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RB C6BBT L2G or OS Speed 21.

RB C6BBT L2G or OS Speed 21.

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Old 09-02-2008, 04:00 AM
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Default RB C6BBT L2G or OS Speed 21.

I have narrowed my choices down to these two engines and now i'm completely stumped on which one to choose,RB C6BBT L2G or OS Speed 21.

Does anyone know how these two engines compare? which one has more top-end and which has more bottom end? I do realize the OS speed has better fuel economy, and that the RB will take longer to run in and will last longer but i don't really know the power differences between the two.

i would run the 2045 on the RB and the 2060 on the OS speed.

Please help and share some info.
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Old 09-02-2008, 04:06 AM
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I never ran an OS speed .21, but I have run an EB modded V-spec. I also currently run a RB C6 BB which is non turbo. I personally think the RB is a much better engine for the money. Fuel milage is really really good as well with the RB.


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Old 09-02-2008, 04:34 AM
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I would say RB. Very inpressive top end, excellent bottom end, and incredibly smoothe powerband! But the 2045 is rather restrictive... But it gets better fuel economy...

I run mine with a JP-3; way more power and still great economy!

I will add that the OS Speed AL V-Spec is a very impressive engine, from seeing a couple in action...

But in a "Monies no object" world, I would personally go with the GRP.
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Old 09-02-2008, 05:20 AM
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Own and run both.

Performance-wise, nothing to choose between them. Both perform excellent. The RB is still a bit softer on the bottom.

As far as longevity, this season both motors are still running strong. So, I have no data on the new RB. In general as far as this whole debate on longevity. I've seen V-Specs run strong for 6 or 7 gallons, I've seen RBs last only 5 gallons.... Alot has to do with how you treat and maintain your engine....

I've seen and heard of guys getting 12 gallons out of an RB. I checked out a motor like that, While it ran, it wasn't making nearly the power it should have been. Just cause it still runs, doesn't mean its producing good power....

Also a consideration is price. You can find a V-Spec on the net for around 275.00 The RB goes for around 439.00. Again, I feel you can't go wrong with either. Great engines, it comes down to a matter of preference for brand...
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Old 09-02-2008, 05:27 AM
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i personally run the speeds, but i can be a bit biased, i sell speeds and speed parts on ebay under cjm-recycling if u decide on the speed i sell them for 399.95 plus shipping on there, i have run the c6 in the past, before they switched to turbo head and 7mm restrictor, it was a good engine, wasnt quite as smooth as the speed, another bonus to the speed is the tuning, it basically is set it and forget it, the c6 can be a little trickier but not bad enough to the point that i wouldnt run it, either choice is gonna be strong, fuel effiecent, and last a long time
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Old 09-02-2008, 05:29 AM
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The RB would be my pic in a money does matter world. lots of torque, great top end, good fuel consumption, long enging life.
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Old 09-02-2008, 06:16 AM
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I was kinda thinking the RB might have a fluffy bottom end. I love a snappy bottom end. I do realise this can be tuned out with correct clutch settings but most of these engines these days have great top end, its the bottom end which is hard to find.

Originally Posted by cjm1126 View Post
i personally run the speeds, but i can be a bit biased, i sell speeds and speed parts on ebay under cjm-recycling if u decide on the speed i sell them for 399.95 plus shipping on there, i have run the c6 in the past, before they switched to turbo head and 7mm restrictor, it was a good engine, wasnt quite as smooth as the speed, another bonus to the speed is the tuning, it basically is set it and forget it, the c6 can be a little trickier but not bad enough to the point that i wouldnt run it, either choice is gonna be strong, fuel effiecent, and last a long time
Do you ship to Australia? Thats a pretty good price. i would get it now.
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Old 09-02-2008, 08:07 AM
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Both are the top 2 motors out now IMO, but the Speed has a bigger bottom, and spools to the top faster. Plus I rarely hear of a C6BBT getting 10+ minutes of run time like the Speed can do all the time. Speed is my pick....

Go to most Big races, (Nitro Challenge, SS, etc. etc.) and look an see what the top non-motor sponsored drivers are racing with, and you'll 90% Speeds.
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Old 09-02-2008, 08:11 AM
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Originally Posted by Steve Walters View Post
Both are the top 2 motors out now IMO, but the Speed has a bigger bottom, and spools to the top faster. Plus I rarely hear of a C6BBT getting 10+ minutes of run time like the Speed can do all the time. Speed is my pick....

Go to most Big races, (Nitro Challenge, SS, etc. etc.) and look an see what the top non-motor sponsored drivers are racing with, and you'll 90% Speeds.
90%? Wow... The big races I have seen have been 60-70% GRP's, 20-25% RB's. I have only seen 2 speeds and they looked really soft on the bottom but off the hook top end....
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Old 09-02-2008, 08:14 AM
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I'm running a RB C6 BB with a Dynamite 053 pipe in my Mugen truggy with stock gearing. I can get 9 minutes out of a tank with no problem. I still have fuel in the tank left. Maybe enough for a half a lap.

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Old 09-02-2008, 08:45 AM
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A RB C6 soft on the bottom? Considering it's one of the choice engines for a truggy I would tend to think torque is what it has plenty of. Some say it's to much engine for a buggy but soft bottom is not how I have ever heard it described. RB's last only 5 gallons! Geesh those are the 2 things I never hear or experience with an RB and are generally the upside to a C6 is longevity and power. Sounds more like someone who sucked at caring for his engine.

