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Old 07-12-2007, 08:04 PM   #1
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Engine tuning tips

I've recently gotten into nitro with a Hyper 7. I am pleased with the car and how it handles. It orignally had a hyper 21 8 port race engine, which I got tired of trying to get that thing set right, so I switched it out for a sportwerks 21 v2. The sportwerks seems to be a pretty good engine with plenty of power. The issue that I'm running into is tuning the blasted thing, particularly for weather changes. I'm not too far off I think. But, then again, I'm not that experienced in the nitro world. I've been basically tuning the high needle to get the engine up to temp which is around 200-220. Then setting the low end to approx 2 to 3 seconds with a pinch test. Then setting the idle to a reasonable speed without bogging the engine out and keeping the clutch disengaged. However, if the weather changes by anything, I'm not quite sure how to deal with it. What changes are necessary to work with this as I've ended up out of races due to the engine leaning out on me and overheating. Thanks in advance!!
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Old 07-12-2007, 08:32 PM   #2
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the main thing is to temp the engine often and make adjustment as needed....i always get the engine good and warmed up before a qualy and then i get the engine temps knocked down then and there....as far as other things you will need to change, most likly most all of the tuning will be done from the HSN, you also might need to change plug temps once an awhile depending on how humid it is the more the hotter the plug, but you tend to loose power with a hotter plug cause i have noticed i need to fatten (richen) up the HSN, along with the fact that you have advanced the engines timing...well thats about all i really do for different temp and weather, but im sure there will be alot more advice on the way....

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Old 07-12-2007, 08:43 PM   #3
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Put your temp gun in your pocket and don't take it out until your engine is running the way you want it to. Using temp as a target is a mistake. For starters, the Sportwerks engines I have seen run absolutely RIP at 250+ degrees. The best application for a temp guage is to help you decide which way to go with your tune if you can't decide based on what you see. If the engine is blowing smoke off the turns then forget temp and tune the engine to run the way you want it to (crisp throttle response, clean top end). Most of the time, if you're too lean, the engine will run poorly. It will usually lean bog off the turns. If you are experinecing this and the engine still makes good top end power then richen the LSN. You might be surprised to find the engine seem to wake up everywhere.


Tune the HSN first and then the LSN. When you have that engine running correctly you will be scared of the trigger on your radio.
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Old 07-12-2007, 09:47 PM   #4
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Davidka - Best post regarding tuning I've seen in a long, long time!

Your engine requires fuel to make power. Too lean is not fast!

Temperature and weather changes won't make too drastic of an effect that you'll go from spot-on, to out in the weeds, from day to day. You shouldn't really need to change glow plugs or anything.

When the temperature gets colder, you will need to richen the engine. Colder air is thicker than warmer air, and this means you'll need to add more fuel to compensate. Likewise, higher humidity or a lower elevation would mean the same thing.

In extreme cases, you would run a colder glow plug when it is very hot outside, or a hotter plug if it is very cold. If you live in an area that reaches either extreme, it might be something to try.
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Old 07-12-2007, 09:58 PM   #5
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great info, makes sense
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Old 07-13-2007, 07:20 PM   #6
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Talking thanks!

I appreciate all the input! Now if I can remember to keep it all straight in my head

Again, thanks!!
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Old 07-13-2007, 07:28 PM   #7
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All this advice is spot on, especially what Aaron said about the glow plugs (hot vs cold).

I have witnessed people running Hot plugs on their .12's when it's 90 degrees out and they cant figure out why it flames out 1 minute into the the race.
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