smooth1

I have never heard that warmer weather can improve mileage. That is counter intuitive. Cold weather air is normally more dense that hot air, meaning more specific energy per cubic foot of air. Plus, efficiencies improve as the difference between intake air temp and exhaust air temp increase. Maybe the thinner air when the air is warm has less aerodynamic drag..?? Where did you hear that warmer weather can improve mileage? By the way... my IS350 is regularly getting about 23 mpg per tank with mixed city driving. Very consistent for the past 2 years. I've never seen it go above 27 for an extended highway trip. Oh, this could blow up into another huge debate........LOL!! The temputure of the air has no bearing on fuel mileage in a modern engine as the ECU will adjust to maintain the same ratios, no matter the air temp. The only thing that may change is the amount of power the motor will produce, but even then we are talking a very small number.

I drive from Orlando to Miami pretty regular, and that trip, in my 350 I get a measured 24 mpg. (Not according to the display calculations.) It can vary some by a mile or two per gallon, but I would say that is a pretty fair average MPG number. So, while I don't know the efficiency specifics of the 250, it does sound like you should be able to do better than that. I don't drive my car any differently from any one day to the next. Atleast not consciously. So if your granny driving and getting those numbers, I would track how much fuel your putting in and tack your mileage on the trip odometers to find out for sure. I know my on board computer calculation is off pretty regularly. I only use it as a general idea. ( Actually I don't use it all.) I like to leave it on the outside temp or the gear display.) :)

Actually it does, if you leave your lights to "on" all the time, the car will still shut them off as if they were on AUTO after the car is turned off. Unless you leave a door open theres no way to leave your lights on in a Lexus. Which is way better than the beeping warning that you can so easily ignore while hopping out of the car anyway. That is a nice feature.

It generally means that most people who attach thier self worth or identity to what they drive and the things around them are generally the only ones bothered with this. I drive what I want, I mod it the way I want, it's the color I want. I don't care what other people think, or say about it. While I admit that I may raz,(harrase) others, I personally don't really care.

I can understand your frustration, although the dealership has nothing to do with the Lexus as a manufacturer. So anything they do would be out of thier pocket. The only reason they are fixing the car is because Lexus Corperate makes them do it! LOL!!! I'm really sorry to hear about your issue though. A car with only 12k miles on it, in a wreck and on a lot for resale in such a short period of time, I don't know, just sounds like there should be more to the story I am sure your not being told. You said it was a lease, a 1 year lease? Somebody somewhere knows more than they want to say. I suspect the entire ECU is bad, and replaceing those are never easy, especially on these cars!

Look, I'm over this already. Your applying one braking test results to all braking applications, and that's not correct. They measure that way so as to compare one car to another, not one braking system to another. And actually even in ABS systems, that measurement form car to car is more of a gauge used to judge other componenets of the car such as suspension, vehicle weight, and the distribution of that weight. I mean come on, if what your saying is true in all cases of braking, then they could just take the size of the contact patch, the weight and speed of the car and tell you how long the braking distance is, yet that formula never translates to the actual stopping distances as the rate of decelleration is not a constant. Hence my question about the raised truck and the Lambo. If everything is equal in the brakes sytem, pads, and tires, and the ABS system, the Lambo will have a better stopping distance than the truck because 1, the trucks center of gravity is much higher, and the weight bias is already all at the front of the truck, so in that case, considering both cars have the exact same tires, also, the braking distance isn't determined by the ABS system, the tires or the pads, it's determined by the inertia and the trucks poor design. You keep leaving out the time it takes to get to lock up. And the ability to maximize that time. The only thing the braking distance in an ABS panic stop demonstrates is how well the ABS system brakes the car during a panic stop. In all other cases, the ABS system doesn't engage, so the pads, rotor, fluid, all matter then, as they all effect the amount of force needed on the pedal to produce a stop. take a 15 mph panic stop for example, no ABS required, the amount of force pushed on the pedal clamps the pistons on the pads that grip the rotors and bring the car to the quickest stop capable within the limits of the tires. No ABS needed. Are you still certian that changing the pads to a higher friction won't slow the car any faster? Going in the opposite diection, while changing my tires to a softer compound would help make my car faster, but only if when I touched the gas pedal it created instant wheel spin and I couldn't get any traction as the throttle simply over powers the tires. BUt my car doesn't have anywhere near that amount of HP. Yet I can still spin the tires right now! And if I put 50 more hp under the hood, and translated that to a higher usable torque curve, I would still be faster with the same exact tires! Again, room for improvements way before I have exceeded the limitations of the tires! Even in an ABS system, improving the suspension could improve braking distances in a 60-0 panic stop, but would offer little help in a slower, less dynamic braking situation where the weight of the car is still fully maintained.

