Intake & Exhaust

Intake Shootout! 2004-08 Acura TSX Intake Systems Compared

Heeltoe’s Intake Shootout, 04-08 TSX

An air intake is probably the most commonly purchased power bolt-on item in the automotive aftermarket. Everyone is on board with the idea that a higher flowing intake system is a great way to change the power of the car (typically for the better). However, it is interesting how different companies formulate their designs. Fluid dynamics is a tricky science, and sometimes the more obvious solutions are not the best. Likewise, the more complicated answers are rarely the best for any given question. The only way to really see how designs compare was to do a dyno comparison.

The main categorical difference between intakes is between “short ram” and “cold air” intakes. The typical chrome tube with an open-air element filter on the end is a prevailing design cue, however, where that filter is located can change the power that is created. Systems that locate the filter in the engine bay are known as short rams. This is in contrast to longer-tube systems which place the filter outside the engine bay (usually behind the bumper) to draw in cooler ambient air. The physics at play is that cooler air is denser with oxygen. Since engines produce power by igniting mixtures of oxygen and hydrocarbons, the more oxygen in the intake charge, the higher the power produced. Playing in the cold-air field are ice-boxes, which are generally systems where the filter is a panel or cone housed inside an enclosed chamber with a tube running to an area with cold-air supply.

To get some contestants, we actually checked our own site to see what offerings there were for the TSX, as this is the car we’d be testing. The usual players were no brainers. The best-selling CT Engineering Icebox, the presumptive power producer Injen SP, and what intake test would be complete without K&N and their Typhoon? A few others added some spice; A’PEXi’s Power Intake, Trust’s Airinx, and Weapon-R’s Secret Weapon all provided some contrast for the test. Our initial plan for this test was to include a larger array of intakes including a Mugen Intake and J’s Racing Tsuchinoko (both ice-box type designs), however, cost and availability limited the test to only ones that people regularly purchase. People buying J’s and Mugen many times value the brand over the benefit, although we do expect both these systems are admirable performers. An HPS entry was requested as an “eBay” entry, however, again, supply issues got in the way. AEM Induction declined to participate (we suspect parent company K&N wanted to shine brighter).

The testing was done at Church Automotive Testing, one of the best in the business. Dynapack chassis dynamometers provide a very low degree of drivetrain loss making them sensitive to small changes. The installation of the intakes in this test was of the “quick-n-dirty” methodology without taking the car off the dyno. For the most part, we did not affix the clamps or tubes that would serve as permanent installation requirements. For the 3-4 pulls on the dyno we were doing, and given that were being charged by the hour, it seems perfectly fine to do things this way. If there is any dispute in the power numbers we are providing, I would kindly suggest such scrutineers validate themselves by testing on their own. The entire test took about 2 hours, and the ambient temp was about 84 degrees F. No tuning of the computer was done to complement these intakes as that would have been too costly in time and resources. The test TSX is not equipped with a reflash of any kind.

The point of this test is not to see how much power each part makes, because every car is going to have a different result based on the other mods it has (Incidentally, our HTSpec TSX was equipped with a Fujitsubo exhaust and UR Pulleys at the time of the test, otherwise it was stock). Instead, we wanted to get them all cycled through on one car with static conditions to see how they performed relative to one another. We are not able to publish every chart, and honestly, since we didn’t have a stock intake to compare everything to it seemed like it wouldn’t be necessary.

We also took sound clips from each intake from inside and outside the car. This was in an effort to really show readers how the intake sound changes the attitude of the car, and to see which intakes sounded “better.” Much to our chagrin, the videos really did not reveal much of a sound difference at all, and even in person the only intake which seemed significantly different from the others was the only one without an open-air element; the CT Engineering Icebox. You are going to get a lot more noise with wide-open throttles with an open intake. The sound of the intakes in many cases over-powered the exhaust sound while doing this test. Most people don’t make a fuss and even like the sound, as with normal driving, you don’t hear much of anything in terms of noise. That being said, we’ve been in automatic cars with intakes and nothing else, and they can get pretty boomy.

