XtremeJumpin16

I have heard people tune to the temp their car is at. The hotter the car gets, the richer they set it. I have also heard people tune to smoke and performance. When their performance drops and/or their smoke cloud lessens, they richen it and vice versa. What do you guys prefer? Which is better?

sdtech58

iTrader: (30)

NEVER tune to a set temperature. There are too many factors involved that can change temps without changing the tune. Tune to performance/smoke and use temperature only as a reference to make sure you aren't going to burn anything up. Over the course of a race day, I've seen temps vary from 215 to 255 without changing the tune. Performance was good all day long and I always had good smoke, so the fact that it varied 40 degrees didn't bother me at all. Might even vary more than that, depending upon weather, clouds, humidity, etc.

Use the wintertime as an example. If i'm bashing in January and it's 20F degrees outside, I can lean it out a TON and still not be hot. But if my magic number is 230, i'm going to kill the engine because I had to lean it so much to get the desired temperature. Make sense?

xray808-11

depends on the person who do it.How experienced he is.
If you know what you are doing you wil find it easy to go by sound,smoke and performance.
The only time i use the tempgunn is to verify that the temp is stable.

Here in norway the airtemp goes from 41 to 86 in the summer.
So we can not tell somebody to always have 240 on the plugg.

outside temp and humidity and nitro prosentage and engine are all making a difference.
So in both way u can ruin your engine.

PTP Racing

iTrader: (2)

Tuning an engine is about its performance not its temp. The temp is a good way to gauge where you are with your tune but you cannot set an engine purely by the temp because of the example above. I do the majority of my tuning by sound. An engine running well sounds good and when its out of tune it will sound bad and the sounds different lean or rich. What your looking for is an engine that sounds good and still blows smoke. For me the smoke gets hard to see going around the track but I can always hear it.

xray808-11

100% agree.
you type faster than me

XtremeJumpin16

How much smoke should be coming out? If oil is dripping out of the exhaust is it too rich?

PTP Racing

iTrader: (2)

Yes oil coming out of the pipe when accelerating is way too rich. Sounds like you are just starting a break in.

305M3

iTrader: (43)

+1. This is the way to do it.

The ironic thing is that you can tell when the engine is too hot. When my engines are pinging AND there is still smoke, I know it is around 270-280 - too hot.

I think temperature is just another way to confirm where you want your engine to be. It is a function of being "in tune". An engine that is clearing out through the power band, has good bottom end snap, and maintains a nice smoke trail is likely in the manufacturer's "temp band" too.

Flanno

iTrader: (2)

Power & Performance ALWAYS, with smoke trail, how thick or how thin it is, well that will depend on the fuel you run, and you can usually hear it one way or the other if it is too rich or too lean, if power starts to drop off during a race when below 1/4 tank then your too lean.

I only spit test mine after a race before shutting it down, for self assurance I'm not cooking anything, and if it stays idling until I get it back to my pit table then the bottom end tune is good too.

GizmoJunkie

iTrader: (5)

I am by no means a nitro expert, but i think ive had a swell learning curve, and am fairly mechanically inclined. But say it makes that "skipping" noise but the engine temps at 210-220. Would you say this is time for a colder glow plug?

It gets hot and humid here during the summer and it fluctuates, so glow plugs and tune are always a guess at the start of each race or play day.

Stubbs

iTrader: (58)

What do you mean by "that skipping noise"? I think I know what you're talking about, but I'd like to make sure. If it's what I'm thinking, then I'd be interested in hearing the answer too....

Rock333

iTrader: (51)

Judging by your temp sounds like its to rich and the motor is trying to clear itself out. Take your glow plug out if its really wet then you are to rich.

Boinker

Lets understand skipping for a second. Is it smoking like a frieght train and popping while accelerating or is it bogging down and loosing power and no visable smoke can be seen??

If you can see smoke, this crackling or skipping you may have a too cold glow plug, a clogged air filter or its simply to rich on the top end.

If you do not see smoke then its potentially to lean and has an air leak in the system somewhere in the carb, exhaust, fuel system ect. If that is the case check all points of the engine for wet spots and the check the fuel and exhaust system.

As far as glow plugs i can run a medium cold year round without an issue. Really if you are up to 210 area you could be running the wrong plug.

Try that and we shall see. Oh and btw if its an os speed motor the put a medium plug in it.

GizmoJunkie

iTrader: (5)

See i was trying to look up to see if it was what they call "pinging" or pre-detonation. Looked for a video and couldnt find one

I havent had the issue since last year, usually it does it when engine is hot, say above 250. Exception being the first run i had this year. I couldnt get the engine to stay above 200 and it was kinda lean at that. Hasnt done it since.

I have opened the engine up a few times, even recently and havent seen any signs of pre-detonation such as the grainy surfaces.

The noise im talking about usually happens when idling down from a lean top, while the engine is up to temp. Not sure if this was a lean thing or a "ping". I was thinking if i encounter this again id use a colder plug.

If i come across being unable to temp above 200 again would you suggest a hotter plug?

Just a quick edit to add: I feel im fairly competant as far as tuning goes, I always tune to performance but use the temp gun to make sure im in range. It does however get a little hazy on plugs. I know hot weather means use a colder plug, but humid weather means use a hotter plug. What about hot AND humid? Its like guesswork so far and trial/error to see what performs best on those days.

XtremeJumpin16

How do you do the spit test?