Airbox mod (new thread)
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Thanks for the links..
Have a question though.
When dyno testing, the environment is closed and usually a fan is running. Don't all these mods to the airbox yield barely noticeable differences especially when the external conditions to the car are the same every single time? The only thing that's changing is some of the airflow to the MAF and intake.
Have a question though.
When dyno testing, the environment is closed and usually a fan is running. Don't all these mods to the airbox yield barely noticeable differences especially when the external conditions to the car are the same every single time? The only thing that's changing is some of the airflow to the MAF and intake.
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
Originally posted by Lvangundy
Thanks for the links..
Have a question though.
When dyno testing, the environment is closed and usually a fan is running. Don't all these mods to the airbox yield barely noticeable differences especially when the external conditions to the car are the same every single time? The only thing that's changing is some of the airflow to the MAF and intake.
Thanks for the links..
Have a question though.
When dyno testing, the environment is closed and usually a fan is running. Don't all these mods to the airbox yield barely noticeable differences especially when the external conditions to the car are the same every single time? The only thing that's changing is some of the airflow to the MAF and intake.
The reason for increasing the air PRESSURE to the filter area is that ANY loss in pressure decreases power. On the stock setup the pressure loss begins at the feed over the intake and continues with every turn and bend to the filter, the filter itself, the MAF, the feed from the MAF to the throttle body, the TB itself, the intake passages, the intake valve and seat area. The pressure that actually gets into the engine is substancially less than the outside air pressure. At sea level this pressure starts at 14.7psi. If your engine, after all the restrictions, gets say 12psi into the cylinders and makes 250hp... you are making 20.83hp per psi of available pressure (250 / 12 = 20.83). So, if you can increase the pressure to 13psi you should pick up another 20hp.
Lexus Champion
Joined: Feb 2001
Posts: 3,124
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From: Texas
Originally posted by Lvangundy
Thanks for that input, but that's not what I meant..
ok how about..
How do the HP/TQ numbers change when making modifications to the airbox in a controlled (usually closed) dyno garage?
Thanks for that input, but that's not what I meant..
ok how about..
How do the HP/TQ numbers change when making modifications to the airbox in a controlled (usually closed) dyno garage?
This is all because of the mod NOT the ambient conditions. If the air temp, the barometric pressure and or the humidity changes... the relative power will change with the modded engine still making its relative higher power number.
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From: California
Originally posted by jbrady
Well... Ah... I didn't notice that you had reversed the air filter in you "tape" picture :eek:
Yes, keep the filter in its STOCK position. Mearly use the tape to take up the slack that the front cover leaves that the V clamp holds on to.
Now, the mod that I did on my LS400 creates as much flow and KEEPS the stock air feed over the radiator. This feed is cold air and also seals off some of the engine compartment heat. YOU MUST fabricate a cold air box. Look closely at my mod and you will see I am actually using cardboard to block off engine heat/air flow. I am drawing cold air from around the headlight area and the stock cold air feed over the radiator. The modified front cover helps form both part of a cold air box AND supports the factory cold air feed.
Well... Ah... I didn't notice that you had reversed the air filter in you "tape" picture :eek:
Yes, keep the filter in its STOCK position. Mearly use the tape to take up the slack that the front cover leaves that the V clamp holds on to.
Now, the mod that I did on my LS400 creates as much flow and KEEPS the stock air feed over the radiator. This feed is cold air and also seals off some of the engine compartment heat. YOU MUST fabricate a cold air box. Look closely at my mod and you will see I am actually using cardboard to block off engine heat/air flow. I am drawing cold air from around the headlight area and the stock cold air feed over the radiator. The modified front cover helps form both part of a cold air box AND supports the factory cold air feed.
I just did my air box mod and notice some nice results from stop and high revs. Hung pretty close with a SLK AMG at high speeds so Im happy. Gas mileage has improved a bit, I think I am getting around 22-25 mpg on the highway, I cant tell by stop and go driving because I only drive 4 miles each way everyday so it is hard to tell.
Last edited by LOTC; Dec 10, 2002 at 11:29 PM.
Lexus Champion
Joined: Feb 2001
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From: Texas
Originally posted by E-Dogg
Hey Jbrady do you leave the cardboard shield in there all the time? If so how secure is it.
I just did my air box mod and notice some nice results from stop and high revs. Hung pretty close with a SLK AMG at high speeds so Im happy. Gas mileage has improved a bit, I think I am getting around 22-25 mpg on the highway, I cant tell by stop and go driving because I only drive 4 miles each way everyday so it is hard to tell.
Hey Jbrady do you leave the cardboard shield in there all the time? If so how secure is it.
I just did my air box mod and notice some nice results from stop and high revs. Hung pretty close with a SLK AMG at high speeds so Im happy. Gas mileage has improved a bit, I think I am getting around 22-25 mpg on the highway, I cant tell by stop and go driving because I only drive 4 miles each way everyday so it is hard to tell.
Yes, I leave the cardboard in all the time. The picture shows the first shield I made. It fits snugly between the filter housing, the ABS block and the radiator with the "flaps" cut to help seal around the stock air feed box. Since the picture was taken I made an additional cardboard heatshield that fits around the back of the air filter box and creates a complete seal between the hot engine air and the filter inlet. That piece is held VERY tightly by the air filter housing itself. I intend to replace the cardboard with something more durable but it has been working perfectly for a couple of months now with no heat or moisture problems at all.
