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Old 12-15-2007, 09:05 AM   #31
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Originally Posted by COBRARACING View Post
Hi Guys

I know it's not my thread but id like to just give a little by me on this question about engine modifier.

All you really need is a polish and balance to the engine just to allow a smoother fuel flow thats all.
Dont forget once you start cutting into the sleeve you gain power from one place and lose it in the other .You either gain mid ,top or bottom or lose mid ,top or bottom you can't have it all .
so i suggest don't mod the engine at all (like cutting into the sleeve ,crank etc the factory is the only one who knows better .tuned engines are perfectly fitted parts like a matched battery pack its not a dremil cutting sequence and from my experience i have never come across a modified engine that is faster,more reliable,fuel efficient or has outlasted the lifespan of a factory tuned engine.
Also dont forget you can gain some of the characteristics mention above by experimenting with pipes,headers ,gearing and glow plugs .no need for cutting.
also don't skimp on fuel always use quality fuel.You dont see the worlds best running after market modified engines.

just my two cents worth.


You must have tagged up with some pretty low end modders then........I am myself a modder, and I really don't agree with much of what is being posted in this thread..

first myth... if you cut the sleeve your taking power from one area and adding it to another.............. This statement is simply not true, i have modified plenty of engines ( which have fully re-timed sleeves) and the motor has gained torque across the whole RPM range from idle too top end...no sacrifices anywhere in the powerband whatsoever. These nitro engines are very crudely made with much room for improvement, the factory port shapes are a result of a factories machining limitations, not ideal port design and engineering......

second myth...a modded motor is harder on fuel........... Well yes and no... depends on the modding that is done..... my motors all have reworked port shapes and port entries.. by doing so I manipulate and improve the engines combustion patterns and shnerle effect, creating a motor with better volumetric efficiency, and much less fuel wastage out of the tuned pipe....So the motor does make more power and can also get better mileage.... Now very very few modders actually bother(or even know how) with altering port shapes and timing, I'd say 99% of modded motors have stock port shapes and timing....

In the end my modded motors are no worse on fuel then stock( they are usualy better) , they make huge power gains over the stock engine from bottom end all the way to top end.... they have a broader, smoother power curve and will outperform the stock counterpart across the entire RPM range.........

remember every modder is different, most modders don't play much with timing, and IMHO if you don't alter timing your not really gaining much from the motor...the Key to power is in port shape and port timing

Last edited by Maximo; 12-15-2007 at 09:52 AM.
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Old 12-15-2007, 10:55 AM   #32
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IMHO if you don't alter timing your not really gaining much from the motor...the Key to power is in port shape and port timing

Sounds familliar........Neil?
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Old 12-15-2007, 10:59 AM   #33
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Sounds familliar........Neil?
Tubber !!!!! LOL
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Old 12-15-2007, 12:28 PM   #34
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I need help finding the best engine modifier for my RB C6BBT7. This is for a Mugen truggy.

Thanks for your recommendations
To answer your question... NONE! Just buy a good quality engine like a Novarossi, Sirio STI, RB, or OS V-spec. Modified engines used to have tremendous value because the manufacturers hadn't really learned all the tricks to make an engine go fast, and the lack of CNC machining made all those "tricks" very time-consuming and expensive to implement on a production engine. The advent of modern CNC machinery and CAD allows all the exotic cuts and shapes pioneered by the engine greats of years past, and it now costs nearly nothing extra – just a few more seconds of machine time.

Stay away from people that claim to be able to make your engine “SO MUCH BETTER.” The truth is, the vast majority will charge you good money to F-up your engine. The fastest guys in our area (which are generally the fastest guys in the world) simply pull the engine out of the box and put it in their car - no mods, no fuss. Engine modifiers will always argue this point because they want to believe they know something that the engineers at the factory do not, and wish to continue selling their “service.” Team drivers for said engine modifiers swing off the nuts of those that give them free engines, so they’ll always tell you they’re great (but somehow never manage to place well in any major event), and their customers generally want to believe the money they spent actually made a difference. Take it or leave it, but my own observations and many years of experience wasting thousands of my own money trying various modified engines of the Dremel generation has taught me one thing – keep ‘em stock and you’ll be a lot happier and have a little extra walking around money.
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Old 12-15-2007, 12:46 PM   #35
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I too have modded engines, and I had access to a flow bench ! I know all about port timing ,the different port scavenging ,be it rotary valve or piston port and all variables in between, And it is a trial and error game with out a flow bench and smoker !
I laugh when I hear "It's a compromise" Oh brother, you don't think that O.S. or Novarossi or any of the other top brands don't have 5 axis cnc ?? Your kidding your self !! They do and it can do ANYTHING your shaky hands can do and then some !!I know I have run them !
The guys saying they alter the timing ? with what shims ? you cut chrome you loose bottom end!! You raise the ports you you increase rpms ,big deal you loose bottom end ,unless you cork up the crankcase. Then you need to fight off pre detonation, I've done all this it is not easy with out the correct tools.
Goodluck with the mods though , and yes AB does know his stuff !!! He has the goods !!!! As for EB........
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Old 12-15-2007, 12:55 PM   #36
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@ this thread!!
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Old 12-15-2007, 12:56 PM   #37
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A CNC mill cannot cut what I can achieve by hand....the work on the inside of the sleeve that I dois impossible for a CNC mill... I hand cut my ports with diamond files.... MY ports have ramped opening angles and notched internal port corners..... a production CNC mill cannot make these cuts... No matter how fancy the outside of these modern motors sleeves look the internal angles on the ports are all the same as they have always been..... Wether you guys beleive it or not but there is alot of room to work with these modern engines to make more... its not that I know anything the factories don't know its just that I am capable of doing what their production lines cannot.......... Since I have had the ooportunity to have my motors tested on a X-Dyno I can assure you that I have not lost power anywhere in the powerband......and yes I do cut the chrome, no sleeve shimming required.....

here is a stock Ninja 28 and my Modded Picco 28... FYI a stock Picco 28 makes about 1.8 HP and 75 oz/in on this particular X-Dyno.... the modded motor canmake 90 oz/in with a long header, and will pull over 2.3 HP with a short header...Modders can lie, dyno's do not !

