Need to calm down bottem end power

[*_"Got Paint?"_*]

A newbie here in Nitro... I'm running a Losi 2.0 Truggy, just got a new OS Max Version II .21 engine. This thing is hella fast, I love it! BUT!!! I would really like to tone down the bottom end power. It's like a light switch, either full power or not, lol... I'm used to racing 2wd Electric Buggies, so I know throttle control, but when I try to barely put the throttle on the Truggy it feels like full power... I've heard a few things to try, the carburetor came with the yellow restrictor (7mm) someone said try a smaller one? I have the OS 2060 pipe, someone said try the 2090 pipe? Would either of these be noticeable? I thought of changing the speed of the throttle servo, but when the truggy is on the starter box I barely pull the throttle and can tell its just the power ban... Don't know if any of this makes sense, but hopefully someone can help with suggestions...

 

[*_"Got Paint?"_*]

Nobody has any thoughts, ideas, or opinions on this??? Bummer...

 

[Rolex]

Unless you're too lean on the LSN, you'll need to practice trigger control. If you're using a computer radio then you can set the exponential curve for the throttle.
If you're getting too much as soon as you start it, without any warm up time, then you're definitely too lean on the LSN.

 

[moe7404]

Unless you're too lean on the LSN, you'll need to practice trigger control. If you're using a computer radio then you can set the exponential curve for the throttle.
If you're getting too much as soon as you start it, without any warm up time, then you're definitely too lean on the LSN.

try it change the throttle over all lever slower. make the hole in the lever on the servo closer to the servo. OR make the hole at the carb longer. the experts here can tell you about useing a slower servo.

 

[Greywolf74]

I'm not familiar with that engine so its hard for me to comment on this one. I have a Picco.28 in mine and I dont really have the problem your describing. A pipe isnt going to make a huge difference, at least not big enough for what you're describing. Putting a smaller venturi (if I understand them correctly, again not a lot of personal experience with them) will actually give you even more bottom end power which sounds like is the opposite of what you want. I believe the bigger venturis (venturii? lol) or no venturi will give you more top end. I'm also pretty sure that the main use of a venturi is to compensate for less dense air in higher elevations. Someone feel free to correct me if I'm wrong about any of this. As Rolex mentioned setting a throttle curve on your radio sounds like the best fix since you seem to have experience with trigger control already. Wish I had more to offer in the way of answers.

 

[*_"Got Paint?"_*]

Awesome guys... Thanks for your opinions! Didn't even think that the smaller venturi would give more bottem end, makes sense, I already ordered a 6mm, oops... lol... we'll see what that does... I like the idea of moving the mounting point on the servo arm as well... I'll try these few things next time I can get out and get back with you all... keep the ideas coming, I can use the help!

 

[WinnersCircle]

Another thing to try is changing the springs in the clutch. There are a number of weights of clutch springs available for most clutches. The softer the spring the sooner the clutch engages and a clutch that engages early will take a lot of the snap out of an engine. I would try the softest springs available for your clutch and see if that gets you were you want to go. You can use a combination of spring weights at the same time to get the clutch engagement you want. On some clutches there are different shoes you can run that will impact the way that the clutch engages.

I run a BUKU clutch on all my cars because the tension on each spring is adjustable externally thru the edge of the flywheel. This allows me to soften up the clutch when the traction is low or crank up the spring tension when the traction is high. It is all about the RPM that the engine is at when the clutch engages. The higher the RPM the more violent the initial acceleration will be.

Lee

A newbie here in Nitro... I'm running a Losi 2.0 Truggy, just got a new OS Max Version II .21 engine. This thing is hella fast, I love it! BUT!!! I would really like to tone down the bottom end power. It's like a light switch, either full power or not, lol... I'm used to racing 2wd Electric Buggies, so I know throttle control, but when I try to barely put the throttle on the Truggy it feels like full power... I've heard a few things to try, the carburetor came with the yellow restrictor (7mm) someone said try a smaller one? I have the OS 2060 pipe, someone said try the 2090 pipe? Would either of these be noticeable? I thought of changing the speed of the throttle servo, but when the truggy is on the starter box I barely pull the throttle and can tell its just the power ban... Don't know if any of this makes sense, but hopefully someone can help with suggestions...

 

[*_"Got Paint?"_*]

Another thing to try is changing the springs in the clutch. There are a number of weights of clutch springs available for most clutches. The softer the spring the sooner the clutch engages and a clutch that engages early will take a lot of the snap out of an engine. I would try the softest springs available for your clutch and see if that gets you were you want to go. You can use a combination of spring weights at the same time to get the clutch engagement you want. On some clutches there are different shoes you can run that will impact the way that the clutch engages.

I run a BUKU clutch on all my cars because the tension on each spring is adjustable externally thru the edge of the flywheel. This allows me to soften up the clutch when the traction is low or crank up the spring tension when the traction is high. It is all about the RPM that the engine is at when the clutch engages. The higher the RPM the more violent the initial acceleration will be.

Lee

Now that makes a lot of sense there! I'm not sure where in the spectrum my set-up is so i'll have to do some research. I went with Adam Drakes setup, 2 Aluminum shoes with Gold springs, and 2 plastic shoes with green springs... But that BUKU clutch system sounds like the hot ticket! Adjustable without taking apart? Gonna look into that as well... Thank you Lee for the comments!

 

[Greywolf74]

Winner makes an excellent point. never even occurred to me. Buku clutches are extremely nice too.

 

[olds97_lss]

I always thought the smaller venturi just toned things down a bit and helped conserve fuel for racing. As simple as it is, you may as well put the smaller one in and see how it feels.

 

[Greywolf74]

You may be right Olds, The only thing I know about venturis is just a little bit I've read here and there. I've never really used them much.

 

[WinnersCircle]

A smaller venturi will result in lower overall power but the effect is more on the top end than the bottom because it reduces the RPM that the engine will reach. Also a smaller venturi is more difficult to tune than a larger venturi but It is worth trying. The only time I put in a smaller venturi is when I am trying to extend my run time in order to eliminate a pit stop during a main event.

Another thing that impacts where in the RPM range that the power comes on is the exhaust system. The exhaust can make a big difference.

On my truggy I want strong low speed power in order to be able to be able to accelerate fast to clear jumps that have short run-up. When I am having trouble with excessive power (wheel spin/no traction) and I have the proper tires on it for the conditions, I will first adjust my transmitter by changing exponential to the throttle servo so that I get less servo movement for the first 1/2 of the trigger travel. I really don't like to put in much exponential because it makes it hard for me to control the attitude of the vehicle when it is in the air due to the trigger feeling numb. The 2nd thing I do is adjust my Buku so that it engages sooner.

Get an experienced nitro guy to help you tune the engine in order to make sure that the tune is correct.

Good luck. I hope I helped.

Lee

I always thought the smaller venturi just toned things down a bit and helped conserve fuel for racing. As simple as it is, you may as well put the smaller one in and see how it feels.