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The formulation of both the tread and sidewall is different in summer tires vs. winter tires. It's a fact, and if you choose not to believe it, that is your business. But for the sake of everyone around you, I hope that you do chain up at the slightest hint of a snow flurry. I can guarantee you that appropriate tires on packed snow and ice are superior and safer than summer specific tires. I have seen it, and independent organizations test it. http://www.canadiandriver.com/winter/tires/snow_tires.htm http://www.tripcheck.com/Pages/RCMap.asp?m...v=TractionTires "It's a fact..." Facts are almost always printed in hardcopy somewhere but try as I might I cannot find any references that indicate that summer tires are any less capable of remaining "soft" than are winter specialty tires. Granted, there is lots of documentation indicating that many winter tires have specially formulated rubber compounds so as to keep their grip in COLD weather. But where does it say that those special rubber formulations are not used in "summer use only" tires...??? And keep in mind that it is in the industries BEST interest to sell EVERYONE two sets of tires. And I see NOTHING in the links you supplied that refutes my overall position. The Oregon link was especially interesting to me because not too many years ago we would often pile into the car about noon on Friday and head south to Mt Hood or Mt Bachelor. As I remember it in those days the Oregon "road patrol mounties" didn't give a nat's behind about the type of tires you had just that you had to have chains on if/when required. If road conditions ahead required additional traction then it became chain up time regardless of drive types (our Jeep had RWD/AWD/4WD and 4X4 modes) or tire tread. And front tire chains alone DID NOT SUFFICE for FWD vehicles. I remember at least one time that the Oregon "mounties" required me to take my front chains off the front of my Jeep and install them on the rear before they would allow me to proceed. Anyone out there that can give us the latest approved procedure for the road to Mt Bachelor beyond the Sun River cutoff when extra traction is required...??

Your LS430 deserves nothing less than to be shod with the quietest and most comfortably riding tires in the marketplace. For me that has always been "summer only" Bridgestone Turanzas for my '92 LS400.

Bosch Icons seem to work wonderfully on my RX.

You must be talking about all-season tires, not summer tires. Summer tires turn to hockey pucks somewhere around 35-40F and are insanely dangerous in any type of winter conditions. Having driven the same vehicle in snow on different tires, I can assure you that winter specific tires are vastly superior to all-seasons in ice and packed snow. It has more to do with the tire compound than actual tread pattern, but the effectiveness is both real and profound. NO, I truly, really, meant SUMMER tire. "Summer tires turn to hockey pucks somewhere around 35-40F....." Assuming tire manufacturers have a rubber formulation that allows winter "specialty" tires to remain "soft" in cold weather what makes you of the mind that the same formulation would not be used for summer ONLY tires..?? Not too many years ago it was an accepted fact that winter specialty tires had shorter tread life than their summertime counterparts. Have you checked those tread mileage wear ratios lately...?? "Insanely dangerous....." I might say that about your winter specialty tires running on hard packed snow or ice....... Again, my need for running on really adverse road conditions is fairly rare, 2 or 3 days most winters provided I don't go off snow skiing or travel off to central MT. So, for those rare times of need it is FAR more practical for me to simply install tire chains and be on my way, on my way around and generally passing anyone that thinks their 4WD/4X4, with the absolute BEST winter specialty tires, can go where I can. Oh, when was the last time you saw a winter specialty tire tested other than on the "loose" stuff, or up against a "summer use" only tire on packed snow or ice..?? All I have ever seen, going back maybe 10 years, is one winter tire against another brand or type of winter tire and always with the ability to "fling" that loose surface stuff to the side. Marketing, showmanship.....

Ask me why I care NOT how fast my brake pads wear....!! Relatively inexpensive preservation of MY LIFE.

I'd be willing to bet bet you a beer that the difference you are experiencing has more to do with your tires and brake pad material than it does with your rotors. ;) You owe me a beer...! With the 78 in the rain if I remember to dry the brakes via a slight application before I really need serious braking my stopping distance is acceptable. My experience at looking over the various cars participating in the 24 hours of Daytona for the past seven years is that almost all run solid rotors with center venting/cooling.

"..Tach jumping erratically...." I beleive the tachometer is driven via an output from the engine management/control ECU and tehrefore is NOT directly related to actual engine RPM. I would find the ECU and unplug and reconnnect ALL of the connectors to it.

Keep in mind that the "wiggleing" might have NOTHING to do with the engine starting. It took an hour(??) for AAA to arrive and that's lots of time for some component that was, had, overheated to cool down. Modern day fuel injected engine aren't as subject to vapor lock as was the old carburated engines but it does still happen. Or a "clogged" fuel line that "cleared" by pure happenstance?? Had you by chance just recently run the fuel tank to an unusually LOW level..??

