Expansion Chambers for DMH

[Bob Dunlap]

Look at the results for the SE Divisional last weekend at Jesup GA These people were running expansion chambers on the 44 Mercs.
!st place Dick Willard, 2nd place Steve Dunn, and Patrick MacMillian

[RandY Aveline]

ok and the chambers got passed from behind and beaten at dayton ohio !!

so what is your point ???

[Tim Weber]

I think the point is Jesup is one of the few places left that open pipes are allowed.

Open pipes have killed mod races at some long standing race sites. Ocoee for one no longer welcomes megaphones.

Die hard mod people may have to come to the realization that expansion chambers may be the only way to race. So you go a little slower, but if everyone is running chambers whats' the problem?

Tim

[Dave M]

The Problem

Is there are a TON of places that welcome the loud pipes.. Why go somewhere you are not welcome ? That holds true to any boat racing. If the place is tough on racers and getting permission, etc, why bother. Go somewhere else. There is a LOT of water around....... In FL there are places that like the noise. Dayton Ohio does not seem to mind, Brighton MI loves the noise, Huntington IN likes the noise, Just about everywhere in IL likes the noise, places out west like the noise.... see my point ?

Just because a small handfull of locations don't want the noise does not mean we need to change an entire categories heritage. Besides, chambers work on a couple engines. Ask Dick Willard how many years he spent getting the right ones to work...... Ask Steve Dunn how many years it took him. Ask Bob Goller why his good C Merc is no longer.... and you will find your answers.

Besides, you find a race course that does not like the noise, they probably don't get 100% behind the race no matter what is racing there.

[39R]

Maybe that is true for Florida and some of the other states that have an abundance of locations that are either undeveloped or where those that do live there do not mind or even like the noise; but out here in the west we are loosing locations rapidly due to noise levels. In Region 10 two locations no longer allow megaphones; Lake Lytle and Cullaby Lake have both forbidden there use at these historical race sites. Cullaby has even been host to Pro and Mod Divisionals, but no longer for megaphones engines.

What is occurring is that these once remote or seasonal residence locations are being developed by those with vast disposable incomes and they are lobbying the local jurisdictions to ban load engines even for a weekend. Another example is California’s Shadow Cliffs, long a favorite race site attended annually by Regions 10, 11 and 12, is no longer available due to million dollar home owners on the cliffs who successfully had our welcome mat pulled out from under us. Why – NOISE!

Certainly the mod guys don’t need me to tell them what they can or should do, but if they want their classes to survive, I think history will judge that the out dated megaphones need to go in favor of modern performance options that are a little friendlier on the locals.

[Morris85C]

we did lose shadow cliff for noise but it was mod pro and inboard all combined. so i guess we all need to run stock from now on. some stock classes make noise to B STOCK. so now what. o well i guess we better start raceing dirt bikes or cars. the peopel complaning about the noise they are not going to support boat raceing go fine new water

[39R]

Lonnie, you are correct that Shadow Cliffs was a combination of all loud classes, Stock, Mod, Pro and Inboard all combined; certainly no one can argue that a full field of Cracker Boxes wasn’t the nosiest class to run there and they have nothing to do with Mod. But I think the mod guys are missing a point that is being made that will have an impact on where you run in the very near future.

People are becoming more sensitive to many types of pollution, not limited to the water and noise pollution that we are all contributors to. Simply ignoring their concerns and doing nothing where the issue is raised or worse yet, being pushed farther and farther out from civilization until we find locations that are so remote that no body cares about them will not solve this growing concern. Further, I will repeat that I expect no one to change what they do because I think it might be a good idea; by all means continue with what you do no matter what the outcome if that is what you believe is the right approach.

But let me ask you this: at what point will you concede that public opinion does have a very real affect on what and where we run, when Mod is no longer accepted anywhere but at some remote location that is convenient for no one to travel to including the racers?