To help make this one of the most informative tests we could, we are also critiquing the packaging quality and highlighting the CARB status of each intake. Being smog-legal is a make-or-break factor in many people’s purchase choice. Without further delay, here is what we found out!

Trust/Greddy Airinx: #6

First up we have the Trust Airinx. Trust, the parent company of Greddy Performance, is a trusted name in the Japanese aftermarket. They have a long history of producing some really high performance items for cars, especially with turbo applications.

This intake is not normally available in the USA and we had special ordered it from Greddy a while ago. It took about 60 days to come in. The box is small and light but was packed well to avoid product damage. This intake is not CARB exempt.

We were surprised to see how simple this part was, the kit containing only three pieces. A nicely fabricated intake tube, an adapter to mount the filter, and a high-quality filter assembly with replacement element. We had heard in the past that foam filters perform better than cotton ones, so we thought while this kit seemed like it had little engineering work done to produce it, it might show well by having really low restriction.

Upon closer inspection, we were happy to see that the filter adapter had indeed a greater amount of detail work than we expected. The ring locks into the toothed flange area on the chrome filter assembly for a simple, hardware-free fit. Also, it has a curved surface lending us to believe it would promote better airflow around the inner boundary of the tube.

Here you can see how the filter installs. Much better than the typical band-clamp that you see on every other part out there.

Once installed there is a completely smooth transition from the filter to the tube. While we are not sure how much this detail work actually benefits performance we can say that there was considerable effort to reduce as much restriction as possible.

Installation was stupid-simple. One bolt which is re-used on the car already, tuck the inlet pipe into the OEM intake arm, and you are done. We think a pre-schooler could figure this out. Given this was a Japan-special order item and the instructions were not much help, this is a good thing. It also looked great under the hood, giving a splash of glitz and color to an otherwise plain engine bay. This is the only yellow filter we know of.

Power notes:
The short tube, foam filter combination did no favors for the HTSpec TSX. It registered a paltry 212 horsepower on the dyno. This was the lowest power-producing part we tested. We suspect this arrangement works really well on a forced induction car where more suction is created by the engine and the length of the tube is irrelevant. This design does not translate over to NA 4-bangers if this is the case!

PROS: Low cost for high quality, Easy Install, Exclusivity of rare JDM item, Underhood eye-candy.
CONS: Didn’t produce on the dyno, Need there be anything else to avoid recommending it?
VERDICT: Stick to Supras Greddy, Trust us.

Weapon-R Secret Weapon: #5

Next up is the Weapon-R Secret Weapon Intake. Weapon-R produces A LOT of parts. Historically, they have been somewhat of a cheapish brand, producing whatever seemed trendy at the time for a low cost. Even now their site has nearly as many scantily clad models on display as it does car parts (Hey, don’t leave now! Check it out after reading our article!). That being said, it was made pretty clear to us that the Secret Weapon intake is not to be taken lightly. It does have some interesting features that make it different from the rest of the contenders here.

The packaging is quite intricate. The filter is sectioned off, and the piping is in bubble wrap. Packing seems quite safe 🙂 Nothing worse than getting a kit like this only to find parts are missing or damaged.

Pipe material is a raw, polished aluminum that looks pretty nice. The diameter is about 3″ (metric size). Raw aluminum can have somewhat of a dull look to it, however, the Weapon-R looks quite good. The logo and patent information are actually imprinted on the part itself. This is actually a pretty special cue…one of our with parts today is that they all seem to be the same thing repacked and relabeled. Weapon-R values their identity and highlight their legitimacy with details like this. Even their band clamps have their logo.

Weapon-R has created something different than the mainstream, and something important enough to patent!

Here we see what is different…this inserts in the piping. This must be the “secret.” Very interesting! Perhaps this design is to encourage a more laminar flow through the turn in the pipe. Not sure…a dyno should tell us if the sound or power is different on this kit than the rest.

