Savage 25 vs savage 3.5

[smarty18]

Hi All
I am after some advice, I have recently aquired a savage 25, and a savage 3.5, both require new roto starts which is no problem. The trouble is i know nothing about the savage and i dont need to keep them both, so which one would be the better one to keep?
They loook almost the same to me.......

Thanks

[gnarkill]

Don't take my word for it because I have little experience with the 25 and 35 but I believe the 3.5 should have better drivetrain, to handle a larger motor. I would say no to getting a rotostart, they chew through 1 way bearings, and a mill should not have to be cranked over 50 times to get it to start. If you are properly tuned, have a good glow plug, and preheat (for winter driving, summer is much easier to start mills) a pullstart would save you OWB's some 6 cell packs, and the troubles of carrying around a starter.

[TGL]

Um, isn't the 3.5 the old .21 motor while the 25 is a .25 motor (4.1)?

Smarty, look on the side of the engines below the coolng head, if you have an old stock HPI engine, one should read something like .21 / HPI and then 3.5.

If that's the case, the 25 is a newer and larger engine and between the two Savages. The chassis and the rest of the drvetrain should basically be the same though.

According to HPI, the Savage 25 RTR is is a step up from the original Savage 21 RTR and includes a more powerful S-25 engine, supposedly delivering 20% more power. Neither engine is a world-beater, but all things being equal I'd go with the 25 over the 21...

[Racer 1966]

TGL is correct, the 25 is newer and came with a few upgrades over the 3.5(.21) Not really major upgrades,I'd keep whichever is in the best condition. Actually,I'd keep both unless you need some cash from the second to help keep you running.

For the most part,I disagree with gnarkill. You do have to have a 6-cell battery and charger and you do have an extra item to tote around but a properly tuned engine with roto-start is no harder on a owb than a pull start. I run roto start on every engine I have.

[gnarkill]

Originally Posted by Racer 1966

For the most part,I disagree with gnarkill. You do have to have a 6-cell battery and charger and you do have an extra item to tote around but a properly tuned engine with roto-start is no harder on a owb than a pull start. I run roto start on every engine I have.

Yes, that is true in your case, but may not be in his. The proper way to prime a nitro engine is not always the technique done with people that don't understand the anatomy of the owb, and how they wear out. Necessarily, I am talking about when the exhaust stinger is covered and the motor is cranked over multiple times to get the fuel to the carb, other than blowing back into the back pressure side.

I should have explained that further in the previous post.

[smarty18]

Hi All
Thanks for your replys.
The Engine in the 3.5 is indeed a .21 so i think the 25 is slightly more powerful. I assume either of these trucks can be upgraded to a larger engine?and upgrded with most savage spares?
As for the roto start, i already have a MT2 with roto start and i find it works ok so i will just replace faulty units.
As i dont know the history of these trucks is there anything i should be looking for, would i be best to repeat run in procedure before i start?

Thanks

[TGL]

You can upgrade either of these Savages to a larger engine without having to do much to the drive-train. Overall, the weakest point in the drive-train is probably the differentials, but you should get driving in before that becomes a concern.
There's a lot in interchangeability of parts between the various Savage models and if you don't have manuals, you can go to www.hpiracing.com and download one for pretty much any model. I think the Savage X is the first model where you really need to start paying attention to differences with your models.

What should you be looking for - looking to do?
I'll assume that you're not looking to spend a wad of money...
1. Did these come with the HPI AM controllers - if so, first off I'd get a failsafe.
You can upgrade to a controller with a built in failsafe (FM or Spektrum) - but that costs and the failsafe is cheap insurance - especially with the AM controller.

2. The original .21 Savage came with an SF-1 throttle servo and an SF-2 steering servo. If that's the case, buy a good high torque servo to act as your steering servo and replace the SF-2 with this. Then throw the SF-1 away and replace it with the SF-2. It'll steer and stop much better.

3. While you're upgrading the servo, if it doesn't have one, put in a rechargeable 6 volt battery and a 3 plug on/off switch. The battery will boost the available volts and make the servos stronger. The 3-plug switch will allow you to set it up so you can recharge without having to open up the radio box dust cover (which can be a royal pain). If you don't have one, you'll also need a charger too. You can find adequate battery and charger combos cheap on eBay btw.

There's a lot of other things that you can do too, but you can always build on these upgrades. To me, these first three items make the Savage a much more enjoyable experience.

4. Early on I'd also upgrade the shock springs and shock oil too. Personally, I never liked the red springs that came with the original 21. Don't know what springs came with the 25, but when it comes to springs and oil viscosity you'll get many divergent opinions as to what is the set-up to have.

As far as repeating or conducting the break-in procedure - personally I'd only worry about it if the engine looks like it hasn't been used - or if you think the guy you bought it off of was inexperienced or an idiot. Just watch the temps and tune it from there.

[Racer 1966]

TGL is on it again. A failsafe and servos are the first things those Savages need. If you go to a bigger engine in the .21,I'd recommend you check the diffs at the same time. The .21s came with the 2 spider gear diffs that are easily blown. The 4 gear diff is one of the upgrades on the .25s but you can pick up a complete diff for under $30.

[bigdawg2]

I agree with Racer and TGL. Over a year ago I too got a savage 25 used (my first one). I'm just now doing the upgrades TGL talks about and it make a word of a difference. The Hi torque servos are amazing once I added the 6v hump pack. Enjoy your new truck.