R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Nitro On-Road

Reply
 
Thread Tools Search this Thread
Old 06-20-2004, 06:17 PM   #12961
Tech Fanatic
 
Join Date: Jan 2003
Location: Melbourne, FL
Posts: 787
Trader Rating: 2 (100%+)
Send a message via AIM to kreidel
Default

Quote:
Originally posted by David Joor
Ok, what can be adjusted to get more runtime out of this car? I am running an X12 with a Turbo II pipe, clutch doesn't slip, two speed is almost perfect, top end is perfect, temps at 230 - 240, 30% w/8% oil, stock head shimming, stock plug (r6 I think), and this motor worked great at the Texas Biggie in a NTC3, once it hit this car, it won't make over 5:15 on a tank and that is with me lifting to 75% everytime after it hits second and a Mugen pressure chamber on pressure side and tried fuel side as well with no luck. Always the same result.

I am aware that the some of the Mugen guys are pitting their cars in 5 minute qualfiers, I just want to know what else I could do to help this. I changed the motor and could do 5:45 with the same setup.
Lean it out some more. The problem is we need to get ROAR to change the limit on tank size to 80cc. 75cc was more than enough back when the engines made under 1 hp, but todays standard of engines it not even close. So you are limited in your options, lean it out as much as possible or find a faster pitman!
kreidel is offline   Reply With Quote
Old 06-20-2004, 06:23 PM   #12962
Tech Elite
 
GrandeGixxer's Avatar
 
Join Date: Jun 2004
Location: Waldorf, MD
Posts: 2,929
Trader Rating: 15 (100%+)
Default

I have no trouble making over 6 minutes with omega/picco xt .12 rdlogics turbo 1 piece and stock gearing.
GrandeGixxer is offline   Reply With Quote
Old 06-20-2004, 06:49 PM   #12963
Tech Addict
 
David Joor's Avatar
R/C Tech Charter Subscriber
 
Join Date: Nov 2001
Location: Houston, Texas
Posts: 539
Trader Rating: 1 (100%+)
Default

Yeah, going leaner is just scary, it is borderline already I agree, the touring cars are so much faster now that they should change it on the fuel tank.
__________________
Avid Racing Concepts LLC.
http://www.avidrc.com

AE | Reedy | KO | Tekin | Powermaster | Avid | Upgrade | BCE | Paint by Smiley
David Joor is offline   Reply With Quote
Old 06-20-2004, 07:14 PM   #12964
Tech Master
 
eddiethefish's Avatar
 
Join Date: Jun 2002
Location: Montebello, California
Posts: 1,658
Send a message via ICQ to eddiethefish
Talking Happy Father Day

Happy Father Day to all of you
eddiethefish is offline   Reply With Quote
Old 06-20-2004, 07:40 PM   #12965
Tech Addict
 
Bivens's Avatar
 
Join Date: Nov 2003
Location: Knoxville, TN
Posts: 679
Default Run-time

Lean it out...cooler plug.....less head clearance.....It's not so easy on the motor, but it should help where you need it....maybe could do better with 40%........or try a smaller carb restrictor if you really want to make time....(with less power).

Taller gearing is also a big factor....keep the RPM's a little lower.....
Bivens is offline   Reply With Quote
Old 06-20-2004, 07:59 PM   #12966
Tech Addict
 
David Joor's Avatar
R/C Tech Charter Subscriber
 
Join Date: Nov 2001
Location: Houston, Texas
Posts: 539
Trader Rating: 1 (100%+)
Default Re: Run-time

Quote:
Originally posted by Bivens
Lean it out...cooler plug.....less head clearance.....It's not so easy on the motor, but it should help where you need it....maybe could do better with 40%........or try a smaller carb restrictor if you really want to make time....(with less power).

Taller gearing is also a big factor....keep the RPM's a little lower.....
I am very new to nitro so I would like to question some of these points. Less head clearance will give more actual power, as long as it is not detonating correct?, but wouldn't more power cause the motor to burn more fuel? I also thought that would be the same thing for 40%, more power but at the cost of milage and life span of the motor, do I have these theories backwards? Maybe the better power delivery eats less fuel because it is more effecient?

Thanks for the info everyone.
__________________
Avid Racing Concepts LLC.
http://www.avidrc.com

AE | Reedy | KO | Tekin | Powermaster | Avid | Upgrade | BCE | Paint by Smiley
David Joor is offline   Reply With Quote
Old 06-21-2004, 01:52 AM   #12967
Tech Master
 
theRED5's Avatar
R/C Tech Charter Subscriber
 
Join Date: Aug 2002
Location: near Athens,GA
Posts: 1,022
Default

I run the maximum allowable fuel line length...I think it's 10 inches.
__________________
I [I]AM [/I]the Driver !

