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  #1  
Old 02-04-2011, 11:43 AM
BobW BobW is offline
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Would My Hacker Work in a MRS4 Porsche?

New guy here. I have a MicroRS4 Porsche that is pretty much box-stock except for the front one-way diff. I assembled it from a kit (not RTR).

I have a Hacker B20-31S motor sitting around and am wondering if it would be worthwhile to put it into the Porsche. Here's some spec's on the Hacker... 20 mm diameter, 2903 kv, Peak Watts - 120, Op. Current 5A, Peak 9A, Weight 1.44 oz. Shaft is 2.3 mm.

Couple of questions...

Would this motor work, or is the Kv rating too low... I`m thinking maybe a 3 cell lipo pack and a CC Sidewinder ESC. That motor would sure look sweet sitting in there, I think the stock motor mount should be OK

What size of pinion is recommended, I`m not planning to race it.. maybe some drifting would be fun. Would the HPI pinions work on this shaft size?

Would I be better off getting a Castle motor & esc combo...

Should this be a feasible upgrade... what other mods should be considered to handle the higher power. I can post a pic if this would help.

I`d appreciate any comments or opinions you guys would like to make.

Bob.
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  #2  
Old 02-08-2011, 07:23 AM
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SteveM SteveM is offline
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If the motor fits the stock motor mount then you should be fine. This motor isn't designed for cars, it's more for micro helis and planes, but it should still be fine. The lower power rating might be ideal as too much power in a MRS4 overwhelms the chassis. Try an 11 tooth and a 2S lipo and see how hot the motor gets. You want to tune based on motor temperature. I've had excellent results with the Mystery 2S 900mAh lipo from Dealextreme.com and they sell for a mere $$6.40 and it is even shipped for FREE. Just don't run it too long as draining a lipo will kill it in short order.
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Old 02-08-2011, 11:21 AM
BobW BobW is offline
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Many thanks for responding to my query.

I`ll look for that pinion. I bought the Hacker a few years ago on impulse as the price was good. The LHS has a sidewinder & 4200 kv mamba pkg for $100, not a bad brushless upgrade. The chassis will accommodate a 2 cell 1100 m.a. lipo pack. I already own a lipo charger.

I`ll post a pic of my Porsche when the upgrade is completed.
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Old 02-08-2011, 11:58 AM
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SteveM SteveM is offline
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The MRS4 comes with several plastic push-on pinions when bought new, but I would highly recommend you buy pinion that use a set screw to avoid having it slip.

When my club still ran a micro class, we used the Castle Creations 4200kV motors and sidewinder ESC as a spec power setup. They were plenty fast on a 2S lipo in the Xray M18. The MRS4 doesn't handle quite as well as the M18 and tended to push and traction roll too much.
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  #5  
Old 02-14-2011, 06:58 PM
xxfile xxfile is offline
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go to exotecs website and see if you can beg them to produce a few more EXO 3's they are a great chassis and turn great under power where the m18 tends to push..
However you can still buy a new m18 even one made for lipos and parts are available but its hard to get foams if ur running on carpet,,.. if ur gonna drift u might as well just stay stock with both chassis and motor just add the lipo's and a lipo cutoff..
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Old 02-14-2011, 07:00 PM
xxfile xxfile is offline
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we have been and still are running the mambas with 10 tooth pinions on carpet and still have the throttle turned down to less than 50% to make it driveable
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  #7  
Old 02-15-2011, 09:49 AM
BobW BobW is offline
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I picked up the CC sidewinder/ 4200 combo and a 2 cell 1100 m.a. lipo... the conversion process can begin. Drift tires are on the way.

Does anybody know where to get inner wheel sets for the Mrs4? I've checked around a few sites and they all seem to be out of stock. I was planning to bond the inner and outer rims together and removing some of spokes to make wheel mounting and dismounting easier.

Bob.
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Old 02-15-2011, 02:11 PM
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SteveM SteveM is offline
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That ESC and motor combo was our club spec setup and is plenty fast, maybe too fast for the MRS4. The Xray M18 was able to handle the speeds on foams just fine though.

Gluing the outer rims to the inner hubs was almost mandatory as they too easily slipped off. Shoe Goo worked well enough.

The MRS4 parts are scarce now and eBay may be your best bet. I've seen only a few for sale on local hobby forums and then the posts were for complete cars and not just parts.
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