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 Post subject: boat racing in Australia
 Post Posted: Sat Apr 21, 2012 4:44 pm 
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We just completed racing The Marj Watson trophy event in Adelaide Australia. This event is the Premier circuit boat racing event in Australia. Even more so than the Australian championship. Its an event open to all classes of displacement boats. So you can enter with basically anything as long as its displacement hull. The event is dominated by Supercharged boats obviously but we had a go with our 6 liter carby class boat. The qualification for the event is based upon your heat race elapsed time and only the fastest 6 boats make the final. We qualified 6th with our mates 6 liter carby (tune assisted by me) qualifying 4th. The others were all blown boats and 1 injected methanol boat qualifying 6th. The rest of the blown boats and 6 liters were left on the trailers having either not gone fast enough or experienced some mechanical problems. The race was very good with quite rough water, the weather was rain and choppy water. We finished 4th in the trophy event and were the highest placed NA boat. The 3 boats in front of us were blown boats capable of far higher speeds than us but finished only 1/3rd of the straight ahead as we were catching them for the last lap and a half. It was very exciting with not much in it between the boats. Our mate finished 5th and the injected 6 liter last a long way behind.
We were very happy with our showing for the day, the boat ran flawlessly, without any tune changes from the warm morning to the stormy end of day race. Beating Blown alcohol boats during the days racing is quite fun.


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 Post Posted: Sun Apr 22, 2012 8:04 am 
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We just finished the second day of racing for a different trophy race. The Dorwin cup is a major race meeting here, its open to all classes of boats, not restricted to displacement like yesterdays race. There were tunnel hulls etc competing along with blown displacement and methanol injected 6 liter and carby 6 liter. We run carby 6 liter which is cast iron block with fuel restricted to AV-gas or street fuel. . We came 5th in the final, it was won by a blown boat then tunnel hulls etc. We could have made 4th place but got caught in a wash and spun out but got going again for 5th. We were the only carby boat to make the final, all the other blown boats were left on the trailers, we had a ball. Surprised a lot of people. We took out winner of the 6 liter class for the meeting.
We had to do some tricky stuff before the last race because the oil became very hot and the pressure was down, so we pumped the tank out and cooled the oil by transferring it from one container into another with the wind catching it to cool the oil effectively. It worked a treat and we cooled it right down and sent it out for the final with no problems. Have to do a heat exchanger on the oil next up.
Our boat could take it to the blown boats because it can corner on a pin and then accelerate faster than them out the corner. The blown boats have an edge on our top speed but their lap times are slower. The boat that won the race was exceptional though, we cant get near that one. It was the only blown boat that could out accelerate us so we happy with our weekend.


Last edited by shrinker on Sun Apr 22, 2012 4:24 pm, edited 1 time in total.

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 Post Posted: Sun Apr 22, 2012 11:05 am 
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Congratulations!!!

Sounds like a lot of fun!

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 Post Posted: Sun Apr 22, 2012 4:18 pm 
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Yeah it was good fun. The most obvious observation I and many others made over the 2 days racing is that other boats can match our straight line speed and our corner acceleration for about 2 laps but after that they fade away and cant keep up, especially in acceleration. I'm talking about all the other 6 liters and blown boats as well, the tune on their engines doesnt hold consistent for the duration of the race (especially the blown ones). You can actually hear a slight change in the engines. Our engine sings for as long as the tank holds fuel. In fact we have done testing where we have run the tank dry and it never changed tune by ear or on the data logger. We have EGT and O2 on every cylinder so we know whats going on.
Its good evidence of the importance of vaporization control.


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 Post Posted: Mon Apr 23, 2012 5:45 pm 
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Yeah were the little high reving boat snapping at the back of the blown pack. It was good fun. The winner deserved it, he was far superior than the other blown boats. He's going the speed a boat with that much power should go compared to our speed.
We still have about 6mph to find in our boat as I calculate it, but this boat has now finished its career, its 25 years old and had enough. Were building a capsule boat, same hull etc for next season.
The winner of this race also won the race the next day (Dorwin gold cup) against the tunnel hulls and F1 boats etc. We finished 5th in that one.


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 Post Posted: Sun May 27, 2012 5:27 am 
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Just got home from the races. It was the last meeting for the season. Had 3 races and won them all. Beat blown boats too. It was a white wash, total domination won each race by half a lap. So have to find out now if we got top point scorer for the year. It will be close.


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 Post Posted: Sun May 27, 2012 11:50 am 
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Congrats!!! \:D/ \:D/ \:D/

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 Post Posted: Sun May 27, 2012 12:16 pm 
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Congratulations also!! Always good to finish the year off winning! =;

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 Post Posted: Sun May 27, 2012 4:14 pm 
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Way to go!

