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I'm glad I found this thread, looks like I have sizable targeted audience here.
Why bother to go through all of these mods. I have these specialty pills that you can drop in the gas tank which will improve your vehicle's horsepower and its fuel economy. It'll sound awesome, too!
Hmmm.....snake oil!! LOL! Hell, put the blue pills down the tank!!
I'm glad I found this thread, looks like I have sizable targeted audience here.
Why bother to go through all of these mods. I have these specialty pills that you can drop in the gas tank which will improve your vehicle's horsepower and its fuel economy. It'll sound awesome, too!
You are aware that the point of this "mod" is the increase in sound, not power, right?
Besides, I don't know how shoving some pills into the tank is going to change sound...
Last edited by arentz07; Aug 22, 2025 at 04:54 PM.
I used to manage the largest independent Auto Research lab west of the Mississippi. I have tested over thousands of AM products.
People have always reached out to me and asked for my comments about certain products that I have tested. Of course, I can't comment about the results of the products because it's proprietary information. However, this is what I told them: "If it seems too good to be true, then it probably is."
This is our > $1 mil AVL 4 wheel dyno in the cold room, temp can be adjusted from -40°F to >140°F.
I used to manage the largest independent Auto Research lab west of the Mississippi. I have tested over thousands of AM products.
People have always reached out to me and asked for my comments about certain products that I have tested. Of course, I can't comment about the results of the products because it's proprietary information. However, this is what I told them: "If it seems too good to be true, then it probably is."
Well, those pills definitely seem too good to be true.
I'm puzzled why some of the peeps are getting so bent out of shape over other people doing stuff with their cars. Now I know this is a more mature audience here with this car, and some cosmetic or noise related mods may be viewed as RICE, but truly if theres nothing hugely dangerous or debilitating going on, why bother (nobody yelling at people in spacers thread that its dangerous). I hope there are still some more adventurous souls on here, who want to have fun modding with probably one of the last old school cars.
I admit the concern raised here about potential impacts to MPG/power on low end due to change of intake is valid and gave me a pause, healthy discussion, and while one reference was linked, I'd probably want to see more evidence if indeed this mod is detrimental, so without more precise testing/data I concluded mod is safe for me, given that a few people measured MPGs and noted nothing drastic. If i lost horsepower, those 340s, M2s and M3s would have beaten me anyway.
Sorry if this came off as a mini rant, now I'm off to drive my riced out Lexus (and yes I did pop a couple of those Fuel Pills with my coffee)
I'm puzzled why some of the peeps are getting so bent out of shape over other people doing stuff with their cars. Now I know this is a more mature audience here with this car, and some cosmetic or noise related mods may be viewed as RICE, but truly if theres nothing hugely dangerous or debilitating going on, why bother (nobody yelling at people in spacers thread that its dangerous). I hope there are still some more adventurous souls on here, who want to have fun modding with probably one of the last old school cars.
I admit the concern raised here about potential impacts to MPG/power on low end due to change of intake is valid and gave me a pause, healthy discussion, and while one reference was linked, I'd probably want to see more evidence if indeed this mod is detrimental, so without more precise testing/data I concluded mod is safe for me, given that a few people measured MPGs and noted nothing drastic. If i lost horsepower, those 340s, M2s and M3s would have beaten me anyway.
Sorry if this came off as a mini rant, now I'm off to drive my riced out Lexus (and yes I did pop a couple of those Fuel Pills with my coffee)
I don't think anyone is getting bent out of shape. Fair point to bring up that no one SHOULD be getting bent out of shape - a lot of open-air intake designs are suboptimal but do so for the purposes of increased sound. This is similar.
Actually, this isn't a bad mod. However, having the intake air control valve open at all times allows hot air under the hood to enter the engine as opposed to cooler air. It could skew the ECM fuel/air mapping. The risk outweighs the benefits.
If someone has $4k laying around and doesn't know what to do with it. I'm more than happy to perform a FTP-75 and an US06 on your vehicle with the mod to get more precise testing/data that you're looking for.
For the OP, make sure to reconnect your mod back to the original before you get an emissions test. By modding it, your emission control devices are considered tampered.
The ticket would be to retain the cold air source, while eliminating the sound damping of the stock pipe. Lexus may have been wise to do that rather than this bimodal system.
The ticket would be to retain the cold air source, while eliminating the sound damping of the stock pipe. Lexus may have been wise to do that rather than this bimodal system.
Whatever they did to the LC 500, it worked. Shame it didn't get added to this one.
Whatever they did to the LC 500, it worked. Shame it didn't get added to this one.
The colder air source is important. All my Acuras, BMW M2 and Mustangs the "cooler air source" was always from a "snout" than brought
air in from the grill in to the intake air box.
I haven't looked under hood yet and studied the IS 500...mine is a week, 10 days from arrival. I'm seeing warmer air being
"mixed?" with outside cooler air. Is that what's going on here??
Actually, this isn't a bad mod. However, having the intake air control valve open at all times allows hot air under the hood to enter the engine as opposed to cooler air. It could skew the ECM fuel/air mapping. The risk outweighs the benefits.
If someone has $4k laying around and doesn't know what to do with it. I'm more than happy to perform a FTP-75 and an US06 on your vehicle with the mod to get more precise testing/data that you're looking for.
For the OP, make sure to reconnect your mod back to the original before you get an emissions test. By modding it, your emission control devices are considered tampered.
I'm waiting for more rants!
The valve itself opens at 2,800 rpm when the system is plugged in and operating as designed. Any modern fuel injection system will factor in airflow and air temperature. As that's measured after the flap and not before, the system won't have "fueling issues" as it will take that into effect. So while ingesting warmer engine bay air isn't ideal, the car is already doing it as designed from factory.
By 2,800 rpm in first gear you're at 15.79mph with the stock tires. After you pass 16mph the flap is open at WOT and every gear change will result in your rpms remaining higher than 2,800rpm. The car does have a cold air inlet as diagrammed above that feeds from around the front grille. This will provide some cool air to blend with the warmer engine bay air. Any power loss would be only from introducing a larger portion of hot air below 16mph than would otherwise be provided. Otherwise there is absolutely 0 impact as the system is operating as designed.
As it stands the car is more traction limited than power limited between 0 and 16mph so I don't understand any of the claims made on the older ISF related posts about this affecting 1/4 mile times or trap speeds. I'd love to see the exact timeslips for those runs.
