Ofna2005

Just my 2cents worth maybe you should try a Werks #5 glow plug and then re set your jets to flush . Then see what you have.

Werks

iTrader: (3)

In a nutshell I've already told you a few weeks ago what to look for and how to address the issue that you are seeing in my post #4146 on page#277. The important stuff from your post yesterday:

What I told you in post #4146 on page 277:

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In any case to test idle run a couple of laps and get the engine and chassis heat saturated and up to temperature (this is very important before you do any kind of tuning). Then bring the car back into the pits, grab WOT for 2-3 seconds to blow out any fuel accumilated in the crankcase then immediately hit brakes and listen to what happens to the idle. Idle should drop to a low idle and stay there. If after chopping throttle the idle is initially high and then starts to drop down lower (and or ultimatel conks out) that is an indication of the HS being lean and the LS being rich.
**************

Obviously from reading that if you go to WOT and then chop the thottle and the idle is high that means the HS is lean. If the idle does not drop back down to a smooth, steady idle but stays elevated that also means that your LS is lean. So....you are too lean on both needles which is confirmed by you saying that you are 2 turns in on your LS which is about 1 to 1 1/14 turn leaner than I've ever needed to run it my self, so way, way too lean!

Then in this post you stated:

Good, that is the way to do things when you get lost tuning. Go back to flush and flush which as we allways say is a "safe, rich point from which to start tuning your engine".

Good again, that is basically the same as the tuning method that we came up with.

It's supposed to be rich, that's why we call it a "safe, rich point from which to start tuning your engine". The 0.5mm idle gap, is simly a fixed air gap around which to start runing so depending on your location, weather, fuel, altitude, glow plug etc. your engine may stay running or it may not, does not really matter. All that matters is that you can start your engine, you can keep it running by blipping the throttle if needed. So as we wrtie in our guide, once you have the engien running lean the LS 1-2 hours, blip throttle to clear it out and let come back down to idle and check to see if you have a smooth, steady idle. If the idle is low lean the LS 1-2 hours, blip throttle, let come back down to idle and check again to see if you have a smooth, steady idle. If not keep repeating this until you do. So that easily and quickly takes care of getting your idle speed adjustment taken care of through adjusting you LS because if your engine will not idle, you can not drive the car hence you can not tune it.

Well that is why you have a high speed needle, to adjust WOT performance of the engine and obviously with us having set the engine to...."a safe, rich point from which to start tuning" it's not only going to initially be rich on the LS (which we just took care of in the step above by adjusting the LS) but we are also going to have to adjust the HS. Which is why in the next step of our tuning guide we say that once you have your LS set so that the engine has a smooth and steady idle put the car on the track and take a couple of laps to heat saturate the engine and case and then do a WOT run down the straight and see how the engine behaves. If you feel it needs more top end pull back into the pits and lean the HS 1-2 hours (so now we are adjusting the HS needle). Then blip the throttle to clear out any fuel accumilated in the crankcase, let the engine come back down to idle and check to see if you have a smooth, steady idle so now we are checking the LS again. (I obviously know what you will see which is you will notice that the idle is higher becasue you leaned the HS which by default leans the LS fuel delivery and will give you an elevated idle which you have to compensate for then by richening the LS but I'm trying to teach readers how to tune). So I'm telling you to blip the throttle, let it come back down to idle and check the idle speed so that you pay attention to how your engine behaves. It's obvious and right there in front of you and you then have to richen the LS 1-2 hours, blip the throttle, let it come back down to idle and check again. If the idle is still high repeat otherwise put the car on the track and do another lap or two checking the high speed performance and if you need more come back in and lean the HS another 1-2 hours, repeat the idle check/adjustment procedure, go back out and do a few more laps, if needed come back in and adjust the HS again, repeat the idle check/adjustment procedure etc. etc. until you have your top end performance with the HS needle set to where you want it to be and obviously your idle speed and hence you LS needle setting will be proper becuase you are adjusting that each time right after you adjust your HS.

