eclozon

To begin with, I am kinda new to boats. I have lots of r/c nitro experience, planes, cars, helicopters. Six of us went and bought new miss Vegas boats and spent three days at the local lake. I have read just aout all of the forum info and I still am confused about engine performance. The first weekend out my brother and I set our Miss Vegas boats on the back of my full scale boat. I thought he put them inside and he though I did. You can guess what happened next. Both boats fell off and I ran them over. Radio box, engine case, hull, well everything. Well we did the only thing we could, drove 200 miles and bought new boats. We finished the weekend with the new boats and had a great time. It was worth the extra $249 for the new Miss Vegas. Anyway, after the weekend was over we decided to rebuld our crushed boats. I bought a new modified .18 aqua from TLR and put it in my newly repaired Miss Vegas. (by the way, the folks at TLR got the new motor to me in three days and saved my vacation, thanks)My brother put in a new os 18 stocker. The following week we spent at the lake, between the six of us, we used almost four gallons of fuel. Probably the best time I have ever had at the lakehouse. We tried endless setups on the different boats. After all of the tuning and adjusting we got everyone running amazingly fast. The stock OS was a bit faster than my TLR aqua motor and I was a bit faster than everyone else. One of the guys with us couldn't take it any more and went to the local hobby shop and bought a new Miss Vegas. This guy has never had a boat but like the rest of us has been into R/C. We helped him set up and break in his new boat, just like we did. After six tanks, he was blowing by everyone, even in the straights the built aqua, the OS with a mac pipe, everyone. We all spent the week in the same house and shared setups.

I ended up running in third place during most of the racing. We drag raced, tried each other's boats and tried to get them all as fast as possible. Everyone was running 30% except me, I was using 50% Odonnell boat fuel.

Bottom line is I hate to loose.

I want to by a new Miss Vegas and a new motor, whatever it takes. I don't like the idea of spending $200 on a new motor but the thought of bying a new OS and a pipe and the getting passed by a stocker really sucks. I can just hear everyone now, it's the driver. Well no, it's not. We switched boats many times. And yes they do handle differently but my buddies new stocker is way fast.

So on the engine choices, stock aqua, stock OS, TLR aqua or TLR OS?
What is the difference between the two and is it worth the money? How about the OS 21. I don't what a boat that is unreliable. I have read the hull isn't strong enough and then there is the electric starting hassles.

thanks for the help.
Ed

eclozon

Jerry Dunlap

IMO - "Best Bang for the Bucks" - O.S. 18CVR-M - That's the belt start version.

JD

Sean Bowf

I gotta agree with Jerry. I like the CVRM so much, that when I heard they are doing to discontinue them, I bought a spare.

I would invest in a GPS and do some testing of the hulls. I do agree, that 2 MVs can run very different from each other. Some think it is hull differences, some think it is engine differences. It is probably a little of both. But I would be VERY surprised to see a stock MV outrun a PROPERLY TUNED Vegas with a CVRM in it. Best I got out of the stock engine was 33.1MPH, best out of the CVRM is 43.6 MPH.

Which pipe are you using, and what is its tuned length (length from the center of the glow plug to the widest part of the tuned pipe following down the center of the header)?

Sean

Dan S

Ed,

one thing you need to watch for or for better words is to listen to your engine, when your Vegas was running at its strongest try to remember what she sounded like.

Now remember what she sounded like when the stock Aqub was faster. The slight change of sound regardless how small it may be is telling you something, it could be that the coupler has loosened up a bit, or it has a small crack. Glow plug could be tired (its not because its still running that your getting the same performance), Small change in the outside temp meaning you may have to go just a tad richer or leaner, your tune pipe could have moved being a bit longer or shorter.

Turn fin could have moved or have a small bent and not be true creating some drag and the change or bent doesn't need to be that big to make a difference.

I'm sure I could be forgetting other things but the most important is listen to her tune, any change to it is saying something.

I run the OS 18 CVR-M and is by far faster than a stock Aqub.

What prop are you and your bud's using?

Dan.

eclozon

Thanks for the input. We are all running the stock prop at this point. I have tried prop depths from 1/2" to 1 1/4", most of the effect seemed to show up in the turns. Prop angles from -2 to +2 with about 8 adjustments for each between those numbers. I know the sounds you are talking about, it's that crear crisp shreek you get when your tuned well. I can usually tell I am close if it's running at "song" 1 or 2 minutes into the run. It's not like my boat is getting slower, I think the other boats are just getting faster. (a radar gun is on the way) I have been into r/c nitro hobbies for the past 30 years, I thought I knew how to tune an engine very well, of course that was before I tried boats. That's OK, trying to climb the learning curve is always the best part of any new hobby. From the response it appears the OS is a good platform to work from. I ordered an OS .18 pull start. We usually take our full scale boat, load it with the r/c boats and try to find a quiet glassy cove. I can only carry so much support equipment so we are sticking with the pull start for now. I also ordered a MAC pipe, the 3.5 high nitro unit. I planned on using the stock header, bad choice? We are all running the stock prop, both the fast guys are running different fin's though. The fastest guy is running a "Razor" and the other is the first generation Vegas fin, everyone else is running stock second generation. New 535's will be installed as soon as I can find a good article on how to cut, polish and balance it. Glow plug has been changed to a #8, fox I think. The pipe is stock, until my new pipe comes in. As far as lenght, stock. I have no clue to what the mac or the stock pipe lenght should be. As long as I am on the subject, I am a bit confused. I used to race Karts and dirt bikes. If I remember right, very small changes to the expansion chamber had a significant effect on engine performance. I have a computer program to design pipes for small nitro engines. To be brief, pipe size and shape seem to be very engine specific on the nitro engines as well. I plugged in some of the numbers for a .21 and the .18. The computer recommended size and configuation is a lot different between the two. I haven't seen any discussion on the forum and it just seems there could be a lot of horse power to be found. Any thoughts?

Once again, thanks guys
Ed

Jerry Dunlap

Props can make a significant performance difference on the MV. You are right about not a lot of choices for a tuned pipe. One of the best pipes I've run across is the O.S. 18 truck pipe. It actually provided better performance and was not as loud as the stock AQ pipe. However, you need to cut a hole in the cowling because the pipe outlet sticks upward. I would imagine other 18 car pipes would also work well.

JD

f16man

My sons vegas had about 5 tanks of fuel and was losing performance we ended up pulling the pipe off and found the end of the header pipe was curled over from the pipe hitting it, had to clip 1/4'' off the header for more clearance.

f16man

O ya the stock props dont cut the musterd.

Dan S

I don't know about the Fox #8 plug, maybe you mean OS #8?

you didn't mentioned what percentage of Nitro you were using.

The stock header is fine with the Mac 3.5, also keep an eye on your header if you haven't put some locktite the screws tend to loosen up, the small leak will make you lose performance.

Dan.

fast9

Can you get away with pulling a head shim out of the cvrm like you can with the aqua motor? My cvrm runs great, but for some reason I always want to go faster.

Sean Bowf

I think the CVRM instructions talk about the head shims...and which to pull when running which level of nitro fuel. Personally, I feel I am running well enough with both shims still in, so I left them alone.

Sean

Dan S

Same here.

Dan.