Flame arrestor whistling

[Fman]

I am getting a lot of noise coming from the flame arrestor (air filter) when the boat is running at different speeds/RPM's. Its enough to annoy my wife and daughter, so I have to try and figure something out. Has anyone else with a 2010/11 VLX/LSV/24 noticed this noise? The dealer is claiming this is normal, but he also mentioned people who have been demoing boats are noticing it. So this tells me we are not the exception.

I noticed a substantial gap inbetween the center rear cushion and plastic tray that will allow a lot engine noise to filter in the boat. Has anyone here plugged that gap with a piece of plastic strip? and added any noise dampening material to the bottom of the plastic tray? any ideas for a good material to do this?

The Flame arrestor is right behind the seat, super close to where you sit, so it does not surprise me you can hear the air sucking into the motor. Never experienced this noise with my Supra, but the intake was much further away from the seating area, and there were no gaps for sound to escape.

If anyone has any ideas please send me a post..... thank you.

[Chia]

Will a larger k&n fit, that might provide more surface area to draw air from?

[Bobby Light]

It is normal. If you can't stand it take it off and take it into your local autoparts store that sells K&N filters and find the biggest one you can fit on there. It will minimize it but probably won't eliminate it. This will require a little measuring on your part, be warned though you can't go to much bigger. I know another crewmember that did that on here and I can't recall if he has any of the whistle on his boat or not, not noticeable though.

Insulating the engine compartment would be the next step but you probably don't want to do that given the temps you get in the summer.

Edited April 18, 2011 by 06vlx

[Guest J-Ro]

The gap in the tray is there for the seat to seat properly. At least thats how it is on mine.

[tvano]

is the spark arrestor the cause of the problem or is it intake noise?

[Bobby Light]

is the spark arrestor the cause of the problem or is it intake noise?

One in the same.

[LS-One]

I don't think the newer motors are set up this way but... I had a 97 Sunsetter that was fuel injected with the older style fuel rails. There was a tube that came off the top of one of the valve covers and was mounted to the exterior of the flame arrestor so the crankcase gases were sucked back into the flame arrestor. It used to whistle fairly loud but I found by bending the bracket a bit and changing the gap between the arrestor and the tube I could make the noise pretty much go away. I think it was something to do with the large volume of air being sucked into the motor by aspiration versus the small amount of air being pushed in by the crankcase ventilation.

[tvano]

One in the same.

not at all.

is there still whistling if you remove the flame arrestor?

[Bobby Light]

not at all.

is there still whistling if you remove the flame arrestor?

Try it out and tell us. I'm not running my boat without the air filter (flame arrestor on there), suck something in there and your motor is most likely done.

Edited April 18, 2011 by 06vlx

[tvano]

Try it out and tell us. I'm not running my boat without the air filter (flame arrestor on there), suck something in there and your motor is most likely done.

perhaps if the op securely taped his hat on then tied his belt to the pylon he wouldn't get sucked into the mill while it was whistling.

i'm not suggesting that the spark arrestor gets tossed in the pond; just trying to reduce a problem to it's component parts.

i've run ic engines short term (think drive-way or dock-side) w/o the air filter / spark arrestor without dropping a block.

certainly some precautions are necessary: standard pre-flight checklist is a must and watch out for the moving parts.

of course if the op feels that such a suggestion is a waste of time or more dangerous than they wish to deal with i will not force them to heed my suggestion.

i'm only trying to help.

[LS-One]

Try it out and tell us. I'm not running my boat without the air filter (flame arrestor on there), suck something in there and your motor is most likely done.

Am I missing something (seriously), wouldn't something sucked in there have to be small enough to pass through a fuel injector ?

[my malibu]

You mean valve I hope

Am I missing something (seriously), wouldn't something sucked in there have to be small enough to pass through a fuel injector ?

[UWSkier]

Am I missing something (seriously), wouldn't something sucked in there have to be small enough to pass through a fuel injector ?

Anything that drops in the throttle body opening, if small enough, can get sucked right into a cylinder through an intake valve.

That's how they killed all the engines in the cars turned in during cash for clunkers. Engines were destroyed by pouring a sand/silicate mixture in through the intake tract. Real "green" of them, eh?

[Fman]

First off, thanks for the replies...

I did order some "second skin" to insulate the back engine panel, and storage bin area. The gap behind the seat can easily be sealed up with a thin piece of plastic and it appears will not impede the seat placement. The air filter is right behind the rear seat, it almost touches the back panel area. Its no surprise to me you can hear this noise when sitting in the rear seat.... The gap in the back is allowing noise to come up into the boat. The second skin is good for temperatures up to 400 degrees, I dont think the engine compartment areas will reach this temperature. Second skin says many people use this for firewall noise reduction/absorbtion in automobiles with great results.

So that will be my first attemp to wipe out the noise.... I am not sure if a different size K&N would work, i dont think there is much room to even fit anything different. I will try the second skin and see what happens.... then goto plan B.

[Bobby Light]

First off, thanks for the replies...