When I get a chance I will post more pics.
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From: California
Originally posted by jbrady
I am glad you made the mod! Cheap, easy and EFFECTIVE. Sounds great also.
Yes, I leave the cardboard in all the time. The picture shows the first shield I made. It fits snugly between the filter housing, the ABS block and the radiator with the "flaps" cut to help seal around the stock air feed box. Since the picture was taken I made an additional cardboard heatshield that fits around the back of the air filter box and creates a complete seal between the hot engine air and the filter inlet. That piece is held VERY tightly by the air filter housing itself. I intend to replace the cardboard with something more durable but it has been working perfectly for a couple of months now with no heat or moisture problems at all.
When I get a chance I will post more pics.
I am glad you made the mod! Cheap, easy and EFFECTIVE. Sounds great also.
Yes, I leave the cardboard in all the time. The picture shows the first shield I made. It fits snugly between the filter housing, the ABS block and the radiator with the "flaps" cut to help seal around the stock air feed box. Since the picture was taken I made an additional cardboard heatshield that fits around the back of the air filter box and creates a complete seal between the hot engine air and the filter inlet. That piece is held VERY tightly by the air filter housing itself. I intend to replace the cardboard with something more durable but it has been working perfectly for a couple of months now with no heat or moisture problems at all.
When I get a chance I will post more pics.
Lexus Champion
Joined: Feb 2001
Posts: 3,124
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From: Texas
My concern about metal would be rattle control. I am not worried about the heat of the metal as it would be easy to insulate and the main objective is keeping hot air from the engine from flowing into the filter. I would prefer to use PVC type plastic or the OEM type the stock box is made from but that is not easy to form.
The cardboard piece you see in the photos is the back of a legal pad. The second part I made from good old corregated box cardboard. Durable, function, cheap and UGLY!
The cardboard piece you see in the photos is the back of a legal pad. The second part I made from good old corregated box cardboard. Durable, function, cheap and UGLY!
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From: California
Originally posted by jbrady
My concern about metal would be rattle control. I am not worried about the heat of the metal as it would be easy to insulate and the main objective is keeping hot air from the engine from flowing into the filter. I would prefer to use PVC type plastic or the OEM type the stock box is made from but that is not easy to form.
The cardboard piece you see in the photos is the back of a legal pad. The second part I made from good old corregated box cardboard. Durable, function, cheap and UGLY!
My concern about metal would be rattle control. I am not worried about the heat of the metal as it would be easy to insulate and the main objective is keeping hot air from the engine from flowing into the filter. I would prefer to use PVC type plastic or the OEM type the stock box is made from but that is not easy to form.
The cardboard piece you see in the photos is the back of a legal pad. The second part I made from good old corregated box cardboard. Durable, function, cheap and UGLY!
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
Originally posted by E-Dogg
I never had insulation on my metal shield. I didnt think it worked real well because any cold air that would have entered would instantly be heated up by the warm sheet of metal.
I never had insulation on my metal shield. I didnt think it worked real well because any cold air that would have entered would instantly be heated up by the warm sheet of metal.
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
Originally posted by Lvangundy
Hey all -
Did a couple more short 0-60 runs. Times have went DOWN with open airbox mod!!
I even ran one yesterday in the middle of the afternoon (high 70's temp) and did roughly 8.6 / 8.7
Hey all -
Did a couple more short 0-60 runs. Times have went DOWN with open airbox mod!!
I even ran one yesterday in the middle of the afternoon (high 70's temp) and did roughly 8.6 / 8.7
that's a nearly a half a second quicker, correct?Do you have any heat shielding?
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From: California
Originally posted by Lvangundy
Good summary jbrady!
Ok- Here's my attempt at the airbox mod from what i could understand from LexusWhoSmokedU's post.
Yes, I used electrical tape, and was in a hurry and it was a night, I figured it would take 5 minutes so I ran outside and did it. I can clean up the tape later.
Good summary jbrady!
Ok- Here's my attempt at the airbox mod from what i could understand from LexusWhoSmokedU's post.
Yes, I used electrical tape, and was in a hurry and it was a night, I figured it would take 5 minutes so I ran outside and did it. I can clean up the tape later.
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No,,,, well..kinda
It's the mod, but done the correct way. That picture you see is me putting the filter on backwards (duh) I turned it around so the lipped edge of the filter is in the way it should be - just like if the cover was on.
Jbrady - Well, I wouldn't say the airbox mod is giving me a whole 1/2 second off 0-60 times, maybe 1/4 sec. The numbers are a little lower than with stock box, and alot less than with K&N (booooo!).
It's the mod, but done the correct way. That picture you see is me putting the filter on backwards (duh) I turned it around so the lipped edge of the filter is in the way it should be - just like if the cover was on.
Jbrady - Well, I wouldn't say the airbox mod is giving me a whole 1/2 second off 0-60 times, maybe 1/4 sec. The numbers are a little lower than with stock box, and alot less than with K&N (booooo!).