I only modify motors for a hobby... I sent my motors to Adam from AB Mods to have them tested on the X-Dyno...


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Old 12-15-2007, 01:05 PM   #38
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internal port cutting...this is only a little of what I do inside the sleeve...and taking pictures is difficult, so this is the best i got

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Old 12-15-2007, 01:08 PM   #39
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Old 12-15-2007, 01:13 PM   #40
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Lookin' good there, Maximo! I can vouch for his ability......I've seen some of his mills run....and boy, do they run (and good fuel economy too)
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Old 12-15-2007, 01:26 PM   #41
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Old 12-15-2007, 01:53 PM   #42
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Originally Posted by pwnzor View Post
a RB C6BBT7 does not need modded, no good quality racing mill does.

Beleiveit or not but a RB C6 has alot of room left to make more power, wether making more power would make it a better motor or not Is a matter of opinion, but the C6 is very far from maxxed out.. I could see making at least a 30% increase in peak HP and a 15-20% increase in tourque... For its internal design the C6 is a underacheiver on the dyno, so its port timings are likely left on the conservative side,,,relying more on design then timing.......... A C6 dynoes i thin 1.16-1.4 HP and 55 oz/in on the X-Dyno...a good modded .21 will make 1.7-1.8 HP and 68 oz/in of TQ.....
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Old 12-15-2007, 02:00 PM   #43
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I too have modded engines, and I had access to a flow bench ! I know all about port timing ,the different port scavenging ,be it rotary valve or piston port and all variables in between, And it is a trial and error game with out a flow bench and smoker !
I laugh when I hear "It's a compromise" Oh brother, you don't think that O.S. or Novarossi or any of the other top brands don't have 5 axis cnc ?? Your kidding your self !! They do and it can do ANYTHING your shaky hands can do and then some !!I know I have run them !
The guys saying they alter the timing ? with what shims ? you cut chrome you loose bottom end!! You raise the ports you you increase rpms ,big deal you loose bottom end ,unless you cork up the crankcase. Then you need to fight off pre detonation, I've done all this it is not easy with out the correct tools.
Goodluck with the mods though , and yes AB does know his stuff !!! He has the goods !!!! As for EB........
a flow bench isn't nearly as effective on a 2 stroke as they are on a 4 stroke...... You can increase the airflow in the engine all you want, but unless you control the pattern of that extra flow you will just end up wasting fuel out the tuned pipe.... By manipulating the intake angles I can shape the flow pattern inthe combustion chamber to make better use of the intake charge...... By doing certain procedures I am able to strengthen the engine shrnerle effect , which in turn produces more power and better run times..... a raw flow analysis will not show anything to with the engines shnerle patterns and I am very skeptical it would aid much in modding these engines....or at least not when concerning some very key elements of 2 stroke performance....
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Old 12-15-2007, 02:32 PM   #44
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Your correct sir! Flow bench alone is not good ...... BUT with smoke added you know EXACTLY what angles to put your ports and you know when they need to shoot to the pipe and when to change to the edge of the glowplug as the exaust port closes . How many sleeves did it take to get the first one correct? Bottom end power is created from crankcase pressure , rpm from port timing/tuned pipe resonense so how are you creating this might I inquire ? When you carve up the crank and sleeve? You need to put something back ?? Or sacrifice bottom grunt. Or just clutch the hell out of it and get poor milage. And all that I saw is easily achieved on a 5 axis cnc. It can do anything your hands can. Now a 3 axis it requires multiple set-up changes not worth the effort.
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Old 12-15-2007, 03:01 PM   #45
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Your correct sir! Flow bench alone is not good ...... BUT with smoke added you know EXACTLY what angles to put your ports and you know when they need to shoot to the pipe and when to change to the edge of the glowplug as the exaust port closes . How many sleeves did it take to get the first one correct? Bottom end power is created from crankcase pressure , rpm from port timing/tuned pipe resonense so how are you creating this might I inquire ? When you carve up the crank and sleeve? You need to put something back ?? Or sacrifice bottom grunt. Or just clutch the hell out of it and get poor milage. And all that I saw is easily achieved on a 5 axis cnc. It can do anything your hands can. Now a 3 axis it requires multiple set-up changes not worth the effort.
a 5 axis will not cut inside the sleeve at a varying intake angle...If it could manufacturers would be doing it....all ports on every manufacturers motor are straight cut, not one motor employs anything like what I do.....

How much time and money did it take me to perfect what I do ?? one word ALOT !!!!!! I have thousands of hours, thousands of dollars and countless engines.............. But in the end i can create a motor that will run the pants off the stock counterpart, from idle to 40 000 RPM my motors make more power, tunes easier, idle better and have a smoother powerband....... I have the dyno graphs and reviews to back my bold claims.... Chances are you have never run a truly modded motor like I am showing so I can understand you not being able to relate............. I will tell you though there is a whole world of modded engines you likely didn't know existed. Basing what I know of engines and seeing the work that has been available on the market I can definitely see where a persons skepticism would come from......... For the most part people assume you can't cut the chrome on the sleeve without advers affects, ranging from losing bottom end to ruining he motor...../ But honestly if a modder knows what to do he will not lose power anywhere... in most cases motors gain power across the board.
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