Slide Carb VS Rotory?

[c3racing0082]

Hello
I Need Some Advice On The Diff Between The Two. I Have A RS4-3 RTR. And I Heard That The Slide Carb Style Is The Way To Go With A On-Road. Because Of It's Faster Throttle Responce (i hear) Than A Rotory Carb Style . Which Is Ideal For Off-Road..
Whats Your Take On This.

 

[parris001]

I think a whole lot of this depends on your tuning abilities. I've always found rotarys to be easier to tune but they give up some performance to the slides. Slide carbs to me always operated more like an on-off switch. It was either idle or hauling a**! I had a 1/8 buggy with a .21 Enya with a rotary carb at first but then upgraded to a .21 Paris Picco with a slide. Running offroad didn't seem to favor one carb style over the other and any disadvantages presented by a particular carb were offset by other advantages.

My experience has been that slide carbs tend to have a slight hesitation (that's not a real accurate description).... more of like a "hunting" sound when transitioning from idle to WOT. It's never in my experience caused a power issue but if just sounds funny. The last slide carb I tuned on was a Hot Bodies 1/8 buggy with Hot Bodies own .21 with a slide carb. I masked the noise by slowing the rate of the throttle opening with the radio. Now the carb opens slower up to a certain point and the acceleration is crisp and clean without any wierd noises

 

[Diver6127]

I can't answer what is better for off-road since I am mainly an onroad enthusiast.

When I had my OS15 CV-R, it came with the rotary carb. It was fine. I thought I had good response and performance. I one day decided to get the slide carb for it. I was very impressed with the response off the line. Throttle response was better and takeoff was "snappier." Ever since then, I have been going with a slide carb and never looked back.

When you get a high end engine for touring (Italian mega basednengines are all I run now), a rotary is rarely seen. I have yet to see a high end engine come with anyting but a slide carb. Most of the sport versions of the italian engines come with slide, but I have seen some with rotary.

 

[G8RMaxx]

Rotary carbs are a little more forgiving off-road, but the 'snap' of a slide carb is great if you have the grip or throttle finger. The response is more important for on-road, IMO.

 

[CorradoPsi]

i really doubt you will notice the difference. i use both types on different high end engines. if your tuning is good, the performance difference of the carb in negligable. i run a rotary on my onroad car (sirio .15 outlaw) and it certainly lacks NOTHING off the line. i have slide on my nova .28, and os v-spec. both are great carbs.

parris, it sounds to me as if your lsn is out of tune. most people can pic up on the sound of bogging and know to lean it out. so your issue sounds as if your lsn is too lean to me. try richening it up, your hesitation and that sound will go away when properly tuned. you will know for sure it is WAY lean if you idle rpms come up as you richen it a little.

 

[parris001]

I tuned that thing every way imaginable. I went rich until it was a dog off of the line and started leaning it out to make it better. It's just like the sweet spot was unobtainable. I performs like a banshee but it just has that noise. The owner insists on running Blue Thunder 20% (I hate that fuel) and I think it might do better on a different fuel. Has anyone ever noticed that Blue Thunder stinks really bad when it's running? It smells like a full dumpster on a 100 degree day...........

 

[c3racing0082]

LOL pariss!! i hate Blue Thunder myself esp the 10% blend. that's what I'm using in my rs4-s rtr until i run out . i can't wait until i do!! that 10% esp made my S/T Off-Road Doggie as hell!! 20% can't be any better. I heard good results out of the 20% Sidewinder fuel ! i know a couple of guys w/ Savage's that use the stuff and they love it. the same guy's that used to use Blue Thunder . They said it was a night and day diff!!!

I'm Going W/ The Slide Carb Style Engine!!!!!! With Diff Brand Of Fuel!!

 

[CorradoPsi]

ok, parris, yeah the fuel could cause that quite easily. i swear by 30% race blend fuels. preferably trinity or odonnel. I've NEVER had any trouble tuning with either one, and certainly no hesitation.

C3, i wouldnt use 10% if it was given to me. use the rest of what you have to clean air filters with, and go pick up a nice 25-30% blend with about 8-12% oil. the lower the oil content (within reason) the less hesitation you will have. and the more nitro, the more power you will make. simple as that. if you let me know what engine your using i can point you in a better direction, since some engines can't run 30% without shimming them for it. almost all engines can run 25% without a problem.

 

[Maxx Trooper]

I have used both rotary and slide carb on my off-road r/c's, t-maxx, sportmaxx, HPi Nitro MT, Nitro Hawk, Nitro stampede. i have found that the slide carb is better in my opinion, there is quicker throttle responses and more of a mid-range.


later

 

[c3racing0082]

ok, parris, yeah the fuel could cause that quite easily. i swear by 30% race blend fuels. preferably trinity or odonnel. I've NEVER had any trouble tuning with either one, and certainly no hesitation.

C3, i wouldnt use 10% if it was given to me. use the rest of what you have to clean air filters with, and go pick up a nice 25-30% blend with about 8-12% oil. the lower the oil content (within reason) the less hesitation you will have. and the more nitro, the more power you will make. simple as that. if you let me know what engine your using i can point you in a better direction, since some engines can't run 30% without shimming them for it. almost all engines can run 25% without a problem.

That 10% was givin to me and i hate it !! What fuel should i use for the ave .12 engine ( O.S./ Fhantom ./ Wasp.) all in the 150- 170 $ range!!

 

[CorradoPsi]

it depends on the particular engine. my .15 fantom loved 30% right out of the can (they are packaged in boxs now :-( ), my .12 OS CV-R i had to shim to use 30% in or it would overheat, and my .15 Sirio loves 30% out of the box. it really is dependant on the individual engine. you can try 30%, and tune it properly ignoring temps. once that is done. bring it in for a temp reading, if its too hot or blows plugs a lot, you need to shim it a little, 1 copper shim is all thats needed 95% of the time.

 

[c3racing0082]

an added shim for the glow plug?

 

[dougc]

nope the shim goes between the block and cooling head.

 

[parris001]

You aren't meaning to suggest that 30% Nitro would cause an engine to run hotter than 20% Nitro, are you?