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Old 05-09-2007, 02:43 PM   #1
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Default .12 engine with lots of "bottom end"?

Hello guys.
I know that, by asking something like this, I am hitting a wasp's nest, but:

What do you think is the best .12 engine for bottom end ? Consider best clutch set up, what engine accelerates faster than any other ?
Even if it can't keep with others on end speed(again considering best gearing possible for the situation).

I am considering what I should look for my track here, very, VERY short and most turns are "U" type, if you know what I mean ...

I am very new to this game, but I must say I got kinda frustated with what I have now, can't make it work ... especially for my track here. It looks like that, when the engine is thinking about "Now I WILL rev!", I should be on the brake for a meter or so already, else its wall time!
But thats another story. Just want some views on the top engines that perform really BIG on the bottom end ...
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Old 05-09-2007, 02:46 PM   #2
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I would go with the Orion wasp CRF .12 has lots of bottom end, or a nova plus series engines..
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Old 05-09-2007, 02:50 PM   #3
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bud have you geared shorter for 1st gear on your G4S and do you have the ED tranny ???
If no to ED maybe look at 18t 1st gear with 52 spur and also change the brake and side pulley to 18t.
Also on your current clutch setup have treid more tension on the clutch spring ??? Might be a option to try Mugen super hard clutch spring and try Muppetracing's setup he posted on teh G4S thread.
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Old 05-09-2007, 02:53 PM   #4
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Even as awesome as the CRF is it dont gaurantee that its solves your problem.
Took us 2 months of tweeking and fiddling to get his Mugen working very well with the CRF.
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Old 05-09-2007, 03:58 PM   #5
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Clutch setup is essential when it comes to torque. Your engine can bog down if the clutch is hitting too soon, at lower RPM’s. Make sure you have the proper clutch spring and compression on the spring. You might just have to play with this setting a little to get it to hit right. You may find out that the motor you are running is just fine on the bottom end if you find the right clutch setting.

Also, sometimes racers make the mistake of thinking that their motor is not tuned properly when it is actually their clutch engaging too early.

I have an MTX4 and in my case I am running the stock spring with 1.2 mm of compression on my clutch spring. I have several motors that I run with this setting and they all hit hard on the bottom end (Max Power, Rody Roem RB V12, JP Mod Plus 12).

I adjust the clutch for track conditions as well. If you have high bite on the track you can have the clutch engage harder at a higher RPM than if the traction is low.

I also play with header length after the clutch setting addressed. This is something most 1/10-scale racers neglect. A longer header will give you more bottom end. I have better luck with faster lap times with a quick motor rather than one with top end. I have a tendency to admire the speed too much on the top end and overshoot the turns.

I do not want to leave out the proper gearing for the track you race running at.

If you are looking to get a new motor this topic is very volatile. Many different opinions and some racers seem to have blind loyalty rather than hard facts. I would try the clutch thing first. It is the cheapest. If you are still not satisfied. Check with the experienced fast guys at your local track. I personally only run NovaRossi based motors. I have always been satisfied. I hear the Sirio’s are fast as well. Mugen has the new Ninja 12. Still too new to know much about that one. OS TZ has been a good long lasting reliable inexpensive motor. The new Fantini tuned Max Power is a good one. But if you have $300 plus bucks for a motor, I would get a NovaRossi. For about $400 you can get a Murnan Moddified Plus 12-3sct which is wicked fast. I know several guys who run these at our track in St. Louis, Evolution Raceway and they are the fastest cars on the track, after my JP mod Plus 12 of course.

Seriously though, I would check with the fast guys at your local track and get their opinion on how to set up your car and clutch and what engine to buy.

I hope this helps. Good Luck
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Old 05-09-2007, 04:29 PM   #6
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Quote:
Originally Posted by Rawz
Hello guys.
I know that, by asking something like this, I am hitting a wasp's nest, but:

What do you think is the best .12 engine for bottom end ? Consider best clutch set up, what engine accelerates faster than any other ?
Even if it can't keep with others on end speed(again considering best gearing possible for the situation).

I am considering what I should look for my track here, very, VERY short and most turns are "U" type, if you know what I mean ...

I am very new to this game, but I must say I got kinda frustated with what I have now, can't make it work ... especially for my track here. It looks like that, when the engine is thinking about "Now I WILL rev!", I should be on the brake for a meter or so already, else its wall time!
But thats another story. Just want some views on the top engines that perform really BIG on the bottom end ...
To answer your question. IMO The mega zx12 is the best motor for the bottom end power.

