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carb info and tunning guide!

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GBDUO View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GBDUO Quote  Post ReplyReply Direct Link To This Post Posted: 27 July 2006 at 8:35pm

Yah, the LSN note should actually be the idle screw setting.  Sorry!

The LSN should be like 7 turns i think...although that one is trial and error as i can't remember how many turns it is! lol!

The hops ups i got from Apex Models in Crowthorne, Berks (www.apexmodels.co.uk) Apex are the largest supplier of Schumacher bits and bobs and are just awesome, thourghly recommended!

The air filter is just for show (look at me, i have a K&N filter on my RC car! lol!) , but the alloy hop ups add a huge amount of strength to the car, it does not break that much anymore...

Graham

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mrmaggoo View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mrmaggoo Quote  Post ReplyReply Direct Link To This Post Posted: 28 July 2006 at 9:03am
cheers
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NilSatis View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote NilSatis Quote  Post ReplyReply Direct Link To This Post Posted: 21 September 2006 at 10:42pm

Ooooh Look wot I found...hope it helps someone. I thought it was quite well laid out and simple to understand for noobs.

" Rather than tell you to tune your engine to a specific temperature or number of turns out, your best off tuning your engine based on how it is behaving. Even if this is your second engine, most people have an understanding of how the top end needle affects the vehicles performance. Richening (backing the needle out) makes the vehicle travel slower, leaning makes the car faster. Getting the ideal setting and correct balance of top end and bottom end is simple task through a few simple rules of engine tuning.

To begin, we have 2 main needles to adjust, the top end and the bottom end. They adjust each end of the end of the rpm spectrum. The two needles are independent from one another, but they can be mistaken for affecting one another. What is sometimes misunderstood with regard to a top end is the need for the engine to “clear out” of the lower rpm range to get to the top speed. Meaning the bottom end is so rich it needs to overcome the flood of fuel just to get to the maximum rpm. The point here is when adjusting the top end; make sure you have a large enough area to reach the top end.

The bottom end is much more elusive to most tuners. The deception lies with the belief that the bottom will do just what the top end did. Yes, leaning the bottom end does give more power, to a point. You want your vehicle to pull wheelies and flip over backwards from the power. But, much like a real engine, a glow engine has a powerband. The engine can’t overcome an incorrectly setup clutch that is engaging just above idle. (The clutch is whole other article).

Much can be known about the low end mixture just by looking at how far the carburetor is opened for idle. Understanding the relationship between the bottom end needle and the idle stop screw (opening of the carb) is important for adjusting these 2 needles. If you followed our break-in procedure, you found yourself adjusting the idle with the low end needle, not necessarily the so named idle screw. This was to insure a rich idle setting. Assuming the engine idles appropriately, and there is large opening for idle (set at 1.5-2mm 15% opened), the idle/low end mixture is quite rich. If there is a hairline crack of an opening for idle (.2mm 2% opened), and the engine idles appropriately, the mixture would be considered lean. It’s important to understand the relationship between these two needles to know how to adjust these two in tandem. If you richen the low end, anticipate the idle to drop (slower less rpm). Sometimes the drop will be to low for the engine to keep running, so adjust the idle stop screw accordingly (turning it in [more open] to compensate). As you lean the bottom end, anticipate the idle to rise, back out the idle stop screw.

Generally, if you lean the engine down and gain power, all is ok. Which brings me to the golden rule, “when in doubt, richen it”. A common and detrimental mistake is leaning the engine unnecessarily. If you’re not sure of which way to to turn a needle, always make sure to richen it (counter-clockwise). Richening should make the vehicle loose power. If you do not see a loss of power, or question if there is even a loss, richen the engine until you see it. Only then, after going to rich, can one decide where the engine operated ideally. This is true of the top end, and of the bottom end. Top end of course is just that, maximum speed. The bottom end is acceleration. If you lean the bottom and there is a gain in acceleration, so be it. The same is true of the top end. Just check yourself occasionally by richening it.

