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Old 12-07-2008, 02:42 AM   #1
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Default RPM vs HP

Can anyone share how they choose their engines between the HP and RPM?

I am looking to upgrade from my OS TZ for my NT1 and am looking thr several engines. The differences seem to be mostly a tradeoff between the two, vs gaining both.

Is this correct?

Cheers
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Old 12-07-2008, 05:43 AM   #2
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It is not wise to select an engine on the base of numbers. For sure the factory specs are crap and could be that a Force engine is better than a Picco which is not.....

Search for the user experiences in the several topics you can find on your choosen engines. The specs also does not tell how long the engine will live, how easy it is to tune and which exhaust is needed, the topics on this forum do !
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Old 12-07-2008, 12:16 PM   #3
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Originally Posted by bboy View Post
Can anyone share how they choose their engines between the HP and RPM?

I am looking to upgrade from my OS TZ for my NT1 and am looking thr several engines. The differences seem to be mostly a tradeoff between the two, vs gaining both.

Is this correct?

Cheers
I know that Power and $$$ are correlated

Seriously now, highest but still flat ( broader ) curve of horse power are more important numbers than maximum rpm.

In simple english, buy as expensive as you can afford, and take care that engine like your own.
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Old 12-07-2008, 04:57 PM   #4
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yea specs are not everything to look for also not price. I do a lot of 200 feet outlaw drag racing and i have a os tm .21 motor thats on film""check it out on youtube""(757rcdrag)""" beating 5&6 hundred dollar
motor ohh yea and some thanks to """"ROELOF""" big up!!!!

i'm lou
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Old 12-09-2008, 07:57 AM   #5
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The problem is the price range between many of the engines are "similar".

Say Novarossi 353 vs Max XXL3 vs RB ... so on.

I know we all have a favorite brand, but as a beginner (I am only running OS TZ right now ..), how should I go about choosing one?
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Old 12-09-2008, 08:50 AM   #6
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Quote:
Originally Posted by bboy View Post
Can anyone share how they choose their engines between the HP and RPM?

I am looking to upgrade from my OS TZ for my NT1 and am looking thr several engines. The differences seem to be mostly a tradeoff between the two, vs gaining both.

Is this correct?

Cheers

Motors are more powerful not just because HP number is higher.
HP numbers are coming from torque multiplied by RPM (where max torque was read) and multiplied by some coefficient, I think it is .53. So if you look on the numbers correctly, then you will find it is not what it looks like.

Please keep in mind that our clutches usually engage at about 25-29 K RPM, so please look which engine has more torque at that RPM range, and how you have to set up other engines to get the same torque.
Also look which engine has more torque at the end of the power curve, and it will show you how an engine will keep pulling at the end of the straight.

So after analyzing all this points you will understand that HP sell engines, torque wins the races.

AFM
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Old 12-09-2008, 10:49 AM   #7
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seriously AFM? clutch at 25k? wow

silly virtual r/c it has the shift point into second at 16,000


I always wondered what part of the powerband we use if the track is mostly first gear
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Old 12-09-2008, 11:08 AM   #8
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Default os tm 21

check us out http://www.youtube.com/watch?v=7b7m5K9Sh7k
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Old 12-09-2008, 11:53 AM   #9
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seriously AFM? clutch at 25k? wow

silly virtual r/c it has the shift point into second at 16,000


I always wondered what part of the powerband we use if the track is mostly first gear
Highest RPM ?
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Old 12-09-2008, 01:04 PM   #10
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seriously AFM? clutch at 25k? wow

silly virtual r/c it has the shift point into second at 16,000


I always wondered what part of the powerband we use if the track is mostly first gear
That is what we try to do when setting the clutch for max efficiency.....just check out any dyno graph from a top engine, and thei max torque is around 25K rpm.

Lets take for example a JP .12 FX TO3 engine.
You set your clutch for engaging at 25K rpm (max torque for that engine is produced there), then you are using the power band from there up, and since max HP for that engine is at about 35K rpm, you have a very narrow and peaky power band....you need to keep that baby singin high.

AFM
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Old 12-09-2008, 02:05 PM   #11
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Highest RPM ?
In combination with the right gearing
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Old 12-09-2008, 08:29 PM   #12
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That is what we try to do when setting the clutch for max efficiency.....just check out any dyno graph from a top engine, and thei max torque is around 25K rpm.

Lets take for example a JP .12 FX TO3 engine.
You set your clutch for engaging at 25K rpm (max torque for that engine is produced there), then you are using the power band from there up, and since max HP for that engine is at about 35K rpm, you have a very narrow and peaky power band....you need to keep that baby singin high.

AFM
Maybe for that .12, not for all engines and certianly not my JLR.12, stock or modded. As you can see from the AB Mods X-Dyno. My crazy, insane, sick .12 makes nearly 40oz. in. not .25 and holds it from about 31K rpm to 37K rpm and still making your stated 25oz in. at 40K rpm.

My drag modded JLR.12 Evo3 boasts numbers slightly better than this stage(2) evo2.

Tork gets you going and will move the weight quicker for sure, but rpm is king...and you don't need a 1/2 mile runway or custom made tall gearing or a modded chassis to use it. Ben there done that. You can always gear shorter or stall the clutch higher to get more acceleration, but when you run out of rpm on your high tork engine, it's over and the higher rpm engine will just keep spinning......and with your taller gearing you may catch me on the return trip.....just my 2 cents.

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