So the only way to get completely out of whack like you are right now with as you say the engine being really fast on top end but showing little smoke and having an idle that does not come back down etc. etc. is by not following the procedure of adjusting your LS first to set idle, then adjusting your HS followed again by adjusting your LS to maintain a proper idle. So...please go back to flush and flush on the needles again, fire the engine up, set the LS so that you have a smooth, steady idle then take a couple of laps to warm up everything and start adjusting your HS to give you the top end that you need. Each time that you adjust your HS, check the idle and adjust your LS to compensate for how the HS adjustment is going to affect your fuel delivery. Do that any you will be fine. Hope that helps!

Apco1

iTrader: (2)

Check just now and the HS is about 1.5 turns in from flush.

Werks

iTrader: (3)

I just editied my post above and wrote you a long reply that addresses everything, please take a look.

Apco1

iTrader: (2)

I am also at about 3200 ft above sea level, I know altitude affects tuning.

Apco1

iTrader: (2)

The first time I tried the Werks method(before this series of posts) of LS first then HS, I thought it worked well car went up and down the street in front of the house behaving nicely. Put the car up until the next race day about a week later with similar weather. Didn't touch the needles, put it on track I began having issues again with the same settings that ran fine at the house a few days earlier.

Now I think its safe to say that the most common recommendation on nitro tuning is HS first then LS. The Werks method is LS first then HS, then adjust LS again. What advantage is there to adjusting LS first if in the end you have to re-adjust it after setting the HS?

grizz1

You need to read Ron's very thorough post again in depth. It's all explained in there fully.

In a nutshell you set the LS needle first (around a fixed idle gap) to gain the correct relationship (air fuel ratio) between the two.
Without this being set you can chase your tail all day long in an effort to "luck it" unless you have an experiancd ear and a full understanding of what is actually going on inside the engine / carburettor.

If you start with the HS first you are very likely to end up altering the idle screw to get what you think is the right mixture / idle speed. That means your now juggling three needles at once instead of two - an exponential leap in difficulty if your not an experianced tuner.

As Ron also explained, the HS needle (by vitrtue of how these carbs function) directly effects the fuel supply to the low speed needle - therefore altering it's setting. That's why your better off to set the LS needle first to get a reference point if you like, then get the best WOT performance you can with the HS needle (which will as we have discussed slightly change the low speed seeting). But because you had the correct idle speed as a reference point for the LS needle setting - you can now reset the idle speed back down using the LS needle and bring everything back to a balanced tune (or balanced needle settings if you like).

Think of your carb as a garden hose. The tap on the wall is the HS needle - setting overall flow parameters.
The adjustable spray nozzle on the end of the hose is the LS needle spraying fuel into the carb at idle.

What happens if you turn off the tap a little ? The flow from the nozzle lessens - so your engine runs a little leaner on the LS needle, and beacuse your idle gap is constant the engine will lean slightly and the revs will rise.
To faciliate this you need to open the spray nozzle a little further to maintain the flow.

Going a step further with this analogy - if you close the tap on the wall too far, ie overly lean the HS needle - you will get little to no water out of the nozzle. This is your classic lean bog scenario when the HS needle is leaned too much.

Think of your carburettor as a garden hose and I think it will help you to visualise what is actually taking place when you adjust the needles.
In order for this to work though - the idle gap (or in the hose scenario the size of the nozzle jet the manufacturer sets - and you can't adjust) must stay constant.

Hope that helps

grizz1

You have PM

thommi

I like that explanation! very good!

Werks

iTrader: (3)

Thanks Grizz for giving some additional input/calrification on what I was trying to say!

Apco1, if the first time that you used our method it worked well then it will work well the second time. Also when you are tuning your engine if it is se/tuned properly at the end of one day, you put it away then take it back out and fire it up a few days later and as you mentioned absolutely nothing changed i.e. the air density, humidity and temperature then the engine will run exactly the same as carburetor can not adjust them self.

If indeed something has changed just pay attention to and listen to your engine on the box and it will tell you what is going on. Meaning if you put it away tuned perfectly with a perfect idle and fire it up and now and after warming up on the box for a few minutes (IMPORTANT, never bother tuning a cold motor) your engines idle is suddenly higher it's the engine telling you that "hey, look at me! Something is different, my idle is high that means the air is denser and I have leaned out!". So you can immediately tell that the engine is lean and when it leans out it leans out accross the board. So you have to richen your needles. If when you fire it up again, warm it up on the box and then check idle it is low then you know that the air is less dense and it has richened the engine up across the board and when you go on track you will have to start leaning it.

