Do throttle body spacers work on Jeep Wrangler TJs?

Chris

Chris

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There are some products out there that claim to be able to improve on the already significant engineering that has gone into your motor. The 4.0 engine in the Jeep Wrangler TJ is well known to be a hard engine to get power out of in terms of "bolt-on" modifications. You don't stand to gain any power on these engines from cold air intakes (that's been debunked by the Jeep engineers themselves in this thread) and another big one that I keep seeing people waste their money on are throttle body spacers.


airraid-throttle-body-spacer.jpg


Designed to be installed between your Jeep Wrangler TJ's throttle body and its intake, these devices claim to be able to create an intense “vortex” of air which will help better atomize fuel when the two are mixed together. According to the manufacturers, this is accomplished by a series of grooves which are carved inside the device itself.

Unfortunately, there are some flaws behind the engineering in this device. From a common sense perspective, if it were really that easy to add significant amounts of horsepower or fuel mileage gains, then these spacers would be stock equipment from the factory.

Automakers need every competitive edge they can get in today’s market (especially when it comes to fuel economy) and none of them are leaving anything on the table in that area. The idea that a “vortex” could help the air and fuel mix together is not a bad one. However in the modern fuel injected engine air and fuel are not mixed together until they both find themselves in the cylinder.

In primitive forms of fuel injection (such as throttle body injection or old-fashioned carburetor models), where fuel was sprayed directly at the throttle body and then mixed with the air immediately before being routed to the cylinders, then perhaps a spacer would be of some benefit. However, the technology used in the Jeep Wrangler TJ's fuel injection system precludes any useful effect from such a device. The chances that the air would still be feeling the effects of a vortex by the time it got through the intake to the cylinder are very low.

Bottom Line: Do not waste your money on a throttle body spacer. They will not give you any power gains on a Jeep Wrangler TJ, or any modern vehicle for that matter. There is no throttle body spacer out there that will give you any power gains on your Jeep Wrangler TJ
 
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I have one of those on my truck (04 gmc sierra), which the throttle body has the same purpose as our jeeps, and all it did for me was made a whistle at a certain rpm. I got it for free. Some people claim they do, but I'm not sure how it could. I can see how they would work with throttle body injection, but not when the throttle body is just an air valve. They are shiny and red though, so they have that going for them. I almost think they would be better if they were a fiber reinforced plastic that didn't transfer heat as well as aluminum.
 
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X2, TB spacers don't do anything for the type of throttle body our Jeeps use. Spacers can and do help performance when placed under carburetors or first-generation throttle bodies with a fuel injector screwed into them called TBI (throttle body injection) system. Those are 'wet' systems where an air-fuel mixture is being sprayed into the air intake manifold. No fuel injectors below as modern TB systems use. Modern TBs pass air only, the fuel is injected well below the intake manifold... spacers don't to crap for them.
 
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There was already one installed on my TJ when I bought it, along with a K&N intake. I like the intake just for the fact that I can clean it out dry it and put it back on and never buy an air filter.


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Zen chisenhall said:
There was already one installed on my TJ when I bought it, along with a K&N intake. I like the intake just for the fact that I can clean it out dry it and put it back on and never buy an air filter.
Click to expand...
You might like that K&N a lot less if you knew how much dirt & silicates it was passing into your engine. It filters out fine dust about as well as a screen door does during a Texas dust storm.

I ran a K&N filter years ago until a friend had me pull off the air intake tube and wipe my finger around inside it and inside the throttle body opening. It was grimy/gritty/filthy. Before I could replace it with the stock filter box again, I placed two pre-filters over the top of it so it'd at least keep more dirt out.

This is my previous K&N with its two prefilters pulled back enough so you can see them. Without those prefilters my K&N was passing dirt like I couldn't believe.

K&N.jpg


There was an ISO (International Standards Org.) 5011 certified lab test performed on a whole bunch of air filters that I have a copy of. Here is one chart that is very telling. The text below the chart is the lab's comments, not mine....

K&N-Filter-Chart.jpg


The below words are directly from the lab test...

"In the chart above it’s important to note the different test durations for each filter. The AC Delco filter test ran for 60 minutes before exceeding the restriction limit while the AMSOIL and K&N tests each ran for 20 and 24 minutes respectively before reaching max restriction. In 60 minutes the AC Filter accumulated 574gms of dirt and passed only 0.4gms. After only 24 minutes the K&N had accumulated 221gms of dirt but passed 7.0gms. Compared to the AC, the K&N “plugged up” nearly 3 times faster, passed 18 times more dirt and captured 37% less dirt."

