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  1. #1
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    New Revo Running HOT!

    Ok man in starting to feel like every thread i create starts with "New Revo" followed by "hey in a noob"

    Anyhow, Got my Revo running pretty well. Still leaning HSN out, this thing smokes more than my diesel.

    Anyhow, I'm seeing 290-310 after a WOT pull. Both Traxxas link and IR gun.

    some googling showed that this is not uncommon...

    Just wanting to see whay y'all's opinions were.

    Sent from my Sig Sauer

    here's a short vid showing how rich she was earlier today, I was still hitting 300-315

    I've since leaned her out, still hitting the same temps. Been tuning by sound and she still sounds a bit rich

    Last edited by Double G; 02-16-2017 at 07:50 PM. Reason: merge

  2. #2
    Marshal Double G's Avatar
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    With a newbie to nitro yes it is common because we think that both needles need to be leaned out. What I found out is the HSN is rich and the LSN is a little lean for factory settings. Start with the idle gap at 0.7-1.0mm open and leave it. Go back to factory settings, warm the engine for a bit and tune at a half tank - this way you have a slightly rich mixture at full tank and slightly lean at empty rather than spot on when full and too lean when empty. You may find that the LSN will need to be richened a little and that is okay. What has to happen is the LSN takes over the tune down low and the engine needs to cool when off throttle. If the LSN is lean then the temp will continue to climb. With the engine warm bring it in for idle and with the temp gun you should see the temperature drop a degree or two every few seconds. Plus, these engines are not designed to be WOT all the time (like a plane engine) but rather on/off throttle.
    The Super Derecho

  3. #3
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    Ok so what I did yesterday was start at 4 1/2 out on HSN and 2 out on LSN (which is past flush)

    Ended up leaning both out from there. Basically leaning HSN until I got good RPMs and speed, making sure it dropped to idle after wot (in 1st, in 2nd it feels engaged to trans).

    Once that was done I leaned out LSN until temps dropped at idle 1* every 4-5 seconds.

    Fiddled with idle because it was still high but didn't get too much change.

    LSN might still be a tad rich, temps can drop quickly and idle still has a little bump in it.

    Still getting 290-310 with body on. Did a few runs with body off and hit around 280.

    I dunno. I've read stuff online, some say it's not normal, others say they run 330 all the time on perfect tuning.

    FWIW I'm running VP Powermaster Master Basher (20% / 14% oil) and it was approx 65* yesterday

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  4. #4
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    Never in all the years I've messed with any brand of engines I've owned would I consider 330 safe or perfect tune. Ever.
    280 is my max on any engine. With 3 different fuels I've ran. Blue thunder years ago. And still use either Byron's or traxxas 20% never had any real headaches with em. Now I will say a fresh engine first 2-3 tanks I've had em close to 300. But constantly fell on temps tank after tank without touching the needles. Also I'm a firm believer in the pinch test for the lsn as well.
    Hitting 290 with the body on is also not uncommon. And as I'm not a real fan of hacking holes in bodies. My tmaxx 2.5. I've got holes in the grill. As well as a square out of front and rear windows. To keep it @265-270 !!!!
    Newer max 3.3 only have a square in the front window. I know it makes no sense to me either really.
    But honest opinion. You run that thing at 330 for extended periods and it won't hold up long bud.
    That ambient air temp you was running in. That rig should hold a tune at around 270 and SCREAM !!!!! Tank after tank with no worries. Providing its not super dusty where your intake filter would get clogged up and then start messing with your tune.
    Hope you can get it lined out. Maybe start from scratch again for one tank. That's what I'd do.
    Try the pinch test for your lsn after you get your high set. 2-3 seconds she oughta rise in rpm and try and creep forward on you then die.

  5. #5
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    Any by any engine. I mean in any of the numerous ones I've owned truck or car wise. I've never delved into the plane or helicopter world. Maybe those run super hot !!! Not sure. Just to alleviate anyone saying that their this or that loves running at 330. Traxxas engines dont. Not in my experience.

