RBconcept V12
 

I've Got a nice deal on a V12 430, waiting for it, will run it with sidewinder 30 percent, additional shim, and the rc logics turbo 2, suited to my mtx3 that came with the mt12. any comments on this engine, my lhs told me they have excellent performance for its price, 250 or less and go head to head with the mugen x12 which is non turbo but that costs 300. expect more than top end, performance and durability, like my mtx3, tough!

They do have excellent performance for the price. For whatever reason, the non Rody version seems to lack on the top speed. Good luck with yours, maybe you will have better luck than what I have seen.

I love these engines for off-road.

what are you talking about, I have the 410 and I geared it differently and as soon as I hit second gear I let off the gas, and I run on a big track.

It has plenty of top end, unless you geared it wrong there will be problems. I can stay will all the 1/10 scales on the straight and I'm still using stock spurs and stock shifting point. The only thing i changed was the pinions.

I run a V12 too and I'd have to agree with Scott. I don't think that the top end range is much of an issue though. The motor is REALLY strong in the bottom and midrange. My feeling is that you get more usable power that way. Unless you run at a flowing high speed track, it not going to be a problem at all. And you could always gear up like Compaq posted. Think about it, on most tracks you are only at top speed for a second on the straight before you decelerate, but you use the midrange all the time on the infield.

I run RB Rody X12 5-Port and still slower than compaqboy's on the straight. My gearing is right, but just not any faster...

come to think of it, 5 supposed to be faster than 3 on the straight, but it isn't!:cry:

track will have a 200 feet straight, and two additional straights of 120 feet. and withing the boundaries of the straights kind of short straights with 180 degree curves. just to take advantage of every space on the track. guees that the engine should perform well, I expect more than top, response, top non a issue, i´ve got several gearings for the top of my mtx3. any comments on the setup of the centax when I´ll install this engine, running now the mt12.

compaq:

Don't get upset because I said the I think the engine you use lacks a little on the top end. Remember that it is my opinion and observation only.

2nd: If you have to let off as soon as you hit second gear, how do know if the engine has good top end anyway. You never know what the top is if you are getting off the gas as soon as you hit 2nd.

Scott, everybody else that I know of shifts as soon as they get on the straight, I shift 10-15 feet before the straight ends and let go off the gas as soon as it shifts. I still keep up to everybody else, and even beat them. I don't even touch the top end and I can hang with everyone.

Eddie I have been told by lots of people that the RB v12 non turbo makes the same power as the RB X12 turbo, we should be neck to neck on the straight, but on the corners you will win because I don't know the track much.

I changed my shift point to earlier but haven't gotten to test it out yet, maybe i'll finally see WOT in second gear.:sneaky:

I think you both are saying the same thing. Compaq has geared up to take advantage of all the power in the lower RPM range by gearing up. Thats why he can pull as hard as the other guys.

one thing that you need to aware of, at most track, straight only like 2 seconds of full throttle for the most part and the rest are all infield say if an experienced driver does a 16sec lap, and straight probably took the most 2 secs.

It's not the straight I'm worried about, It's the corners.

Rapid, I actually geared up the tranny for the OS TR motor, but I got tired of waiting for it, so I bought the RB v12 and just geared it like I wanted to gear the OS TR r-spec

i think it might benefit you more if you change your shift points later, use 1st gear in infield instead of shifting everywhere!

I only changed the shift poin half a turn. So right now it's 3.5 turns out. Due to my gearing I don't know where it will shift so if it's too much hassle I'll just put it to stock settings.

95% of the track I use 1st gear, I only shift at the end of the straight into second and let off the gas. So basically the whole time i'm in 1st gear.

something is not right here! you mentioned your car would shift before the straight away, and how can you be in 1st gear infield??? especailly at crystal park!

well at least for my car, i had to make the shift point to 2nd like 10 feet after I enter the straight away in order to keep 1st in infield!

my car always shifted late. I never mentioned it shifted before the straight. I mentioned that if i go WOT on the corner right before the straight it overpowers the car and it spins out, but doesn't shift.

your car is a mtx3 and mine is RR, big difference. When I changed the gearing on the car i kept the stock spurs, I was suppose to change the spurs too, but I just changed the pinions so my car is geared high. I run 18/22 pinion and 48/44 spurs. You run 50 something for spurs, I think one of them is 52, big big diffrence.

if you look at the final drive ratio, there is not much difference. your is 5.06, ah10's probably around 4.9. but anyways, glad your car can hang with other cars using 1st gear only at the end (well, almost) of a rather long straight away. if that is really the case, maybe you can just remove the 2nd speed completely to save some weight, since you don't really need it.

I am smarter than that. You see if I removed the 2nd gear then when it gets to the end of the straight and doesn't shift it will just burn my motor out. Anthony got a 8 spur difference between his spurs, I only have 4, plus he uses bigger gears.

I said my car can hang with other cars on the straight, but not the corners. I have even been told by some guys at the track that they shift as soon as the straight begins, I don't. I changed my servos and my shift point, so now I should be doing the same thing.

I don't want to make anyone look bad or anything, but when I say something that works weird and people start doubting me and then there are arguments, and people start saying I'm wrong or something, it looks bad.

The guy with the black Mercedes didn't believe me that my engine ran so low on temp, so he took his temp gauge and we went out on the track, and I went WOT on every place I could and even crashed a couple of times because I wanted to go WOT as much as possible. The temp never got over 170F. Marvin said the same thing that i was bullshitting, he went with me to the track, got his temp gauge and it ran low temps too. Now that the temperature of the engine arguments are over, now people doubting me about the transmission. Some things sometimes work weird, just because I'm a newb at the track doesn't mean I exxajarate a lot.

it is ok to exaggerate a bit, but you have got problems when you start to belief it too.

that thing with the 1/8 scale wasn't exagurating. I was indeed dead even with a 1/8 scale on the straight, It doesn't matter if the 1/8 scale driver wasn't going WOT or his car was broken or he let me pass. The statement is true anyway you cut it. Now if you say that your car beat a SAM missle than that's exagarating.