No, the actual topic of the thread was about brake dust. Then someone mentioned they felt a difference in stopping distances, and you made it this thread about 1 specific scenario regarding total stopping distance in an ABS situation. Your the only one who has spoken of that.

This is pure conjector semantics btw! If 250lbs of pressure on a pad/rotor combination stops a car in 60 feet from 40 mph without engaging the ABS system, and you changed only the pad and stopped in 55 feet from the same speed with the same brake pressure, the pad created a shorter stopping distance. Period.

It's a trick question! the pads in that scenario are not the controlling force, it's the ABS system that controls the braking based on the information coming from the speed sensors monitoring the tires. The scientist, and you are correct in that in the ABS system, the pads don't matter, as the ABS system dictates the distance needed for stopping. But if they came out with a pad and rotor combination that could achieve tires threshold of adhesion without going over, then we wouldn't need an ABS system!!

I understand your wanting to make your point, especially after beating on the huge drum for so many pages. This was your first statement. You stated here "given" stop, not Full out braking distance panic stop or 60-0 best performance stop. Any given stop. then later you said: You yourself typed that. So up to the point of ABS kicking in, there is room for improved braking, be it the pads, the rotors, or the system that incorperate those. And the EWB system proves that. I know you think my examples are not relavant, but I'll try again, if you put a 36 lbs tire in the air and spun it up to 60 mph, and applied a brake to the tire, it wouldn't stop imediately with 1 lb of pressure. It would take a huge amount of clamping force just to overcome the energy built up. Add to that the load the car is putting on the tire, and you have almost 3 tons of spinning force that as to be broken before the traction issues even come into play. The fact is that ABS systems are not designed to acheive the shortest stopping distance, they are designed to create a controlled stopping distance. the new EWB is a system that is designed to use the maximum grip available by BOTH the pad and rotor, and the tire and road. the fact that the system targets the pad and the rotor clearly indicates that the hydraulic system used for braking today STILL DOES NOT ACHEIVE THE SHORTEST STOPPING DISTANCES. If your reverse rocket theroy makes the pad and rotor relationship stop the car in a shorter distance, then it is relavant, as the friction between the pad and the rotor are the stopping force for the tire. going back to my Dragster comparison, we have tons of HP that can easily break and over run the tires, yet, we have learned that by applying light throttle and waiting for momentum to be created can help us apply additional throttle and more power as we go. Thus creating huge amounts of acceleration along the way. Simply saying that the accelleration is limited to the traction ability of the tires is, well, like an understatement, or over simplified. Theres ALOT of dynamics that come into play to completely understand that statement. Take the IS 350. It can accellerate 0-60 in under 6 seconds with 306 hp, but to going from 60-120 in that same amount of time would take a sick (although desireable ) amount of HP! the same is true for braking, only in reverse. there is alot more to stopping in the shortest amount of distance than that. I'm not going to get into the semantics of right and wrong here. I think we are beyond that, and keeping the forum in persective, I will repeat myself. THE ADHESION ABILITY OF THE TIRES LIMIT THE ENTIRE PERFORMANCE ABILITY OF THE CAR, CORNERING, ACCELERATING AND BRAKING. But there is still room for improvemetns in all aspects within the limits of the tires. ABS can still be improved and offer shorter stopping distances. The grip of the tires can be further manipulated and controlled by improving components in the braking system, wether that be the pad, the rotor, or the system that operates them. Improvements in suspension and weight distribution can further improve acceleration abilities, and effective cornering, all within the limits of the tires.