    Watched your clip there. You do have a smoke trail in those short bursts.
    But after tweaking on the carb. Run that thing down the street a ways at high rpm to clean er out from loading up at idle
    Last edited by Geeps1; 02-17-2017 at 11:47 AM.

  6. #6
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    Quote Originally Posted by Geeps1 View Post
    Any by any engine. I mean in any of the numerous ones I've owned truck or car wise. I've never delved into the plane or helicopter world. Maybe those run super hot !!! Not sure. Just to alleviate anyone saying that their this or that loves running at 330. Traxxas engines dont. Not in my experience.

    Watched your clip there. You do have a smoke trail in those short bursts.
    But after tweaking on the carb. Run that thing down the street a ways at high rpm to clean er out from loading up at idle
    in that vid, she smoked to the top. I've leaned her out more since then.

    Going to go to factory settings and get a baseline for temps. If she's running 290+ at factory temps I'm going to run her as-is, mayne contact Traxxas. they're about 30-40 minutes from me.

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    Last edited by Double G; 03-20-2017 at 09:01 AM. Reason: language

  7. #7
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    Little update... this truck is nutts!

    Went back to factory settings and gave her a full tank. Bashed around to 1/2 tank and then made a few WOT pulls. Temps were well above 300, hovering between 310-330 and at one point over 360.

    Backed HSN 1/2 turn out and LSN 1/4 turn and started tuning from there. No idea where I'm at temperature wise, buse she still leaves a trail through WOT, smooth idle, and plenty of torque down low to lift the front wheels.

    I am convinced my truck is an anomaly. Any richer and she dribbles fuel/oil out of the stinger and has a hard time moving.

    Also, in the 8 days I've had it, I'm about 3/4 of a gallon through. I strictly bash, and she's extremely thirsty. Possibly another sign she's rich...

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  8. #8
    RC Champion rizz0d's Avatar
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    I say let her eat. I've never tuned by temperature, seems like it could drive you nuts. as long as it idles smooth, cleans out good, makes good power, leaves a smoke trail, and falls right back to idle after a WOT pass I don't care what the temp is.
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  9. #9
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    If you are using the on-board it is accurate for taking the temp - where the sensor is - but not in the area commonly held as the true engine temp. Secondly, your IR gun may not be set to the correct emissivity for the metal.

    Tune for smoke and performance with an eye on temps. Chasing after temps will cause you to dump nitro completely.
    The Super Derecho

  10. #10
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    Quote Originally Posted by rizz0d View Post
    I say let her eat. I've never tuned by temperature, seems like it could drive you nuts. as long as it idles smooth, cleans out good, makes good power, leaves a smoke trail, and falls right back to idle after a WOT pass I don't care what the temp is.
    Quote Originally Posted by Double G View Post
    If you are using the on-board it is accurate for taking the temp - where the sensor is - but not in the area commonly held as the true engine temp. Secondly, your IR gun may not be set to the correct emissivity for the metal.

    Tune for smoke and performance with an eye on temps. Chasing after temps will cause you to dump nitro completely.
    Thanks guys, temps at the glow plug are still high, maybe 20-30* lower

    temps at the inside of the head are very similar to the Telemetry sensor - which I assume was internal near the glow plug?

    either way she rips and she smokes.
    My main concern at this point is my fuel consumption. At this rate I'll be at a gallon in 2 weeks. Can't afford a new motor every 2 months or less..

    Then again, I have yet to break anything, knock on wood. My 2 1/10 ECXs bust parts almost every single outing.

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  11. #11
    RC Champion rizz0d's Avatar
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    Quote Originally Posted by aceniza View Post
    At this rate I'll be at a gallon in 2 weeks.
    lol yep. back when I had the free time I bought a lot of nitro fuel. one time I ran my 1/8th scale buggy for almost 2 hours straight without shutting down once and burned a half gallon.
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  12. #12
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    Quote Originally Posted by rizz0d View Post
    lol yep. back when I had the free time I bought a lot of nitro fuel. one time I ran my 1/8th scale buggy for almost 2 hours straight without shutting down once and burned a half gallon.
    time? nah, I'm just bad with priorities haha.

