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How Can I Make My Is250 Perform At Its Best?


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The IS250 reaches the speed limit quite swiftly. I pull out of my neighborhood I can't drive more than 35mph. I reach it pretty swiftly.

Next I go about 50mph. 35mph-55mph is not bad.

Next I get on the interstate and 55-80mph is pretty good too.

So basically from 0mph-80mph might not be too good. But for normal driving the IS250 is fine.

WITH THAT SAID.

I took my car out the other day after not driving for a while and BOY was the car feeling slow. I checked the tire pressure and my rear tires were 10 (TEN) POUNDS BELOW!!!

Filled it up and now it's good.

SOOOOOOOOOOOOOOOOOO my question is this

What other things can I look at besides tire pressure to ensure my car is accelerating the best it can?

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The IS250 reaches the speed limit quite swiftly. I pull out of my neighborhood I can't drive more than 35mph. I reach it pretty swiftly.

Next I go about 50mph. 35mph-55mph is not bad.

Next I get on the interstate and 55-80mph is pretty good too.

So basically from 0mph-80mph might not be too good. But for normal driving the IS250 is fine.

WITH THAT SAID.

I took my car out the other day after not driving for a while and BOY was the car feeling slow. I checked the tire pressure and my rear tires were 10 (TEN) POUNDS BELOW!!!

Filled it up and now it's good.

SOOOOOOOOOOOOOOOOOO my question is this

What other things can I look at besides tire pressure to ensure my car is accelerating the best it can?

Make sure you: change all fluids, filters, pcv's, plugs, lubes, etc as per maintenance schedule. To clean out any carbon buildup, do 3-4 backtoback WOT runs, taking her up as far as you're willing to risk. Be sure your tires are prop inflated first of course. :P You can run some injector cleaner occasionally. You can read up on seafoaming to see if you want to do it. Or you can trade her in for a 350. :D

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Take out every 5000 or so miles and drive several miles in 3 or 4 gear at 4500 rpm. That will keep the cobwebs out of it.

I heard this before. Is there any validity to that practice?

Sure there is, especially if you reset the ECU prior to making that drive.

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Take out every 5000 or so miles and drive several miles in 3 or 4 gear at 4500 rpm. That will keep the cobwebs out of it.

I heard this before. Is there any validity to that practice?

Sure there is, especially if you reset the ECU prior to making that drive.

I need help with this. :huh: Can you please elaborate? :)

Well in the first place we used to blow the carbon etc out of motors by driving at high speeds. Since that isn't all that safe etc you can do the same thing by gearing down and running somewhat high RPM without having to drive 100 plus mph.

I think that even with high tech engines and good gas that over time there is some buidup that can be somewhat cleared this way. For instance if a car is driven slow and idled a lot like a taxi, the motor is going to get crud built up.

As for the ECU. When you reset it, it goes to new car default and leans how you drive. So if you drive a little hard once in awhile it's going to learn that.

There have been tests on dyno of normal driven car power and then reset ECU and drive fast power and there is a significant difference.

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Take out every 5000 or so miles and drive several miles in 3 or 4 gear at 4500 rpm. That will keep the cobwebs out of it.

I heard this before. Is there any validity to that practice?

Sure there is, especially if you reset the ECU prior to making that drive.

I need help with this. :huh: Can you please elaborate? :)

Well in the first place we used to blow the carbon etc out of motors by driving at high speeds. Since that isn't all that safe etc you can do the same thing by gearing down and running somewhat high RPM without having to drive 100 plus mph.

I think that even with high tech engines and good gas that over time there is some buidup that can be somewhat cleared this way. For instance if a car is driven slow and idled a lot like a taxi, the motor is going to get crud built up.

As for the ECU. When you reset it, it goes to new car default and leans how you drive. So if you drive a little hard once in awhile it's going to learn that.

There have been tests on dyno of normal driven car power and then reset ECU and drive fast power and there is a significant difference.

How do you reset the ECU?

