I've had my RL for 6 months now and love the car. The one issue that bothers me however is the engine thrashing that occurs at around 3500 RPM. I recall reading a magazine review of the car that also mentioned engine vibration at higher RPMs. Have others noticed this as well?

Maybe this is just normal with the RL and I'll just have to live with it. . . I've had the 027 TSB applied, but that didn't fix it. Anyone know what I should ask the dealer to do - like update/flash engine software?

 

I don't have this, and I suspect that it is not normal.

 

What is your VIN? Mine is 48xx. I have a little "harshness" from the drivetrain between 3500- 4500 RPM. I suspect that it isn't "normal" either but I have had all of the updates, etc.

Anyone else have similar issues or solutions?

 

Smooth as silk...you need to go talk to the dumdums at the service department.

 

I see that over 100 people have viewed the post, but only a couple of comments. Does this mean that the rest of you aren't experiencing engine thrashing/vibration?

 

No problems here.

 

I too notice a slight vibration/rumble at certain speeds. To me is almost seems like at certain speeds/rpm too high a gear is selected. By using the tip to force a gear down the issue seems to vanish.

Something to live with....????

 

no problems here

 

Perhaps bad gasoline ? I was using Union 76 and started to have a ruff idle thus went back to Chevron and smooth again. I have an 04 which are known to have a ruff idle which is common for ours with no fix. As mileage stacks this can get worse as I've read in this forum......

 

No problems here, 14 months and 14,000 miles

 

Got my car back from the dealer. They said they noticed a bit of rumble, but that it may be coming from the exhaust and seems comparible with other RLs. They also said there was too much transmission fluid and that they drained it to normal levels.

After driving the car it seems it may be slightly better, but I still hear/feel that minor harshness at around 4000rpm. Perhaps they're right in that it's simply the exhaust note, or maybe normal engine sound at that rpm level. .. humm? Then again I don't trust these mechanics as far as I can throw them.

I'm pretty fanatical about my car so any engine noise in the cabin bothers me in this otherwise perfect car.

 

I do not own an RL, but have test driven them quite a bit in the past month or so. I too noticed a bit of harshness of the engine in the 3500-4000 rpm range in at least one of the cars I drove. It was not bad, but noticeable. It seemed to occur just before transmission shifted into a higher gear. It seemed less in another car that I drove and I've noted that nearly all the reviews in the media have talked about how smooth the engine is up to the redline. Just my observations.

 

There are two changes ocurring at 4k rpm. Could they be responsible?

"Two-Piece Dual-Stage Intake Manifold



The RL uses a dual-stage intake manifold that is designed to deliver maximum airflow, to the cylinders. The 2-piece cast-aluminum manifold is also very light. Compared to the one-piece, dual-stage unit used on the MDX, the RL manifold saves 2.6 lbs



Working in concert with the VTEC(TM) valve train, the induction system significantly boosts torque across the engine's full operating range. Internal passages and two butterfly valves commanded by the powertrain control module provide two distinct modes of operation.



These valves are closed at lower rpm. In this mode, the three cylinders on each bank draw air from only the nearer half of the manifold's internal chamber, or plenum. The volume of the plenum and the length of inlet passages are tuned to maximize the resonance effect, wherein pressure waves are amplified within each half of the intake manifold at certain rpm ranges. The amplified pressure waves significantly increase cylinder filling and the torque produced by the engine throughout the lower part of its rpm band. Funnel-shaped intake ports-similar to those used on racing engines-are built in at the uppermost end of each intake runner to improve airflow.



As the benefits of the resonance effect lessen with rising engine speed, the butterfly valves open at 4000 rpm to interconnect the two halves of the plenum, increasing its volume. An electric motor, commanded by the powertrain control module, controls the connecting butterfly valves. Now each cylinder draws intake air from the full plenum chamber. The inertia of the mass of air rushing down each intake passage helps draw in more charge than each cylinder would normally ingest. This phenomenon is the same effect produced by a low-pressure supercharger. The inertia effect greatly enhances cylinder filling and the torque produced by the engine at higher rpm.



Close-Coupled Catalyzers and Variable Flow Exhaust System



The exhaust manifolds of the RL are cast directly into the alloy cylinder heads to reduce weight and to put the engine's two primary catalytic converters as close as possible to the combustion chambers. The 600-cell per-square-inch, high-efficiency converters mount directly to the exhaust port of each cylinder head for extremely rapid converter light off after the engine starts. By eliminating traditional exhaust header pipes, this arrangement results in a significant weight savings.



A hydroformed 2-into-1 collector pipe carries exhaust gases to a single 350 cell-per-inch secondary converter under the passenger cabin. To balance the engine's need for proper exhaust backpressure at low speed and free flow at high speed, the exhaust system incorporates a variable flow rate feature. An exhaust pressure-operated valve in the system has two operating modes. The low speed mode has a flow rate of 130 liters per second; when the engine reaches about 4000 rpm, the exhaust pressure rises enough to open the valve, which increases the flow to 150 liters per second."

 

JKJJPC - You described this to the tee. I really only notice it when the car shifts from 1st to 2nd gear at around 4000rpm. My feeling is that other RL owners just aren't paying much attention to it - or are enjoying the awesome sound system intensely.

AcruaRLBlue - Thanks for the detailed explanation! You're probably right on the money. It sounds logical that this is what's happening. I just wish there was a way to reduce the harshness. And I'm surprised that more people aren't complaining. . .

 

In all the time I spent driving a new RL, isn't at 1~>2 shift at 4000rpm pretty aggressive acceleration? If I remember, most of my casual driving resulted in shift at 2500-3000rpm or so. Same for my current TL.

The RL's engine seemed restrained to me. I never experienced this harshness, though.

 

[QUOTE
AcruaRLBlue - Thanks for the detailed explanation! You're probably right on the money. It sounds logical that this is what's happening. I just wish there was a way to reduce the harshness. And I'm surprised that more people aren't complaining. . .[/QUOTE]

Sorry, I didn't come up with the explaination and the quotation marks I used didn't make it clear. I got this from a website.

 

You're right. Most shifts btwn 1st and 2nd occure around 2500rpm, but every now-and-then you hit that 4000rpm mark when taking off from a dead stop. I just think the engine could be a little more refined btwn shifts at this RPM level - not just below 3500. . . And I mainly wanted to know if this was just an issue with mine. .

 

Since I learned how to burn my own Mp3 discs, I don't hear A NEE THING (except the sound system, of course).