Hi, I'm just wondering what engine would be the best to install onto a Mammoth ST to bring out the max top speed. I would like to stay in the .21 size engine range (because I have a roto start that'll fit .21's), but if there are any that're better, please tell me. Thanks!

Just what you guys suggest, you know more than I do about engines. Thanks!

You may want to take a look at the soon to be released OS.30. I believe they will have a version that will have a a rotostart on it, I know that Sirio.30 comes with a rotostart.

Hey Nitrohead thanks, but what will that Sirio engine increase on the car and decrease? I mean like top speed, torque, and HP. I like the Sirio cuz my roto start (21 roto start) will fit it. Just let me know the answers to the question above. Thanks again

try the STS .28 you can buy one at www.racernine.com it the best motor

Umm just because it fits SOME .21's does not mean it fits ANY .21's. Actually most .21's from the same manufacturers as larger up to .28 or higher are the same. What engine is your roto-start for?

The roto start is for an XTM 24.7 engine otherwise known as the stock engine.

That same rotostart backplate fits a lot of other engines, including Ofna Force and the Picco engines. It is not limited to .21 either. It will fit engines like the Force .26 and Picco .27, so don't limit yourself to .21 unless it is for racing restriction reasons.

Also, what are you going to do with the stock 24.7? If you are going to put it on another vehicle, you're gonna need a starter for it too. I have a brand new Mammoth ST and I'm dropping in a Werks Racing Collari .32MT. The stock 24.7 in being transplanted into my Ofna Blazer SST.

For you, I would look into .26 or larger. Not all of them are tuned the same. It all depends on what you like. Ssome are speed demons that can pull high RPM, while others are stump pullers that product prodigious amounts of low and mid torque. The SH .28 is not a bad choice if you're on a tight budget. Hobby People usually has it on sale for less than $150. You might have to tweak the gearing ratio if the new engine powerband is very different from the stock 24.7, but it's not a requirement if you are just bashing.

how do you guys think this truck is compaired to the other truggy rtrs out there? i don't really see people looking at it as an option and seems like the choice for someone for a lessor budget.

personally I love mine, it is very durable and I have not had any problems with it at all so far. It is pretty fast and on my small local track it can hang with the other mt's and truggies and I think with a larger engine and a better driver it could be doing very well. if you go to www.racernine.com you'll see pictures of his mammoth he won a few races in as well as other information on racing the mammoths.

the savage .25 motor is suppose to be almost identicle, i know for a fact that my roto start backplate on my xtm 24.7 will fit the savage .15, and i have compared the 2 and they look just alike, you should check out that motor because it has more power than the xtm 24.7, my buddies savage will beat my x factor in acceleration and top end and he has the .21 savage

The budget problem isn't really an issue in my case because if i need something I kinda need to suck it up. I appreciate all the information, but is the Sirio .30 or OS.30 VG an engine I would be good with? If not what specific engine would be the best for a Mammoth ST all around? (Savage .21 rotostart compatible) Thanks again!

i know were there is a nice BN Mach .26

The best is the SH .21 or the STS .21 just go to the xtm forums

THe Sirio .30 and OS .30VG are good engines I'm sure, but I doubt the backplate will fit. The latest review in Xtreme RC Car isn't 100% positive on the OS .30VG, though. They were somewhat concerned about the durability of the ABN construction. I would wait a bit on it before spending the cash.

IMHO, the best backplate compatible engine would be the Picco .27 big block. At less than $200, it isn't that expensive either.

The Savage 21 roto start will fit the Picco .27 right? Just checkin!

That one I don't know.

I could always call before I buy the engine, but thank you for all your help Volfy. I now have an idea of what engine size range I should stay in. Thanks again! Any other suggestions are gladly accepted!

I was just pokin around on eBay yesterday, and I found a Mammoth ST for sale with a Racers Edge .32 engine in it. It claims to have 3.6 hp and 38,000 rpm. It was 210 on sale at KillerHobbies. Is this a good engine for a Mammoth ST or will it make my truck do uncotrolable wheelies? Also, will the Savage 21 roto start fit it? thanks

It's been a while since I checked this thread. I've since dropped the Werks Collari .32 MT into my Mammoth ST. Wow!! This is one torquey motor. I don't think the top speed is any better. In fact, top speed might have dropped some. I don't own a radar gun so I don't know for sure. Plus it's still plenty fast enough for me. Off the line acceleration is tremendous and that is what I bought the engine for. I can pull a wheelie if I really try, but the Mammoth ST has a pretty long wheelbase, so it doesn't hop on every throttle squeeze like my short wheelbase S-MAXX with .21 Wasp.

If that Racer's Edge .32 is in good shape, it will be a very fun engine for bashing your Mammoth.

You've really helped me a lot Volfy, and I'm cutting down the possibibilities of what to get. Like the Sirio .30, OS .30, Picco .27, and the SH .28. This may take a while to make up my mind, but please check the thread every so often! THANKS!

what about th team orion wasp .28 on the mammoth st ????

I just searched on hobbypeople.net for the SH .28 and found a Peak Racing Diablo .28 with 2.85 HP and 42,000 RPM. Is this engine durable and will the roto start be compatible?

I know this post kinda went downhill, like all of them eventually but I'm back. What would you guys think of a OS .30, or Axial .32 in a Mammoth ST? I also need an engine that will be compatible with the Savage 21 Roto Start, just cuz i don't wanna get rid of it for the money I spent on it. (I don't have the money for a starter box) Thanks, and any other engine suggestions are greatly appreciated.