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  13. #13
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    I called Traxxas this morning and they told me that yes, my engine can run in the 300s just fine, but for longevity the 250 range is the "golden spot"

    The guy I spoke to also said I could have clogged jets, or a leak.

    He also said warranty only covets manufacturer defects, and if this is overheating and frying bearings, that would be my fault...

    weird since it's been running hot right out of the box, even at 4.5 out on HSN and 2.5 out on LSN

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  14. #14
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    A couple common areas to have air leaks are the silicone adapter between the header and pipe and the fuel tank lid (make sure the lid is pushed down on the tank!).
    The Super Derecho

  15. #15
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    Quote Originally Posted by Double G View Post
    A couple common areas to have air leaks are the silicone adapter between the header and pipe and the fuel tank lid (make sure the lid is pushed down on the tank!).
    ill check the exhaust coupler

    i did notice they changed the design on the lid to a double screw vs the single screw to tension /widen the oring. I'll have to doubpe check that seal as well

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  16. #16
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    Honestly I had the same problem, seemed like no matter how I fiddled with it and tuned it that it would run hot after putting a new 3.3 on my Revo(Also on my new T-maxx), eventually either the little motor either calmed down on it's own and decided to run at nicer temps or I got better at tuning.

    One thing I read that seemed to help was, if it's running too hot, to richen the HSN a little until the temps come down to where you want. I saw 212F-220F last time I had it out, before that it was 300F, 320F, in the end of break-in I had an accident across a parking lot and by the time I got to it, telemetry claimed that the motor was over 400F by the time I reached it and shut it off, but it doesn't seem any worse for wear for it.

  17. #17
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    Just wondering, how leaks on header can make temps rise??? Is this due to low preasure in tank, and then not enough fuel??(same goes for fuel lid i guess??)
    nitro rusty, t-maxx and 2 revo 3.3's. Slash 4/4 bl

  18. #18
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    I got the Losi 3.4 carb on there now. Still trying to tune it, factory (Losi) settings are too lean for my thirsty truck. Been busy so i haven't had a chance.

    My last run I ran it pig rich, temps were extremely low, along with top-end power :/

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  19. #19
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    Quote Originally Posted by Joller79 View Post
    Just wondering, how leaks on header can make temps rise??? Is this due to low preasure in tank, and then not enough fuel??(same goes for fuel lid i guess??)
    Not enough pressure to push the fuel to the carb causing a lean condition - especially at high rpms.

    Quote Originally Posted by aceniza View Post
    I got the Losi 3.4 carb on there now. Still trying to tune it, factory (Losi) settings are too lean for my thirsty truck. Been busy so i haven't had a chance.

    My last run I ran it pig rich, temps were extremely low, along with top-end power :/

    Sent from my Sig Sauer

    Surprising as I had no issues with the stock Losi carb settings on my 3.3. It wouldn't even start with Traxxas settings.
    The Super Derecho

  20. #20
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    Quote Originally Posted by Double G View Post
    Surprising as I had no issues with the stock Losi carb settings on my 3.3. It wouldn't even start with Traxxas settings.
    yeah, factory Losi settings give me a bog at takeoff from a standstill

    With stock carb, I start tuning at 4.5 out HSN and 2.5 out LSN

    the weird thing about the Losi carb is the idle screw doesn't seem to widen/narrow the opening at all



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  21. #21
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    There is NO Idle screw, there is an Idle Gap screw, used for setting the idle gap(0.7-1mm), not the idle RPM's, that is done by richening or leaning the Low Speed Needle.
    Look out for the tree/crunch!

    LiPo? Naw NITRO!!

  22. #22
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    Quote Originally Posted by Wildman4910 View Post
    There is NO Idle screw, there is an Idle Gap screw, used for setting the idle gap(0.7-1mm), not the idle RPM's, that is done by richening or leaning the Low Speed Needle.
    sorry, that's I meant, hence referring to widening/narrowing the gap.