The filter itself uses a foam element. As mentioned with the Turst intake, we heard in the past that foam actually promotes the best airflow as a filter substrate. If that is true the choice of foam was good in this case. The filter is a highly engineered design. It looks in itself to be a well-made part. This filter has an exposed surface area around the outside, as well as a secondary open surface on the top with an “inner filter.” There is also a flange on the top and I was wondering what that was for…

And here we go! The intake actually comes with a snorkel that will draw cold air from behind the bumper. We guess this is the other part of the secret. Under the hood, you see a Short Ram Intake, but the snorkel actually makes this somewhat of a Cold Air in disguise.

We are wondering though much cold air is drawn in with this configuration since the outer surface of the filter is still open to draw in under-hood air. We will see if there is a power difference in both configurations.

The kit comes with decent hardware and looks to be quite complete. All the intakes in this test have permanent filters, and you can get cleaning kits for them online. However, the Weapon-R Secret Weapon was the only intake in the test to come with a filter cleaning spray

The instructions are in English and look fairly complete. They are a bit general but intakes are fairly easy to install. The hardest part, in this case, is getting the stock stuff out, and Weapon-R leaves you a little on your own there.

Installation of the Weapon-R Secret Weapon intake was reasonable. The pipe could have fit a little better, and I prefer the auxiliary inputs for the breather and IAT sensor of some of the other parts better. However, this part certainly did fit fine.

We decided to run the test with and without the snorkel tube on it. It was easy to fit the tube to the end of the filter and route it to the bumper. The HTSpec TSX is running a EuroR front lip but does not have fog lights installed. This provides ample air to the area where the cold-air intakes draw from. The tube on the Weapon-R was shoved right up to the fog hole, which we imagine would give more of a ram-air effect.

Here you can see the air inlet created by the fog lamp hole, and the Weapon-R intake snorkel right inside. This seemed like an ideal mounting point.

The Weapon-R performed easily as well as the other short rams in the test given consistent temperatures. When tested without the snorkel, we did see a lot of loss to heat soak. Run after run the power was dropping (more than with the other short rams). Once the snorkel was put on we did not see any power increase however the power stabilized quite a bit. We were able to do multiple runs without losing power to heat.

We think this is because of the extra material built into the tube near the throttle body. As heat builds under the hood the tube gets hotter, which in turn heats the internal structure Weapon-R devised. This probably is serving a good purpose for airflow however it could be acting as a heater for the intake charge as well. With the snorkel on, the tube is supplied with a cooler intake charge which, instead of gaining power actually counter-acts this heating. We are speculating, but it seems like they would be better off without the extra bits inside the tube, or possibly make them in plastic instead of metal.

PROS: Different from the rest, Unassuming appearance, Quality tube and filter, The most “complete” kit with cleaning spray.
CONS: No better than the average short ram, The brand-conscious might look past it.
VERDICT: The secret’s relevance was lost in translation.

A’PEXi Power Intake: #4

A’PEXi’s Power Intake we had high hopes for. Yes, we know it is a shorty. Yes, we know it isn’t CARB exempt. But it does represent a really great value as the cheapest in our test. Also, we had heard of testing done year ago that placed A’PEXi’s filters very high on the performance scale, not just for airflow but for actually cleaning the air as well. In looking at it, this part represented a good comparison to the Trust/Greddy part as it is close in design but with a different element.

A’PEXi packed the parts well, providing instructions that are all in Japanese (not much help but pictures are provided to aid). This was a pretty simple kit though to that wasn’t a bother.

And here it is. The Power Intake consists of A’PEXi’s proprietary filter, a 3″ stainless steel tube, and a couple mounting brackets. Stainless is a good choice compared to aluminum as it doesn’t transfer heat as quickly. If fed cool air, this pipe could feel warm on the outside but actually be pretty cool on the inside still.

There is also a supplied foam strip that is supposed to provide a seal at the body gap between the fender and the hood. The idea here is to prevent water intrusion at that gap in the rain. Many people think short rams are immune to water issues, but this is not the case. There is no risk of hydro-lock, but a saturated filter will definitely reduce power and can even stall the engine or prevent starting.