Definatley the ones on the right!

It's not a hydraulic system, but it's a system that improves the relationship between the pad and the rotor, not the tires and the road. So taking that into account, then there is room for improvement in the rotor and pad friction design then right? I mean they are still using both. And although I can't find it now, and I wasn't going to say it till I did find it, I thought I might mention that 2 of his 40 patents are a new pad design that maintains a higher friction capacity which was used in those tests to get that shorter distance. It did not say that the pads themselves were a contributing factor or not, but I think then why did he invent them or patent them as part of his new design? I guess I am of the opinion that many scientist and engineers have come along and said "This is the law..." only to be overidden by new technology and a new scientist later. Nothing is ever absolute. Especially when it comes to such a diversified and complex physics nightmare like the car. There are so many acting and overriding laws of physics being applied at so many different stages of every act. take braking for example.......You did erroniuosly mention, or post an article with some now infamous scientist which stated that brakes tranfer mechanical energy into heat energy. That is not right. You can lock up the brakes, which will stop the car, and not produce any heat on the rotors or pads. You are transferring mechanical energy to the ground. The tires are doing that part, not the rotors. So I think you were both right. I know that sounds like a cop out, but in truth, you both were. The adhesion limits of the tire do in fact limit the braking ability. I think Bartkat, and myself included are just not convinced that we have acheived a system that effectively maiximizes the limits of those tires yet. There is still room for improvement.

Heres another link that explains it a little more. More Wedge info

Ok, cool, Then what about the new Electronic Wedge braking system that Seimans is developing? It's not new tires, but a system that maximizes the pad and rotor friction ability to create even shorter stopping distances? How can that be then? The Wedge

Knightshade Post #10 Bartkat Post# 15 Knightshade Post # 16 Knightshade Post #20 Is this the discussion? the braking distances are solely determined by the tires as the braking components are sufficient enouph to cause wheel lock in an ABS system and therefore the threshold is the tires? Is that where we are right now?

You ended up going with the Pilots? Great tires huh? I have to say, so far, for DOT tires, they are a great tire!! Hands down. I think awhile back you and I had debated the Pole Positions, the GY F1's and the Pilot's. All of which are great tires btw. I just like the Pilot's with a bit stronger shoulder and sidewall design. The input responce is spot on!

Todays braking systems utilize every aspect of braking from the driver input to the road and the surface your driving on. The entire braking system is only as good as the weakest component. Sometimes that's not the tires. I don't drive from 0-60 and then just slam on the brakes and get out. I drive my car in the real world. And in the real world, pads matter, rotors matter, tires matter, everything matters. That's great. None of it was the actual topic though. We went through this the last time you tried to make a post that sounded informed and had nothing to do with the discussion. The discussion was stopping distance. Which is generally measure as a slam-the-brake-pedal stop. Most commonly from 60-0. By pretty much everybody who tests stopping distance. You keep wanting to bring in racing (last time) or "real world" (this time- which you don't actually define) and then insist it has bearing on what we're discussing. I've said since the begining I am NOT talking about racing or other abuse of brakes...but also mentioned repeatedly how pads -can- matter there, and in what ways. Are you just grasping for something even marginally related you can try to be right about now? Because it's a topic I already covered pages ago in the thread. And even then, better pads CAN NOT improve stopping distance. They CAN increase the number of stops you get before stopping distance gets _worse_ due to fade though.. which isn't at all the same thing. They still don't shorten the distance of an initial stop. They can't. Again, I suggest you read the conclusions of the PF article... it explains the 4 things that brake system modifications can accomplish, most of them having to do with changing the feel of the system or increasing its ability to handle thermal extremes you might encounter on a track. I went over them more simply earlier in the thread. none of the things that those mods changed was stopping distance though. Even the folks trying to -sell- you brake upgrades (the honest ones anyway, like stoptech and brembo) admit that. I don't know, I tend to think that when I apply the brakes from say 45 mph, and the car comes to a stop, that is a stopping distance. Just because I haven't engaged an ABS system, doesn't mean I have or haven't acheived a point at which the brakes are applied and the car comes to stop. If I apply more pressure on the rotors, the car will have a shorter stopping distance. If I apply less, then it will take longer to stop, coorect? So if I change the brake pad, and I find myself having to apply more lever force to achieve the same stopping distance from 45 mph, then the pad did make a difference in my stopping distance correct? Even though I have compensated for that by pressing harder on the brakes? Or no, it's all the same?