You are claiming a 25% increase in fuel mileage from different spark plugs and an air filter. That's ridiculous. "Ridiculous..." Well, maybe not... Suppose the oil wicking off that K&N into the HIGH SPEED intake airstream quickly contaminated the MAF/IAT module sensors and now the engine is running EXTREMELY lean, maybe even only in "cruising" mode.... Did the 1990 LS have knock sensors...?? But then at 300,000 the compression ratio might be so compromised that even severely leaned it doesn'y knock.

Why not discard the intake filtering altogether and maybe improve FE another ~20%...?? At 300,000 miles that engine is likely overdue for an overhaul anyway.

Yes, and at least $0.50 goes to the cost of relabeling a standard $2.00 off the shelf spark plug to a "private label" one. I'm sure we can all imagine where the remaining $22.50 goes....

Yes, I suspect that arrangement does more, a LOT more, to contributing to BLINDING oncoming drivers vs extending the night distance night vision for the owner. I can't imagine that the forward beam pattern of the foglight assembly/reflector, even if the lens were of the clear type available on Ebay, would contribe anything anything significant to night distance vision. Note that all of the provided pictures are with the camera look AT the car, no pictures of the forward beam pattern. But then those would really be worthless absent Before and After pictures. To be fair I have often thought of somehow putting bi-xenon projectors in the main headlight assembly of my "92 LS. But if I do so I will first switch, DIY, to a CLEAR lens. Almost all bi-xenon projector assemblies also use a standard halogen bulb for high beam "fill in", enhancement, so a separate set of driving lights would still likely be required.

Insofar as I know there are only TWO reasons for using drilled or slotted rotors, Brake pad "outgassing" under SEVERE use, and RAIN. Very few passenger car drivers ever use their brakes in any manner that would be severe enough to result in outgassing of MODERN day brake pads. Trying to maintain a speed slightly above "sensible" while driving down a curving LONG mountain pass road, for instance. Here in the Puget sound area we often have, encounter, the RAIN situation. My 78 911 does not have drilled or slotted rotors and I have had instances of sliding almost into an intersection as a result. My '01 911 does have drilled rotors and I haven't notice any such problem. On the other hand back when the '92 LS was our daily driver, as is the RX300 today, I haven't had any instances resulting from rain or water puddles and both of those have SOLID rotors. But I am intrigued by the industries latest idea which seems to be to pre-dry the brakes via slight application of braking pressure if the windshield rain sensor triggers.

No, it seems that battery post/connection corrosion raises it UGLY head in the springtime, MOSTLY.

You can often accomplish the same thing by COMPLETELY bleeding the brake system, including use of the bleed valves on the ABS pumpmotor (front passenger side of the engine bay) and the TC pumpmotor/accumulator assembly. If you have a dealer do a brake bleed/flush be sure and tell them of the two eaxtra/additional bleed valves. Another procedure some more knowledgeable Lexus dealers might use is to elevate the vehicle and "force" the TC to activate via driving the rrear wheels while elevated. Traction control will immediately activate thereby moving "fresh" brake fluid through the two pumpmotor systems. Now step lightly on the brake and ABS will activate...

Do I need a new wiring harness for these - something heavier duty? I've been reading this is adivseable. The problem, a MAJOR problem, for the early LS series, is that the "angle" between high beam use and low beam use is simply too great, by factory design. If you set the headlight assembly for good, proper, forward low beam coverage then the high beam mode will mostly illuminate the night sky. There is a HIGHLY effective, simple, and relatively inexpensive solution. Add a set of driving lights and power them with the OEM high beam circuit which you have disconnected from the headlight assembly.

Our '92 LS400, ~130,000 miles, has been fueled with regular from the get-go. Knock sensors....

5HP out of 300 is ONLY slightly more than 1.5% 20 dyno runs, 10 runs each, switching plugs back and forth each run, would be necessary to prove the 1.5% wasn't just PURE happenstance. And just what spark plug was used as opposition, one from a Ford model "T"...??? And was it a 2005-2008 engine with all the engine management ECU functionality in place..??

1] For the clear and certain majority of time your engine is running the throttle plate is the primary RESTRICTION to intake airflow. 2] the oil impregnated K&N series will eventually, possibly quite quickly, contaminate your MAF/IAT sensor due to oil molecules being continuously "wicked" away into the high volume airflow. 3] Assuming there might be a "freer-flowing" K&N without oiling then it should be obvious that it will provide less engine protection than the OEM version. But yes, the Porsche GT3's we have run each year at the 24 hours of Daytona always use non-oil type K&N filters, or the equivalent thereof. But those cars spend an inordinant amount of time at/on FULL throttle and it is expected that they the engines will be torn down, inspected, and fully overhauled after each race. But yes, a K&N filter might well last over 100,000 miles, but at what other $$$ cost...?? This is, after all, a LEXUS you own.

I have converted almost all of my '92 LS400's interior lighting to halogen bulbs, slight higher or same wattage but BRIGHTER. Why do you think LEDs will not work for LCD backlighting..?? LEDs bright enough to "light" the passenger cabin usually generate so much heat that the required heat sink makes them unusable.

