Caling all Nova Rossi & 3.5cc experts

[Martin Fields]

Hi All,

So I've now had some good running with my KEPS T2 with a Nova 7 Port, and would happily say that its run in. So now's the time to start making it go quicker (something we all want right!). Its a standard set up at the moment, using the Nova turbo head and super silenced pipe. I've got a selection of H6 props to play with, but its the engine/pipe setup that I need advice on.

What kind of squish clearances should I be getting down to? What exhaust pipes should I try out? How short do I need to go with the pipe? Is there a better carb that I can try? How much water cooling do I need and how hot is too hot?

So many questions

Please all feel free to chip in, the more help the better,

Martin

 

[shoboat]

Martin,

What H-6 are you running? Cup & Pitch Numbers?

The ABC 50 x 69 is working very well on our boats. More

Leading edge pitch more speed.

You need more leading edge pitch added to them.

Or more RPM from your engine and pipe set up.

What kind of intake numbers are you running?

How much fuel % are you running?

Thanks,

Mark Sholund

 

[Niklas Edlund]

Hi Martin,

What does it do and how does it perform?

Is your "issue" to get it working ok, or O K?

What i know your props can take you to winning speeds. But they can sure make it even faster if its good already... But we've had it to race speeds with old style Andy Brown 1445's! Never used the NR silent pipe myself (looks like a CMB copy tho) but I would think its ok...!? Get it down to at least 200 mm. I use either the CMD parabolic or the K21 from Al Hobbs. Not a whole a lot diff between them. Squish height to any where around .2-.25 mm to begin with on 60% nitro. What turbo plugs have you used? How much nitro and what oil combo? Ive never heard of anyone that have got a std NR carb to get them to work though. Go with the suggested ones or send it to anyone that can make the stock work...

 

[Tim_Duggan]

In this video I was using a Mac21 carb on mine with a BVM needle in the side of it. SPP RS21 pipe as short as I can get it, Frank Orlic head and cooling jacket set to 0.008" clearance, Odonnell OD97t plugs, 50% nitro, H7 with 3.75" cup (Ozspec)

http://www.youtube.com/watch?v=MfWguAG5Be0

The boat in question was very loose with it's early front sponson design - thus the blowover. Once I made some changes to it I got it going a lot better, did a 1500m race in 55 seconds at a club day once. Also with a different prop on good water saw 128kph on a Stalker Pro radar gun. Sadly too many blowovers early in it's life took it's toll! Now building a KEP's T2.

Temp is very important - for the first few laps in the video the motor wasn't really hitting the pipe but right before the end it starts to come on (watch the rooster tail). I also like to "rich launch" and lean it down a bit once it's up on plane - I get more consistent launches that way. Maybe a different carb could alter that aspect.

From my testing the new NovaRossi Muffled pipe is fantastic in Mono's. In MOTA that pipe drops off power if you go too short without much gain in rpm.

Hope this helps,

Tim

 

[David Murany]

The only mod I would suggest to the motor is to check the induction timing numbers and knife edge the crank. ABDC 35 degrees and ATDC 65 degrees. Head clearance of .006 to .008. We run cooper S pipes at 8". Engine temp of 200 degrees F to 220 degrees F when you first bring it in. Other than that most of the speed is gained at the propeller.

 

[Tim_Duggan]

Tim the NR pipe is shorter than the RS

I found the opposite of what you have said and run the RS on my mono

Just reporting what I found in my testing, Greg. The stopwatch and the Stalker didn't give me any reason to doubt it.

Tim

 

[Tim_Duggan]

No doubt Air density is way better at your pond than ours. I know others have said the same thing with having to change props.

 

[Ian Inverarity]

Check the exhaust timing on the 7 port, some liners I have had have been pretty good out of the box, some are low timed on the exhaust.

 

[Martin Fields]

Martin,

What H-6 are you running? Cup & Pitch Numbers?

The ABC 50 x 69 is working very well on our boats. More

Leading edge pitch more speed.

You need more leading edge pitch added to them.

Or more RPM from your engine and pipe set up.

What kind of intake numbers are you running?

How much fuel % are you running?