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Take out every 5000 or so miles and drive several miles in 3 or 4 gear at 4500 rpm. That will keep the cobwebs out of it.

I heard this before. Is there any validity to that practice?

Sure there is, especially if you reset the ECU prior to making that drive.

I need help with this. :huh: Can you please elaborate? :)

Well in the first place we used to blow the carbon etc out of motors by driving at high speeds. Since that isn't all that safe etc you can do the same thing by gearing down and running somewhat high RPM without having to drive 100 plus mph.

I think that even with high tech engines and good gas that over time there is some buidup that can be somewhat cleared this way. For instance if a car is driven slow and idled a lot like a taxi, the motor is going to get crud built up.

As for the ECU. When you reset it, it goes to new car default and leans how you drive. So if you drive a little hard once in awhile it's going to learn that.

There have been tests on dyno of normal driven car power and then reset ECU and drive fast power and there is a significant difference.

How do you reset the ECU?

Disconnect the negative (black wire) battery terminal for 10 minutes.

You'll have to reset your window switches by running each window all the way down and back up after that.

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How do you reset the ECU?

You used to be able to simply disconnect the battery for a number of minutes. (Fifteen minutes seemed to be the magic number everyone threw around, but I always figured once you disconnected the power it only took a few seconds.) Anyhow, I'm not sure if there's any sort of battery backup on our cars these days. In which case, I suppose you'd be looking for a "reset" switch/combination/etc. Somebody here should be able to respond accordingly.

One thing to note is that your car's computer is "optimizing" itself for the way "you" drive. If you're not going to drive WOT all the time, there really is no benefit to resetting it. Afterall, its just going to relearn your everyday driving habbits. BUT - If you wake up one morning and decide you don't want to drive like a nancy anymore, go ahead and start from clean slate. Same goes for the opposite and you are suddenly concerned with poor gas mileage. You get my point.

But fear not, your car will hit WOT with or without resetting the ECU. How quickly it responds is open to debate.

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How do you reset the ECU?

You used to be able to simply disconnect the battery for a number of minutes. (Fifteen minutes seemed to be the magic number everyone threw around, but I always figured once you disconnected the power it only took a few seconds.) Anyhow, I'm not sure if there's any sort of battery backup on our cars these days. In which case, I suppose you'd be looking for a "reset" switch/combination/etc. Somebody here should be able to respond accordingly.

One thing to note is that your car's computer is "optimizing" itself for the way "you" drive. If you're not going to drive WOT all the time, there really is no benefit to resetting it. Afterall, its just going to relearn your everyday driving habbits. BUT - If you wake up one morning and decide you don't want to drive like a nancy anymore, go ahead and start from clean slate. Same goes for the opposite and you are suddenly concerned with poor gas mileage. You get my point.

But fear not, your car will hit WOT with or without resetting the ECU. How quickly it responds is open to debate.

The battery disconnect reset is in the owners manual.

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There have been tests on dyno of normal driven car power and then reset ECU and drive fast power and there is a significant difference.

bartkat... you'll need to show me where there have been these tests?????? :huh:

Please.... :D

Yes, please. It would be particularly helpful to share the tests on factory stock cars (i.e. non-tuned/non-flashed ECU's) like most, if not all, of the IS's on this forum.

Thank you.

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Take out every 5000 or so miles and drive several miles in 3 or 4 gear at 4500 rpm. That will keep the cobwebs out of it.

Take it out and run it up to at least 6000rpm in each gear. Then add a can of BG44k engine treatment to the gas every 5k miles. If you drive over 100mph add 3lbs to each tire pressure. Add an K&N lifetime air filter and check it every 3 mo to see if it needs cleaning and reoiling. Make sure 4 wheel alignment stays in check.

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Take out every 5000 or so miles and drive several miles in 3 or 4 gear at 4500 rpm. That will keep the cobwebs out of it.