If you perform the above check, with the top end and the bottom end, there will not be a need for a pyrometer. Temperature devices sample heat differently, some read by means of reflected heat, others are infrared, or even a remote probe. Each method yields different results. The important point about temperature is that it is relative to your device, in your climate and environment. A cold day will result in a cold reading and hot reading on a hot day. Don’t lean your engine down for the sake of temperature, lean it down because it makes your engine go faster. If there’s a gain, go for it, but make sure your right. A few times at a track I’ve heard, “Hey Eric, my engine is slow at 240 degrees, what’s the deal?” “When I lean it down the temperature spikes up to 290 and then it’s a rocket”. What is usually the cause is an extremely lean bottom end and a very rich top end (if it’s not a bearing going bad internally). As soon as the low end needle pulls out of the spray bar, fuel is dumped in the engine and it goes rich. When the top is leaned, the speed comes back. The issue of course is the bottom being too lean; this is where the temperature comes from. Richening the bottom would bring the temperature back down. Again, check your engines setting periodically.

When in doubt, richen it. "

From Werks Racing.  Cheers.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote danniuk Quote  Post ReplyReply Direct Link To This Post Posted: 02 April 2007 at 8:23pm

my mt2 revs too high and moves a lil forward when idling... but when i have the car idling any lower it cuts out, ive tried everything i could think of.

cheers

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Winfield Quote  Post ReplyReply Direct Link To This Post Posted: 01 May 2007 at 12:04pm
Originally posted by danniuk danniuk wrote:

my mt2 revs too high and moves a lil forward when idling... but when i have the car idling any lower it cuts out, ive tried everything i could think of.

cheers

If you have tried all the mixture settings and still cant get the revs low enough without cutting out.

It may be the centrifugal clutch enagaging and putting load on the engine.

My clutch got bunged up with dirt and the above happened. The clutch bell shouldn't really move much when you pull the starter cord.

Or if you are electric start spin the clutch bell it should run freely and sound nice not gritty.

Hope this helps

 

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Post Options Post Options   Thanks (0) Thanks(0)   Quote teddy1981 Quote  Post ReplyReply Direct Link To This Post Posted: 27 February 2008 at 12:16pm
Hello all, sorry if this has been asked before, if I remove the carb restrictor from my Rascal, is it going to go NUTS on me? or should I just play it safe and go for the 2-speed gears instead? or both?

Any opinions considered.

Thanks.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote teddy1981 Quote  Post ReplyReply Direct Link To This Post Posted: 03 March 2008 at 2:04pm
No need to worry about the carb restrictor question now.

Once removed, the Rascal went like S**t of the proverbial shovel ....until I lost it in a 6 inch deep puddle and killed it.

Think it needs a little TLC after that.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote menacemike Quote  Post ReplyReply Direct Link To This Post Posted: 14 May 2008 at 10:58pm
hi i am new to all of this and have got a menace fitted with a venom speed meter on the front drive shaft it is set up correctly but am only getting top speeds of about 50 mph and yes that is f,ing fast.Wher is my other 20ish mph if i screw the hsn in any more it is to lean and dies at top end i think the wheel bearings are a bit worn but any other help would be a help
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Paul M View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Paul M Quote  Post ReplyReply Direct Link To This Post Posted: 14 June 2008 at 8:39pm

The Menace will only hit those kind of speeds under optimal conditions; your tuning, belt tensioning, mesh, lubrication, even body-shell design (affecting your aerodynamics), everything has to be pretty spot-on usually.  I've had mine in 3rd gear plenty of times, courtesy of the fact that I've had a few monster carparks and the odd runway to let her loose on, but once she gets into 3rd, you'll probably be a long-time waiting to hit the maximum.  I can't honestly say that I think I've ever hit 70mph.  Maybe downhill with a trailing wind...

