View Poll Results: Do you have exhaust or intake mods on your LS400?
Voters: 28. You may not vote on this poll
Have you done exhaust or intake mods or both?
03-31-08, 08:07 PM
#6
I think due to our filter being right next to the MAF is the reason it is so prominent. Some cars have the filter a good 2-3+ feet from the Sensor, (ie: closer to beginning of tubing) -- Which wouldn't allow the oil to get on the sensor nearly as easily.
Just my 2 cents.. It isn't guaranteed your MAF will have troubles, but the benefit of a K&N is basically zero on this car. I just don't see it being worth the risk. If you do go with it, at least put on very LITTLE oil -- Less than you think it needs.. and let it dry for an hour or more outside the vehicle before you put it in.
Exhaust,.. go to town on that -- Just on the tubing (not including tips, tips can be whatever size you want) -- Don't go over 2.5inches -- and preferably keep it at 2 and 1/4" -- The V8 of the LS 400 needs alot of backpressure, and huge tubing without a power adder up front will hurt low end torque.
Have fun.
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03-31-08, 08:44 PM
#10
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03-31-08, 09:10 PM
#11
That is my thoughts, which is why I said it first 
Don't overoil, underoil if anything, and let dry for a long time. This is why most people end up messing up contaminating their MAF.
Again, I didn't say it was definite, and that K&N would cause the problem -- I just said there isn't any reason to add one. All evidence points to no savings in fuel economy, no power, and no increased protection on filtering.
I would use one for the heck of it if it didn't require oil. I just don't chance my sensitive MAF sensor for such a negligable effect. This isn't to say those who have them made a mistake, its a personal risk vs reward preference.
The whole argument it saves money and is easier to clean than replace with a new one is bunk on these cars imo. K&N is an easy $40 -- A new air filter is 8-10$. So you can get at least 4 new air filters for the price of a K&N. I typically don't have to change air filters but about once a year. So I'd rather pull old out throw away and have a brand new one in. Just me though.
Anyhow --
The MAF sensor is a simple device really.
It measures the volume of air coming into the engine. Hence "Mass Air Flow".
The electronic element(s) inside hold a voltage/current that is altered by the amount of air coming into the intake (passing through the MAF) -- This difference or addition is sent to the ECU which makes the appropriate commands for the engine.
To simplify -- The V8 Engine is an Air Pump.. meaning more air in = more air out. Thus more power in this scenario.
Of course the engine isn't just an air pump -- but it does the job. Make sense?
Of course there are much more technical ways to explain the MAF, but this is a good generalization.
Don't overoil, underoil if anything, and let dry for a long time. This is why most people end up messing up contaminating their MAF.
Again, I didn't say it was definite, and that K&N would cause the problem -- I just said there isn't any reason to add one. All evidence points to no savings in fuel economy, no power, and no increased protection on filtering.
I would use one for the heck of it if it didn't require oil. I just don't chance my sensitive MAF sensor for such a negligable effect. This isn't to say those who have them made a mistake, its a personal risk vs reward preference.
The whole argument it saves money and is easier to clean than replace with a new one is bunk on these cars imo. K&N is an easy $40 -- A new air filter is 8-10$. So you can get at least 4 new air filters for the price of a K&N. I typically don't have to change air filters but about once a year. So I'd rather pull old out throw away and have a brand new one in. Just me though.
Anyhow --
The MAF sensor is a simple device really.
It measures the volume of air coming into the engine. Hence "Mass Air Flow".
The electronic element(s) inside hold a voltage/current that is altered by the amount of air coming into the intake (passing through the MAF) -- This difference or addition is sent to the ECU which makes the appropriate commands for the engine.
To simplify -- The V8 Engine is an Air Pump.. meaning more air in = more air out. Thus more power in this scenario.
Of course the engine isn't just an air pump -- but it does the job. Make sense?
Of course there are much more technical ways to explain the MAF, but this is a good generalization.
04-02-08, 02:57 PM
#14
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Do you know of a good article or website that explains exhaust system design well?
For instance, I have heard that when optimizing an exhaust system, you should not think in terms of backpressure, you should think in terms of velocity.
For example, when people say the LS400 needs backpressure, what they actually mean is that the velocity needs to be high (i.e. by not using too large diameter tubing). Another way of achieveing backpressure is by using 4 inch tubing but filling it with steel wool...but that is not the way to make good power/torque either.
For instance, I have heard that when optimizing an exhaust system, you should not think in terms of backpressure, you should think in terms of velocity.
For example, when people say the LS400 needs backpressure, what they actually mean is that the velocity needs to be high (i.e. by not using too large diameter tubing). Another way of achieveing backpressure is by using 4 inch tubing but filling it with steel wool...but that is not the way to make good power/torque either.
04-02-08, 03:31 PM
#15
Lexus Test Driver
Do not go over 2 1/4" piping for your exhaust.
I'm thinking about having my entire ehaust system done into an "X pipe" type setup in 2" just to keep the quieness and get some more flow out of it. Just an idea for now though.. any thoughts on that??
Oh and if you do a mod to your intake like the "JBrady" or "Lexcost" setup, expect to get at least a 2mpg loss in mileage
I'm thinking about having my entire ehaust system done into an "X pipe" type setup in 2" just to keep the quieness and get some more flow out of it. Just an idea for now though.. any thoughts on that??
Oh and if you do a mod to your intake like the "JBrady" or "Lexcost" setup, expect to get at least a 2mpg loss in mileage