I did order some "second skin" to insulate the back engine panel, and storage bin area. The gap behind the seat can easily be sealed up with a thin piece of plastic and it appears will not impede the seat placement. The air filter is right behind the rear seat, it almost touches the back panel area. Its no surprise to me you can hear this noise when sitting in the rear seat.... The gap in the back is allowing noise to come up into the boat. The second skin is good for temperatures up to 400 degrees, I dont think the engine compartment areas will reach this temperature. Second skin says many people use this for firewall noise reduction/absorbtion in automobiles with great results.

So that will be my first attemp to wipe out the noise.... I am not sure if a different size K&N would work, i dont think there is much room to even fit anything different. I will try the second skin and see what happens.... then goto plan B.

Hey report back on your thoughts of the mod and whether you think it worked or not. Interested to hear how it goes..

[skurfer]

I have it on my MC (Indmar MCX), too. Only happens at one certain RPMs/Speed. If you want to eliminate it, drive at a different RPM/Speed I like the whistling (sucking) noise. Reminds me of how much air is going through the engine!

[Fman]

Hey report back on your thoughts of the mod and whether you think it worked or not. Interested to hear how it goes..

I will let you know, planning on doing it by end of week and going out Saturday.

[LS-One]

Anything that drops in the throttle body opening, if small enough, can get sucked right into a cylinder through an intake valve.

That's how they killed all the engines in the cars turned in during cash for clunkers. Engines were destroyed by pouring a sand/silicate mixture in through the intake tract. Real "green" of them, eh?

Momentary lapse of reasoning This is one of those "I knew that" moments.

[Fman]

Got some clarification from Indmar on the engine whistle. Below is the email I recieved from Larry at Indmar...

"The noise is caused by air being sucked over the throttle plate in the throttle body assembly that the flame arrestor is attached to. At certain RPM/throttle plate positions, we hear of this "whistling" noise occurring. Some do it and some do not. Your 08 Supra had the same throttle body but the airflow through the air intake system was slightly different so you didn't here the noise.

We have had some people modify the throttle plate slightly as per the attached diagram and have had positive feedback. You just need to slightly round the edges of the throttle plate as shown. I can't guarantee it will work and it is not a warrantable job but if you want to try it you can. You need to take the throttle body off the engine and use a fine file or fine abrasive paper and then make sure you blow out all of the filings so they don't get ingested into the engine."

Larry Engelbert

Indmar Service

Power to the Sport

My dealer offered to do this at the 20 hr service if the sound continues, thought I would pass this along to anyone else experiencing this... If anyone does end up trying this, please post some results.

Thanks....

[thtrog]

Fman,

My boat it out for stereo work, but I took a VLX for demo day yesterday and noticed a loud whistle. I turned the storage tray around under the middle seat so the larger flange was toward the engine and it helped a lot, but there is still a gap this way. After getting home I was curious because I did not remember any noise or opening like that on my last boat.

Here is a picture of the "09 and it is completely sealed.

Here is a picture of '11 and I believe this is with the larger flange toward the engine. I was surprised how load the boat was before I turned the tray around. I believe if this area was closed it would not be an issue.

[Fman]

Fman,

My boat it out for stereo work, but I took a VLX for demo day yesterday and noticed a loud whistle. I turned the storage tray around under the middle seat so the larger flange was toward the engine and it helped a lot, but there is still a gap this way. After getting home I was curious because I did not remember any noise or opening like that on my last boat.

Here is a picture of the "09 and it is completely sealed.

Here is a picture of '11 and I believe this is with the larger flange toward the engine. I was surprised how load the boat was before I turned the tray around. I believe if this area was closed it would not be an issue.

I was able to eliminate the gap that you see in the last picture with a piece of plastic and some sound insulation. I also did this on the pizza pan above the engine there is a large gap between the rear pan and ski pylon area. This sound is even worse if you have the walkover platform because the ski locker doors dont fully insulate the pizza pan area. I filled this in with some layers of insulation as well. It has made a huge difference in the whistling, I will post some pictures in a couple days when I get home from work.

[thtrog]

Look forward to seeing the modification you have done. Thanks

[Fman]

Here are the pictures of the second skin luxury liner pro sound deadning material.... rated to 400 degrees, I used 3M heavy duty spray on glue to apply (also high heat rated) and used some stainless bolts to double hold all material. It has drastically, if not completely removed the whistling/turbo sounding noise coming from the throttle body intake. I also plugged off the gaps between the pizza pan and rear center seat section that was allowing noise to come into the rear seating area of the boat.

There is 4 layers of the second skin between the pizza pan and crossmember, this was about perfect to completely eliminate the gap. If you have the walk-thru center plank it creates more of a chance of noise coming in because the ski locker doors do not completely come together and leave sound gaps. I did have to notch out the second skin to allow the ski locker doors to lock up.

Here is the link: http://www.secondskinaudio.com/noise-barrier/Luxury-Liner-Pro.php

Edited May 2, 2011 by Fman

[Fman]

more pics....

[Fman]

more pics...

Edited May 2, 2011 by Fman