Now the one thing that sets off warning bells for me is the part I undelined:

You tuned your engine on the street in front of your house then went to a race a week later and put it on a track and began having issues?? If I cooked bacon a week ago in a skilet and it was perfect but when I tried to do it last night on the BBQ it burnt does that mean there is something wrong with the bacon??? No it means I need to use a different techinque! So is your street made out of dirt? Does your street have jumps in it? I'm guessing no. The street is made out of asphalt and there is very little rolling resistance, on dirt there is a lot of rolling resistance. The street is flat, on race tracks you have jumps. Those two factors increase the load on your engine which means it will run much hotter (hence leaner) when on a track. You can break in an engine on the street, you can start tuning an engine on the street but you can only properly adjust your needles for race tune on a race track. I've found that the increase in load on the engine between asphalt and dirt will result in roughly a 40 or so degree increase in temperature. So if you had set your engine to be sharp (crisp) with good performance on the asphalt lets say it was running at 230F, when you tossed it out on the track and did a couple laps it was probaly in the 270's! Hence way too lean, the idle was probaly high, the engine was probably running on and probably had little power.

Funny enough we used to sell them then everyone started doing wraps for their cars a few years ago. So no one bought stickers anymore and we stopped selling them. Now people are starting to ask for them again so we will just be including them in the box with engines in another month or two.

Herrsavage

That garden hose analogy is an excellent one.. Good job. That should be a sticky somewhere, or in a youtube how-to video.*

I haven't seen that before, but I like the explanation about doing LSN first with the idle gap, then HSN, then re-adjust LSN. Makes sense. I have never thought about it that analytically, but over the years in very general terms my take on nitro tuning has become basically "it's all about the idle gap and having the right idle level", and the idle has more to do with the LSN - the HSN setting is in a way secondary. Well "secondary" is perhaps not the perfect word to describe it. But again, in very simple terms, a good tune is mostly about the balance between the idle gap and the LSN. The HSN you can tweak on top of that depending on weather or whatver... But the idle has to be right first and foremost. Which very roughtly put is similar to what was explained above..

* Actually, it should have been 6-7 years ago when nitro-hating flashlight drivers started badmouthing nitro has being "too difficult" bla bla.. Or when Losi started introducing stupid wannabe' gas engines based on the same false premise..

Werks

iTrader: (3)

I've been promoting this method of tuning an engine for a long time, I think it was since back in 2006. A few years before I became active on this forum. Actually now that I think about it I do not even think that this place existed back then, most of us more hardcore guys were posting on the Starting Grid back then. In any case the I first posted about "the system" on RCTECH back in 2009 on the first post of the B5 thread here:

http://www.rctech.net/forum/offroad-...ng-engine.html

Herrsavage

I'd heard about the "Werks method", and read it at some point on here probably, but always sort of thought of it as something specialized, and - no offense - perhaps a bit too complicated in the explanation. People need simple explanations, and the garden hose analogy makes it seem much more accessible. I have seen people refer to it over the years, so it's obviously been a good thing for some folks..

But unfortunately electric people, Traxxas-pushing hobby McChain shop employees, and now Losi and co., have really pushed through the false idea that nitro is "difficult". Which is ironic in the case of Losi, given that a decent nitro engine is WAY easier to break in and tune than their dumb attempt at a gas engine..

grizz1

Cheers

We used that garden hose comparison a few years back on the GO engine thread on here that was quite a prolific thread back then.
A lot of guys struggled with the long needle carbs that GO introduced and the garden hose thing helped a lot of guys to "see" what was actually happening inside their carbs.
Guys struggle a lot with the large idle gap scenario - what we affectionaltely call the "average woman tune" (sorry ladies) - lean on top with a fat bottom and a wide gap............
Tuning the way Ron has explained will totally prevent you ever getting into the wide idle gap and rich bottom end / lean top end situation, because you set the relationship between the idle gap and LSN first - from there it's hard to go wrong.

fizzy

iTrader: (15)

Wow...! Talk about the best customer support and service in the business...