Yeah, i understand the reality of it, but more people are drawn to drugs and those are sttill illegal.

I don't mind being wrong anywhere near as much as I mind your " Ultimate Ego I'm right" attitude! I think everyone can see that broccoli you have stuck between your teeth from the big grin on your face. I keep reminding myself your not tech, you just found an article or info that soemone else has put together and studied. So, about your Pulp Fiction article, it was written in 1991. Alot has changed since then. In 1995, those same scientists argued that the maximum amount of g force that could be applied to a tire is 1G. Yet, we have all seen and sometimes been the person who has exceeded that limit. Are you familiar with the formula to acheive a hp rating for your brake system? Do you know how many ft. lbs. of energy are lost during that braking? Do you know the formula for calculating braking power? Do you know that since that article was published, Brake assist, Electronic Brakeforce distribution systems, and stability control systems have been invented, advanced and refined? Which by the way, have been able to produce even shorter and even more controllable stopping distances? And all those systems incorperate the formulas listed above. The ABS system your comparing to is actually called a Reactionary prevention system. the new systems that have since replaced that out of date ABS system now use those formulas to calculate input from alot more sensors than just the tires as before. Of course in those systems the pads don't matter, because they didn't have a sensor on the pad, they had a sensor on the tires only. So that's why the tires were the important factor. So you can keep carrying your big club around whacking people on the knees with it all you want to. Todays braking systems utilize every aspect of braking from the driver input to the road and the surface your driving on. The entire braking system is only as good as the weakest component. Sometimes that's not the tires. I don't drive from 0-60 and then just slam on the brakes and get out. I drive my car in the real world. And in the real world, pads matter, rotors matter, tires matter, everything matters.

and So your saying that your normal road conditions and "non-racing driving style" require you to use maximum braking forces? I think we need to keep the same circumstances or keep the same controlled scene to referrence. Are we slamming on the brakes or not? Are we talking about doing it just once or repeatedly? Are we talking about all cars or one make? But my driving expereince says that both driving style and braking techniques, and reaction time effect stopping distance. OOohhh!!! I get it, you think the ABS system IS the shortest stopping distance! It's not. A trained driving proffesional will and can outbrake most ABS systems. ABS is designed to help the driver maintain control of the vehicle during emergency braking situations, not make the car stop more quickly. ABS may shorten stopping distances on wet or slippery roads and many systems will shorten stopping distances on dry roads. On very soft surfaces, such as loose gravel or unpacked snow, an ABS system may actually lengthen stopping distances. So what I would like to know is how your getting maximum brake force applied WITH ABS! Your not! You getting maximum controlled braking distances. Very different. This is a ridiculuos argument or debate. The scientist in that article is only putting fourth data from an ABS results standpoint. You seem to think that the acceleration example doesn't apply here, but it does. the scientist in your article is a moron! ALL MEASURABLE PERFORMANCE LEVELS ARE LIMITED TO THE TRACTION ABILITIES OF YOUR TIRES!!!! Acceleration, cornering, braking, suspension, all of it. Why are you just selecting the brake system to apply that statement to? Heres a question for you to chew on: A truck that weighs 3500 lbs with the body of the truck raised to 35 inches, an SUV that weighs 3500 lbs, and is 24 inches off the ground, and a BMW M6 that is 3500 lbs. that is 14 inches off the ground, and a LAmbo that is 3500 lbs that is 6 inches off the gorund. All have the exact same tires and all have the exact same brake system, and brake pads. Your saying they would all stop exactly the same distance from 80 mph? And yes, all have the same ABS system. Hmm, why do I not think so? There is alot more to the math of physics than you have touched upon. So, let's again talk about the pads only here for a moment. There are only two friction points for braking. The pads on the rotors and the tires on the road. And your saying, or atleast the report your citing states that the pads on the rotors don't matter, all that matters is the friction point between the tires and the road? And if I use a full race pad, like a Porterfeild R-4's or Performance Friction Brakes Compound 01, and 03 which offer great cold bite, coming in at 250 degrees and maintains a higher torque rate thru 1200 degrees with a smooth release in order to not overslow the car or overwhelm the cars set up. We are talking about just pads here. Which can easily be obtained. I think you have just misinterpreted the article. Oh, and btw, he said of course stopping distances were measured with several different compounds to see what produced the shortest stopping distances and they tested wear life.

