vasek

My Feedback: (4)

hi all,

I'm not sure what pipe to get. On TH site it states:

"IMPORTANT: A .65-.90 size tuned pipe MUST be used with this engine.
Using a smaller tuned pipe will cause engine failure"

However, they don't list a .65-.90 size tuned pipe!

- there's a .90 - 1.30 sized Macs tho, is that too big?

Thanks,V.

fast9

I bought one used and have always run it with a .45 pipe. I was never aware of that recommendation. I have probably 20 tanks through it now and it runs great without any problems so far..

wave waker

here's the pipe i used, .46 OS runs on these pipe, i prefer using the irwin silent pipe(the cylinder shape lookin)..still in the process of comparing what the best combo.

Vertical3-D

My Feedback: (20)

I have a MACS muffled pipe on my youngblood .45 and am happy with it so far but the boat isnt dialed in yet, acceptable noise though, and previously I had a MACS 2.5cc pipe that ran well on a past boat...heres a picture and Ill see if I can find somewhere that sells them...

Vertical3-D

My Feedback: (20)

perhaps tower had a misprint, cause macs rates the 7.5cc pipe for .40-.46, they do also list a pipe for 8.5cc which is a little bigger, tower has misprinted some stuff in the past...or if you want to be absolutely sure you could always call O.S.

vasek

My Feedback: (4)

vertical,

it's NOT a misprint, i've read this recommendation elsewhere too

just curious, there are std. OS tuned pipes & OS marine pipes, is there a significant difference?

would a standard tuned pipe be also good for the Marine engine?

f16man

Go directly to macs pipes they have their complete line of pipes and recomendations or specific engines or you can even call them as they are very helpfull.

fast9

VASEK- If you talk to MACS they probably can tell you why OS is recommending a larger pipe. Please post if they do have the answer as I am curious also. Ran a couple tanks through mine with the OPS 45 pipe yesterday, still no problems.

vasek

My Feedback: (4)

Fast9, take a look at this OS page:

http://www.gpdealera.com/cgi-bin/wga...pgm?I=OSMG1647

"REQUIRES: Fuel with a lubricant content of 16% and a nitro content between 10%-
20%
Glow plug (OSMG2691), the O.S. #8 is recommended for 5%-25% nitro
fuels)
Header (OSMG2723), Flywheel (OSMG2646), Joint, and Tuned Pipe
IMPORTANT: A .65-.90 size tuned pipe MUST be used with this engine.
Using a smaller tuned pipe will cause engine failure
3-20-96/eke
ir/jl
updt jxs 3/31/03"

basically TH copied the recommendations from OS

I heard it could have something to do with the resonance interference using the .45 pipe

I wouldn't run it on the smaller pipe if I were you[:@]

I'll let you know if I have other info.

Cheers, V.

Getnoff

Interesting to find this thread...I've been going crazy trying to get the skinny on this issue myself fro several weeks now. I posted the exact same question on one of the other RC boating forums and the responses were pretty universal..."ignore the stupid warning from OS in regards to damaging the OS .46 VX-M engine by using a pipe smaller than a .65-.90 size!"

Obviously, it scares me to ignore a manufacturer's warning like that, but then again, I can't find a solid reason for this unusual pipe/engine configuration. When I went to OS to ask them directly, I got a response from Hobbico Product Support. They said that they had nothing solid from OS on this warning, and that they could only tell me that they were aware of a lot of customers who were running .45 sized tuned pipes with the OS .46 VX-M without having any reported problems. Of course they did clarify that they were NOT recommending that I do that!

In talking to several pipe manufacturers, I could not get any feedback that they could think of that warranted this requirement for the .65-.90 sized pipe either. None of them could think of any solid rationale for such a warning or reason to run that large of a pipe with a .46 engine. All of them suggested that I run their .45 pipe with the OS .46 VX-M engine.

So, I am still somewhat perplexed. I hate to damage my engine by ignoring this manufacturer's warning, so I have since purchased a Macs #1369 muffled 11cc pipe, a Macs unmuffled 1365 11cc pipe, an Irwin Fat Belly 11cc pipe and the new Andy Brown AB 45 XTS pipe. To date, I've only run the Macs 1369. The boat is a Cajun Bullet .45 rigger hull.

With the Macs 1369, the boat ran good, but not as well as I thought it should. It didn't ever seem to get on the pipe. I am going to run the Macs 1365 next followed by the Irwin pipe and lastly the AB 45 XTS. As you can see, I am trying to be a good consumer and heed the manufacturer's performance instructions. If none of these 11cc units do what I'm looking for, I will take the risk and run the .45 pipe. Given all of the input I've received, I have a feeling that this last step with the new Andy Brown 45 XTS pipe will produce the "right" result. We'll see. I'll keep you posted.

vasek

My Feedback: (4)

Pete, it's good to know i'm not alone in this agony
PLEASE LET US ALL KNOW HOW IT GOES

I have not ordered any pipes yet, but since i am overseas, my choice limitation lies mostly with TH as the give me good shipping prices.