Here is A’PEXi’s filter. The part is all hard plastic, with the open element around the outside. The cone shape protrudes inside the filter body.

It is difficult to see but the cone inside protrudes pretty far in. This is supposed to aide airflow somehow. A similar idea to the air-horn many companies use, however in reverse we guess.

Also, note how the filter mounts to the tube. No silicone and band clamps here. All bolts and secure hardware. We do find it interesting how both participants from Japan have more dedicated mounting solutions for their filters. Worm-drive clamps, while effective, are not very elegant.

Here is the A’PEXi Power Intake installed. This was ridiculously simple, almost as easy as the Greddy. We also think it looks great. The stainless piping has a high-class look to it, and the filter looks like it means business. Normal cotton air filters are pretty generic looking and this one is definitely not categorized this way.

Power Notes:
As a short ram, we were not expecting much and since didn’t get much but weren’t let down much. Right around 215 hp and 178 ft-lbs, this intake was nearly identical to the Weapon-R. Unfortunately, it seems like A’PEXi is more experienced with turbo cars, similar to Greddy, as it didn’t produce numbers that say “you have to buy me!” Hey, Japanese guys, NA cars like cold air! That being said, this intake did not seem prone to heat soak in the way we expected.

PROS: JDM with a low cost, High-end materials, Great filter.
CONS: Not a cold air kit so the power is down, Not CARB exempt.
VERDICT: We’d never tell you not to get this one, but beyond the brand and cost we would have a hard time promoting it.

A’PEXi Power Intake Versus Weapon-R Secret Weapon

Here we see a dyno comparison of the Weapon-R Secret Weapon (red) versus the A’PEXi Power Intake (white). Even though the A’PEXi has a little mid-range torque advantage the overall graphs indicate these parts are pretty interchangeable in terms of the output. Both bested the Greddy no problem. The slight power difference is what gives the A’PEXi the nod over the Weapon-R. We’d like to see what the A’PEXi does with a longer tube though.

Injen SP Intake: #3

When we announced this test on, the vast majority of people were focused on the Injen intake as the power winner. We have to admit, that was the outcome we expected as well. We were really surprised to see that was not the case, and this resulted in their 3rd place ranking. Really, it could be considered more a tie for 2nd place, but there are factors outside power putting the Injen where it is.

Also note, that despite the fact it isn’t indicated on their website or their downloadable instructions, this intake is CARB exempt and therefore street legal.

The packing here is seriously thorough. Similar to the K&N which shares a short-ram/cold-air configuration option, there are a lot of parts in the Injen kit. They have packed them masterfully.

Here is how the Injen looks in short-ram mode.

The elbow going to the throttle body is a really nice piece making it a little unique in design. Many users have this intake already and like it. This inlet tube is a pretty huge 3.5″, the largest in this test. Interestingly enough it necks down to 2.75″ at the throttle body side of the rubber elbow.

While we are looking at the Injen here as a short ram we wanted to address the possible question asking why would this be a desirable feature? It is mostly because of fear.

Cold-air systems place the air filter behind the bumper much lower to the ground. There have been horror stories for years about cold-air intakes sucking up water when it rains. We would like to formally clarify and refute much of this claim.

Yes, while the placement of the filter does make it more susceptible to water this is only the case in situations of flooding. WHEN INSTALLED CORRECTLY, the air filter will be completely protected from splashing water by the bumper, fender liner, and splash shield. Simply driving in the rain–even torrential rain–is not enough to cause the engine to ingest water. One would need to drive through a flooded area to hydro-lock the engine. If someone doesn’t have enough sense to drive around floods (not a puddle, or a deep puddle, actual flood conditions 6-8 inches deep) or fails to properly install their splash shields, the cold air intake should not be falsely demonized.

Here is the intake in cold-air form. The extension tube is 3″ in diameter and connects directly to the 3.5″ intake tube with supplied hardware. Piping is polished aluminum, but it should be noted that this kit comes in a black powder-coat finish as well for a more subtle look under the hood.