Pro boats are not only running tuned pipes, but now they even run them competitively with silencers installed on them. So why are the Pro guys able to overcome this and Mod is left in the past with what is not only antiquated equipment, but increasingly harder to find? Just a causal observation form someone on the outside looking in is that this situation cannot ultimately sustain your chosen classes.

Someone much wiser than I said that “if you chose to change nothing, then you would be crazy to expect a different outcome”. Isn’t this exactly what Mod is doing if they choose not to experiment and improve the situation that the communities where we race have already begun to raise to their city and county council members? We’ve already lost 3 favorite sites on the West Coast to loud classes, one is now gone to everyone and the other two exclude Mod, how many more sites do you get excluded from before you take action?


I'm not criticizing; I'm trying to help with a very real problem that is already affecting my friends here on the Left Coast and doing nothing just doesn’t seem to be very realistic.

[Cameraboy]

Maybe that is true for Florida and some of the other states that have an abundance of locations that are either undeveloped or where those that do live there do not mind or even like the noise; but out here in the west we are loosing locations rapidly due to noise levels. In Region 10 two locations no longer allow megaphones; Lake Lytle and Cullaby Lake have both forbidden there use at these historical race sites. Cullaby has even been host to Pro and Mod Divisionals, but no longer for megaphones engines.

Another example is California’s Shadow Cliffs, long a favorite race site attended annually by Regions 10, 11 and 12, is no longer available due to million dollar home owners on the cliffs who successfully had our welcome mat pulled out from under us. Why – NOISE!

Don't forgot Lake Lawrence, where loud stuff can't run until after noon (give or take a half hour), and if the program gets delayed they risk losing heats. Had to run all of the loud stuff in one flight Sunday - those guys were hopping to be ready it was scheduled so tight.

Sounds like this will remain a regional issue to deal with.

[Bob Dunlap]

My point is expansion chambers are definitely faster. All the bikes and the other 2 cycles run them. I had a motor cycle racer at the boat races a few years ago and he thought we were way behind, I told him that was true we like doing things like they did in the 50's and were too lazy to change. He explained how hard it was to design 4 chambers on a 500cc bike and keep them under the fairing but it was well worth it. The noise is a big problem everywhere and we need to address it, I don't like it but but if we don't do something those liberal tree hugging democrats will keep eliminating our sites.

[sam]

I am not certain that expansion chambers are faster on our motors ... it hasn't consistently proven out in all classes. B and C Mod come to mind quickly. If it was as simple as it seems to outsiders, Yamatos with pipes would consistently outrun those without.

I talked about this with my brother who has successfully built pipes for dirt bikes and chainsaws ... he says he thinks our problem is trying to use too brief exhaust port timing; that the idea that the pipe can be built for short timing is not fully accurate. Rather the pipe actually is a compensator for using drastic exhaust port timing that would not be otherwise usable.

Some of the history of the expansion chamber might be helpful. They were developed in East Germany in the 1950's on motors running extreme exhaust port timing and rotary valve intake timing ... also extreme compared to motors not using expansion chambers. The whole scheme was stolen by Suzuki and refined by the other Japanese bike makers.

[Jim Porter]

My point is expansion chambers are definitely faster. All the bikes and the other 2 cycles run them. I had a motor cycle racer at the boat races a few years ago and he thought we were way behind, I told him that was true we like doing things like they did in the 50's and were too lazy to change. He explained how hard it was to design 4 chambers on a 500cc bike and keep them under the fairing but it was well worth it. The noise is a big problem everywhere and we need to address it, I don't like it but but if we don't do something those liberal tree hugging democrats will keep eliminating our sites.

Well Bob Dunlap I suspect that actually most of those who try to get race sites closed down because of loud pipes are in fact rich NIMBY republicans! Speaking for myself I am a lifelong Democrat and a dedicated enviromentalist and I dearly love loud pipes. I liked them even better back in the 50's and early 60's when the only thing holding back that beautiful noise was a short 2" stack! Course I can't hear worth s^&* now but I enjoed it! Hope you were just trying to be funny but, seriously, politics is best left out of this forum.

