OS V-Spec vs RB C6BBT
 

Hi I am deciding on which .21 class engine to power my new buggy (Xray XB8EC). The RB engine is slightly more expensive at my LHS. Any much difference in their Power range, durability etc. As this is my first pro kit buggy i need some advice. Perhaps those guys who own these engines can share the experience with us. There are many of us out there who are deciding on a new engine for our buggy. Any comments will be greatly appreciated. Thank you.

the V-Spec makes a little more power ( dyno tested) but the C6 uses much better materials, so it will be more durable and last much longer...... by feel on the ground the C6 is just as fast as the OS....

I have never run a V-spec so I can not say anything about it. However I do know alittle about RB mills. I would sajest getting a WS7III. I have a WS7II and it has lasted a full year and is still going strong. The power curve is very driveable.

From my investigations, this is what I have found. Both motors are good motors there is no doubt there. The Vspec has better bottom end punch, but the c6 has better top end, but with that being said, you need a real long straight to see the c6 top end. I believe in a 200 foot test the c6 just caught upto the vspec at 180 then took the lead, but where do you have 200 foot straights? Most tracks you need good bottom end to get you throught the infield. I run Vspecs on my Buggy and Truggy. I would run a Vspec in my CRT.5 if i could get it to fit. LOL so I just have a 18tz. All OS for me. They hold a realy nice tune. And as far as the bearing issues go in the OS engines, you could pick up a tko ceramic bearing for like $30 and change it right away or wait. I changed mine right away on one engine and am gonna wait for the other since I have spare stock bearing now.

I have run both , and seen many others go of each , the RB C6BBT WILL MURDER A V-Spec if you can harness the power !!
the V-Spec is smoother through the middle to top so it may feel faster, The C6 will be blazing the tires from start to stop !! The C6 needs to really have a good pipe choice to use all it's power wisely and utillize the best possible fuel economy too.
So it is really up to the user , for a rookie starting out I would go with the V-Spec ,alot easier to tame and tune;):nod:

A thread like this will always start some kind of argument. Its a presonal prefference, both engines kick ars

The OS is good (yes I've used it) but the C6 has power to spair across the whole RPM range. Guys who tell you the C6 has less bottom end than the V-spec had the wrong clutch or pipe on the C6 (or both). In addition given the same care, any RB will outlast any OS.

the C6 does not have power like you guys are saying...common please..its a fast mill and all but its far from being the most powerful 21...it has average output for a .21...the dyno graphs show exactly what the mill makes... The C6 may have more snap on trigger due to the blunt tipped LSN as compared to the V-Specs constant taper.. its port timings and volume are very restricted from factory and its dyno results reflect this...to say a C6 blows away a V-Spec is completely unrealistic and untrue.. if the C6 had that kind of power it would show on the dyno ..Now when I re-time a C6 and open the ports up it turns into an animal..but in stock port timing trim its not anything special when it comes to output... not knocking the C6 but its nowhere near the animal you guys are making it out to be..Sorry to sound like a dick, but the C6 has never impressed me with power, the Picco P7 is to me a much stronger engine...

ive drove both motors.. and the c6bbt does have more power then the vspec. but IMO the BBT is way over priced and the vspec if u watch and check the right places u can get one brand new for 230. id say buy the vspec just because u can almost buy two vspecs for the price of one c6bbt...

I agree with RBMike.

Yes I agree the C6 is pricy but beleive me it will last way longer & make up for it.


As for dyno #'s, they don't tell you how the motor feels on the track. In addition most of the dyno #'s I've seen where taken with the wrong pipes.

rbmike makes some good points.. the RBs do last pretty well. and as for the dyno numbers im not sure on that.. the rb bbt feels strong from bottom to top with smooth transition. good luck on your purchase... id also think about the new ws7x3 with the turbo button and all in it...

Speaking as an engine modder i like the C6 and feel it has alot of potential to make big power , but I truly don't feel the stock C6 is overly powerful.. Looking inside the motor I can clearly see where the engine has been restricted and timing turned way down... the exhaust timing and configuration is heavily restricted, with the 2 eyebrow ports being responsible for 90% of the exhaust flow....... Anyways back on topic I like the C6 and definitely agree its a well made motor as well it has huge potential for making more power with the correct mods..... As i type this I am modding the sleeve on my C6 getting it ready for the Winternationals....

here is pics of my crank

http://i107.photobucket.com/albums/m...dcranks008.jpg
http://i107.photobucket.com/albums/m...dcranks007.jpg
http://i107.photobucket.com/albums/m...dcranks006.jpg
http://i107.photobucket.com/albums/m...dcranks003.jpg
http://i107.photobucket.com/albums/m...dcranks002.jpg

heres my Picco crank as well..

http://i107.photobucket.com/albums/m...dcranks010.jpg

Maximo looks like you do good work judging by those crank pics.

O, I forgot to add the C6 with a 2045 gets great fuel economy. At the indoor (winter track) I regularly go too, I get a reliable 12+ minutes at race pace from a "legal" 125cc fuel system in a buggy.

thank you for the compliments...

I can see the c6 getting fantastic mileage.. the way they have the ports closed down it shows economy weighed heavy on the engine design.... Chances are I will take a slight hit to mileage with the mods I am doing to my C6......The motor will make better use of its fuel, but it still needs to burn more fuel to make more power..... I can improve the loop scavenging over stock quite a bit, but in the end mileage will still drop from stock...But the good news is there will be a pretty significant power increase to offset the slight economy loss... I do not run on clay tracks, all my tracks are dirt/soil so i need significantly more power then someone running on a hard clay track.

