RcSuCkA

hey guys. i got my buggy today. it looks to be an ofna 1/8 ultra mbx rtr. Anyways, this thing is friggin HUGE, seems to be bigger then my friends t-maxx. I was wondering whats the biggest engine you could put in this thing without doing any modifications.
thanks.

Foxy

You can put a .32 in there (by collari) if you want, without eating the drivetrain or anything like that, but the competition class .21 engines are much better (but more expensive). Some important questions for you:

1) Are you bashing or racing?
2) How much do you want to spend on an engine?
3) Have you put a decent steering servo in yet? (Stock ones are absolute rubbish)
4) Have you bought a proper 6v receiver battery yet? (These things make a huge difference to the speed and response of the electronics)
5) Have you filled the diffs with appropriate weights of silicone?
6) Have you bought a decent toolkit (hex drivers, good ones).

If the answer to questions 3, 4, 5, or 6 is 'no' then do these things first, then consider an engine.

thopper

If you wantto SCREAM put a NovaRossi .28 8 port in it. Price is about 300.00 It is the fastest engine out there.Period

plaidfish

I'll be the dick and play devil's advocate here....
Why is it the fastest?
it will make my buggy faster even if I have 12/55 primary gearing???
what about the specs on it?

I'm really not doing this post out of spite, but stating it's the fastest w/ no reasons is like screwing air......it's pointless......besides My Fantom .27 in a truggy smoked guys running those big rossis in truggies as well....depends on your track and gearing for what ENGINE is fastest....

montrealer

Yup,

What he said.

RcSuCkA

I'm gonna be going for bashing. I was just wondering what would be the biggest engine I could fit Can I put a pullstart engine in the Ultra MBX?

RcSuCkA

also, what size of a flywheel do I need to use a starterbox? thanks.

Super_Dave

You should make a flow chart foxy . Well done.

Sense your just bashing the collari .32 seems like the best motor for you but I don't know the price on it.

For the flywheel question... It depenends on how tall your motor mounts are. I honestly don't know how tall the mounts are on the MBX. Just get whatever makes the flywheel set just a tiny bit higher than the bottom of the chassis so it doesn't hit the ground if you bottom out and cut off the motor.

RcSuCkA

its goes in about 2mm from the bottom of the chassis, would that be enough?

Hoese37

i would say you could fit a Hot bodies or CEN .46 in there. the CEN is reliable and puts out 5+ HP

xrichs

i would get .21 race engine instead those super block engine

plaidfish

ina buggy you want High RPMs not low end grunt.....look at teh sirio .27 if you really want to just kill speed and torque..it's pricey but give everything you need...also DO NOT get the 11 port model if you are not a super tuning guru.......the sleeve looks like swiss cheese and does not like to overheat...I've seen them literally warp while running and just destroy the mill...the 8 port is more than enough......if budget is a concern look athe wasp .28....about 160 new and it revs like a rossi 421b......but less than 1/2 the cost.....the fantom .27 is by far the meanest mill I ran in my buggy but the last one I got was such a lemon I just gave up on them, besides it's iffy as to whether he's going to do nitro engines for a while......I have a brand new .27 and the case is bored out too big...it let the sleeve chatter, that's bad...nothing holds the pinch on it now.....

Foxy

Sure you didn't mean the other way around? On road wants RPM, off road wants grunt. Depends entirely what you're doing of course, but the extra weight of buggies has an automatic requirement for a little more torque, not to mention additional surface friction from off road (bumps, etc).

RcSuCkA

but i read that the team orion engines always have air leaks in them. and what about the starter box, the flywheels 2mm into the chassis, is that enough for the starter box to reach it? thanks, keep the posts coming.

RcSuCkA

will the hyper 7 starter box work with the ultra mbx?

xrichs

i think every starter box can fit to all cars.

it has adjustment point that could make your buggy fitted

plaidfish

okay a lil clarification...in off road engines the .21 mills provide enough torque for that quick snap in a buggy...if you want real screamers you look at RPM and where the torque band comes in, within that RPM range.....usually the RPM range between on and off road .21 mills is very close.....also depends on your gearing....the super block mills have WAY more low end grunt than your buggy will ever need......and then you have to start playing w/ gear ratios to tame the power on the bottom.....that's when your headaches really begin.....really the super blocks are designed for MTs...look at where their power comes in...usually down low so it can lug around those extra lbs on a truck.....there are some suoer block engines that turn high RPMs but they are usually super priced too....the sirio has to be one of the baddest .27s out there....but it's definately not for the tuning newbie......

RcSuCkA

anyways, since im new to buggies, i have a couple questions; When do I have to apply differential oil, and what weight is good for bashing? whats a good weight for shock oil, and what is a servo saver used for?

plaidfish

Diff oil is put in the diff case for tuning the amount you want ti to slip....heavier oills make it act more like a posi traction diff.....typically I like 5k in front 7or8K in center and 1 or 2K in the rear....for bashing you'd probably want it more on the heavier side of that combo......SHock oil for bashing I'd say 45 front 40 rear and med springs.....2 hole straight tapered piston heads.........and a servo saver isolates those little jerks your steeing system takes when it's landing from a 30 ft triple........if your servo was directly connected to a rigid style linkage it would get torn up real quick.....

RcSuCkA

oh good thing i have a servo saver, lol. i was wondering why it said (indirect) on my steering servo but now i know why. thanks for the great info plaidfish.

anybody know if the hyper 7 starter box will work on the ultra mbx?

plaidfish

when you get into higher end RCs the servo saver is actually part of the Steering linkage.....so the plastic ones you have now won't be needed......