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Old 11-26-2004, 06:13 PM   #1
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Default Revo temp stuck!!

Ok I have broken it in and I am stuck in between 5 minutes.
I have leaned it out to where I want it but it shoots over 300 degrees, so I richen it up and then it isn't as powerful...and the temp is low enough to lean out more but I dont even do it 5 minutes(if it were a clock) and then it shoots past 300. Its like 5 minutes is waay to much but when I take it back 5 minutes its to low...... What could it be......or am I not making any sense?

Could the temp gauge be jumping?
Is my engine screwed?
Gas?
HELP!!



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Old 11-26-2004, 07:35 PM   #2
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well, that extra power you get by leaning it out over 300 is comming at a price... engine life. of course we could squeeze a bit more juice out of our mills but it would seriously shorten the life of the engine. try only leaning it out 1 or 2 "minutes", that might get you where you want to be.

does it otherwise run strong and consistantly?
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Old 11-26-2004, 07:52 PM   #3
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Default Re: Revo temp stuck!!

Quote:
Originally posted by TurboLancer
Ok I have broken it in and I am stuck in between 5 minutes.
I have leaned it out to where I want it but it shoots over 300 degrees, so I richen it up and then it isn't as powerful...and the temp is low enough to lean out more but I dont even do it 5 minutes(if it were a clock) and then it shoots past 300. Its like 5 minutes is waay to much but when I take it back 5 minutes its to low...... What could it be......or am I not making any sense?

Could the temp gauge be jumping?
Is my engine screwed?
Gas?
HELP!!



Dante`
You wanna be careful with temps on the Revo. Over 300 will kill the motor's compression and you'll loose power permanently. I had a Revo and it screamed. If you break it in per the instructions, it will perform outstandingly. I used an American CNC Enormous cooling head (http://www.acncm.com/detail.aspx?ID=30) and it dropped my temps by at least 40 deg. I also used Megatech 25% fuel that has 14% oil and allowed the Revo to really open up. It really liked that fuel and held it's compression well. You could also use Byron or Maxy fuel, both of which are considered really good fuels. White Lightening is too low on oil (8%) for the Revo in my opinion. Traxxas just released 33% nitro fuel, so might look into that. The main consideration is temperature. Keep it below 260.
The other area that the Revo benefits well from is lightening of the chassis. The Traxxas web site has lots of options to do this and the Revo really comes into it's own when lightened. I removed the Opti-drive, the reverse servo and replaced the dual steering servos with a single Airtronics 94358Z at 200 oz. This lightened the Revo dramatically. Lighter means faster.
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Old 11-26-2004, 08:50 PM   #4
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nah i would worry myself about the oil levels in most high end racing fuels like odonell, white lightening, or byron. they use lower oil content but its a synthetic oil blend. essentially less oil that does more. and having a lower oil content will run your engine a little cooler.

a couple years ago that was true, but this day n age oils are so high tech that the 8% in white lightening and odonell get the job done just fine.
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Old 11-27-2004, 05:02 AM   #5
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Quote:
Originally posted by beetlebz
nah i would worry myself about the oil levels in most high end racing fuels like odonell, white lightening, or byron. they use lower oil content but its a synthetic oil blend. essentially less oil that does more. and having a lower oil content will run your engine a little cooler.
That statement belies Horizon Hobby's own magazine ads for White Lightning that states "White Lightning brings your engine up to racing temp faster...". That can't happen if it makes your engine run cooler. Horizon Hobby's web site states "White Lightning was developed for competition-level racers who are experienced at engine tuning". White Lightning is directed at the pro level racer where winning is more important than engine longevity. There is less protection against over leaning an engine with low oil content. I run White Lightning myself in my RB C5 for racing only but would only recommend it to a seasoned Racer who knows how to properly tune an engine, always uses a temp gauge and knows what temp not to exceed. It's definitely not for the average backyard basher where going too lean could result in a seized engine.
Quote:
a couple years ago that was true, but this day n age oils are so high tech that the 8% in white lightening and odonnell get the job done just fine.
Odonnell has 11% not 8%. Most people I know that run Sportsman class and use these low oil content fuels, also add 4 oz. of Klotz per gallon for additional protection.
My advise to anyone using very low oil content fuels is to be careful not to over lean the engine and be diligent in monitoring engine temps.
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Old 11-27-2004, 06:16 AM   #6
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Default OK then

I guess I will stick with the richer of the twp settings lol... Thanks for the help...
Highly appreciated...

Say I did loose some power by over leaning it....could I replace the sleeve and regain that power...but yet have to then re break in the truck?


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Old 11-27-2004, 04:37 PM   #7
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More oil is not always better. More oil will make the engine run hotter, and having excess oil spewing out of the exhaust is not protecting your engine. White Lightning does allow your engine to get to operating temperature more quickly because it doesn't have to burn all that excess oil before the engine cleans out and starts running correctly.

Synthetic oil is what protects your engine. All racing fuels with low oil contents use synthetic blend oils that will protect your engine. Higher percentage oil fuels use a generous amount of castor, which is cheaper than most high-quality synthetic oils, and helps to protect against over-lean conditions, providing more of a safety blanket when inexperienced modelers tune their engines incorrectly.

