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Your favorite way to tune HSN?

Your favorite way to tune HSN?

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Old 04-05-2007, 01:59 PM
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Default Your favorite way to tune HSN?

At this point I've read three differing methodologies for tuning the HSN. Which do you believe to be "better" (for me better is a good tradeoff between performance and longevity of the engine):

1 - Tune purely based on temperature. Basically if the temp is not around 220 - 250, either lean it to get it higher or richen it to get it lower.

2 - Ignore temperature. Move up the HSN an hour at a time and test each time by running it for a minute or two including all-out acceleration to open throttle. Find when the car begins to lean bog on acceleration or top speed, then move back 2 hours richer and you're done.

3 - Ignore temperature. Start with something clearly on the rich side and slowly run it more lean until the car simply doesn't accelerate and hit top speed any better. This implies you can keep getting more lean with little to no performance improvements. This is probably the hardest of the three as well because I have a hard time seeing small improvements.

On LSN I'm using the pinch trick at this point. Depending on what the engine does when pinching the fuel line near the carb, adjust more rich or lean. This seems to be a pretty universal recommendation, anyone disaggree?
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Old 04-05-2007, 02:02 PM
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3 and 2. i like 3 better but 2 sounds good to me.



1 probably works but you could tune it to that temp and not get it to be as good as if you did it like 2 or 3 stated.
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Old 04-05-2007, 09:16 PM
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Long ago and far away we tuned by ear and eye PLUS spit!!!!

Now we have Temp guns!

I use a temp gun as a help to tuning not the way to tune.

A temp gun should confirm the tune not dictate the tune.
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Old 04-05-2007, 10:02 PM
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Originally Posted by tmail55
Long ago and far away we tuned by ear and eye PLUS spit!!!!

Now we have Temp guns!

I use a temp gun as a help to tuning not the way to tune.

A temp gun should confirm the tune not dictate the tune.
I got caught in the whole temp gun is god thing, but to get performance I had to go higher than i was told and burnt many engines doing it, one day i accidentally left my temp gun at home, and had to go by sound and smoke and it run great. tryed it again with the temp gun and though slightly higher it was running great. Now i bump up the needles 1/8 turn before starting and tune from there
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Old 04-06-2007, 12:31 AM
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Temp, sight, and sound.
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Old 04-06-2007, 06:04 PM
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First of all, engine tuning is really hard at the track. Even the best pros like Jared Tebo will typically go 2 mi. away from the track to an empty parking lot just to make sure his engine is tuned right for a race.

Here's a simple method. Set the top end by sight and sound.

Sight: There should be a thin wisp of smoke coming out of the pipe. No smoke= too lean, cloud of smoke= too rich.

Sound: You should also not hear the "blubbering" sound that the engine makes when it's too rich. It should have a clear, distinct tone of the engine without the pinging sound of being too lean. Experiment with this in an empty parking lot where you can hear the difference.

After the top is set do a high speed run to make sure the engine is cleaned out. Then go full speed towards you and stop the car quickly within 10-15 ft so you can hear it well. If the engine goes straight to idle, you're ok. If it is running fast still while at Neutral (aka "running on"), then richen the bottom end.

Next do a punch off from dead stop. If the engine blubbers, makes lots of smokes, and slowly takes off, then it is too rich on bottom. If you've just richened it because it was running on, then maybe your top end was set too lean and you should re-check it.

If it hesitates on the bottom and blows no smoke on take-off, that is called a "lean bog" and you should richen the bottom end.

This is my general rules of thumb. You should not go by a temp gun except to confirm that you are tuned correctly. My normal gas truck is around 190-200 F, for 1/8th 220-230 F.
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Old 04-06-2007, 06:09 PM
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sounds good Coach. thanks.
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Old 04-06-2007, 06:44 PM
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nice post kdub
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Old 04-07-2007, 08:51 AM
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how many tank's of fuel should you go threw before it's broken in???????
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