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Old 05-09-2007, 04:40 PM   #7
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Edit: - thankx guys, spent so much time raving below, only now I see the other posts.

I will get on learning, and trying for the next race, or the next ... hehe

Hey razzor.
Yes, I have this: 18T/52T and 23T/47T. Brake 18T(with rear side also 18T) and front side 26T. (as a side note, should I have changed the other pulley, the one that matchs this 26T? you know, the one that connects the belt with the front diff pulley)
I am really


See, I am not bashing the engine, even if I wanted to, ( I don't, I think the design on this machine is great, a step forward on the design used till it came out, to my knowledge) I could not, as I am a "newb" on this game.

BUT, I did try, lets see if I can do some writing ...
When I got to the track, to break-in the engine and beging tunning it, I could not start it. The CRF was new, I did not touch the needles. I did open it and flushed WD40 on the internals, and assembled it again. And I hope thats not the falty area, I did set the head screws with even presure, doing the "X", you know?
It was like there was no fuel getting to the engine. Check everything, lines, presure, tank. All good. The carb had fuel to it. The guys at the track by now come to my help. Try and try, and only after we did 2 full turns out on the low needle the engine started.
Well, I went on to break-in, did some acceleration(very mild) on the box and went to the track, to follow the manual.
BUT(hehe ) the engine would not rev on the ground. Guys at the track went on saying that it was too rich bottom. Well, it sure did sound like it, smelled like it and FELT like it, there was oil all over the place ... hehe
I did lean the low a bit, till it would start and rev, engaging the clutch and taking off. (I did try numerous times, lean, try to rev, no good - engine stall - lean, wait cool down, try again)
After 3 tanks I did start to try and bring real power to it. It did seam too rich on the bottom, still. Would go on, but after brakes it would look like a stall, but not, just a LONG hesitation to pass from low to mid(and then really rev). Clutch would engage only when engine would really rev, great sound when it did.
Ok, lean the low a bit more. But when I got to a point where it did not do the extreme bogging thing, the temps went up, to 140C !
Open the high needle, temps down, but also power. I gave up for the day.
Then, I read about the OS carb.
Back to the track I did fit an OS TZ carb on it(it's the 11M).
All that happened above did again, till I got the engine to a point it would go, but was "no power OR high temps", could not tune it right.
I did change to the CRF X-type glow plug #6, and It showed some improvement on that day. (one of the guys here said thats where I am most wrong. I should have lots of glow plugs, covering all the range. He said he has 19! plug types for his Megas. Thats where he tunes it and all... all I have are lots of CRF #6 X-Type, and #8s #7s and #6s OS ones. Did not try OS plugs)
Sunny day, was somewhere near 30C. I live 1000m above sea level, humidity was(I think) near 80%.
By then, after ins and outs, I had the G4S clutch at two threads showing on the spring nut, black nut and red shoe, all the weights on and .6 clutch gap. Minimal end play, .1.
All this time I always had a nice and, what everyone would go on saying, healthy smoke trail, from bottom to high rev. Using Byron 20%.

The next day, race day, I got to the track and was thinking I just need to set a mid term, to race at 120-130C, even if I don't have great power. Start the engine on first stroke! wow - I think he is starting to like me
No power however. Pit and lose some on the clutch spring, half a turn, as it did sound like too much slipage(SP?)
Now the engine would not start. Had to open the low needle till it did, again. After warm-up I could lean low needle, so it would stop bogging, and try to tune right. Lean a bit the high each try, checking temps.
When it was fast, as fast as the 3CTs the guys here all love, my temp went to 160C !!! Stop it ...
But that was for 3 or 4 laps only.(and the track here is THE small hehe)
So, I think ok, no harm. Open the high and start the engine again.
Would not start. Check everything, glow plug, lines, fuel, needles(open, close ... no needles!! hehe, ok, not so much), but no good, would not start. Thats when the call for the director's table came, I started to pack and go home, no race for me ...

I can't recall the settings the needles went to, and I don't think it matter really, the extended weekend I had saw all the spectrum on those ...

Friends at the track all debated about what I was/am doing wrong. But well, I can't just throw the engine to someone an say "hey, tuned that" ... thats my job, not theirs, and, as helpfull as the more sesoned ones are, they have their race to look to, they can at max give some tips, try a bit of work on my engine, here and there, but ...

Ok, nuff raving. Sorry hehe, very confusing read, yes ...

I got the OS, so easy for me to work with it ... I need to learn a LOT before I get back to the CRF ...
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Old 05-09-2007, 05:02 PM   #8
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Its very simple.

