how to increase runtime

[avbrando]

hello all, i'm running (not racing) an aeromarine sprint cat with a 67 green head, 67-80 fat pipe, x457 prop on 50% fuel and am only getting 3-1/2 minutes runtime on a 16oz tank of fuel. i'm wondering if this is normal. if so, is there anyway to increase runtime by swapping props or pipes? which is best for economy? thanks in advance, Brandon.

 

[Tim_Duggan]

16 oz of 50% for 3 1/2 minutes sounds about right for a 67 - maybe a little better than usual.

If you want longer run times on the same tank capacity - try reducing the nitro % down from 50%, then re-tuning to suit. Should give you a little longer run time and the fuel will be cheaper too.

 

[Mike Cathey]

Add maybe a 2-4 oz. sump tank.

 

[tnrcboatracer]

3 1/2 minutes is forever considering 16oz would do well to last 10 laps in a 67. 6 laps at race speed would be about 2~ 2.5 minutes.

 

[Buckshot]

As stated 3 1/2 min. run time is good for a .67 on 50% with a 16oz tank. If you can't fit a larger fuel cell you might go down in nitro %. This should increase fuel mileage and make it a little easier to tune as well.

-Buck-

 

[Greg Hahn]

If you figure the standard scale boat race, 2 minutes for mill and warm up, 6 laps @ 20 sec. lap average is another 2 minutes, one cool down lap @ 30 sec. all ample numbers.

That's a total run time of 4 min. 30 sec. +/- .

My scale boat with a green head will use 20 oz. of 50% nitro on a safe needle to make that number.

I would imagine you would be lucky to gain 30 to 50 sec. of run time with lower nitro to 30%, the flow rate just doesn't change that much. Big bore nitro engines are thirsty that's the way it is. Don't quote me on this but I've heard the flow rate on a top fuel car now is close to a gallon per second you think we boaters have it bad, how'd you like to feed that

You might think about converting one to gasoline? It can be done, Nelson hobbies in texas has a gas conversion kit for a 60 to 90 supertigres.

I had a Saito 180 glow four stroke running on gasoline back in the late 90's took a bit of trial and error but it did run well. Now Horizon Hobbies sells a Saito on gasoline.

Just a thought

good luck

gh

 

[Roxyflash]

I have the same setup i added a sump in each sponsons there 4 oz a piece i normally just use 20 oz but in the offshore it needs more i use three tanks.If you want long run times sell the nitro boat and get a gas one then you can run for a half hour.LOL

 

[ALLAN YUEN]

Are you run " enjoy" not racing better use 25 to 40% fuel :huh: waste money 50% fuel If you make serious racing so use 50% Good luck!

 

[Speed Jr.]

Theres a simple answer to this question boys.......... LEAN IT OUT!!!! :lol: :lol: :lol:

Sorry guys, couldnt resist a smart ass remark like this.

Theres not much you can do if you want to keep the same performanc. Lower nitro is logical. Another thing is to take your boat, and shave as much weight off of it as possible. This will help a ton, but thats not always possible. Good luck....

Larry Jr.

 

[Andy Greene]

I agree with Roxyflash- get a gas boat and send this one to me

Andy

 

[DickJones]

hello all, i'm running (not racing) an aeromarine sprint cat with a 67 green head, 67-80 fat pipe, x457 prop on 50% fuel and am only getting 3-1/2 minutes runtime on a 16oz tank of fuel. i'm wondering if this is normal. if so, is there anyway to increase runtime by swapping props or pipes? which is best for economy? thanks in advance, Brandon.

Using a smaller carb will increase run time.

 

[avbrando]

thanks alot Larry, i leaned it out and it BLEW UP! just kidding. i just want to say what a great experience i've had since joining this forum, everyone is helpful and proffessional, it makes the learning curve of being a begining boater a little smoother. THANKS ALL.