Murnan Modified Motors

Mugen MRx4

Rocket Science Fuels

Auto Racing, Mountain climbing, and Bull fighting are the only true sports, all the rest are just games.
theRED5 is offline   Reply With Quote
Old 06-21-2004, 02:54 AM   #12968
Tech Elite
 
Taylor-Racing's Avatar
 
Join Date: Sep 2002
Location: Melbourne OZ
Posts: 2,066
Default

Quote:
Originally posted by Bivens
yep....it's not flat.....It is indeed well-designed......maybe it should have a "FRONT--->" molded into it though......many of us have made that mistake....
Oooops . . . yes, it isn't flat. Maybe it was around the wrong way when I got the car (it was second hand having done one race) and that's when I noticed the tweak - can't remember, now.
Apologies - next time I should take to the screwdriver before I take to the keyboard.

David,
We run a Nova NSR-12 and the Turbo II pipe. A pretty good stock engine and a pretty good pipe too, I reckon. We always make the six minute heats with juice to spare.
Are you sure you can't go leaner? - I'd expect even the 5:45 figure with the NTC3 is too rich, but it's very difficult without seeing the situation.
Taylor-Racing is offline   Reply With Quote
Old 06-21-2004, 06:03 AM   #12969
rjl
Tech Fanatic
 
rjl's Avatar
 
Join Date: Jun 2002
Location: OZ
Posts: 848
Default

Quote:
Originally posted by David Joor
Yeah, going leaner is just scary, it is borderline already I agree, the touring cars are so much faster now that they should change it on the fuel tank.
If you are using all the fuel in just on 5 minutes and the motor is running at optimum then you're lucky, sounds to me that there may be too much load on the engine though and it's needing the fuel to stay cool.
rjl is offline   Reply With Quote
Old 06-21-2004, 06:42 AM   #12970
Tech Addict
 
David Joor's Avatar
R/C Tech Charter Subscriber
 
Join Date: Nov 2001
Location: Houston, Texas
Posts: 539
Trader Rating: 1 (100%+)
Default

Gotcha guys, you gotta know that the track was 145 degrees and about 95 outside. Maybe I need to invest in the Kawahara low friction belts? I think the taller gearing may be an help as well, I was having run time issues with 53/58 27/21 so I went to 54/60 because if felt as if it was not topping out before, but when I went to the 54/60 it topped out a bit early. I can try going leaner on top but with one hour it jumps to 260 - 270.

I have a NS12 S3 that maybe I should break in and try out to see if it is just something with the X12. I tested the carb for leaks by spraying denatured alchohol all over it white it was running and it wouldn't die. I didn't notice that the lowend needle was strange though. I could back the needle to where the head was all the way out of the cup and it still would not load up and it had tons of rip with a ton of smoke. The oring looked good on the needle as well but it would slide easily. Is that oring supposed to be tight? I put some lube on it but I gave up by that time. Maybe it is just a problem with the motor. But like I said, it was ok in the NTC3 so that is what has me wondering.

But what I really wanted were some tips on improving runtime other than leaning and you all gave a few ideas to work with. Also I think I could have gone to a lower deck height because the height worked great with 40% and I went down to 30%. My train of thought though was more power less runtime though, am I wrong?
__________________
Avid Racing Concepts LLC.
http://www.avidrc.com

AE | Reedy | KO | Tekin | Powermaster | Avid | Upgrade | BCE | Paint by Smiley
David Joor is offline   Reply With Quote
Old 06-21-2004, 07:11 AM   #12971
Tech Adept
 
Join Date: Feb 2004
Location: colorado springs
Posts: 225
Default

I'm currently running the X12 engine with the Turbo II as well. When is gets hot outside (around 90 deg f) these newer engines are running out of fuel after slightly over 5 minutes. Most of us had our engines in the 260 to 290 deg range, anything less was sputtering fuel out of the exhaust. Point is, as long as these new engines are getting lubrication the temp really doesn't play a big role in tuning.

Is this on a brand new Mtx3? If it is, there is more load on the engine due to the tight fit of the drive train, should free up within a couple of race meets (if not sooner). Remember also that the Mtx3 is heavier and has more rotational parts than the NTC3 as well.

Unfortunetly for me I was running in the new engine in this condition and I was not enjoying running the engine that hot. This engine is really strong. The only problem I've had with it is the o-ring on the idle adjust needle was torn and we had to replace it and I bent that needle somehow (replaced it with the one out of my RB).

More power does mean less runtime, in general. Be carefull as to not to detonate the engine when lowering the head clearance. Lowering the head clearance adds power to the top end and uses less fuel due to the less aif/fuel mixture that can fit in one rev of the engine. Motorman recommends (for those looking for more power) approx 0.022 in of head clearance. There is a thread on this board that provides more information on this subject.

Enjoy running the engine and car. Best combination I've driven yet.