Take it out and run it up to at least 6000rpm in each gear. Then add a can of BG44k engine treatment to the gas every 5k miles. If you drive over 100mph add 3lbs to each tire pressure. Add an K&N lifetime air filter and check it every 3 mo to see if it needs cleaning and reoiling. Make sure 4 wheel alignment stays in check.

I think back in the 60's, before FI, multi-cam, variable valve control, ECU controlled, etc., etc. like to days engines, "blowing out the carbon" might have been effective. But, today's engines don't have the same problems. They are extremely advanced in terms of automotive design, HP/Torque per cubic inch, and fuel management. I'd have to see some certified tests that demonstrate that taking a well-maintained IS250 driven by my wife (she is a very conservative driver) for example, testing it on a dyno. Then taking the same IS and letting me drive it (a lead foot, WOT kinda driver), then testing it on a dyno to compare any differences in "performance gains"..... I doubt that I will see any significant difference that has been attributed to some kind of "blowing out the carbon" or something that the ECU does to "learn my driving habits"......

By the way... K&N filters are not going to add any power or performance gains to an IS250 or IS350.

SHOW ME THE MONEY!!

That's just my worthless opinion.

I disagree. Advancements in engines don't keep them clean if they are driven mostly in town. And an ECU that has learned that type of driving isn't going to relearn from a couple high speed runs.

I've read of the dyno tests on reset ECU's on IS300's but don't remember where. If I run across it I'll post it.

Most all the general principle of older engines and cars still hold today. Tires aren't the same now either, but listen to the care suggestions. Still the same.

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I can understand the ECU learning how you drive and resetting might give you tad bit of hp. But I'd be willing to bet you could not tell the difference. Maybe the dyno will show a small gain, but you will not feel any significant increase in hp.

The most helpful and accurate information for the OP is, just keep your car maintained according to your manual. That will optimize the cars performance w/o any "modifications".

Having said that, and having read numerous posts from the OP, I think you really are not pleased with the IS250's performance and are longing for something with a bit more pep. It's not that unusual. The 250 just isn't a fast car plain and simple. And you aren't going to make it a fast car, plain and simple. Many of us who drive one are happy with them. They do what they are advertised to do, and we love them. But we didn't buy them for their exhilirating performance characteristics. I'm afraid that's what the OP is after here.

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K & N air filter-- DO , per dyno test, add 3-4 hp on almost any car--including IS 250. Increased air flow to the fuel/air mixture definitely increases performance on any car. Why do you think the larger ISF air intake system uses a different air filter than the standardj cotton Lexus filter? To increase air flow naturally. Obviously the person that said K & N doesn't make any difference has no experience with performance enhancements and related dyno tests. Just look on line or "in your hands" at the difference between the "standard" long cotton pleated filter on any stock filter and then look at the pleats on an K & N or FAE filter. Now try to blow air through both. Which has less air resistance? Not the cotton filter. Both aftermarket (and more expensive) allow for increased air flow and these are facts backed by "real world" tests on both street and race cars. Any person can look this up in 2 minutes on line. I have used K & N filters on Porsches and BMWs for 20 years and autocrossed both as well as an occcasional Lexus 250, 350. No, the 250 is not a Porsche or BMW but air filters are all not created equal. The facts and related articles speak for themselves

Fact--look up Dinan's larger air intake box for BMWs--and the related air filter. It does NOT use standard

cotton for one simple reason--too much air intake resistance vs a performance synthetic filter. Can you "feel" 2-4 hp?

No --but it is still there and also helps (very minor) with gas milage. Once again, people, this is not about creating a race car out of a 250 but simply doing all you can at a small cost to improve drivability.

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Take out every 5000 or so miles and drive several miles in 3 or 4 gear at 4500 rpm. That will keep the cobwebs out of it.

I'm interested in the spiders that make these "cobwebs".... ;)

Are they Black Widow type, or perhaps the Brown Recluse?? B)

Please explain these "spiders"? :huh:

Spiders make spider webs.

Cobwebs come from lack of use and lack of cleaning

Cobwebs could be considered an lesser version of dust bunnies.

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