1. Tighten clutch spring (engagement will be at higher rpm). If your track has good grip to to match the spring tension.

2. 1st gear needs to be lower so you can get up to speed quicker. Feel free to also make 2nd gear lower too. This will increase acceleration.

3. Try leaning your bottom end some.

Also WASP CRF is not really good on bottom end and needs lotssssss of room to spread its legs. The jlr red dot motor is good though , piccos are very crisp and get up to rpm very nice and quickly.

Play with these things and run hotter than usual plug. Hotter plug will give you more bottom end , aka advancing the timing.
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Old 05-09-2007, 05:46 PM   #9
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come come guys he's asking for motor with best bottom end not clutch setup.hands down my choice would be the O.S. TZ.this motor rips like hell from down low.the mega is not a very durable motor,fast as hell but dont last too long.motors made for very high rpm usually lack down low,and vice versa.the tz will give you what your looking for,its no slouch down the straight either.for about 170 bucks you cant beat it.and its an O.S. easy to tune!
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Old 05-09-2007, 05:46 PM   #10
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Hey RAWZ what carb did you end up using the Orion , or the OS..
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Old 05-10-2007, 06:26 AM   #11
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Quote:
Originally Posted by Rawz
Hello guys.
I know that, by asking something like this, I am hitting a wasp's nest, but:

What do you think is the best .12 engine for bottom end ? Consider best clutch set up, what engine accelerates faster than any other ?
Even if it can't keep with others on end speed(again considering best gearing possible for the situation).

I am considering what I should look for my track here, very, VERY short and most turns are "U" type, if you know what I mean ...

I am very new to this game, but I must say I got kinda frustated with what I have now, can't make it work ... especially for my track here. It looks like that, when the engine is thinking about "Now I WILL rev!", I should be on the brake for a meter or so already, else its wall time!
But thats another story. Just want some views on the top engines that perform really BIG on the bottom end ...
Tight clutch, long header, short gears, and 40% nitro. This combo should give you the bottom end you are looking for. I have used this on some very small high bite tracks with success. Just that runtime becomes an issue with high nitro. If you can't get the high content nitro, try dropping the head. This will give you more bottom end on any engine. The Novarossi +12 engines deliver plenty of bottom end for any track. Just a note. If your clutch is not right, even the fastest engine will look slow off the line. Make sure your clutch is set properly. Very important.
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Old 05-10-2007, 07:00 AM   #12
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Quote:
Originally Posted by Artificial-I
Also WASP CRF is not really good on bottom end and needs lotssssss of room to spread its legs. The jlr red dot motor is good though , piccos are very crisp and get up to rpm very nice and quickly.
If I may, the CRF engine has no bottom end problem and the updated carb and also the new 2007 version improve even further on that. As far as needing room to spread it's legs, that is only if your clutch is too soft and/or you are using the wrong pipe.
The CRF home track is a small technical track with loads of grip were you use full power from one turn to another.
So I know 100% that a CRF engine with the proper clutch and pipe running on a small technical track will be at least as fast (probably faster) as anything you could put it against.
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Old 05-10-2007, 07:41 AM   #13
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Yeah I was speaking about the regular version. Havent seen or tried the 2007 / updated carb parts.

Ive seen the CRF in work @ the CRF test facility and that is true it moves pretty well in that environment. But settings aside , its probably not producing a lot of bottom end torque vs other current motors and it revs higher and probably needs a team orion clutch kit to work properly.

But your right that thing was moving pretty quickly in that short track environment. Im sure as good as any other.

Last edited by Artificial-I; 05-10-2007 at 10:36 AM.
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Old 05-10-2007, 12:50 PM   #14
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Quote:
Originally Posted by MRX4-R03
Hey RAWZ what carb did you end up using the Orion , or the OS..
The day I did the break-in I had the CRF carb on. The original, first "edition".
After the 5 tank with increasing slowly the RPM, I started to try leaning the needle(S)(low needle was VERY rich, I had so much oil from front bearing that every tank I had to open the clutch and clean it all ...)
Doing the leaning the engine would not start, start but not catch rev, bogging all the time. I gave up for the day(and day light ended, I am blind at night, on the track here)

So, the next day I fit the OS, and thats what is on now. Did not change the high needle, all OS 11M carb. With black insert.

Clutch, I went all in, all out, in-between ... One wight, two, gap from .35 to .65. ...

But see, I know the problem is my dimmed knowledge, I will practice and practice ... same day I will learn the basics!

Thankx for all the input guys. My OS is so docile(SP?), I will paly with it for the time beeing ...
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