Yes, but JDM Lex had all the options and earlier, I have seen the filters but that was at the AC repair place. Also car-stuff.com has cabin air filters for your model 92 thru 94 and they look just like the one that came out of my Celsior. I have the actual Lexus shop/repair manuals for my '92 LS400 (and the '90 set) and there is NO cabin AIR filter. Could you be mistakenly referring to the A/C's REFRIGERANT filter..??

It could, possibly, work but with a more sophisticated design than $15 indicates. Yes, if the IAT sensor signal is constantly modified the engine management ECU will quickly null it out, reset the baseline. But if the modifying resistor were OUT of the circuit at idle, throttle closed, AND/OR with the torque converter lockup clutch engaged, then the A/F mixture could probably be enriched otherwise. During idle times or at constant speed cruise the upstream oxygen sensor is used exclusively to control the A/F mixture while at the same time reseting the MAF/IAT "baseline" parameters.

I'm pretty sure the Cadillac STS was FWD. Also quite sure it had an over-running clutch in the driveline such that it had NO engine compression braking. Additionally I seem to remember that it would dethrottle the engine if TC (stabili-trac??) activated. The control system would NOT allow full use of the NorthStar engine if the driver went WOT to "dig-out" from a full stop due to the danger of loss of control. Methinks that it was all THAT that convinced Cadillac to abandon FWD and return to building REAL upscale cars.

Thanks for the response. My Subaru had proper winter tires, with the snowflake emblem, and in my experience they stopped and turned better than all-seasons (M+S stamp) with chains. I will definitely be looking into a second set of wheels to wear winter tires on the Lexus, as well. Just for clarification, when it snows in the Sierras, CalTrans is right there scraping the roads and folks are busy driving on them. It gets packed and icy pretty quickly, and you the biggest danger is the person in their SUV who has never driven on snow before plowing into you. That is precisely why I spend the extra dough on proper tires - it increases my chances that I can maneuver out of the way of such an idiot. Since I have gotten by for so long (back to 87 at least) running nice and quiet and comfortably riding summer tires throughout, summer, fall, winter & spring here on the eastside of Seattle, and you're being in the bay area I would advise the same. Hereabouts we rarely have snow and ice "events", and for those few I don't mind making the chain-up effort. I am also of the opinion that since my summer tires have more tread contact area than almost any, if not all, specialty "winter" tires they actually give me better performance on ice or packed snow. IMMHO winter specialty tires are only advantagous if the surface "stuff" is loose enough for tread "bite". So, most of the time my RX is nice and quiet riding and comfortably so.

Hmmmm... Fact: Having the A/C "on" helps to prevent a CEL (and by default, a VSC code).. FACT...it is RARE that the A/C compressor will run continuously, FULL TIME, with the A/C "on". But.... The electric radiator cooling fans always run at high speed WHENEVER the A/C compressor clutch is engaged. Conclusion: Your engines are over-heating, or threatening to overheat. Until this moment I was puzzled as to why a "windy area" would have something to, would be pertinent, to the CEL and VSC. Not if my theory, above, proves to be correct.. A "tail wind" or a "quartering tail wind" vs, say, no wind at all, or a head wind, might very well result in making it harder to keep the engine coolant within a reasonable temperatrue range. Conclusion (#2): The engine direct driven radiator cooling fan's VC (Viscous Clutch), and/or the low speed mode of the electric radiator cooling fans, has/have failed. Conclusion (#3): Some engine component/sensor has failed resulting in the engine operate in a non-optimal range wherein it is highly subject to marginal radiator cooling capability. The A/C operation provides just enough cooling "boost" to make a difference. Throttle body can't be cleaned...BS, PURE BS, more dealer profit for/from installing new parts. Probably cleans the old one in preparation for the next..... lol, they probably do clean the old one. Some of the things you explain about the a/c I don't understand. I understand how the compressor works but what is a CEL? In my assumption, I figure since when the a/c is running the rpms rise somewhat and therefore do not give the throttle a chance to settle in it's lowest position. I have no hypothesis for my theory and it may not make any sense, but that's my theory. And is my engine really threatening to overheat. I've been running the a/c for the past couple of years now. I just make sure I add R-134 so it doesn't run out. CEL, Check Engine Light. Do you know, have you noticed, where the engine coolant temperature gauge normally sits..?? My '92 sits, always has, just a tad above the second mark. If the engine management control system detects that the coolant temperature is above normal, or is rapidly rising but not yet "overheated", the electric fan will be switch on. Keep in mind that the engine coolant need not actually overheat in order for the system to "note" that the heating level is above "normal" or is rising too rapidly for overall conditions. If turning on the electric fan doesn't reverse the trend then the engine will be put in limp home mode. And..., as a general rule for modern day cars the engine RPM does not rise to compensate for additional loads at idle. Even before, as, when the A/C compressor clutch is enaged the engine management system will open the DBW throttle, or idle air bypass, slightly, only as necesasary, in order to maintain the FIXED idle RPM with the additional load.