Arrma infraction mmx8s 1717 speed run

[jimbo1977]

Any hints for setting up the 1717motor? Infraction V1

Have always had the mmx8s, but just upgraded motor to 1717 from the standard 2050.
Was hitting 112mph with old motor and 34 pinion 46 spur.
Batteries HRB 6000mah 4s 50c 100c burst.

Now running 1717 sensored

Gearing 34pinion 39spool
But not getting more than 102 mph.. is it the batteries that aren’t strong enough?

As id have thought that 125mph with that gearing was possible

I ordered some Turnigy Graphene Panther 6000mAh 4S 75C Battery Pack w/XT90 So hopefully these will help

 

[SrC]

I like the feel of sensored with my XR8+ HW, But not in full sensored mode for high speeds, UsingHybrid sensored for that. But Castle does it differently.
I would try with Sensor cable disconnected. More efficient at the top end as many speed runners like Raz Shifrin state.
Also, running 8S and up requires a better larger connector IMHO. Larger Castle bullets or similar. Or like Offshore Hobbies black connectors.
The Infr. Can do 140mph with a flat slightly raised rear wing aero wise. But Not with the stock one. And not without any rear wing also.
Regarding gearing and else ( perhaps 1:1 Spur: Pinion, and taller is needed (over gear it), hopefully others have better experience with your Castle setup.

Edit: as you get to 100+mph speeds, Drag is the dominating problem. Underbody aero is important also. (need chassis skirts)The Infr. can be daunting to hook up. But a great challenge nonetheless.

Edit2: Your temps are cool. Appears you are not even pushing it. All at roughly 28000 RPMS. The 1717 with 1650Kv's running 8S can be geared taller to get closer to your target speed. Ripple is in check. A 2.2ms sustained pull was nice. She's maxxed out where it is at 28000RPM's. Need to push it more? Amps were up there, maybe Aero Drag is holding it back.?‍
The gearing calculator tends to always be conservative in general IMHO. And it doesn't consider aero in the real world. I could be wrong?

 

[jimbo1977]

I like the feel of sensored with my XR8+ HW, But not in full sensored mode for high speeds, UsingHybrid sensored for that. But Castle does it differently.
I would try with Sensor cable disconnected. More efficient at the top end as many speed runners like Raz Shifrin state.
Also, running 8S and up requires a better larger connector IMHO. Larger Castle bullets or similar. Or like Offshore Hobbies black connectors.
The Infr. Can do 140mph with a flat slightly raised rear wing aero wise. But Not with the stock one. And not without any rear wing also.
Regarding gearing and else ( perhaps 1:1 Spur: Pinion, and taller is needed (over gear it), hopefully others have better experience with your Castle setup.

Edit: as you get to 100+mph speeds, Drag is the dominating problem. Underbody aero is important also. (need chassis skirts)The Infr. can be daunting to hook up. But a great challenge nonetheless.

Edit2: Your temps are cool. Appears you are not even pushing it. All at roughly 28000 RPMS. The 1717 with 1650Kv's running 8S can be geared taller to get closer to your target speed. Ripple is in check. A 2.2ms sustained pull was nice. She's maxxed out where it is at 28000RPM's. Need to push it more? Amps were up there, maybe Aero Drag is holding it back.?‍
The gearing calculator tends to always be conservative in general IMHO. And it doesn't consider aero in the real world. I could be wrong?

Thanks for all the information, it would appear running it sensored is holding it back, tried again today unsensored and there was definitely a lot more power available.
Problem I have now is it’s winter and roads are damp / greasy, so can’t get a good clean run,
Again thanks for all of the above info