Hhmmm, Yeah, so I've been reading up on this thread and thought I would of course put in a few words. I can't take it anymore. LOL!! Knightshade, I have to say, in my opinion, your just not qualified to read those articles. If all tires being equal determine the stopping distance and not the components, then how do you explain why my car can out accelerate other cars with the same tires? I mean, the road force friction being the only thing that stops a car is also the only friction that causes a car to accelerate also right? If both cars have enouph HP to cause the tires to break loose, then the amount of horsepower and torque become irrelevant then? Do I have to post a video of my car out accelerating other cars for that fact to be reinforced or are we on the same page with that? OK. Good. So, let's go back to the article you posted for a moment. His article on the chalk board is correct. The maximum amount of braking distance is going to be limited by the friction between the tires and the road. We all know that. That's a big "Duh!" in my book. But that friction and grip relationship between the road and the tires can be manipulated and changed with suspension set up, and break force distribution. (Putting more braking force to the front rotors than the back for example.) And also breaking input and technique applied by the driver can have a huge impact on the stopping distances. My point here is, Let's suppose a Top Fuel Dragster is capable of quarter mile times of 4 seconds. Do you think you could hop in one and produce 4 second quarter mile times? Regularly? No, probably not. In fact, you wouldn't even come close. So the maximum friction numbers never come into play then do they? That is the point of his article. It's not like you drive around town using maximum acceleration and then apply maximum braking forces to stop the car regularly, therefore testing the limits of all the components. My dad was brought in to help supervise and consult with the NLECTC back in 1996-2000 regarding this very issue for the National Institute of Justice. NLECTC Report The problem was that everyone was using different and sometimes "cheap" brake pads on their protol cruisers. And it was becoming a huge problem. So they put together a board to evalutate break pad performances for thier cruisers and then put together a model recommendation listing for brake pads. Like the Crown Vics were found to be better with a certian brake pad and the Chevy Malibu's were fitted with a different pad that worked better for it also. To say that the pads don't change braking distances is ridiculious because of the ABS systems, not despite them. Heres another test : Ford Club Brake Pad Testing That is from the Ford Muscle that my dad frequents and again helped to put that article together. ( He races Mustangs......alot of em!) LOL!! I can assure you all they did was replace the pads. I know what you think your reading there, but I promise you, I have myself replaced and upgraded entire braking systems to race ready levels and beyond, and we used the same tires we have always used and the before and after braking distances aren't even close!!!!! I've taken 80-90 ft off stopping distances plus, and greatly improved thier hot performances in some very harsh environments. Like giving a car to a rookie driver on the track is probably the worst and hardest conditions you can subject to a braking system. And after those races, usually only 10 laps on a 1/2 mile track, it's the pads being replaced for the next race, not the tires at that point.

In catalog #275, it's on page 47. The item number is 13019.

I don't think you can get a custom made head unit, I would think you would have to find one that fits the bill for what you want and then make it fit and completely rewire the install. I'm sure you will lose some features, but anything can be done with enouph money.

Turn the vehicle off. 1 - Press & Hold the ODO trip reset button on the instrument cluster. 2 - Turn on the ignition on without starting the motor.(Push IGN switch without pressing the brake.) 3 - Continue to hold the trip reset button until the ODO shows "000000" The light will now be reset for another 5k.

The idle is controlled by the ECU, so it may just have a programming issue, or somthing in the fuel delivery system is off. Which is probobly why the cel is on (Check VSC). And the 2008 IS model does have stiffer steering than before. I have jumped from driving a Camery to my IS and the steering is night and day in comparison.