why does it seem that my .15 rustler seems faster than my .18 x cellerator

Cause it is. Xcell isn't as fast as people think. .15 rustler mgith do 40-45mph outta box...xtm xcell 35-40mph if the clutch assembly stays together.

why if its a bigger motor

top speed is a function of torque, rpm, and gearing, NOT engine size.
why does a Savage not go 50 mph like a Jato will? it has an engine almost 2x the size

thats why its twice as big

topend isnt really a factor on the track mid range is correct? would my rustler be faster on the track then my x cell

does the x come witha restrictor. you might have to upgrade the clutchmake sure your dif isnt slipping make sure your slipper isnt slipping to much.

mmmm.. no. The x-cellerator does anywhere from 46-52 when tuned properly.. out of the box. I have NEVER seen it clocked below about 45mph on a good tune!

im going to take it back and get it tuned again its fast but just doesnt seem to hit the high rpms

do you mean it seems sluggish to accelerate? if so, it's because of the gearing.

I've had mine clocked via a radar gun and it's tuned right and runs a os 18 cvrx and doesn't do 52mph with the stock engine it ran 36-39mph with the os was 43-46....keep dreamin but get realistic

ThunderbirdJunkie is right it's all in the gearing if you want loads of speed.

Weird. Ive seen it clocked much higher than that, and have read reviews of it doing so (RCCA and R/C411). One of us has a broken radar gun! [&:]

Also.. how did you gain in top speed with the O.S. motor? It maxes at around 28,000rpm.. doesnt the xtm do ~29k or so? Definately not less than 28k.. did you change gearing?

On another note... i didnt think the .15 rustler was that fast?? I thought it wasnt until it got the 2.5 that it hit the higher speeds? (i know nothing about traxxas vehicles)

They're both .15 engines though. The 2.5 has the same displacement, but they used the marketing scheme of saying 2.5 cubic centimeters instead of .15 cubic inches. For the beginner R/C-ist, it seems like it is a bigger engine.

different temp and climate

Yeah i know they are the same displacement.. i just thought the design was different on them yielding more power on the 2.5

Not really. a .12 CVR will keep up with a typical TRX 2.5 powered ST all day long.

Gun could have been off...after all it was a cops so who knows...as far as speed gain goes it just ran faster...altitude shouldn't have mattered much since airs denser here which causes the engine to be leaner at a richer setting than say in florida...my os .18 cvrx's are only just 1/4th turn in from stock setting of 2 turns on the hsn...guess I could do some clocked runs on the salt flats...friction free surface just hate what that salt does to everything...os engines are always stroked more than other engines...xtm .18 stroke is 14.7mm while os is 15.0mm don't seem like much but basically makes displacement on a os bigger...os is 3.0cc while xtm is 2.74cc....it's basically a xtm engine on steroids i guess is easiest way to put it...max rpm range is about the same on both engines...just os develops its full power faster due to the larger stroke. I run stock gearing on my xtm with a associated clutch bell/clutch..cause the xtm one is crap. The so .18 is alot of motor for it tho..the stock output axles are always getting worn to the point it jumps when throttled bad....haven't found stronger shafts for it yet...

As far as rustler speed I imagined he was talking about the 2.5's which are really .15's....

Wondering why your X-C is goin slow? The stock air filter is crap. Too restrictive. Get a motor saver 1/10 scale filter and the truck will scream. It will hit 50 when tuned, I know that for a fact. This is why not the X-Cellerator isn't raced though, its geared very high. Although it's fine with the XTM .18 (which is a pretty nice engine IMO), you probably won't get the low end punch you are looking for while running a .12 engine. Those of us on the XTM forum have found that the Losi 51 tooth kevlar spur gear fits the X-Cellerator with no mods. The stock slipper pads fit, and the gear goes right over the shaft. Only problem is that the stock CB doesn't mesh with it correctly. But, if you run the mesh really tight, the gear will wear in after about 3-6 tanks. That way you have race worthy gearing. Racernine (racernine.com) ran his X-Cellerator in the O'Donnel race at Rev Raceway in California last weekend and placed 2nd in the A-Main against factory sponsored drivers. He was running a non-modified SH .12 engine as well, which has no problem keeping up with the Sirios.

Why are those airfilters always junk? I guess that's why MotorSaver does so well.

stock os air filter ain't bad...but motorsaver's are better....guess the engine makers own stock in motorsaver

Heh, probably so... Probably a smart move...

before calling the x-cell slow did u lean it out[X(] i have one and its been clocked at 50

only a month and a half late...