Thanks for the opinions. The choice is made..... OS V Spec (cost+performance). I have read that RB parts last longer, but being an infrequent club racer, i don't think it makes much difference. Overall i am paying $100 less by getting os. I saw the Novarossi 367.21(very tempting) but at the price of $550, it is way beyond my budget. Though it includes the pipe, extra plugs & other accesories. The track where i am playing is the size of 2 basketball courts. There are a few high slopes & a number of little jumps. Thanks again & enjoy this great hobby.;)

if thats a stock vspec you are buying look around for a OS 2050 pipe to go with it. A stock vspec/os2050 pipe in a buggy is a great combo. if you can't coin up for the os 2050 then go for the JP3 is work just about as good but with less fuel millage.
Have fun the vspec is a great mill.

This is good advice as well, we found the 2050 felt best on the stock V-spec as well.

Just thought I would throw this one out there. The MSR1005 pipe makes more power and torque from bottom to top than the 2050, 2060, or 053. Quite a bit more at that.

For pure low end grunt the 2050 would be great, but for mid to top end tracks, the 1005 screams.

The X-Dyno doesnt lie.. PERIOD. To put it simply it cant... it has no choice but to read the power thats put to it. And it has shown the Vspec has more power in the upper RPM range of any off road engine I have ever tested. EB Mods has also said he has experienced this as well in open forum. it has also proven the Vspec stock to stock to be more powerfull then the C67T. XRC just dyno tested the C6. SO I am not biased here. I honestly don't think the engine magically changes when u put it on the ground. lol :blush: There both great engines. But the power output has been proven time and time again by more then 1 party on a machine that has no choice but to be un biased. You cant really argue with that. Well I guess you could but.. lol. Now as far as what engine you chose to get that's all preference. There both great engines!! So IMHO you cant go wrong with either. Both have been proven time and time again.

I am talking about the 2007 and up spec Vspecs. If you had a earlier version they didn't have near as much top end power as the 2007+ Vspecs.

With the dynos did they use the correct pipes? Also, a dyno says little about drivability.

Yeah it does. You must not be able to read a graph very well.

Yes XRC used the RBs recommended 2045 pipe and the engine produced 1.18HP... They threw a MSR 1005 pipe on there which is there TEST pipe and it did about the same throughout the power band but peaked up to 1.39HP for a short burst and came right back down. it mostly hovered around the 1.2HP area throughout the pull until it started falling off on the top end.

Don't get me wrong I'm not saying the RB C6 is a bad motor AT ALL. I'm not saying ANYTHING bad about it at all actually. I'm only stating facts. The C6 is actually a great engine and I like both engines. I have no preference. I own and operate an X-Dyno and I see and modify MANY different engines and test many different engines on the ground and on the dyno. And I am just trying to straighten out mis information that so easily gets passed on Internet forums. Stock to stock the Vspec has proven to be a more powerful engine with a more powerful power band with more average HP through out its entire power curve. They both have been proven to win races and be liked by MANY drivers.. But what this discussion has turned out to be is "which engine has the most power" Well the Vspec is THAT engine. Average, peak and top end HP.

Please dont take any of this information the wrong way. I am only stating facts from actual dyno testing, and not by what I think im personally feeling on the ground or what my preference is. And I must make it clear that I am TOTALY un biased on either engine. I think there both top notch engines in there own way. And heck if every engine was the same then what good would that do all of us. We all have our own preference of what we like in an engine and how we all drive. Both are great... pick ur poison is how I see it. :nod:

I hope you understand that I am talking about the V Spec in my wording above. I to feel that the V Spec is the baddest stocker out and I run the hell out of them. The C6 is alot of hype according to the charts.

I hope you didn't do all that explaination for my sake as I feel the exact same way. :)

No? :sneaky:

Any updates on the modded c6 Maximo?

Put them in a truggy then you will see which one makes power..

My C6BB Turbo head is pretty damn quick when tuned right, it pulls away from most .21's within about a 20-30 metre straight and hangs with the OS .28's most of the time (serious top end engine).

the vspec and the c6 are very close. for the extra cost of the c6, you could buy an aluminum head speed, and that motor will destroy any motor on the planet AND has 9 minute run-time.

I would get a Rb c6 over the Vspec. I have had both, and being honest, my vspec lasted about 2 gallons, and had little to no pinch, wouldn't hold a solid tune. I did change the bearings soon as i got it, so that was no issuse. Other hand, i have and still own 5 rb motors. 3 c6BB, and 2 ws7IIx3 motors. My ws7II motors have well over 12 gallons of fuel each, and are about 3yrs old now, and still kicking strong. My c6 motors run flawless, and i never had flame out issues at all. I do get great fuel miles out of both ws7 and c6 around 8-10 mins depending on what track and how hard i drive it.Also with rb motors running them between 240-270 drg. will wake there motors up. I have never run a OS speed, so i cant knock it, but if you want more for the money, buy RB if you want a long lasting motor and not have to buy another for years to come.

If you're concerned about the long term reliability of the V-Specs, you can put a Speed crank and con rod in them to fix the problem of the stock crank being relatively soft. I'm about to do that to the two I own.

Also, the AE/TTR 2035 pipe and manifold work very well on those engines, even compared to the OS 2050. I've consistently gotten over 10 minutes a tank with the 2035 pipe/manifold.

Maximo nice work on those cranks. I have a question for you, I see you cut into the rod thrust surface of the crank on the RB, does that affect reliability of the rod?