Thanks,

Mark Sholund

HI Mark, hopefully these props sound familiar to you as they're ones from you. I've got a H-6 3.10" Cup and 2.73" Pitch (45.56mm dia), 3.21" Cup and 2.84" Pitch (45.61mm dia) and 3.33" Cup and 2.90" Pitch (45.72mm dia). I've not checked the numbers for the engine yet, but its completely standard at the moment. In regards to fuel I'm running 50% Nitro with 14% oil (50/50 )

 

[steve wood]

Check the exhaust timing on the 7 port, some liners I have had have been pretty good out of the box, some are low timed on the exhaust.

for the last 3 years they need the liner lowered and the exhaust raised.shoot for 127 transfers

 

[Martin Fields]

Hi Martin,

What does it do and how does it perform?

Is your "issue" to get it working ok, or O K?

What i know your props can take you to winning speeds. But they can sure make it even faster if its good already... But we've had it to race speeds with old style Andy Brown 1445's! Never used the NR silent pipe myself (looks like a CMB copy tho) but I would think its ok...!? Get it down to at least 200 mm. I use either the CMD parabolic or the K21 from Al Hobbs. Not a whole a lot diff between them. Squish height to any where around .2-.25 mm to begin with on 60% nitro. What turbo plugs have you used? How much nitro and what oil combo? Ive never heard of anyone that have got a std NR carb to get them to work though. Go with the suggested ones or send it to anyone that can make the stock work...

Hi Niklas,

The boat is running really well, and with the setup that I've got at the moment it throttles and is really easy to drive. What I need to do now is get the engine to really rev out as its not "screaming" yet So I've now dropped the squish to 0.2mm and taken some more off the pipe to allow me to get down as short as people are suggesting.

I assume that the Orlic and Zoom carbs are a bigger bore??? What diameter are they usually???

We've got a race on the 21st July so I've got a little time to hopefully make some more changes and try them out.

Martin

 

[Andrew Tuckwell]

Hi Martin

All 3 of my Orlic carbs have 350'' engraved on the carb body .

 

[Martin Fields]

Hi Martin

All 3 of my Orlic carbs have 350'' engraved on the carb body .

Hi Andrew,

Do you know what the diameter of the barrels are?

Martin

 

[anthony_marquart]

Unless you are really trying to go crazy., the 5 or 7 port only need glens carb mod, deck height at 6-8 thou, water restricted and as much nitro as you can get. From there it's pipe and prop to match your boat. Work through 3 or 4 props and a pipe or two and you really should be able to heat race high 60s to low 70s. Just my opinion

 

[Kris Flynn]

I run nova carbs in my rigger and mono (7 ports) and I am quite happy with them. Aaron modded one (cut off 3rd channel and ground back spray bar) and I copied him with the other.

 

[Rene Danner]

I am running a stock Nova carb on my 5 port in my Ninja,seems to work well.I have a S-pipe at 7 7/8 pulling a H-7 from Mark.Still looking for more LOL..Here is a quick vid.

 

[Martin Fields]

Hi Martin

All 3 of my Orlic carbs have 350'' engraved on the carb body .

Hi Andrew,

Do you know what the diameter of the barrels are?

Martin

.350 bore or 8.9 mm its not only the carb bore its also the spray bar and bell mouth

Thanks for the info Greg. I don't suppose you have an email or website where I might be able to get one do you?

 

[Martin Fields]

Thanks for all the info, I'll put some of it into practice this weekend and let you know how it goes

Martin

 

[shoboat]

Martin,

I doubt if you are going to get beat on speed in most heat races.

The most consistent cornering boat with good speed will win most of the time.

Your motor will not rev out more unless you change some numbers inside the motor.

I doubt if a carb changes is going to make much difference on your total RPM. Changes

in your intake timing or a small bump in exhaust timing numbers will give you just a little more RPM.

I would keep it pretty close to where you are now and work with your propellers a little more.

The leading edges can be opened up around .030" to .050" and you will pick up more speed without

any other changes.

Good Luck Racing,

Mark Sholund

 

[Martin Fields]

Martin,

I doubt if you are going to get beat on speed in most heat races.

The most consistent cornering boat with good speed will win most of the time.

Your motor will not rev out more unless you change some numbers inside the motor.

I doubt if a carb changes is going to make much difference on your total RPM. Changes

in your intake timing or a small bump in exhaust timing numbers will give you just a little more RPM.

I would keep it pretty close to where you are now and work with your propellers a little more.

The leading edges can be opened up around .030" to .050" and you will pick up more speed without

any other changes.

Good Luck Racing,

Mark Sholund

Thanks Mark,

I would pretend that I know what you're on about when it comes to the dark art of propellers, but at the moment it doen't Although I have a bit of an idea

I think you should write a book on it, you'll make a fortune. And just think of all the extra props you could sell when people go wrong when they try themselves