Air intake and exhaust. Is it worth it?

[Odinsink]

So far I have been very focused on the gear and the external stuff for my FJ. Lift, bumpers, tires, wench etc. How many of you bothered switching out your air intake and exhaust? Is it actually worth it or would that money be better spent else where?

 

[El-Dracho]

Hi!

I have upgraded my rig with another air intake at a very early stage. The snorkel w/ pre-filter and proper intake system to offer the engine cleaner air at roof level (in comparison to the dusty air on bonnet level) as I go quite often to remote areas where to expect sand, gravel and dust.

I always recommend to not just look at a snorkel because it looks more fancy but to take into account the whole air intake. I see many rigs equipped with a snorkel bu the rest of the intake is stock and in many cases still not sealed. From my point of view it makes only sense if the whole intake is properly sealed.

Same with the exhaust, the whole chain starting with the intake and ending with the last pipe of the exhaust is a complex system. So better get good advises and proper products from pros who are familiar with the specific vehicle instead of just adding something which looks or sounds good.

Cheers, Bjoern

 

[Odinsink]

Hi!

I have upgraded my rig with another air intake at a very early stage. The snorkel w/ pre-filter and proper intake system to offer the engine cleaner air at roof level (in comparison to the dusty air on bonnet level) as I go quite often to remote areas where to expect sand, gravel and dust.

I always recommend to not just look at a snorkel because it looks more fancy but to take into account the whole air intake. I see many rigs equipped with a snorkel bu the rest of the intake is stock and in many cases still not sealed. From my point of view it makes only sense if the whole intake is properly sealed.

Same with the exhaust, the whole chain starting with the intake and ending with the last pipe of the exhaust is a complex system. So better get good advises and proper products from pros who are familiar with the specific vehicle instead of just adding something which looks or sounds good.

Cheers, Bjoern

Thanks. I am 100% only worried about my trucks performance and it holding up long term. If I get a little bit of power thats nice. But I dont want to spend money on something that isnt truly functional

 

[El-Dracho]

So it is a Toyo FJ Cruiser you own? Maybe there are some Toyo guys around here who know this vehicle well and could give some advises?

 

[Odinsink]

So it is a Toyo FJ Cruiser you own? Maybe there are some Toyo guys around here who know this vehicle well and could give some advises?

Correct.

 

[M Rose]

Watch @Michael newest YouTube video where he talks about why he replaced his stock exhaust in his 80 series.

 

[USStrongman]

Couldn't agree less. These engines used to be big air pumps that could be manipulated with increased air, fuel and spark timing, but with EFI and ECU's, not so much. The computer will do what the manufacturer has it tuned to do, and adding anything else to it is a waste... expect snorkels, which provide a completely different performance. Exceptions are things like filters that allow the engine to work slightly less restricted but does not improve power in any meaningful way.

Find one cold air intake (CAI) or exhaust manufacturer that has a DYNO sheet (not bulletpoints in their ads) of before and after on your vehicle and I will change my my mind. CAI and exhaust on modern vehicles are marketing hype with no real dyno proof that their products improve anything. The only way to improve power is with improved air flow, improved ability to provide extra fuel, spark ability and most importantly, a way to tune your ECU. Without changing the mapping in your ECU, your engine will default to the power curve developed by the manufacturer based on current sensor readings.

Dont waste your money unless it can be proven with dyno sheets.

 

[Highplainsdrifter]

You need to be careful with cold air intakes the location can actually make it get hot causing power loss. The best thing for an fj power wise would be a supercharger but I would say lower gears is all you need

 

[RoarinRow]

I changed mine because my truck came with an open style K&N air filter system. I did not like how it was so open to the elements. Instead I replaced with with a S&B enclosed box. Looks and sounds better. I already changed my exhaust to a Magnaflow exhaust. The stock or exhaust that it came with needed replacement.