Traxxas engines have always run their best around the 240-290 mark. If you are running in a very confined area and cruising around at a slow pace, your engine is going to run hotter than if you're blasting up and down the street every once in a while because the engine is air-cooled and needs airflow to cool it. I would not run an aftermarket engine headbecause leaning the engine excessively is harmful regardless of the temperature of the engine. Running your engine too lean is worse than running too hot.

turbolancer - One or two runs into the 300 club (haha) isn't going to kill your engine. If your motor is significantly low on compression, you can replace the piston and sleeve (and it's usually best to replace the rod as well), re-break it in, and keep running.
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Old 11-27-2004, 07:34 PM   #8
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see? told you guys i wasnt lyin
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Old 11-27-2004, 07:57 PM   #9
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Also..I've heard from more than one experienced tuner that the new Revo 2.5R engines run much better on higher (30%) nitro fuels.
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Old 11-27-2004, 09:32 PM   #10
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Having owned and raced a Revo every weekend for months, I just have to chime in here. I would never run White Lightning with 8% oil in my Revo although I run it in my RB engines in my 1/8 scale buggies. Even Traxxas, that recommends only it's own fuel for the Revo, has more than 8% oil. If Traxxas thought that 8% oil was the solution for it's 2.5R engine, then they would be formulated as such. Aaron is right, the Revo does like to run hot only because of the puny little stock head. I changed over to the American CNC Enormous cooling head and temps dropped over 40 deg. My Revo was king at 3 tracks, climbing up the back of other Revos and I was using Megatech 25% nitro with 14% oil. I ran 3 gal. of that fuel through the Revo before I sold it and it still had compression comparable to new when I sold it.
The oil content is not as critical as proper tuning technique with particular attention paid to monitoring engine temps at the plug not the head and that larger cooling capacity (bigger head) does NOT mean you can crank the temps back up to 260 ( as Aaaron indicated). 300 deg. is way too hot for the Revo and is not recommended by Traxxas or necessary to achieve maximum power. A larger cooling head coupled with a proper understanding of tuning will provide you with max power at lower temps and a much longer lived engine. RB engines understands this concept. Their cooling heads are larger than most other engines in the same class yet provide incredible power while maintaining reasonable temps.
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Old 11-29-2004, 12:49 AM   #11
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A larger engine head is not always the answer. Most, if not all, engines made nowadays are comprised of quality materials that can withstand normal running temperature in the mid 200's.

Larger engine heads can actually cool too well, which can make the engine load up as it cools in the infield of a track, making the tune of the engine very inconsistent. The stock heads of most race-inspired engines are a specific size for a reason.

Traxxas, as well as most engine manufacturers, recommend fuels with large amounts of oil (O.S. is another I know off the top of my head). An uneducated consumer is going to see a fuel with lots of oil and buy it to care for his engine, and these fuels are usually cheaper due to the less-expensive ingredients used.
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Old 11-29-2004, 05:02 AM   #12
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Default Awesome Thanks Friends

I finally got my step father to break in and run his T-max after 2years......So we went out to the dirt fields here in Pa and bash the living sh#t out of our trucks.

Dont know if it was the tuning...but the Revo and Tmax are same off the line, handling, stoping....and power.

I did beat him though ssshhhh dont dont him I said that haha..


Revo is working greeat.....I have new pics on the thread ( Calling all Revo's)




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Old 11-29-2004, 08:22 PM   #13
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Quote:
Originally posted by Aaron Waldron
A larger engine head is not always the answer. Most, if not all, engines made nowadays are comprised of quality materials that can withstand normal running temperature in the mid 200's.

Larger engine heads can actually cool too well, which can make the engine load up as it cools in the infield of a track, making the tune of the engine very inconsistent. The stock heads of most race-inspired engines are a specific size for a reason.
[/i]
While, in general, I agree with you in most applications, the Revo can easily run way too hot if the needles are set too lean in an attempt to gain power. I had a friend with a stock Revo who ignored temp monitoring and wanted only to get max speed from his Revo. I pulled out my temp gauge and it was running in the 320s. The Revo is easy to get that hot mainly due to the inadequate surface area of the head vs. the high performance nature of that engine for off road use where higher speeds cannot be maintained to aid cooling. Unfortunately, it won't last very long. To deal with this dilemma on my own Revo, I cut a hole in the windshield of the driver's side of the body and used a larger cooling head which keep the temps down to between 210 and 220. The Revo will not load up at these temps if your needles are tuned correctly. If it does, your tuning is off. If you live in a 4 seasons climate with relatively cold winter temps, then switching back to the stock head during the colder weather is advised along with heating the engine with a heat gun before a cold start. After 4 months of racing and running 3 gal of Megatech 25% nitro with 14% oil content , I sold the Revo and it still had compression equal to a new engine. That wouldn't happen with the stock Revo and stock head when raced every weekend, tuned for power, and is a testament to a properly tuned engine (not too lean) coupled with good fuel.
Bottom line: If you want longevity, tune your 2.5R Traxxas engine to run in the 220-220 range max. If you're looking for max power tune it for 260-280 with the stock head then change to a larger capacity head without changing the needles. This should result in a 20-40 deg drop in temps depending on the head. DO NOT retune with the larger head back to the 260 range.
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