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Old 10-02-2007, 04:46 PM   #16
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Yep my motors which i hand MOD do loose some bottom end due to slower air speeds internaly at low RPM which is good in my 5 Port as it is a wild beast when stock but i gain a lot more Mid range and top end power which suits my driving style. While i still retain bottom end to an extent it doesnt " Over Power " the track like a standard engine does, which give me a linear power band and more run time. Nothing worse than coming out of a corner and blazing the wheels and not getting enough traction to clear jumps etc. Makes me a smoother driver and i spend less time on my roof, lol.

Yes Blue printing is what its about, CnC machines while do a great job do NOT have the capability to increase flow where it counts. Most engine are machined to a specification and left at that to save on costs, sure this is fine but for those who want a different power curve, more run time and a more efficient engine, modding them is the way to go.
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Old 10-02-2007, 06:04 PM   #17
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+1 to the no mod argument.

Buy a good engine to start with and spend the extra dough on ceramic bearings, tires, etc. (yes, I have had modded and unmodded engines).

P.S.
Once you have a modded engine suck dirt you'll agree with me even more!
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Old 10-02-2007, 06:42 PM   #18
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Unless you are a top notch pro level racer do not buy a modded motor. I have never owned one and never will. Simply because i know this much.

When you start porting and modding these motors the way many of the mod motor guys do, tunning is much more difficult and much more of a science. Secondly, high dollar race motors are just that, and they are harder to tune than budget minded motors just due to the fact of to get that kinda power there is a fine line of great tune and destroyed motor. The modded motors cost even more than a stock high-end race motor, even if you are a great engine tuner, what happens if you lose your airfilter mid race. Or bonehead out and for some reason you get a runaway and break the crank. Kiss your $350+ motor good bye.

I know the advantages of the modded motors, im not saying that they are worthless or anything like that. Im sure they are easier to drive, but you can make up the difference with smooth driving on a stock motor. Unless you are top notch there is no point in owning one of these motors.
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Old 10-02-2007, 06:45 PM   #19
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Also, I come from a karting background where we spent hours and hours on clutch setup and testing, and I can be one of the first ones to point out that most people do not do enough / understand CLUTCH tuning. It makes a really big difference in the application of power. The worst part is that it is all relative to one another.. snappy clutch pairs with a motor built with mid range in mind (low port count or modded for smoothness), paired with a mid range pipe. Still amazes me how much there is to the equation, which is why most run what they see fast drivers run (including myself in the beginning)

Also in the end: feel, power application, motor smoothness, it all takes a backseat to throttle control. Perhaps you are not making it over the jumps because of a heavy trigger finger. People coming from an electric RC background know what I mean.

+1 NO mod
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Old 10-02-2007, 06:55 PM   #20
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Quote:
Perhaps you are not making it over the jumps because of a heavy trigger finger.
LoL, you called my bluff

The difference is for me i can do all my Mods for free and to suit my style, where as some one new has to pay for it then try to work out how to tune it.
So its a case of each to their own. Yes clutch is a big part of it as well.

Yes ive got a heavy trigger finger but my mods seem to have made the power curve alot more forgiving for my driving style. Yeah i think i need to restrain my trigger finger, but it aint gonna happen for some time to come, i was born a rev head and thats hard to shake once you have been bit.

Besides my modded motor, Go Tech .21 5 port owes me like $300 AUS, and with the mods ive done it can hang with the best motors out there for a 3rd the price, but i personaly would not pay top dollar for an Italian mill when i can do it myself for a 1/4 of the cost.

PS: a Rotax is not a small capacity Nitro motor and generaly are top notch from production.
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Last edited by GenReaper; 10-02-2007 at 07:38 PM.
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Old 10-02-2007, 07:19 PM   #21
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I still have to laugh at those that say "nay" to a modified motor based on what they believe they know rather than what they know from first-hand experience or from facts.

I'm not trying to convince anyone that a modified motor is the way to go. What I'm trying to do is dispel misconceptions from people who argue against modified motors simply based from their limited knowledge as opposed to "fact".

Another example where modifications work great is in the case where I purchased a Werks B728. That had to be the most anemic engine I've run. No top-end, but tons of bottom-end. No matter the combination of clutches, shoes, springs, and pipe, couldn't really bring this engine to life. But after some modifications to the port, crank, and sleeve, its a darn good engine. One that I'll actually use. Had it not been for the mods, this engine would have languished in my pit box or been up for sale...