The very last thing I'd ever install onto a Jeep that gets driven in dusty/dirty areas is a K&N air filter. They're ok for the street or dragstrip but that's about it. And for anyone claiming some professional offroad racers use K&Ns, those guys rebuild their engines on a regular basis & K&N pays them to run their filters.
 
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Jerry Bransford said:
You might like that K&N a lot less if you knew how much dirt & silicates it was passing into your engine. It filters out fine dust about as well as a screen door does during a Texas dust storm.

I ran a K&N filter years ago until a friend had me pull off the air intake tube and wipe my finger around inside it and inside the throttle body opening. It was grimy/gritty/filthy. Before I could replace it with the stock filter box again, I placed two pre-filters over the top of it so it'd at least keep more dirt out.

This is my previous K&N with its two prefilters pulled back enough so you can see them. Without those prefilters my K&N was passing dirt like I couldn't believe.

View attachment 13734

There was an ISO (International Standards Org.) 5011 certified lab test performed on a whole bunch of air filters that I have a copy of. Here is one chart that is very telling. The text below the chart is the lab's comments, not mine....

View attachment 13735

The below words are directly from the lab test...

"In the chart above it’s important to note the different test durations for each filter. The AC Delco filter test ran for 60 minutes before exceeding the restriction limit while the AMSOIL and K&N tests each ran for 20 and 24 minutes respectively before reaching max restriction. In 60 minutes the AC Filter accumulated 574gms of dirt and passed only 0.4gms. After only 24 minutes the K&N had accumulated 221gms of dirt but passed 7.0gms. Compared to the AC, the K&N “plugged up” nearly 3 times faster, passed 18 times more dirt and captured 37% less dirt."

The very last thing I'd ever install onto a Jeep that gets driven in dusty/dirty areas is a K&N air filter. They're ok for the street or dragstrip but that's about it. And for anyone claiming some professional offroad racers use K&Ns, those guys rebuild their engines on a regular basis & K&N pays them to run their filters.
Click to expand...

Thank you so much for the info! I had no idea. I guess I'll be going to the traditional filter asap.


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Jerry is right about that. K&N relies almost entirely on marketing hype and brand.

I've seen the information he posted before as well as numerous other articles that pointed out that the K&N filter often time does more harm than it does good (harm to your engine I mean).

I don't expect everyone is going to ditch their K&N now, but I stopped using them in favor of the stock air filter about 5 years ago, once all this information came to light.

On many vehicles you can gain power from an air intake (the TJ isn't one of them, but there are plenty out there). However, you can often times end up doing your engine more harm than good by opting to let in all that grime and dust. So I guess it's one of those sacrifices you have to make. Sure, you might gain some more power, but at what cost to your engine?
 
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I ran KN filters on various vehicles before ditching them for standard filters. My Silverado had an AirHog, same as KN, and I kept getting codes popping up. After some internet research I found that minute amounts of oil would accumulate on the air sensor wire in the throttle body and cause it to throw codes. Cleaned it up, new Wix filter, not a single code since.

As far as our rigs; consider that the KN is covered in oil. Wheel around any dusty locations and it doesn't take much to figure out what is going to happen.
 
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How's the stock air box/filter in terms of blocking dust particles? Is there any brand of air filter that would provide better protection in the stock air box?

Edit: does anyone have any experience running AC Delco filters?
 
Ken97 said:
How's the stock air box/filter in terms of blocking dust particles? Is there any brand of air filter that would provide better protection in the stock air box?
Click to expand...

It does an exceptional job of blocking dust particles. It will do a better job than anything else out there on the market, that's for sure!
 
Great thread! Something like this was long overdue. I always laugh when I see all the Jeep owners who think that throttle body spacers and larger throttle bodies will actually make a difference.

It's like the say, "A fool and their money are soon parted."
 
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I only want to add one comment on stock air cleaners and living on a ranch in the middle of no where. When the first snow comes all of gods critters want to come inside the house the cars the feed bins etc. The intake bell on the stock air intake is just perfect for mice etc. A small piece of screen mesh held in place with a hose clamp stops this problem. Window screen mesh is too small in my opinion.
 
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