One question remains for me: why are there specific pipes designated "marine"? are they better than the others for this engine?

Cheers, Vasek

Vertical3-D

My Feedback: (20)

I believe part of the reason for the "marine specific" pipes, would be that they are tuned for a boats needed powerband, whereas a car needs more torque and needs to get on the pipe quicker, whereas with a boat(at least a surface drive)it can get off the line fast anyway, planes also normally run lower RPM then boat engines would...I think thats most of it...could be wrong though, this is also why I think a .45 pipe should be used, a larger pipe is not designed to make power with the .45 engine...maybe fina a number from O.S. call them and really question them on this...see what they say...

Kelly Miller

I have used the Cooper pipe on mine.........absolutely screams some insane RPMs. the 40-45 size with a single stinger. Only chucked a rod 1 time.............second engine has been running great for quite a while.

Kelly Miller

Getnoff

Kelly, I assume when you say, "mine" that you are talking about the OS .46 VX-M, right? Who sells the Cooper pipes? Do you think the rod incident you had was related to the pipe?

Sean Bowf

http://cooperpipes.com/

Sean

gooycheese

I use a 60 size pipe on my .45's and yes it is alot of people choices to use the bigger pipe. I am using an OPS6280, so far I really like the pipe. I also am using a rumrunner muffler on that pipe, Because " If you don't use a muffler you are going to eventually ruin the hobby for everyone else with complaints of noise".


Paul

ps. I have heard alot of people do try and reduce the ID of the stinger to 3/8" too.

Kelly Miller

I have run the O.S. 46 quite a bit over the years...I believe the first time was in the early 80's. the rod is the weak part....I run a x450 2 blade with a bit of cup and it really spins some RPM. I don't know that I would attribute the rod to the RPM...but I am sure it gives opportunity. the cooper pipe is quiet and seemed to be a great match to the engine...easy to tune.

Getnoff

So Kelly in your opinion is the newer OS .46 VX-M engine comparable to their older .46 VR-M engine? I guess I'm wondering again if there is anything unique about the .46 VX-M that justifies this pipe idiosyncrasy. Did OS publish this same pipe warning with the older .46's? engine?

Getnoff

forgot to put this in my last reply.........

Paul, where do you find OPS pipes? Can you send me a link. Thanks.

fast9

I've probably run another 10 tanks through mine since my last post. Still no problems with running an ops .45 pipe. This engine does sound like it turns a lot of rpm. It is also probably the loudest engine I've ever had(don't worry, private pond out of town). Getnoff- I get anything OPS from Aeromarine Laminates. They've been really good to deal with.

terry kelly

i tried to get on their website with no luck at all.. i need a ops 3280 pipe actually 4 of them , if anyone can help me out please email or pm me.. thanks alot fellas

terminator

Getnoff

Fast9...thanks for your feedback. Hearing that you've run the OS .46 VX-M that long using a .45 tuned pipe without any problems provides a lot of confidence in regards to my wanting to do the same thing. As mentioned earlier, I bought a new Andy Brown .45 XTS pipe and that's the one I really want to run. I haven't had a chance to get the boat in the water since my original post days ago, but hopefully will be able to do that here soon.

Terminator...The guys at Aeromarine Laminates are easy to get a hold of. Just call and talk with Remy or Troy at 302-628-3944.

1150ap

Fast9 i just got a new os 46 vx-m i have been out of the rc boat thing for about 15 years and i used to run the ops .45 and decided to make a change and get the os 46 i have a old ops pipe that i ran back then i was wondering if you could advise as to what length you are running your ops pipe on the os 46vx-m
i was just about to get a new 60 pipe and i do not have to i would rather not

thanks in advance

fast9

I was just measuring the other day, but I already have forgotten. I remember that the length from the center of the plug to the end of the OS 180 degree header was something like 5". But I forgot what the total measurement is. I will try to check tomorrow and get back. I ended up cutting quite a bit off to make up for the header length.

Getnoff

Fast9.....how do you figure out exactly what the "right" pipe length measurement should be? I have always heard that you're suppose to measure from the glow plug down the header and pipe to the fattest part of the tuned pipe...BUT...what is the right measurement for any engine pipe combination? Do you just cut a little at a time off the tuned pipe until the engine performance is what you're looking for, and how do you know that you've gotten to that point? What exactly are you looking for? Please help.

I went on the net trying to research this, and Oh my God! I came across one of the mot technical write-ups that I've ever read, and quote frankly, it was beyond my mental capability to comprehend. There must be a "Tuned Pipe for Dummies" write-up out there somewhere, but I haven't found it. Is there an easy way for us "newbies" to grasp this? If so, PLEASE share it!