Last edited by darkangel; 06-21-2004 at 07:20 AM.
darkangel is offline   Reply With Quote
Old 06-21-2004, 07:20 AM   #12972
Tech Addict
 
David Joor's Avatar
R/C Tech Charter Subscriber
 
Join Date: Nov 2001
Location: Houston, Texas
Posts: 539
Trader Rating: 1 (100%+)
Default

Darkangel - That could be it, the pipe was definately sputtering fuel off the low end needle and I could run it hotter as well I guess. The car is new and it only has about 1/2 a gallon through it now. I didn't know it would take this long to break in.

The car is amazing, I TQ'd the Texas Biggie with the NTC3 and was running the same laptimes as the top four guys. 3 of those guys were at the next series race where I drove the MTX3 and I was over a half second faster per lap than they were. I have let people drive it that are full factory guys because they wanted to see how such a fast car felt and no one could get it around the track, lol. It feels like a total dream to me, this is typical though, I can't drive Joel Johnson's, Barry Bakers, or Matt Francis cars either because of too much steering and that is how this car feels now, so I am stoked to be able to run the car like this with 100% confidence while battling with others. Now if I can just get the motor figured out.

Are the Kawahara belts a good idea, or just let the stocks break in? Anyone use wd40 on them or try removing every other gear from the large diff gears?
__________________
Avid Racing Concepts LLC.
http://www.avidrc.com

AE | Reedy | KO | Tekin | Powermaster | Avid | Upgrade | BCE | Paint by Smiley
David Joor is offline   Reply With Quote
Old 06-21-2004, 07:32 AM   #12973
Tech Adept
 
Join Date: Feb 2004
Location: colorado springs
Posts: 225
Default

My recommendation, let the stock belts seat in and when they break try the kawahara ones. Although I have heard of durability probs with the kawahare low friction belts. WD40, umm well I know alot of people use it (I forgot to try it on mine when I built mine) to free them up a bit.

After a half a gallon, your engine is still not broken-in? I think I used around a quarter of gallon on mine and it is broken-in (unless I'm mistaken). If your engine is still running-in, it will run hotter than an engine that has already gone through that process. Btw, this weekend my engine was running at 230 to a max 250 deg with the same settings as I used on my breakin day on a approx 78 deg day (it wasn't a good day to race, we ended up running 2 quals and packing up due to rain, wind, and a tornado warning for the general area)
darkangel is offline   Reply With Quote
Old 06-21-2004, 08:04 AM   #12974
Tech Addict
 
David Joor's Avatar
R/C Tech Charter Subscriber
 
Join Date: Nov 2001
Location: Houston, Texas
Posts: 539
Trader Rating: 1 (100%+)
Default

There is a little confusion, the MTX3 has a half gallon on it, the X12 is fully seated and run a little over 1.5 gallons through it. I ran the X12 in the NTC3 the race before and two practice sessions.
__________________
Avid Racing Concepts LLC.
http://www.avidrc.com

AE | Reedy | KO | Tekin | Powermaster | Avid | Upgrade | BCE | Paint by Smiley
David Joor is offline   Reply With Quote
Old 06-21-2004, 08:45 AM   #12975
Tech Addict
 
David Joor's Avatar
R/C Tech Charter Subscriber
 
Join Date: Nov 2001
Location: Houston, Texas
Posts: 539
Trader Rating: 1 (100%+)
Default

What pipe is Robbie running in that article in Xtreme? It has a square pressure nipple on it and the header appears to be slightly shorter than my Turbo II. I need a new pipe and not sure what to get. Is it the Novarossi 2601? If you know what it is, maybe you possibly know where to get it online?

Also on the car, does the Kawahara rear swaybar require a different rear top plate, I have a adjustable rear sway by some other manfacturer and it requires some top plate with stand off's, does mugen make a plastic top plate like that because I am not going to put aluminum up there.
__________________
Avid Racing Concepts LLC.
http://www.avidrc.com

AE | Reedy | KO | Tekin | Powermaster | Avid | Upgrade | BCE | Paint by Smiley
David Joor is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
MUGEN MBX5R/MUGEN MBX5T PROSPEC/TRAXXAS RACE REVO Jason Halvorson R/C Items: For Sale/Trade 14 01-12-2008 10:32 AM
Mugen 5T Chassis, Mugen 46 Tooth Pinion, Associated Ride Height Gauge bretzkej R/C Items: For Sale/Trade 1 08-19-2007 06:31 PM
USA's Most Wanted FOR SALE Mugen MBX5R,Losi 8 comp, and Mugen MBX5T Prospec Truggy nobike R/C Items: For Sale/Trade 69 04-28-2007 07:45 PM
Another MTX3 prospec w lots of parts and an optional Mugen X12 w Mugen pipe Scott Fisher R/C Items: For Sale/Trade 11 11-21-2005 05:45 PM
drake xxx nt and mugen mst-1+extras......Looking for a kanai 2 or maybe mugen buggy [email protected] R/C Items: For Sale/Trade 5 06-30-2003 09:31 PM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 04:36 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net