sv 27 motor

[Avanti]

you will need adjustable tabs if you don't already have them. taking the turn fins off make the SV very unstable. (however adding the port turn fin is not worth it; if you ask me the only thing it does is make left turn even worse) check out my speed thread if you have not seen it yet. I have some more tricks up my sleeve I have just ran out of desire to mess with the SV right now.

[SweetAccord]

Where is your speed thread? You have a lot of posts. Have the URL please please? What would you recommend as the fastest motor that can be run in the SV? 6XL?

[domwilson]

I say try the stock power with a S&B X642 with lipos. I think you may be pleasantly supprised. Throw in some adjustable trim tabs from here and be even more surprised after you get it dialed in. While you're ordering the trim tabs, get an OSE water jacket for the motor.

[SweetAccord]

domwilson , I have the turn fins the water jacket already. No trim tabs yet. I won't be using Lipos as yet. I just want a Feiago motor suggestion that I believe has been answered? So far the 6XL is workable. What do you think? Any experience?

[domwilson]

The 6XL might work. I'd start with a x637 and watch the temps. The 6XL is a hot motor and will have a higher amp draw which could damage batteries if they aren't up to it. I have the stock motor (for now) with a X642 with lipos and it gets pretty hairy at times. I have an Ammo 2300 or maybe a Feigao 9L w/100 amp ESC that is waiting to go in it with a X640 prop. Just not up to swimming right now to retrieve the boat.

[SweetAccord]

Kewl thank you!!

[domwilson]

I heard of some people adding a weight to the front to keep it from going airborn during high speed passes. That might help once you get it all put together. It's a real balancing act.

[txboatpilot]

If you over prop the 6XL, you will SMOKE your batteries or even the Hydra 120!!!!!!!! You need to do some testing!! Your choices in motor KV are going to get you a lot of SMOKE!!

[Steven Vaccaro]

I think we are confusing drag racing. Are you going to make one or two passes and bring it in? Or make many passes until the packs die? If its the second, that's not drag racing in my opinion. The reason I suggest the xl is because the motor has more metal in it, so it takes longer to over heat. Its more forgiving than a smaller motor. if you are strictly running for drag(1-2 passes than check your temps), you want to run the smallest motor you can, than a L size will be better.

[Avanti]

Where is your speed thread? You have a lot of posts. Have the URL please please? What would you recommend as the fastest motor that can be run in the SV? 6XL?

http://forums.offshoreelectrics.com/...ead.php?t=1956

[SweetAccord]

Yes Steven, I will drag racing till the batteries are dead. :) So does that change your answer now? Which is ideal the L or XL and what KV?

Man I really appreciate all the help here!

[SweetAccord]

Avanti27offshore, thank you I eventually found that thread after finding where to search a users threads! Thanks!!

[SweetAccord]

Ok so which then since 6XL is out?

540 7XL 2,382 RPM / Volt
540 8XL 2,084 RPM / Volt
540 9XL 1,853 RPM / Volt

Another question please (am I a pain?), are these slower than the AMMO 2600kv? Or is that not a fair comparison as the XL are longer so there is more torque etc.? I'm starting to think maybe the XL are not ideal as for the same RPM they draw more give more torque, which I don't think the torque is critical as the boat is not a weight monger and for the same RPM the L is way less draw and higher RPM.

Guess I'm trying to figure out what everyone has done with the SV. Are they using higher kv motors and proping down? or Using smaller kv and proping up? or using XL and using higher KV and proping down? Is anyone using anything else rather than the Ammo 2300 kv in a SV and successfully running it I guess is my $100.00 question. :)

[domwilson]

Not neccessarily. It's a balancing act between speed, runtime, amp draw. The XL's offer more torque so you can run a larger prop with less heat issues. For a given prop size, a higher kv could mean a higher amp draw. If the batteries cannot provide the high amps, the available voltage will drop thus reducing the motor speed and increasing the heat. Running a larger prop or higher kv motor will not always increase speed. A higher kv motor will "bog down" if the amp draw exceeds what your power system can provide. A lower kv motor can reduce amps on a smaller prop but you will see a reduction in speed if it doesn't provide efficient thrust. So you have to balance prop size with the motor and available power. That's not taking in consideration hull size, design, weight and operating conditions.

[SweetAccord]

Well I finally figured out that the stock motor is capable of 41,000 RPM at 18.v. So a 2300kv AMMO at 14.V, the RPM would be less RPM about 32,600 RPM. Interesting that most feel that the hull has it's limits, not that I'm doubting that everything does, but it's interesting that the capability of stock motor allows for the motor to run at a higher RPM than most are running in an aftermarket upgrade 2600kv and blowing over.

Interesting...just pondering.