Went from this:



To this:

 

[Downs]

Not on a FJ but on my XJ I modded the stock airbox to draw air from the cowling area which is where the HVAC system gets it's air from. This also moves the intake up to the base of the windshield. Exhaust I just left stock.

 

[LostInThought]

I hesitate to comment on this one because CAI's are almost a religion with some folks and their value has changed over time. But, here goes...

In addition to what USStrongman said about the ECU/EFI issues, there's another thing to pay attention to if you modify the intake: The oscillation of half of the pistons doing an intake valve cycle for each revolution of the crank, a poor intake design can create a (loud, roaring) standing (stationary) pressure wave at the open end of the intake. This standing wave works against the airflow, so, more recently (at least post-2002) automotive engineers have started adding resonance chambers on the intake carefully sized to reduce/prevent the formation of the standing wave allowing for smoother (quieter, but faster/more consistent) airflow into the intake. (Experiment with your home/shop vacuum cleaner hose: when it's unobstructed, you hear a smooth continuous 'whoosh' at the open end of the hose, but when you alternately cover/uncover the end with your hand, you hear a 'thumping')

If the vehicle is older and has no ECU, and no resonance chambers, a modern cold air intake will probably be helpful. Most of the gains will be at RPMs between idle and the bottom of the powerband.

If the vehicle is older and has an ECU but no resonance chambers on the intake, adding a well designed modern intake that pulls colder air than your current intake *might* gain you a little horsepower at RPMs between idle and the bottom of the powerband - though it's extremely unlikely to make a significant change to the peak horsepower.

In a newer vehicle with resonance chambers, pick carefully and remember that a loud roar at the intake can indicate a standing pressure wave blocking air induction. If you have an OBDII reader, you might be able to watch the mass airflow sensor at several RPM points to get an idea of whether you're actually feeding more or less air to the engine.

As always, more power = more fuel = lower fuel efficiency.

The exhaust side is a little simpler - the design trade-offs are flow and noise - a high-flow cat-back exhaust system will be louder than the stock system, but as above, you might gain a little horsepower, again mostly isolated to RPMs between idle and the bottom of the powerband, (especially so for newer vehicles).

 

[Dilldog]

I am 100% against "cold air" and washable K&N style filters when it comes to a rig used off highway. I always say leave these things to track or street driven rigs. Why, a "cold air" intake requires air movement, so low speed on a trail they wont do any good. I dont think it will harm anything either, but its not worth it. Second washable filters, yeah not with a 50 foot pole. Sure they flow better, but why would something flow better, because it doesnt filter as well. Honestly on a trail your #1 concern should be filtration. As an engine tech I have actually denied warranty replacement of cylinder packs because of K&N style filters, because they just dont do the job.
Second Im kinda meh on exhausts on off road rigs, mostly because of my ideas of what Im doing. My train of thought is I love loud exhaust on the track, find it anoying on the street, and in the woods it flings me into homicidal rage, lol. For an off road rig Im agaisnt most performance exhaust purely out of respect for keeping the woods quiet and serene.
As far as actualy power mods go, most newer engines are so dialed in that bolt ons dont do much.
To add: the legit way to increase air into an engine while not sacrificing filtration is to increase the capacity of the filter. On a light duty rig this would require some custom fabrication work to mount a bigger air box, so you can run a bigger air filter. Filter capacity actually makes more of an impact than flow through media anyway.

 

[Downs]

A must read if you are thinking of running "high flow" oiled gauze filters. K&N is a good marketing company but a garbage filter maker.

K&N Air Filter Review - Debunking the Myths (and why OEM is better)

Before spending your money on an aftermarket intake, let's debunk the misleading incomplete info about filtering and horsepower in the sales literature.

www.nicoclub.com

 

[Smileyshaun]

A small bump in flow on the exhaust can sometimes help but usually people go way to big and to free flowing and while it may sound faster all it’s done is moved the hp up in the rpm range and killed off some TQ on the low end .... the exact opposite of what you want off-road

 

[Odinsink]

Lots of good information here. I was looking into a snorkel and exhaust set up.