I know 1/8 scales are faster, and corner better.

Well, actually if you wan't to keep almost the same gear ratio you are using succesfully with late shifting (almost first gear everywhere), here is my suggestion, which means you can really make use of the two speeds, and gain more inside power.

Right now you have a 6.75 to 1 ratio in first speed and a 5.05 to 1 gera ratio in second speed. That gives you a good speed on the main straight (almost fully in first gear) and you shiftb late for a short time to avoid engine overreving, but then you suffer on the inside.

Put a 17/49 gear set on first speed to give you a total of 7.28 to 1 gear ratio.
Put a 21/45 gear set on second speed to give you a total of 5.41 to 1 gear ratio
The average gear ratio between the two would be 6.75 to 1, which is very similar to your 6.75 to 1 you are using.

This way you'll gain some more top speed and gain a LOT more low end for the inside.

Now you can set your shifting point much earlier and make full potential use of the two speed, with more low end and top end.

Trust me, you'll thank me later. I work a lot with Kyoshos and Mugens at my track.

AFM

Correction to my post, it should read like this:

The average gear ratio between the two would be 6.35 to 1, which is very similar to your 6.75 to 1 you are using.

AFM

fine, now that i know how you cut it. so what was the purpose of that statement ?


not really, as long as the SAM is not moving (and i don't care why it is not moving), my car will always beat it and by your definition, i am not exaggerating.

You missed something here! I am running 0.8 module

lol, so from your theory, a Nissan Sentra can outrun a 360 Modena on straight, twisty road and such right?

anything is possible with money.

I have even seen Jettas that beat a viper like nothing. If you want, you can come to my house and I'll show you the video, or e-mail it to you.

yeah, i guess you're right, an rc would most likely beat an SAM missle do to it's size, it's hard to hit a small target that goes 50+mph. Even if the SAM is chasing the rc car.

That's allright, I dont like rice cooker to begin with!

HUH:weird:

here are my findings:

A:
1st gear 49/17 7.292
2nd gear 45/21 5.421

top speed 45.369mph

B:
1st gear 48/18 6.747
2nd gear 44/22 5.060

top speed 48.609mph

I don't know where you got your numbers, but due to my calculations if I go with the 45/21 gearing combo I will get more accelaration but I will lose 3mph in the top end.

Also i factored in the foams, which are 60mm in diameter, if i go with 65mm foams then my gearing will give me the top speed of 52mph.

you see, the bigger the pinion and the smaller the spur the faster you go. You can't have a pinion too big because it will damage the motor. If you go with 4 stroke motor and gear the pinion really high and the spur really small you'll be as fast as the 2 stroke guys or even faster. I can see a RRR with a 4 stroke whooping on everybody at the track in the future, because 4 strokes got the torque.

huh?

:weird: WHAT A MESS!!!!!!!!!!!:D :D :D :D :D :D :D :D

Compaq
Where i got my numbers is the same place you got yours, just change your attitude and open your mind, and just take suggestions with the right attitude....LIKE THANK YOU.

You stated that you were running all over the track in first gear, and shifting very late on the main straight...so you are 90% of the time running on 6.747 to 1 gear ratio...so do your maths and factoring etc.etc. and tell me what is your average speed per lap.

Races aren't won on just going fast on the main straight, races are won with the best time lap per lap, so you have to compromise.
Break the track in two sectors, inside and main straight, take split times and see were you are strong and correct your weakness.

With my suggestion you might loose some 3 mph on the straight but win so much on the rest of the track, and in average you are running with a 6.35 to 1 gear ratio, and if you still wan't some more top speed just drop in a 44 spur on second gear and try.

I don't know the size of your track, but ours has a main straight of apx 200 FT. and a lot of technical turns and short straights on the inside which makes a total lap of 1,100FT but since it is not a flowing design it is considered a short to medium track, and Kyoshos, Serpents and Mugens are geared 7.135 to 1 in first gear and 5.294 to 1 in second gear with more or less 62 mm tire dia.

Do your math, open your mind, and don't tell me that is normal to run a two speed car on first gear most of the time on a track that can be run with two speeds. Definetely you are doing something wrong. And don't get offended when people are trying to help you. Just be gratefull and experiment.

AFM

good points! gracias...

hope I haven't missed all the fun. :smile:

I couldnt agree more! Well said!

If you don't experiment, you will never get faster. or as fast as the guys that do.

And, if you don't listen, you ain't going no where, eventually!

I'm not offended, I'm just pointing out my results. The first mistake I made was keeping the shift point late. I'm going to change the shift point first and see if my lap time changes. If it doesn't then I will experiment with the gearing. Right now it's 18.2 sec per lap.

The idea on gearing IMHO is to gear your first gear as low as possible to get the most accelaration as possible and the same time not over rev your engine on the straight on second gear. The most time on a track is gained on the infield, not the straight. You can gain on someone on the straight but if he is faster out of the turns he will always have an advantage on you.

The idea of a 2spd car is not to go faster, although it can be geard that way, the idea is to get to the top speed as fast as possible.

Holy cow! What'd I miss??:lol:

How did you measure your lap time? if you were saying your car is all over the places infield, it is next to impossible to do 18sec laps especially at Crystal Park! those fast drivers do around mid to high 15's to low 16's with pretty much perfect drive lines!

Just wonder how you get the lap times that's all!