    Waiting on some LC3s (supposed to arrive tomorrow) and I'm going to give her another go this weekend if it's dry enough.

    Since I've ran this motor hotter than , rich as a pig and leaned out till it bogged, I'm going to finish up my first gallon (about 500cc left) and tear her down and try my hand at porting. Probably toss a Davis Diesel conrod in there. Pinch still seems tight at the moment.

    I've ported dozens or so 1:1 superchargers, intakes, throttle bodies, etc. etc.
    So the hand technique is there. Just a new set of knowledge and hopefully my eyes hold up lol.

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    Last edited by Double G; 03-09-2017 at 07:42 PM. Reason: language

  23. #23
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    Quote Originally Posted by Wildman4910 View Post
    There is NO Idle screw, there is an Idle Gap screw, used for setting the idle gap(0.7-1mm), not the idle RPM's, that is done by richening or leaning the Low Speed Needle.
    Sorry but I dont agree. You shouldn't adjust the idle speed with the mixture screw. You should get the idle mixture correct and then adjust the speed with the idle gap screw. If the gap is too wide and you compensate by richening the LSN then the RPMS will hang after a WOT pass until it loads up with fuel. If the gap is too small and you compensate by leaning the LSN you will be chasing a overheating condition and possibly burn out glow plugs and have a bog on accel.

  24. #24
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    factory settings don't mean anything. If your temps are high at 4 turns out HSN you richin. never make adjustments until the engine Is warm and you are at a half a tank. I couldn't tell you what my settings are. I just adjust to where I like the performance im getting and the temps are a reference point. how the engine sounds though the whole tank will tell me howgood my tune is. IN the late spring I will tune my truck and will not touch the needles unitl the fall.

  25. #25
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    Quote Originally Posted by OS15CVPower View Post
    Sorry but I dont agree. You shouldn't adjust the idle speed with the mixture screw. You should get the idle mixture correct and then adjust the speed with the idle gap screw. If the gap is too wide and you compensate by richening the LSN then the RPMS will hang after a WOT pass until it loads up with fuel. If the gap is too small and you compensate by leaning the LSN you will be chasing a overheating condition and possibly burn out glow plugs and have a bog on accel.
    the engine manufacturers call for a specific gap setting so that the needles are properly aligned. You will chase your tail if you try to tune the idle speed using the stop screw. If you have the stop screw open to much the the idle mixture screw will have little to no effect on the low to mid range tune and you run the risk of running lean.
    All of these little nitro engines use the same fundamentals for tuning. the carbs are super basic and for the most part work exactly the same.
    I have an RC problem...

  26. #26
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    OK well I got an LC3 in there, fattened up the HSN and LSN (losi carb), and had to open up the gap a little to keep her from accelrting at idle.

    After tuning for awhile i got her running really nice, no bogging, pulls the front wheels, smooth idle and acceleration....

    However, she is dying AFTER a WOT pass. I'll run her full WOT to top speed, let off and hit the brakes, she stops, drops to idle for 1 second, then dies.

    before I start moving both my needles everywhere, I'm sure someone here knows the answer.... anyone?

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  27. #27
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    Sounds like it might be a little rich on the LSN. I would focus on making small adjustments only on the LSN and see if it will hold an idle after coming down from a high speed pass.
    I have an RC problem...

  28. #28
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    Quote Originally Posted by rock-rod View Post
    Sounds like it might be a little rich on the LSN. I would focus on making small adjustments only on the LSN and see if it will hold an idle after coming down from a high speed pass.
    makes sense, let off throttle, LSN floods motor.

    i started tinkering with my kids truck (new ring and pinion) and got sidetracked.

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  29. #29
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    Quote Originally Posted by OS15CVPower View Post
    Sorry but I dont agree. You shouldn't adjust the idle speed with the mixture screw. You should get the idle mixture correct and then adjust the speed with the idle gap screw. If the gap is too wide and you compensate by richening the LSN then the RPMS will hang after a WOT pass until it loads up with fuel. If the gap is too small and you compensate by leaning the LSN you will be chasing a overheating condition and possibly burn out glow plugs and have a bog on accel.