Injen, like all the other open-air filter elements here, is proprietary to them. It is nice to see this detail.

Here is the short ram installed on the car. The fitment is pretty good, although Injen, unlike any other competitor, decided to design their bracketry so that the mounting location is on the battery tie-down post. This seems convenient but can really cause an issue for people who change batteries, especially to smaller ones, with custom brackets. Also, since this is not a really hard mounting location, fitment can be difficult and gets even worse if someone installs a throttle body spacer in addition to the intake, or installs a different manifold. No clear alternative mounting can be arranged if needed. This might be a niggling concern but it is something that has always irked us about this intake.

We have to make an apology here as we neglected to take a picture of the cold-air installed. If you can imagine, simply extend the polished pipe until it is out of sight and you have it.

Power Notes:
In short ram configuration, this intake performed like a short ram. The chart is relatively similar to the previous short rams, albeit with a smidgen less torque. We will call it even.

When compared to the other big players here, the CT and K&N options, we were surprised to see this intake perform no better at all than the Icebox, and literally poorly when compared to the K&N. The torque figure is 181, more than the short rams. But the power at 215 hp was not impressive. It scarcely made more top-end power than the short-ram version of itself.

We were speculating on how this could be. My personal thought is that the pipe is just too big. The engine in our HTSpec TSX is not modified in a way that such a large diameter is warranted. Bigger isn’t better in many cases actually. We were told by Injen to monitor AFR readings during our test and found that they consistently hovered right under 13:1 for all parts tested, meaning the engine was pretty consistent in reading intake temperatures and pressures. Perhaps a retest on a later date with more mods on the engine will reveal some more expected findings, but right now we are forced to deflate Injen’s ego.

PROS: Looks great, Has a sound that street turners like, Pretty popular so there are plenty around for easy purchasing, Two color options.
CONS: Little bite to match the big bark, Louder than more conservative drivers might want.
VERDICT: This option will always sell well and is a staple for Acura tuners, but isn’t the winner today.

Injen Short Ram vs Cold Air configuration

CT Engineering Icebox: #2

Showing up without a real fancy box was the CT Engineering intake.

Packing is nice and neat. There isn’t much risk of damage to these parts since they are pretty durable.

This part is made of molded plastic and therefore has the most stock appearance. Also, since it uses the stock intake tube, it is much less prone to heat soak than the metal pipes. The box utilizes an upgraded panel filter which has a foam substrate with an oil catch particles. The upper lid bolts to the factory lower lid, and the resonator chambers behind the bumper are replaced with an air-horn that promotes faster ingestion of air.

Overall, a really simple kit and that comes through in the price, which is neck and neck with A’PEXi for being the cheapest one here. However, there is an important product update we are announcing here: CT is offering the lid material in Carbon Fiber as in addition to the plastic previously used. We had the great fortune of being able to test the very first prototype CF box for this test. While the plastic lid functions well, it is a plain black finish; the new carbon part looks amazing. More pics and pricing details will be announced later.

The Icebox is more than just a plastic lid, as the inlet tube has a nice air horn design. This will dramatically smooth intake airflow as opposed to a straight-cut pipe. The stock airbox has a similar design. However, the stock airbox also has stiffening ribs all on the inside which could interrupt airflow. The inside of the icebox is completely smooth.

Previously, people had issues with installing the Icebox lid onto the factory lower box. This is largely due to the difficulty in producing molded plastic parts. Temperature and material volume must be carefully controlled, which is really hard to do if you are not spending five or six digits on equipment. We assume CT is not. Carbon is a lot easier to consistently produce.

The install of this part was a little better than the previous design. You are supposed to reuse the stock airbox bolts with this lid, but we are finding that longer bolts would make things nicer. If longer bolts come with your Icebox, you can thank us for that.

What we like most about this intake is the sound. With all the other intakes here, under wide-open-throttle, they get pretty loud. In the case of the Injen and the K&N it almost gets too loud to talk inside the car. The CT Icebox keeps the noise level to a reasonable volume by placing the filter inside a box (just like stock…hmmm). It gives the engine an aggressive growl without making it a teenager’s car.

