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All Forums >> RC Cars, Buggies, Trucks, Tanks and more >> RC Car Engines >> Car Nitro & Gas Engines >> You all probably get this question ALOT. Page: [1]

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You all probably get this question ALOT. - 2/7/2008 4:57:55 PM   
jtnktz


 

Posts: 808
Joined: 1/1/2005
From: Winchester, VA, USA
Status: offline 		I would like to learn how to mod my engine. Yes, I did a search. No, I didn't find anything useful. So what I'm asking is if sdomeone could maybe put me in the right direction and get some help. I would even pay for some help as well.

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T-maxx///Revo///Vendetta ST///OFNA Ultra LX Comp///HPI BAJA 5B (Clone but still goes)
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RE: You all probably get this question ALOT. - 2/7/2008 5:02:58 PM   
JB COMP



Posts: 4198
Joined: 11/23/2006
From: Navarre, FL, USA
Status: offline 		couldn't you wait till later? I was going to send you an e-mail but I thought you wouldn't get it till later so I didn't send it. and I'm still doing my school, so I don't have time till later. (e-mail sent)

< Message edited by JB COMP -- 2/7/2008 5:17:22 PM >

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LX Comp: STS21B, JP-3, DX3.0 - CRT: STS 30 Rev2 or Mach 427, STS 0702, DX3.0 - T-maxx: TRX2.5
Airtronics. BlueBird.

(in reply to jtnktz)
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RE: You all probably get this question ALOT. - 2/7/2008 8:09:44 PM   
jtnktz


 

Posts: 808
Joined: 1/1/2005
From: Winchester, VA, USA
Status: offline
quote:

ORIGINAL: JB COMP

couldn't you wait till later? I was going to send you an e-mail but I thought you wouldn't get it till later so I didn't send it. and I'm still doing my school, so I don't have time till later. (e-mail sent)



Hey, I understand man. I read it and I think I might start playing with my TRX 2.5 (Spare). But I would like more information on how to do it!

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T-maxx///Revo///Vendetta ST///OFNA Ultra LX Comp///HPI BAJA 5B (Clone but still goes)

(in reply to JB COMP)
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RE: You all probably get this question ALOT. - 2/7/2008 11:49:39 PM   
Danju



Posts: 1660
Joined: 2/3/2007
From: thousand oaks, CA, USA
Status: offline 		this might help a bit

this might help too but the friggin pics wont work (MVbashers.org closed down or something )

clicky

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RE: You all probably get this question ALOT. - 2/7/2008 11:53:52 PM   
j_blaze



Posts: 1504
Joined: 1/4/2007
From: Tampa, FL, USA
Status: offline 		this may help also, and also the "how to port nitro engines thread" in here.

http://www.e-maxximumrc.com/html/nitro_motor_mod.html

http://www.rcuniverse.com/forum/m_5226191/tm.htm

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RE: You all probably get this question ALOT. - 2/8/2008 1:06:18 AM   
JB COMP



Posts: 4198
Joined: 11/23/2006
From: Navarre, FL, USA
Status: offline
quote:

ORIGINAL: j_blaze

this may help also, and also the "how to port nitro engines thread" in here.

http://www.e-maxximumrc.com/html/nitro_motor_mod.html

http://www.rcuniverse.com/forum/m_5226191/tm.htm



I don't like the way they did their fangs on the boost port in the e-maxximumrc.com and I think where they say to point your fangs is wrong too IMO.

_____________________________

LX Comp: STS21B, JP-3, DX3.0 - CRT: STS 30 Rev2 or Mach 427, STS 0702, DX3.0 - T-maxx: TRX2.5
Airtronics. BlueBird.

(in reply to j_blaze)
       Post #: 6

RE: You all probably get this question ALOT. - 2/8/2008 1:53:14 AM   
SManMTB



Posts: 4833
Joined: 4/28/2005
From: Charlottesville, VA, USA
Status: online 		The flow should be directed away from the exhaust just like they wrote. The article showed a pretty sad looking hack-job.

(in reply to JB COMP)
       Post #: 7

RE: You all probably get this question ALOT. - 2/8/2008 3:19:05 AM   
CBM Racing


 

Posts: 617
Joined: 1/12/2007
From: rhinelander, WI, USA
Status: offline 		Looked as good or better than most jobs seen here. You see it all the time here, people cut in some flow channels, cut some turbo grooves into crank, and go on about how strong their modded engine is. Hey, at least they're trying and learning! As has been said many times by people here, the biggest gains are in adjusting the timing. What I have never seen on here, is what the optimum timing should be. What I mean is, at what point in crank rotation should the crank port open for max power? When should exhaust open for max power? when should boost and intake open for max power? I wish someone knew, and would post them here ! I saw an article in an rc mag about modding a savage engine(can't remember which mag or engine though)and they went into good detail about Adjusting the timing and how to do it on this engine. Haven't seen anything here close to that detail, but I keep hoping! Would love to see a post that went something like "for maximum mid to highrange power and more rpm, the crank should open at x-degrees, and close at x-degrees, the exhaust open at x-degrees, the boost port at x-degrees..." That would make many folks more confident to try it I think.

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RE: You all probably get this question ALOT. - 2/11/2008 5:32:56 AM   
SAVAGEJIM



Posts: 4726
Joined: 7/6/2005
From: behind my 'puter, USA
Status: offline 		The thing to consider about timing profiles (the duations of the ports) is that given the passageways and how the innards are shaped, you want to improve volumetric efficiency such that you maximize BMEP (mean effective pressure) as much as possible for a much of the torque and power curves as possible for the engine's operating RPM range.

Race grade timing profiles will take the following durations (this is not always a given though so don't always shoot for these durations unless you know what the fluid flow characteristics inside your engine will take):

Crank Induction: 210-230+ degrees
Lateral intakes: 110-120 degrees
Boost intake: 105-125 degrees (some engines actually have a longer boost duration than teh laterals, I have yet to dwell on what the fluid dynamics will look like in this arrangement).
Exhaust: 165-185 degrees

Bear in mind: to produce the most output given the best possible volumetric efficiency for the engine in question, you want to have as much BMEP as much as possible. Too high of an exhaust duration will sacrifice your trapped compression ratio which in turn will sacrifice your your BMEP. Less BMEP mean less toque and power output. So, dont cut too high up on you exhaust port.

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I hate stray Tomcats

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RE: You all probably get this question ALOT. - 2/11/2008 3:12:21 PM   
JB COMP



Posts: 4198
Joined: 11/23/2006
From: Navarre, FL, USA
Status: offline 		I read some that you should have the crank induction open either right after BDC, or right after the ports close (can't remember which one) could some one tell me which one it is?

_____________________________

LX Comp: STS21B, JP-3, DX3.0 - CRT: STS 30 Rev2 or Mach 427, STS 0702, DX3.0 - T-maxx: TRX2.5
Airtronics. BlueBird.

(in reply to SAVAGEJIM)
       Post #: 10

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All Forums >> RC Cars, Buggies, Trucks, Tanks and more >> RC Car Engines >> Car Nitro & Gas Engines >> You all probably get this question ALOT.
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