tr0ubl3

Hey guys I have a 99 GS400 and just switched from K&N intake back to stock. It seems that my car pull harder, more responsive, and gives my Borla a better sound. I also had an SRT intake before K&N and didn't notice any difference in performance even with the ecu.

I've been driving with the stock intake for a week now and I notice that I get better gas mileage. One guy in my area had a K&N intake on his GS400 and switched back to stock and noticed the same thing on his car.

KcMoGS430

iTrader: (1)

Interesting. This makes me want to put the factory intake back on with a drop in K&N and see what I get. Any numbers to back up your theory.

mitsuguy

iTrader: (2)

https://www.clublexus.com/forums/mai...highlight=myth

Tested and proven...

tr0ubl3

When I had the K&N I get about 18 mpg on the highway. Now with the stock intake I'm getting 21-22 mpg. I always kept my K&N cone filter clean.

21SF

iTrader: (1)

The whole point of an intake is to increase air flow so you can increase amount of gas as well...expect better gas milage without one.

NEbiker10

iTrader: (1)

Couple things I noticed in that Linked write up.....He used a short ram intake...short rams are never as efficient as a true CAI with a heat shield. With a short ram the filter is in the same location as the exhaust manifolds which create a massive amount of heat which explains the 20 degree increase and loss of power.


I have a K&N FIPK and I have a Positive increase in power and response, not to mention the sound vs a stock box is awesome.

Here is a dyno sheet from stock to K&N FIPK 57-9011. The numbers do not lie and if they do...lawsuit to K&N for false advertising

http://www.knfilters.com/dynocharts/57-9011_dyno.pdf


main reason why you never see positive MPG gain if because A-more fuel and B-you floor it a lot more to hear that sweeeeeet v8 noise

kdick91

This is a gross over-simplification. A stock intake CAN be better. Like in the link posted earlier, if you get an eBay intake with NO heat shielding and NO tuning, then absolutely the stock intake in better. The amount of heat soaking will vastly outweigh the benefits of increased air flow. And above all else, the car is only designed to accommodate so much change, and sometimes adding an intake will be too much change for it. If the stock intake is ALWAYS better, there would be a much smaller market for changed the intake. There are so many variables to consider and without dyno, 1/4, or thorough MPG numbers to slap down, I feel like this is mostly in your head. Sorry to step on toes, but anyone here who has done any amount of considerable modification knows that a ton of variables come in to play and as long as you aren't 'cheaping out', the stock intake, more often than not, will fall short of a nice intake system with adequate heat shielding.

NEbiker10

iTrader: (1)

01LEXPL

iTrader: (10)

I simply modded my airbox [in my ES] for better flow. Removed the resonator [which makes air go thru it to quiet it down], removed it, and added a part of a CAI pipe below the inlet to let more air in - its louder and feel more responsive.

I'd suggest doing that - another thing it gut the airbox [all those raised parts inside, grind them down]. Best way to do it IMO [and proven on a lot of VW's too vs SRI & CAI] so i took this model and worked around it.

I might remove the rubber piping before the TB this year for some CAI piping, but leaving the airbox alone. Look at the Joe Z intake, same concept, retains all the stock stuff but loses the rubber pipe. GL!

tr0ubl3

When I bought this car it already had an SRT intake. Few years ago I sold it and went with K&N. I never experience this car with the factory intake until last week. Even my friend notice the difference. I'm sure most aftermarket intakes are better than stock for other cars. I believe the design of our stock intake is better than most aftermarket intake.

NEbiker10

iTrader: (1)

You "Feel" the difference is just that...having a dyno sheet to showing there is a power loss with a proper gs400 intake is another.

Fact vs opinion

K&N provides a Dyno sheet with Stock box and their FIPK....Are you suggesting they are lying and manipulated it????

Personally I believe the dyno rather than you and your friend "feeling" it pull harder

sam12345

iTrader: (1)

Do you know how to read a dyno sheet? Look at the kn dyno sheet and you will see that you loose considerable power below 3500 rpm. Yes, you gain power above 4000rpm. Now ask yourself how often you rev your car above 4000 rpm. Second point, if you loose power when you are accelerating from 800 rpm to 3500 rpm at a loss of power and then you gain power from 4000 to 6000 rpm vs a stock intake that has more power from 800 to 3500 rpm which one has a faster average. Third point, is the extra power from 4000 to 6000 rpm worth the extra dirt in your engine? (because kn are terrible at filtering). Fourth point noise and power are not mutual. Fifth point, notice how conveniently their dyno sheet starts at almost 3000 rpm, I wonder how much more is lost below 2000 rpm (where your car will be most of the time under normal drving)

http://www.knfilters.com/dynocharts/57-9011_dyno.pdf

GS4_Fiend

iTrader: (22)

That is true. With regular OEM intake you will get good low end torque and reasonable high end torque. With big aftermarket intake you will definitely lose low end and have some gain in high end torque. I just dont think it's worth to spend money for a little gain. But it's your money.

denut-L

iTrader: (11)

Let's see a race between a stock intake GS and a aftermarket intake GS. Who wants to be the pig tester here?

mitsuguy

iTrader: (2)

Read my thread I linked to above...

No two cars will be identical, even brand new from the factory... I tested this on my car with multiple runs, back to back, and never noticed a difference one way or the other... if there was a difference, it was too small to measure, and I actually had times slower with the aftermarket intake than stock...