We at Midwest Performance Marine and Loto powerboat club have been doing R@D testing on various mufflers to see if they will comply with the current J-2005 testing parameters. We are specifically working on horsepower engines over 700hp-1200hp both wet and dry exhaust in 5" and 6" tailpipe sizes. We have had a couple of wet mufflers comply in the 850hp range and down, but with a dry 6" straight transom tailpipe have yet to find a muffler to comply even with performance drop. If any manufacturers have a product they feel will comply please call us at 636 236-4141, as we have a serious problem at loto with sound laws with the Mo. water patrol. We have had huge demand for complying mufflers from hundreds of powerboaters with simply no solution for them. These powerboaters have 60 days to get in compliance and cannot operate there boat at all until they get legal, so you can see the ergency to help them. Any suggestions or advice on helping us solve this problem is greatly appreciated. Jim Midwest performance marine- loto powerboat club, President. thanks . Also no manufacturer, dealer or individual can sell a non complying boat without being subject to a misdemeanor, and the current bill at the Govenors office will soon make switchable exhaust illegal unless it complies to 90 decibels in open position. This is getting ugly.

Man,it's getting ugly. Mufflers suck.

Don't they have anything better to do then chase people arond with loud exhaust!!!

I think that one of the things that the Muffler builders may need to look at is the ability to get the exhaust output to be out of phase with one another. This will allow the two engines to cancell each other out to some degree. Should get at leaste a 3 DB drop or more just from that...

Jon

If you just ran your pipes under water at Loto would that suffice? Do the have a way to test you once you are on plane?

Talked w/ Dave Scott Saturday and he has some new pipes on Bacardi he was testing out. They come out and dive into the water. Said the only thing you here is the whistling on the supercharges. Said he was running 170 at the lake Friday night and noticed no difference in performance..

Steve , I have spoke with Dave recently as well as he was running hpi's, is he testing the gibsons or which muffler, . I have looked at the turn downs but they wont work on a high transom mount straight out exhaust like skaters, nortechs, eliminators, several cats, and also cigarettes or v bottom with no swim platform, or over transom style.

FYI...
I have HP500's and put Gibson exhaust on my boat to quiet it down. They work great and are pretty reasonable ($499.00 a pair) I think they are supposed to work to 1,000HP.
We are dealing with this at Lake Havasu also.

GGB is still working on a solution but the tailpipes are all a little different as we discussed in the earlier thread. We are still working on it though.

I have seen 1 to 2 decibel drop by using 1 motor in lieu of 2 or 2 in lieu of three. The gibson turn downs probably work fine on a v bottom with platform or mti cat but only make up to 5". They will not work on the cats with over transom or at top of transom with 6 " pipes or v bottoms, like cigarette or no platform v bottoms.
I agree with Troutly quieting it down what does that mean in decibels. Its all about the numbers, nobody wants to take the time, money and energy to actually test these. We have invested alot of money in equipments, actual conforming calibration devices and independent testers to come up with facts, thats what it takes, facts. I want to know exactly what the numbers are the test environment, outside influences, and wass the meter approved and calibrated. we are talking very specific information.The numbers we are getting are certified by independent and video taped, and the procedure is documented and we will be taking this to the mo. water patrol up to the capital. has to be officially done to show water patrol that we are investing time, money , energy to comply with the law. We feel this is the approach to take to show good faith that we are trying to comply and make these boats legal.I have spent 2 days with lawyers on strategy on how to address this with success. we are getting there but its not easy or cheap.