    The Idle speed is dependent on the LSN tune and the Idle Gap being set correctly.
    And that's why you set the gap to what the mfg designed it to be(then leave it alone), granted there is a very small window to fine tune the gap setting once the HSN & LSN are tuned.

    All 3 of mine are set right about .9mm and didn't need messed with from there.

    Way too many times you will see people tell others "just turn the idle screw up/down" when what they need to do is tune the LSN.

    There is very little room to play with the Idle Gap before you negate the Idle circuit all together, and that really opens a can of worms, explacialy for those new to tuning.

    Usually after people have gone silly trying to tune, the best advice to give them is to reset everything back to the mfg recommended starting point, HSN, LSN and Idle Gap(along with set the gap then leave it be).

    It doesn't take much turning on the gap screw before you have pulled the barrel far enough out to make the idle circuit non functional.
    Look out for the tree/crunch!

    LiPo? Naw NITRO!!

  30. #30
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    Took her out today and was a little frustrated. Took forever to start, pulled the filter and reset the gap to about 0.6-0.7 (losi spec)

    started up great, but idled fairly high and wheels turned like crazy at idle. fiddled around for a bit before the throttle stuck and I crashed full speed.

    Set her on the table to inspect (still running) and the idle was a little jumpy and she was creeping forward again.

    shut her down and tried to restart her, took FOREVER.

    still learning.... but I'm getting there. getting her to make more power, just need to figure out how to make her more reliable.

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  31. #31
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    Sounds like its lean on the LSN to me. I adjust the throttle trim up to help with starting, like a fast idle on a 1:1 car.

  32. #32
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    Sounds like you are hard at work on it which is the first step it correcting if! I would have to agree the LSN needs richened but do it in small increments, there's no rush for something like this.


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  33. #33
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    i think i'm getting it. I've been super busy lately but hopefully will get a chance to get her out and fine tune her and bash bash bash!

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    Both times i had issues with full throttle hangs have been from the optidrive. sure its nice to know you wont shift into reverse on accident, but it happened to me 10 years ago on my 2.5r and then again on my 3.3 i purchased this year. i have now bypassed the optidrive and never had another full throttle hang. just make certain you dont shift into reverse while driving.

    Quote Originally Posted by aceniza View Post
    Took her out today and was a little frustrated. Took forever to start, pulled the filter and reset the gap to about 0.6-0.7 (losi spec)

    started up great, but idled fairly high and wheels turned like crazy at idle. fiddled around for a bit before the throttle stuck and I crashed full speed.

    Set her on the table to inspect (still running) and the idle was a little jumpy and she was creeping forward again.

    shut her down and tried to restart her, took FOREVER.

    still learning.... but I'm getting there. getting her to make more power, just need to figure out how to make her more reliable.

    Sent from my Sig Sauer

  35. #35
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    Quote Originally Posted by Reaper9789 View Post
    Both times i had issues with full throttle hangs have been from the optidrive. sure its nice to know you wont shift into reverse on accident, but it happened to me 10 years ago on my 2.5r and then again on my 3.3 i purchased this year. i have now bypassed the optidrive and never had another full throttle hang. just make certain you dont shift into reverse while driving.
    how can you tell it was optidrive?

    it did it a few times in the past, but after I switched to a losi carb it never shut properly until I took a dremel to the arm.

    I was planning on just adding a throttle return spring

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  36. #36
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    It should already have a throttle return spring.. I dont really have a way to prove that it was the optidrive, but i remember it happening to a lot of people back in the day and everyone would bypass it. ive run at least 1/2 gallon through it without another full throttle hang since i bypassed it.. (it hung about 6 times before) and its the only thing i changed, i never changed the angle or any adjustments of any kind.
    Right now im just waiting on a new header from some hard bashing the last time out.

    Wish i could remember my old log in, most all of my pictures are gone now, but i had tons of posts as enigma9789

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