Avensis Road Noise!

[MK54]

I recently bought a used 2009 Avensis Estate 1,8 Automatic. Great car. Once you get used to how to drive the CVT gearbox, the Avensis is a comfortable car.

However, my first impression when testdriving was the noise level in the cabin especially on rough asphalt which we have a lot of in Norway. I guess I'm a little obsessed with these things.. a lot of people dont understand what I'm complaining about. Anyway, I thought it would be fun to see how much it's possible to reduce the roadnoise . That is without ripping the car apart .

Of course a Toyota will never be dead quiet. No car will I guess. It’s too many noise sources. Unlike f.ex. american cars from the 50-60's, the suspension on modern cars is physically connected to the entire body and it’s no way you can isloate it. I soon discovered that when i reduced one noise source, other which had previously been masked, turned up.

I at once guessed that the road noise from the wheels was the major noise source. These were Bridgestone Touranzas. Terrible noisy tires!! So the first thing I did was to replace them. I simply selected the tire on a net shop which was rated as the most quiet: Goodyear Efficientgrip Performance. What a difference! Over all I think this was the most important factor.

The next thing I did was to have my car treated at a professional auto body rust shop. They sprayed a thick black stuff everywhere in and outside the wheel arcs on top the usual antirust treatment.

When dry it leaves a hard yet flexible surface. This dampened the road/tire noise picture to a much more pleasant level.

But now I heard a lot of other noises instead. Especially wind noise above 80Km/h and engine noise when accellerating. The windnoise seemed to come from the window/door area at head level somewhere. From an idea on the internet I bought 20 m of 8 mm rubbertubes. I cut a little hole in the weatherstrips mounted on the body around the door openings. With some trial and fail I managed to thread the tube through the rubber weatherstrips. The hole was then sealed with some rubber and glue. When finished I noticed the doors had to be shut with a liitle more force and it sounded differently. But the best thing was that most of the high pitched windnoise was gone! Why cant the car manufactors make some better gaskets in the first place??

Ok, so now the engine was becoming noticably more apparent. I bought some 10 mm thick closed cell Polyethylen maths and cut out an exact fit for the floors. Contrary to the original rubbermaths , I let the math cover as much as possible of the floor and up behind the pedals and dashboard. The original maths I just put on top of the new ones. In addition I stuffed a lot of 3M Acoustic Thinsulate further up behind the dash and behind the plastic coverings around the foot area. The front and rear passenger floor area are much easier. All this dampened the road and engine noise a little more.

The engine was still too loud I think. The middle of the Avensis engine hood is allready sound proofed, but there are large areas around it with not soundproofing at all. So I used the same closed cell material, but now only 5-6 mm thick. I covered as much as possible of the hood underside. I glued it on with Tec7. This helped, both outside and inside the engine sounded more dullish allthough I wish I could soundproof the engine better. But that would require a more serious approach I guess involving isolation of the torpedo wall etc.

All in all I managed to cut noise considerably by relatively simple means.

[Konrad C]

Great insight. I have the manual tourer and the tyres noise is most prominent. My Mk1 also has tyre noise, but the sound is lower in volume and frequency, due to the smaller tyres and wheels. Tyre choice is a major factor.

My Mk1 exhaust is louder under load, then at motorway speed a nice hum. The Tourer engine is more muted with the tyre noise dependent on the road surface. Both cars are manual and the Tourer has 6 gears which helps keep the revs down.

The CVT especially the early cars tend to choose a lower ratio, making the engine rev harder when accelerating. Many complaints have been read about this. I am sure the later cars have had the CVT programmed to not go so low a gearing, hence less revs. Remember the engine does not have the torque of a diesel, and the peak is at 4000 rpm. In normal traffic the engine pulls well from low revs, but for more power, a down change will be needed.

Even the Hybrids can sound strained when accelerating.

See how the tyre noise performs when the tyres wear and the rubber is older.

[MK54]

The CVT especiallyy the early cars tend to choose a lower ratio, making the engine rev harder when accelerating. Many complaints have been read about this. I am sure the later cars have had the CVT programmed to not go so low a gearing, hence less revs.

Yes that's interesting Konrad. I noticed on the last bill from the last 75000Km service that the SW had been updated. The technician told me they always do so if a newer version is available but that I would not really feel any difference. The SW for the CVT was already so optimized that the updates were marginal they told me. If there's no mechanical changes to the CVT on newer models, I really cant see why not earlier Avensis could be updated to the same standard.

And again about tire noise. Yes, a tire brand change can really be the difference between an exhausting or pleasant driving experience.