Power Notes:
Everyone we spoke to assumed the CT would be producing less power than the forum favorite Injen, even CT themselves! A little searching would provide lots of annoying posts about “searching more” etc when someone would ask what intake makes the most power, or whatever. Here, we have proven that there is no such thing as conventional wisdom. The parts need to be tested…period. Even if the Injen in our test was not well represented, we proved that the Icebox isn’t a dog compared to it.

The CT gives up little or no power to the Injen at all. While the Injen didn’t show us impressive numbers itself, we now know that the CT is not to be taken as a low performing part as it did fare much better than then short rams. It also has a really nice torque bump between about 2300-2800 RPM, something that was consistent amongst all runs and didn’t show up on any other charts. We believe the large volume of the Icebox gets the credit here. An initial charge of air is ready to get ingested right as the throttle is opening. However, we are looking at the horsepower figure and thinking that there is something lost in air velocity as the revs climb. Yet, at the very peak, it matches our power winner making a solid 7 hp more than the lowest performer here. Results were pretty consistent as well since the composite materials don’t have nearly the heat-soak factor (again like stock, interesting).
The most impressive thing about the CT Icebox? It is made by a company that isn’t an intake company! CT considers itself a supercharger company. When comparing this product to other solutions, we feel they should be proud to be listed high up among the other intake-only companies in this test.

PROS: Low cost, Very simple kit, Makes power in-line with the best of them, Less prone to heat soak because it isn’t metal, Sound isn’t intrusive…actually sounds good!
CONS: The plastic is ugly and pricing isn’t yet available for the CF, Could fit better (even the CF one).
VERDICT: Bottom line, the HTSpec TSX arrived at the dyno with the CT Engineering Icebox on it, and left with it on as well.

K&N Typhoon Intake: #1

Here is the K&N Typhoon, our winner. Let’s look at what made this intake the top pick.

The packing is really good, similar to Injen. This kit also comes with an Air Filter Wrap which is supposed to help prevent water from saturating the filter, but as we mentioned we don’t think this is a big concern.

Here is the kit. The piping is the smallest here, suspiciously close to the diameter of the throttle body at approx 2.75″. This pipe was the smallest one in the test and was consistent in diameter throughout. The material is aluminum however it is not polished. It has a painted chrome finish which seems odd but possibly more durable. One of the pipes did have a flat at the opening, which wasn’t a big deal but was a little surprising to see. It could have come from a chop or band saw that had too much pressure. It wasn’t going to be visible or affect performance…no biggie.

K&N’s name is legendary in the performance filter market. Everyone else after them really seems just like that…followers.

Here is the short ram installed. Of the short rams, this one does look aggressive. The filter is really large and the placement is nice. It looks like even though is a short ram they made it as long as possible. The mounting is very simple, one bolt in a factory location.

Here is the cold-air version installed. It also fits well, and if we preferred the chrome-tube look would take this one over the others.

Power Notes:
What can we say, this one has a huge bump in torque over the others all the way from 3100 rpm to over 5000 rpm maxing out at 186 ft-lbs, 5 more than the CT and Injen. After the VTEC point at 6200 or so, the torque makes another appearance, again almost 5 ft-lbs more than either the CT or Injen can muster. This translates to a nearly consistent 3-5 hp improvement over the Injen on the power side. The CT is a closer rival but still doesn’t offer the power of the K&N overall.

It is possible that with a highly upgraded engine this intake could be more restrictive, but the level of upgrades most TSX users get into will not likely approach this limit until we are just this side of boosting the engine.

PROS: The most power and torque we had seen, Great fit, Solid name.
CONS: Not really polished, Will be noisy, Higher end of cost spectrum (excluding JDM offerings).
VERDICT: It wins the power race, if you are into the chrome pipe thing look no further.

CT-Engineering Icebox versus Injen Cold Air versus K&N Typhoon

Graph showing our top three finishers. K&N is the red dashed line, CT is the green, and the Injen is the solid red.

