Our PO cut off the snorkle or airhorn on the air box and made a bigger hole. All it seemed to do is make MUCH more noise. I was able to find another airbox that I will replace it with.

Is this a common mod for HP or just somebodies mind game from the 80's when flipping the aircleaner lid was popular?

 

Wranglers have a similar trumpet and I read a while ago that people would cut it off for more intake and power.

No idea if it actually worked.

 

Looks like I'll have to be the contrary one here.

At least in my personal opinion, air intakes don't help on a TJ... not in the least. Better breathing air intakes do help a lot on many engines, like the Mustang 5.0L, where the factory air intake was purposely designed to be restrictive. Many (!) cars have purposely designed restrictive air intakes.

The TJ, at least on the 2.5L and 4.0L versions, the air intake was actually designed to be non-restrictive. It has a wide-open air tube and a huge surface area air filter with no baffles anywhere. And though the trumpet on the air box may look to some to be restrictive, it isn't either... really. The trumpet has two purposes: 1) To help keep water out by how it is shaped, and 2) to speed up the airflow velocity to help quiet the air intake and promote better combustion. Even with the trumpet in place, the TJ's factory air intake can easily flow more air than the engine is capable of demanding even at wide-open throttle and near redline rpms.

The only reason anyone would feel any difference if they put on one of the many aftermarket air intakes is if they were suceptible to the placebo effect. They sound louder so many people erroneously think that means it is flowing more air (it's not) which leads some people to think they're getting more power (they're not).

And no, they don't produce better mpg. If it were possible to pick up 2 mpg by simply modifying the air intake, Jeep would have JUMPED on that because they are desperate to achieve better fleet fuel economy to meet the ever-increasing CAFE fuel economy standards dictated to them by the Feds.

At least in MY personal opinion, you're much better off saving your $$$ and understanding why the TJ in particular really doesn't benefit from an aftermarket air intake. Butt-dynos aren't anything to rely on, that is for sure.

One last thing... you can't even trust the various 4x4 and Jeep magazines on their so-called "dyno tests". First, they never reviewed an advertiser's product they couldn't find something good to say about. Second, dynos can be made to show nearly anything you want and the hp and torque gains they tout are easily within the error range a dyno has. If you test the identical setup five different times on a dyno, you'll generally get five different results. They're not as precise a machine as some people think they are.

Sorry for the rant but I hate to see people waste their $$$ on some products that truly don't help a TJ. At least not in my opinion.

 

Well i cant stand the sound of the throttle quadrajet sound in a classy car. I I bet it will return some better throttle response too.

 

Engine & fuel engineering - value of inlet trumpet on air box?

 

I remember most of my friends doing this back in high school!

Okay... I did it too Made the air intake louder, but that was about it.

 

Good input (especially the link). Stared at my missing intake trumpet for a while and thought about buying a new air box...ended up with a snorkel instead.

Aside from the pressure differential, were there any big temp changes with/without the trumpet? I should have taken more than a mental note about intake temps without the trumpet, but noticed that the UG intake temps were in the low 100's (coolant temps 160's).

With my ARB snorkel I was hoping to use intake temps as a free ambient temp sensor, but it seems to be running about 20-30 degrees higher than ambient at the sensor (much lower than I was seeing stock without the trumpet). With regard to intake temps, do they affect performance much in a NA engine? No change in MPG's so far.