3.5 HPI motor on T-Maxx

[nad]

Okay, I have a 2.5 T-Maxx shell that's missing the motor, transmission, driveshafts and throttle servo.

I came across a cheap HPI 3.5 motor and I'm wondering if I can put this on this truck, and if so, what other parts do I need, do I need a T-Maxx transmission?

Also, what are my options for starters, any electric start setups that fit this motor? I hate pull start and hate roto-start even more.

Thanks for the advice.

 

[Metalhead Matt]

T Maxx parts are cheap if your looking to not spend a lot. That's a lot of parts to round up, though. Ebay has everything.

 

[nad]

Okay, I realize that, but that answers none of my questions. I have a 4908 model 3.3. This is a spare truck I bought a year ago, and I've finally decided to try getting it running.

 

[Metalhead Matt]

With the hpi engine, see if the mount matches the chassis and if the carb and exhaust face the right way. Pretty self explanatory. You can't use a bump start with a Maxx, so it sounds like a recoil or a roto start is your options. Maybe a tiger drive.

 

[Scrogg]

That is a good engine for a Maxx, you'll need to upgrade to all steel gears in the tranny.
You'll also need a big Block conversion. Roto is really the best option. It works fine if used properly.

 

[olds97_lss]

As noted, that engine is not a drop in. Personally, I'd stick with a "small block" engine for that truck since once you go big block, many other durability problems arise.

The TRX 3.3 is probably the best fit and cheapest you will find that won't require other parts.

 

[nad]

That's what I was afraid of. What do you guys mean by I will need a big block conversion kit? For the transmission? Is this motor really that much more powerful than the 3.3?

The truck I'm putting it on was originally a 2.5, it has everything with it except the motor, throttle servo, and linkage.

 

[olds97_lss]

A big block conversion usually includes new throttle linkage, pipe, header, engine mount, rear center axle, longer chassis rails or longer rear skid to give you more room for the engine and exhaust.

This is a small block and a big block:

Notice how much longer the crank case is. It's also wider.

This is with an engine:
http://www.horizonhobby.com/Products/Default.aspx?ProdID=DYN7403

And without:
http://www.horizonhobby.com/Products/Default.aspx?ProdID=DYN7402

Here's a different one that might actually be available:
https://www.ssl-stormerhobbies.com/cgi-bin/seekpart.pl?pn=FLM16050

Back when I had a maxx, I had the XTM version:
https://www.ssl-stormerhobbies.com/cgi-bin/seekpart.pl?pn=XTM233302

Still... you'd be time/money ahead just to get a 3.3.

 

[nad]

Yeah, didn't realize there was that much to it. Now I have this motor and have no use for it. I was gonna go with a 3.3, but wanted to do something different with this one, since I already have a 3.3 T-Maxx. There's no way to make this motor work without using one of those conversion kits?

 

[olds97_lss]

Nope. I don't believe there is. Not without a lot of custom fabrication...

If your bored, you could figure out how to mount a center diff and brakes. Only one aftermarket company that I'm aware of did that and they are no longer in the RC business. Hardcore Racing. Sure it removes two speed and reverse, but makes for a fairly unique t-maxx and also with a center diff may be less likely to grenade diffs and center axles.

 

[nad]

Hmm, yeah, don't think I'm that handy with these things. I've just recently got started in these nitro cars and it seems like I could build a real race car or monster truck for as much as I've spent on this hobby...

 

[nad]

Found a good deal on a 3.3 with some extras so I guess I'll just go that route for now anyway. I dunno what I'll do with this 3.5.

 

[Metalhead Matt]

Sell it.

 

[olds97_lss]

Sell it.

Short and to the point!

If you foresee yourself ever getting a big block rig, then you might as well throw some after run oil in it and put it in a baggie for storage to keep it from corroding and seizing up on you. Never hurts to have a spare engine laying around.

 

[nad]

Okay, so I have the 3.3 here, and it's actually setup for a REVO so I'll need to get a motor mount and linkage and everything for the MAXX.

My next question is, I have a spare 4908 chassis laying around, how much work/money is involved in swapping to the extended 4908 chassis? The only thing I see being an issue is the chassis braces and the front and rear CVDs possibly being too short.

Anyone have any insight on this topic?

 

[Metalhead Matt]

Just the front driveshaft and chassis braces.

 

[nad]

Do I gain anything with this conversion at all? Is there any point of doing it?

 

[Metalhead Matt]

It'll handle better. Jump easier.

 

[2revo1maxx]

Okay, so I have the 3.3 here, and it's actually setup for a REVO so I'll need to get a motor mount and linkage and everything for the MAXX.

My next question is, I have a spare 4908 chassis laying around, how much work/money is involved in swapping to the extended 4908 chassis? The only thing I see being an issue is the chassis braces and the front and rear CVDs possibly being too short.

Anyone have any insight on this topic?

I'm not 100% sure but you should run into some issues with the steering linkage.