Lets comment on OS and there cracked blocks from the manufacture. Umm who would not replace them even knowing it was a defect. Not to mention the notorious leaky bearings. Now if you get a good V-spec its going to be a monster to contend with. But there is always the "IF" factor. Never heard any problems like that about an RB.

I think he was comparing the OS speed if you see them on the net for 275.00 I'll buy 10. Although I already know a speed is $500 from A-main

I was at the preworlds and speeds was not even 25% of what was being ran. Is there any bigger race than that oh The Worlds I'll be there too. I know he said non-sponsored.

bushyar15 wrote:
"Performance-wise, nothing to choose between them. Both perform excellent. The RB is still a bit softer on the bottom. "

"I've seen V-Specs run strong for 6 or 7 gallons, I've seen RBs last only 5 gallons.... "

"You can find a V-Spec on the net for around 275.00 The RB goes for around 439.00"

Last edited by vladconnery; 09-02-2008 at 09:03 AM.
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Old 09-02-2008, 09:32 AM
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Originally Posted by vladconnery View Post
A RB C6 soft on the bottom? Considering it's one of the choice engines for a truggy I would tend to think torque is what it has plenty of. Some say it's to much engine for a buggy but soft bottom is not how I have ever heard it described. RB's last only 5 gallons! Geesh those are the 2 things I never hear or experience with an RB and are generally the upside to a C6 is longevity and power. Sounds more like someone who sucked at caring for his engine.

Lets comment on OS and there cracked blocks from the manufacture. Umm who would not replace them even knowing it was a defect. Not to mention the notorious leaky bearings. Now if you get a good V-spec its going to be a monster to contend with. But there is always the "IF" factor. Never heard any problems like that about an RB.

I think he was comparing the OS speed if you see them on the net for 275.00 I'll buy 10. Although I already know a speed is $500 from A-main

I was at the preworlds and speeds was not even 25% of what was being ran. Is there any bigger race than that oh The Worlds I'll be there too. I know he said non-sponsored.

bushyar15 wrote:
"Performance-wise, nothing to choose between them. Both perform excellent. The RB is still a bit softer on the bottom. "

"I've seen V-Specs run strong for 6 or 7 gallons, I've seen RBs last only 5 gallons.... "

"You can find a V-Spec on the net for around 275.00 The RB goes for around 439.00"
Yeah I will take 10 OS Speeds also for $275!

I have seen some RB's around here last 14 gallons and still have plenty of power... I get around 8 minutes of run time also, but I admit I have it a tad bit fat, but its fairly new at 2 gallons on both the C6 and S3... Barely broken in yet...
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Old 09-02-2008, 09:49 AM
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So are you saying that the RB will have more bottom end then the OS speed? I really am fussy with my bottom end power.

Keep this info coming, its exactly what i was looking for.
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Old 09-02-2008, 09:52 AM
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Originally Posted by josh_c View Post
So are you saying that the RB will have more bottom end then the OS speed? I really am fussy with my bottom end power.

Keep this info coming, its exactly what i was looking for.
In a word YES! Not that OS's lack bottom end cause they don't. However they don't have more than a C6. Truggys require more torque than a buggy thats why C6's are favorites for truggys tons of torque.
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Old 09-02-2008, 10:42 AM
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Hey everyone,

I've run both the OS Speeds and the C6BBT's with good success. Here is how I describe the differences, I'll judge them on Responsiveness, Bottom-end, Power band, Mid, Top-end, longevity, and price.

1. Responsiveness (how quickly the motor clears the fuel and hits the torque)
- OS Speed wins in the responsiveness category. It has to do with the way a Speed tunes and how the RB tunes slightly rich on the bottom.

2. Bottom (how much real power at lower RPMs)
- RB wins this category because the motor just has more wheel spinning power. However you might not want this in buggy.

3. Power band (how well the motor transfer's from bottom to mid)
- OS speed wins this category because it has the most usable power in this range.

4. Mid range power (The RAW power of the motor)
- RB wins here because those C6's just have huge RAW power!

5. Top-end (who can sing the loudest....)
- RB wins here because nothing can touch the RPMs of an RB. The OS speed can hang in this category but longevity will suffer.

6. Longevity
- RB will normally last a bit longer if taken care of, they are made of harder materials and can handle abuse a bit better. I've heard the stories about Speed going 10+ gallons but I haven't experienced it that way at all.

7. Price
- RB is just a bit cheaper but they are both around the same price. If your on a budget here is a sale on 4 of the top race motors that just came out, these are closer to the $290-350 range. Bang for the buck would be the new Mugen JX21, it has the same crank as the speed. On sale here:
http://www.airlandhobbies.com/catalo...1585242210.htm

Summary:
1. In my opinion if you run Truggy, the C6BBT's RAW power will benefit you greatly out of corners and get you over any jump at your track.
2. If you run buggy, the OS Speed's very usable power band is sure to help your lap times, and reduce wheel spin.

They are both good motors, but they each have rules:
1. Dont run you OS speed hot, 270+ will kill that motor as the materials are too soft to handle that abuse.

2. Change your connecting rod on the RB at the 2-3 gallon mark, no matter what! That awesome RPM comes at a price, keep that connecting rod fresh and this motor will last very long.

......and air filters, air filters, air filters!!!!! KEEP THEM CLEAN!
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