[alky6]

expansion chambers on deflectors

Expansion chambers lend themselves quite well to the loop scavenged engines (all new PRO alky engines). This is not the case with crossflow or deflector piston engines (Mercury Mark 55, 58, 75, 78, etc.). Sam eludes to this: there is not enough real estate (time-area) available in the porting configuration along with the piston-transfer port arrangement. We have done extensive dyno testing on expansion chambers and port config on crossflow engines. Further, the ability to get a good clean scavenge process is almost impossible. The only reasonable candidate would be the Mark 30 block as there is a lot of room to increase porting. What we found is that we could make a lot of torque below 6,000 RPM but diminishing returns above that. This again goes back to the available real estate problem. The megaphones do a fantastic job of "sucking" the fuel through the engine as well as doing a pretty good job of "plugging" (pushing a pressure wave back into the cylinder just before the exhaust port closes). The expansion chambers just do not work all that well on a Merc. Not to say they don't, but I would run the megaphones any day of the week and beat the pants off of someone who runs expansion chambers on the same engine.

Bottom line, if you want to run expansion chambers, you need a looper.
Unfortunately, there will be noise pressures from some sites and not others. Just need to be cognisant of the classes put on the schedule and adjust accordingly. There are some races we don't go to because we can't run our alky 6 with megaphones. A choice we make....

-Paul Fuchslin

[Morris85C]

Ken I would be happy to answer your question. You can't compair pro to mod
because of what you can do to the moters. I've played with chambers for about
6 years now and what I have found is that chambers work good on a loop charged motors
because that's what they are made for, if we could loop charge are d mod motors they would
work just fine but in the mod classes there are things you can do and things you can't, unlike pro
back in the day 60's, 70's, and 80's when there were mercs running as pros the mercs could not keep up with the kongs and the
yamatos. The ones that could are still running today or they just don't race anymore. To put chambers on my dmod stuff
you mite as well shoot me in the head. the noise to me is the next best thing to having good s@# if you no what i mean. Theres
nothing that sounds beter then a good running 44 or a good 6. Take the open pipes away and you will have a d stock, you will
kill the mod class. I know i will hang my stuff up. There are a lot of race sites that are far enough out of town that we can run at.
This noise thing has been going on ever since the begineing of time. Some people like it some, people don't. The ones that don't
well they don't need to go to the races. With any kind of motor sports your going to have noise, someof your drag races are out
in the woods but people are still going to them. WE DO NOT ADVERTIZES OUR SPORT thats why people don't, come its not all about the noise.

[David_L6]

Some interesting info in this thread. Thanks for the posts Sam and Paul.

I've seen chambers tried on several Mercs but only saw one motor that raced well with chambers - Bob Goller's C.

I've seen a Mike Weinandt built 44 race with chambers that Mike built. It was a lot faster than the other boats on the start (a one straightaway wonder?). It didn't run well around the course though. I don't know how much of that was set up and how much of it was due to the chambers....????

[39R]

Thank you all, Lonnie, Paul and Sam, your input is all very educational for someone as I’ve self described, “an outsider looking in” at the Mod classes. You clearly know the mechanics of the topic which I have yet to even scratch the surface of.

But I still believe that this issue of noise will continue to grow based upon my own attendance at county commission meetings at the sites in play. The attitude of local lake residence owners is growing increasingly intolerant of what they see as nothing more than noise pollution benefiting a few at the expense of many. These very words have been used against my arguments to keep you on the water at Cullaby Lake. I do not side with them, feeling that boat racing is a long standing tradition worthy of their support and I for one will still try to fight the good fight for your side when I can. None the less, I wish you luck in the feature, as other than the mechanical theory as to why it all works, you still haven’t presented an argument that I feel I can use to prevail over those that want the noise reduced.

On a personal note I feel as if I’m throwing my friends under the bus, as I’ve had to eliminate them from the sanction and because of it we are not only fewer, we are poorer for not having their company.