The K&N clearly has an advantage here. It is hard to ignore the fact that CT makes more torque and power where the others cannot, below 3000 rpm. Automatic Trans drivers will appreciate this.

One glaring issue is what happens at about 6200 rpm, where the TSX with a stock tune has the VTEC point way too high. We can’t see the logic in this, but we have definite plans to fix it!  A Hondata reflash is planned for our next trip to the dyno. At that time we would like to retest the top three finishers here in a more strict power test after installing a heatshield gasket. We’d also like to confirm is the P2R throttle body spacer is as good as we hear it is. Until next time!

Drivetrain You Can Do It! DIYs

Installation Instructions: CT Short Shifter for TSX/TL/Accord

The CT Engineering (Comptech) short shifter adapters for 04-14 TSX, 04-14 TL, and 03-17 Accord are all the same, but they ship with different instructions. In the event you get a shifter with instructions for a different car, so use these links to download the correct PDF!

2004-08 Acura TSX

2009-14 Acura TSX

2004-08 Acura TL & TL-S

2009-14 Acura TL – Part fits, Instructions Unavailable

2003-07 Honda Accord

2008-12 Honda Accord – Part fits, Instructions Unavailable

2013-17 Honda Accord – Part fits, Instructions Unavailable

Chassis Heeltoe Explains You Can Do It! DIYs

Welcome to last week: Sway Bar Bushings Go Bad If They Aren’t Lubricated

I know, I know. Many of the old school Acura people have been telling us for years that they have noisy suspension traced to worn rear sway bar bushings. I always figured it was an issue with installation or grease. And while I know for a fact I was right on some of them (primarily the ones where new installations were claimed to be noisy), the bushings themselves are prone to creating noise after extended periods of use.

I have had two customers come in after a few years in service with noisy bushings. And now I know what the problem is. The polyurethane bushings on popular rear sway bar upgrades can wear out if not regularly lubed and cause a noise.

These bushings require periodic lubrication. The bushings included with the popular Progress rear sway bars definitely do come with high-grade silicone grease. Likewise, Prothane bushings that many people buy to replace these bushings come with good grease as well. The bushings are designed with a ribbed pattern on the inner surface area that holds the grease to provide reduced friction and therefore miles of noise-free smiles.

But, the grease evacuates eventually. Depending on the climate, mileage, driving conditions, and driving habits, the grease ends up getting expelled at some point. Now, without grease, you’d expect noise. However, the noise does not set in right away! The groves provide an air gap between the bushing and bar. The friction is not maxed out at this point, so there is no noise.

What the grease REALLY does is prevent friction that causes wear on the bushing. The friction of metal against rubber or urethane…harder material wins every time.

The inside of the bushing gets polished and then you have full surface area contact between the bushing and the bar. This is a high-grip scenario and this is what causes the squeaking-squawaking noise. So, the key to preventing noise is to grease the bushings.

On this customer’s car, we replaced the worn CT Engineering bushings they had with some new Prothane ones and recommended they re-lube the bushings annually. This does require removal and reinstallation but thankfully it is pretty simple to accomplish. These bushings are spec’d out at 22mm ID but the bar itself is actually a bit larger (22.2mm or 7/8″, which is the case for Progress and CT even though they advertise their bars in metric). Get 7/8″ bushings for “22mm” bars, and 15/16″ bushings for “24mm” bars.

The installation is perfectly ok as many people do it, but you can see how the bushing doesn’t quite encapsulate the bar completely…

22mm bushing o a CT/Progress “22mm” bar that is really 22.2mm or 7/8″ in size.

And the best bet, provided you have a grease gun, would be to get a bushing with a zerk fitting on it to grease the bushing without removing anything. I think if this needed to be done at a more regular interval it would be worth considering, but given that they don’t need to be lubed all that often We think the regular bushings are just fine.

So, you guys told me so, the bushings do wear out and need replacing if the grease gets all squished out. However, simply re-lubing the bushings with the appropriate grease from time to time should prevent this concern.