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 Post Posted: Sun May 27, 2012 5:26 pm 
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Thanks guys.
We have to build the new boat now, it has to have a cell fitted. Dont think we will be doing any engine development work but its getting pulled down for checking and it may get some compression and different cam and go E85 fuel. Currently running Av-gas but Im not happy with Av-gas. The power per cube is too high for AV-gas as I have to run it too rich to keep it safe. The engine runs very good though, tune is consistent in all air conditions, never touch it. Other teams the performance changes a lot from hot to cold etc, we just keep truckin on and thats what wins. It goes the same speed from start to the end of the races, others drop off. The engine has a 1340cfm Smartcarby on it I custom made for the actions of boat racing. It the hardest accelerating boat out of the corners its got the most engine power across the rev range. the driver can choose to go so slow in the corners that the engine drops to 1250 RPM on some of the logs and pulls straight and clean to 8700 which is its max power RPM. So thats a hard task to do with a big carby and its only got 30cc pumps too. The engine is a 358 Nascar flat tappet Dale Earnhardt.
It will be interesting to see how it goes on E85 I think it will make more power than it is now because of the limitations of AV-gas. AV-gas is fine provided its not old, when its old it just looses enough octane to be a concern to me. Some others have ruined engines (nascar ones) on suspect fuel that was supplied at a race meeting once, we got away with it because the atomization is better and the charge is cooler and it didnt send it to detonation, but it got close. But I watch that stuff all the time. the data logger is good it shows me detonation before you can see it on anything.


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 Post Posted: Tue Aug 14, 2012 8:52 pm 
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HI All. we had the end of year presentations and we came second in the point score. It must have been close, we didnt compete the whole season and we had one race where we hit the buoy so we had to stop (the rules) and its a non result race for us so we think that cost us the points. We did however win the Driver of the Year award which we are stoked about. That meant more to us than the points actually.

The last meeting of the season was a really cold day and the other boats had tuning issues. Their speed was down a good 5 to 8 MPH on normal for them we however continued on at our normal full speed. It was embarrassing to go so much faster I kept telling the driver to slow down to make it look good. But he didn't.
The season was fun and now we have to sort out the capsule thing. Still haven't got the hull back from the capsule fitter so we are going to miss the start of this season as well. But as long as when we hit the water we kill them we will be happy.


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 Post Posted: Wed Aug 15, 2012 5:21 am 
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Looking good Bruce and your going to do an E85 smart carby for the boat?? It will make more TQ and may pick up some speed also =; ... \:D/
Do you have any Vid of the race???

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 Post Posted: Wed Aug 15, 2012 9:01 am 
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webermaniac wrote:
Congratulations! \:D/

I thought colder ambient air meant some power increase and not a be cause of tuning issues? :-k


X2 :-k

Although fall air here in the "States" is usually a little better than spring air for some reason unknown to me. May have something to do with humidity that is different between spring and fall. We'll be coming up on our best air of the year in another 3 or 4 weeks.


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 Post Posted: Wed Aug 15, 2012 7:03 pm 
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Beretta, I dont have any video of the races.
Webermaniac. I'll explain why the others had tuning issues.
The rules require the fuel to be av-gas which is not a good fuel for high RPM. Av-gas is actually specified for LOW rpm aero engines operating in low pressure atmosphere and to be suitable for turbo heated intakes etc. Thts why av-gas has high distillation temps but it will also evaporate readily. Its an excellent chemical mix. BUT its not specified for high RPM as is common in domestic race engines. The Nascar engines in use in these boats are still stock Nascar compression so they are at around 11.8 to 1 compression ratio and the guys are using original Nascar carbs. Ive looked at the other racers carbs and worked out why they are setup the way they are and it makes sense for an engine running with a carby CFM restriction. The carbs are a lot different to what drag racers etc run. Ive advised the racers on tuning of their carbs and they have made positive gains however the basic design of the engines carburetion is restrictive resulting in reduced dynamic compression in the cylinder at high RPM. WHEN THE AIR IS COLD you have to heat it up more to reach an equivalent temperature of vaporization as to when the air is hot, so when the engine is lacking dynamic compression it simply doesn't get hot enough to utilize the same percentage of fuel charge during the burn cycle.
The start temperature of the air has a compounding effect upon the final compression temperature. Its not a situation of if you start 10 degrees colder you only loose 10 at the final compression. There is a math you can perform that works out the temperature of adiabatic compression it shows that the final temperature is a greater difference than the start temperature. For instance a 10 degree change at the start may be a 30 to 100 degree change at the final (depending upon the ratio of compression etc). Did I explain that clear enough?
You have to consider that these are boats racing in the sea and the main thing that varies is the temperature and humidity with not much change in barometric pressure. So when the temperature goes down and the due point gets close the engines suffer a lack of heat inside the chamber for vaporization.
I go on all the time about vaporization as the cause of issues but its true without vaporization engines wont run.
Vaporization is the root cause of all issues.
The problem with the Nascar carbys is the design is still basic Holley with the droplet formation of a Holley. Its the wrong setup for av-gas in a high RPM engine. Although av-gas is wrong its still usable if you make very fine droplets and give the engines less restrictive carburetion. Our engine has a 1340CFM carby with fine drops than a Holley and it didn't need any changes to the tune, it performed with regularity.

I'm looking forward to doing the E85. To do it I'm going to reduce the CFM of the carburetor and redesign the atomization system. I'm doing this because the engine is not getting new pistons at this stage so I cant increase the compression, so the engine will still be 11.8:1. Once we have an understanding of the E85 and the pistons are worn out and due for replacement then it will get some applicable compression and camshaft.


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