I also whole-heartedly agree about clutch adjustments, springs, shoes, etc. As I also do with regard to exhaust pipes. Most people don't have the budget to test various combinations of such with modified motors they buy. If you read instructions from people like RB Mods or others they make recommendations as to what components they've found works best with their mods.
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Old 10-02-2007, 08:23 PM   #22
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I have had 3 modified motors. One was a a vspec, Novarossi bt-21 and the other was a p5x.

The 2 novas were impossible to tune but when tuned right, got slightly better than stock run time and crazy power. Not worth it too me.

The vspec is a JP mod black edition. Ceramic bearings, black crank all the goodies. Has a hard time making 7.5 min. Waste of money.

Now i run Ninjas and I get awesome runtime almost, 11 min, power wise it is on par with anythinh out there.


I probably will never buy another modified motor again, its just not worth it.
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Old 10-02-2007, 08:36 PM   #23
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im still up in the air, but ive had better luck and around the same performance with stockers as mods...
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Old 10-02-2007, 09:12 PM   #24
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I've had a couple of modified engines and had very good luck with them. Found them very easy to tune and better power. However I didn't utilize that power very well. I should have geared up and I didn't do that.

I would have absolutely no issues buying mod engines again.
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Old 10-03-2007, 12:11 AM   #25
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Hey all

Just curious , what would make a modified motor harder to tune ? Ive never had a modified motor end up being harder to dial in. Just curious .

Regarding mods . If its done correctly you should realise a better power band all round, slightly better tank times and the engine should last as long as a stock one. But honestly its up to personal prefrence. As is 1:1 scale people like to mod cars that clearly do not need it but do it as part of the experience and also to have a quicker machine. I agree that pipe and clutch should be your first port of call when squeezing more out of an engine. Then if youre still not happy maybe look at modding. Believe it or not manufacturers leave a few areas of improvement . Wether its to change the timings for newer models or that they leave these improvements for team motors or wether its because 1 pass cutting is cheaper than 2 or 3 pass .. Its hard to tell unless they inform you directly.

All in all Modification is an option for the enthusiast that wants more. wether its needed or not is another question. IMO an engine that is slower can get better lap times than a quick one. But a fast motor with a capable driver that can use it is un touchable.

Cheers MM
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Old 10-03-2007, 06:56 AM   #26
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Gen-

Good point. Rotax (Karting) motors are a little more refined out of the box than most nitro motors I have taken apart.

I am guilty of the heavy throttle finger more often than not, despite what I think is an incredible pipe / engine / clutch combo from the beginning.

Here is another thing to keep in mind, IF you do decide to have a motor sent in for modification, pick one of the companies that has a dyno rig, flow bench etc. Technology behind the theory so to speak.

I personally have had a motor modded by a reputable individual, and it was terrible. Having taken it apart and compared with the motor my friend got from him there was a great deal of variance (due to the hand modding process) between them on the porting and crankwork. I suppose thats what you get when something that has to be done so precisely is done with a $3 metal file / dremel rather than a CNC or at least a jig to make them consistent.

BTW I am not flaming anyone, just adding in my input, given that I have been touched by this debate. there is a lot of good information in this thread.. both for and against.
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Old 10-03-2007, 07:01 AM   #27
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Thanks to you all who replied to my question.

I guess it's worth to try a modified engine as long as you know exactly what you are doing with it.

Currently I am running Picco P7R-Evo and will try modifying when it starts to loose power, just for an experience. :P

Anyone using OS 21VZ-B V-Spec Factory tuned version? I am thinking to get it after my picco breaks down and want to know which manifold & pipe goes well with it for small track use.

Wish I haven't started this hobby. It just costs too much for learning!

Once again, thanks for your useful tips.

Last edited by Kevin Kim; 10-03-2007 at 07:15 AM.
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Old 10-03-2007, 08:24 AM   #28
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OS 21VZ-B V-Spec
Pipe 2050
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Old 10-03-2007, 11:50 AM   #29
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OS Speed Vspec, OS 2060 pipe. The mix of pipe and motor compliment one another.
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Old 10-03-2007, 04:24 PM   #30
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Quote:
Originally Posted by bushyar15 View Post

If any of you are out in the Metro Denver area for a race, I'll gladly let you drive one of my modified engines back to back with a stocker and let you decide for yourself...

I live in the Denver area......If I remember right.....we have chatted B4 and I live only minutes from you......

I will be at RAT on the 4th and would love to run some of yr rides......

Or take you up on another day for a test drive,......
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