It may well be your bearings sapping power though; I had not run my Menace for about 4 months and could not persuade her out of 2nd, I thought my tuning was off, or perhaps the fuel was a little bit old, but nothing I did was making much of an effect, but changing all the wheel bearings, diff bearings, and diff balls freed everything up again.  Incidently, now (18 months later) they are all shot to sh** again, and she's back to sulking in 2nd, so now I'm upgrading to ceramics all-round, I'll let you know in a couple of months how much of a difference (if any) it's made.

One thing you didn't mention though is how old or used your Menace is; if it is second-hand, it may be that your engine is worn, or may just not have been run-in properly.  If it is brand-new, it could be that not everything has freed-off yet.  Did you follow the tuning guide?  Also, how much does the speed meter weigh?  If you're putting stuff like that on, it may be the weight that you're adding.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mofi Quote  Post ReplyReply Direct Link To This Post Posted: 12 November 2008 at 11:13pm
Can someone unstick this thread or explain what 'tunning' is please?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote La La Quote  Post ReplyReply Direct Link To This Post Posted: 14 November 2008 at 10:16am

i now where y6our coming from mofi this thread had been hear for flipin ages!

UNSTICK it

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mofi Quote  Post ReplyReply Direct Link To This Post Posted: 19 November 2008 at 11:24pm

I've no idea what "tunning" is?

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Post Options Post Options   Thanks (0) Thanks(0)   Quote La La Quote  Post ReplyReply Direct Link To This Post Posted: 20 November 2008 at 4:24pm
its getting the carb settings right, but i don't see the point in having a stick post about it. its a wasted stuck post
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Post Options Post Options   Thanks (0) Thanks(0)   Quote topbuzz Quote  Post ReplyReply Direct Link To This Post Posted: 17 January 2009 at 7:13pm
Originally posted by newboyaustin newboyaustin wrote:

high speed mixtur needs tweeking a bit, u need to unsrew the high speed mixture!! 1/8 of a turn untill its good!!!
is this the same on a rascal as mine does the same cuts out at high speed.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GBDUO Quote  Post ReplyReply Direct Link To This Post Posted: 29 September 2009 at 12:28pm
How could you say such a thing!

This took hours to compose and I am sure it has helped many people. Carb
tuning is tricky when you are new to the sport, and hopefully by reading this
first it should get new and old guys alike up and running quickly.

I don't think it should be unstuck, it is useful.

Graham
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GBDUO Quote  Post ReplyReply Direct Link To This Post Posted: 29 September 2009 at 12:29pm
Originally posted by topbuzz topbuzz wrote:


Originally posted by newboyaustin newboyaustin wrote:

high speed mixtur needs tweeking a bit, u need to
unsrew the high speed mixture!! 1/8 of a turn untill its good!!!
is
this the same on a rascal as mine does the same cuts out at high
speed.


You are running lean, unscrew it, only a small amount though.

Mind you looking at the date, you probably worked this out! lol!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote alkistsamb Quote  Post ReplyReply Direct Link To This Post Posted: 11 October 2009 at 5:37pm
Hello, i have the menace 21 for about 5 years, it operated a few times on the first year, and now after 5 years i thought i would get involved again, my first question is about the fuel.Does it matter to have it 5 years in the box?Anyway i ask that because it was really difficult for me to start the engine again. once i managed to start the engine i noticed that when ever i took of the glow starter the engine shut of institaneously.Why does that happen? If i left it on for a few seconds it works fine but once i take the glow starter off it switches off.Also, i managed to melt the first gear (plastic)without running at high speeds.I was in the process of trying to make the proper tunning.Finally, for the LSN most say it should be 2-3mm from flush. What does that mean?From flush meaning that is should be 2-3mm off? Any help for my questions?

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menace 21 LSN 2-3 mm from Flush
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Newbie Quote  Post ReplyReply Direct Link To This Post Posted: 13 October 2009 at 10:47pm
What does "tunning" mean?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GBDUO Quote  Post ReplyReply Direct Link To This Post Posted: 14 October 2009 at 1:16pm
Tuning.

make more sense?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Newbie Quote  Post ReplyReply Direct Link To This Post Posted: 14 October 2009 at 7:23pm
That makes more sense - thanks.
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