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Old 07-15-2008, 06:39 AM   #1
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Unhappy Need help tuning my OS 28 engine!

I just got a new OS 28 XZ. I broke it in Thursday and Saturday, a total of about 8 tans or so. Anyway, I raced it on Sunday. Engine seems to run really good and is visibly rich on the low end to the point of a slight bog if left too long.

On the track I raced there is a really long straight away, probably 200ft! This goes into a giant berm that sends you 180 degrees back the other way that you can keep WOT all the way through. This leads to a giant triple. The run up to the triple is not that long.

Here is what was happening. I can keep it WOT all the way down the straight, through the berm and the entire entry to the triple. But what happens is the trucks acts really lean while in the air to that triple. This mad it really hard to down side the triple and control the truck in the air. One or two times it went vertical front end pointing to the sky. The track was pretty large with my best lap being 37 seconds. One other part that gave me trouble was this double triple section. They were small jumps, but if I went for the triple part it was 50/50 whether the truck did that lean mid-air thing.

After the 30 minute main the truck temped at 204. It shut right off when I left off the gas on pit lane. Seems like it bogged out. Still has tons of pinch.

So hopefully I described this good enough so someone can tell me where my tune is off.

Thanks
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Old 07-15-2008, 07:29 AM   #2
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Sounds like you need to left off the throttle while you are in the air. 204 degrees is about right for a temp. I shoot for 210-240 degrees. If your low end is rich, and the engine bogs, then you need to lean the LSN.
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Old 07-15-2008, 07:39 AM   #3
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Thanks for the reply. But I do know how to jump. I was totally off throttle at the base of the jump. I wasn't WOT through the triple. I only use throttle\brake to control the truck in the air. My problem is that in the above described situation AND no throttle input from the base of the jump it would act really lean and make it hard to control. Would make for allot of over jumps, cased jumps and awkward landings. I will also add that this situation got worse the longer I got into a fuel run, so I know it is lean. But where?
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Old 07-15-2008, 11:33 AM   #4
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seems to me ur having a spool down problem. the truck simply rev higher even though u let go of the throttle right?
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Old 07-15-2008, 11:58 AM   #5
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Quote:
Originally Posted by premonitions View Post
seems to me ur having a spool down problem. the truck simply rev higher even though u let go of the throttle right?
In the situation I just described, yes. But I can hear the engine as well, and it sounds lean.
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Old 07-15-2008, 01:22 PM   #6
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i have some thing u can try, add more fuel to the bottom and start leaning out the top, os bigger motor's seem to like alot of low end fuel. i know it sounds crazy but give it a try!! u may end turning the top in a full turn or better. hope it works
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