0 that you haven't had in the 2IS (besides changing gears of course)? You can do everything that the 5.0 could do, but yet with more class :
Drifting -
Racing -
The limits are pretty much up to your driving skill and the tires/brakes. Even in stock form, these IS350s are pretty stout. I have yet to hear a horror story about a 2IS breaking down on a track due to mechanical failure.
What fun did you have in the 5.0 that you haven't had in the 2IS (besides changing gears of course)? You can do everything that the 5.0 could do, but yet with more class : Drifting -
Racing -
The limits are pretty much up to your driving skill and the tires/brakes. Even in stock form, these IS350s are pretty stout. I have yet to hear a horror story about a 2IS breaking down on a track due to mechanical failure.
11-29-13, 12:59 PM
#25
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Haha, those videos were great. I didnt realize this car could drift so well... Might need to look for an empty parking lot soon.
What fun haven't I had? Just getting it sideways, hahahaha. The mustang was so ridiculously slippery. Just a quick tap on the throttle from a turn at like 30mph would easily break it loose. I disabled the traction control on the Lexus though and tried the same thing and the car still had so much more grip. It looks like I'll need to push the threshold.
I really dont know much about tires but I've got Bridgestone Potenza RE760's on my car. From a quick forum search, people say theyre a pretty good value tire, but a few knowledgeable car people (a local car meetup I go to with all these rich people who track their cars) say that my tires are really thin... I know nothing about tires so I thought "thin tires = bad". Looks like I know what I'll be studying up on next.
What fun haven't I had? Just getting it sideways, hahahaha. The mustang was so ridiculously slippery. Just a quick tap on the throttle from a turn at like 30mph would easily break it loose. I disabled the traction control on the Lexus though and tried the same thing and the car still had so much more grip. It looks like I'll need to push the threshold.
I really dont know much about tires but I've got Bridgestone Potenza RE760's on my car. From a quick forum search, people say theyre a pretty good value tire, but a few knowledgeable car people (a local car meetup I go to with all these rich people who track their cars) say that my tires are really thin... I know nothing about tires so I thought "thin tires = bad". Looks like I know what I'll be studying up on next.
11-29-13, 08:36 PM
#26
Yeah man, set it onto "S" mode and click it down into 2nd gear so it'll keep you in the higher rpms and keep you in that gear...and go to town!
Well, you said it right there; it'll actually take MORE effort to make this car loose traction.
Those tires aren't bad actually, and will give you pretty good grip...especially in the summer on a dry surface. When they said "thin", they probably meant the tire's sidewall. Well, the 2IS comes from the factory with a 40 series tire; some might think that's a "thin" tire right off the bat. But the smaller the sidewall, generally speaking, you'll have greater tire stability under heavy cornering situations due to less sidewall flex. Here's some general details about tires that might help you in the future:
http://www.discounttire.com/dtcs/infoSidewall.do
For the past 2.5yrs I've been running BFG KDW IIs; I enjoy having the symmetric tread pattern so I can rotate the tires from side-to-side (must dismount off the wheels though).
Well, you said it right there; it'll actually take MORE effort to make this car loose traction.
Those tires aren't bad actually, and will give you pretty good grip...especially in the summer on a dry surface. When they said "thin", they probably meant the tire's sidewall. Well, the 2IS comes from the factory with a 40 series tire; some might think that's a "thin" tire right off the bat. But the smaller the sidewall, generally speaking, you'll have greater tire stability under heavy cornering situations due to less sidewall flex. Here's some general details about tires that might help you in the future:
http://www.discounttire.com/dtcs/infoSidewall.do
For the past 2.5yrs I've been running BFG KDW IIs; I enjoy having the symmetric tread pattern so I can rotate the tires from side-to-side (must dismount off the wheels though).
12-06-13, 01:58 PM
#29
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Yeah, it was a little embarassing. "Whats the red circle around the... - oh ****."
Buy yeah, sideways is fun, and it still does take a quick depress of the pedal. Car has some real nice grip.
Buy yeah, sideways is fun, and it still does take a quick depress of the pedal. Car has some real nice grip.