 

[Dilldog]

...As always, more power = more fuel = lower fuel efficiency...

I will disagree with this to a point. When using bolt ons to boost power, sure. But if you go into engine internals and select camshafts, cylinder heads, injectors/ carburetors and such properly you can massively boost efficiency and thus get better power and fuel millage.

 

[diabetiktaco]

On the 4.0 the intake is in the wheel well. Not a great place if you plan to go through water. The snorkel will raise that and allow cleaner air to enter the engine. However, I've had a snorkel for about 2 years and the air filter get way dirtier quicker. Is that a good or bad thing? I don't know.

 

[Dilldog]

have to dis-agree with re-usable filters.
they came stock on all our quads and dirt bikes and the
K&N in my stepper is waaay old , bought it in the early '90's and still doing a fine job. a lot of money spent on paper filters for that amount of time.
granted i don't have a CAI, but i do clean and oil it reg.
and i like my trucks to have a growl when i'm on the throttle. sound is the soul of your rig. if i wanted to drive a soul-less no sound appliance, i would get a tesla....
View attachment 168484View attachment 168485

You're welcome to disagree, just presenting my experience as an engine technician. It's not that I'm opposed to this style of filter across the board, my Corvette runs one but it's a track car and like your pickup limited on how big a filter I can run so it's a good option. But for dusty off highway environments, I'm a strong no.
As a side note most power equipment also runs a prefilter, and those engines don't last long enough to worry about losing the cross hatch on a cylinder. It's all a game of balance.
To Add: on modern engines there's also mass air flow sensors to worry about. They can and will be effected by any access oil in a reusable filter should it be over oiled.

 

[MOAK]

I am 100% against "cold air" and washable K&N style filters when it comes to a rig used off highway. I always say leave these things to track or street driven rigs. Why, a "cold air" intake requires air movement, so low speed on a trail they wont do any good. I dont think it will harm anything either, but its not worth it. Second washable filters, yeah not with a 50 foot pole. Sure they flow better, but why would something flow better, because it doesnt filter as well. Honestly on a trail your #1 concern should be filtration. As an engine tech I have actually denied warranty replacement of cylinder packs because of K&N style filters, because they just dont do the job.
Second Im kinda meh on exhausts on off road rigs, mostly because of my ideas of what Im doing. My train of thought is I love loud exhaust on the track, find it anoying on the street, and in the woods it flings me into homicidal rage, lol. For an off road rig Im agaisnt most performance exhaust purely out of respect for keeping the woods quiet and serene.
As far as actualy power mods go, most newer engines are so dialed in that bolt ons dont do much.
To add: the legit way to increase air into an engine while not sacrificing filtration is to increase the capacity of the filter. On a light duty rig this would require some custom fabrication work to mount a bigger air box, so you can run a bigger air filter. Filter capacity actually makes more of an impact than flow through media anyway.

I agree 100% with everything you have said. There is an OB video out there that is a rig walk around with a Toyota Engineer that has built his 80 series, with, you guessed it, no snorkel, no cai, no exhaust mods. And ya, loud exhausts in the woods/wilderness is just plain obnoxious and completely against leave no trace ethics. Noise and light pollution are not cool.

 

[M Rose]

So I have been working on my Bronco the past week and noticed I need to address both intake and exhaust. My muffler hangs lower than the transfer case skid plate, the catalytic converter has been smacked by the control arms at some point so it needs moved and replaced, and then the intake is in a stupid place and needs upgraded... It’s too low in the engine bay and is sucking in way too much dirt and water. So yea it’s getting better intake system and exhaust system. Aftermarket exhaust doesn’t mean louder, just means more efficient and better placement of delicate parts. Making the intake suck doesn’t necessarily mean CAI. Just watch my build over the next couple of weeks as I address these issues.