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Old 12-07-2009, 02:28 PM   #1
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Default Lower the weight on Xray

Hello guys!!
I have a Xray T2'008 with lipo and brushless. I use a heatsink and fan on the motor and on the speed control. I also use aluminium screws.
The thing is that my car weights to much, about 20g extra than the minimum weight. What shall I do to reduce these 20g?
(I don't like the idea of not using a heatsink and fan on the motor)

All sorts of ideas is welcome, even to trim the chassis if that is necessary
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Old 12-07-2009, 02:44 PM   #2
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Post up a picture of your car and will be easier to say. Depending on how long your wires on the esc are you can shorten them to save weight along with a low profile servo.
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Old 12-07-2009, 02:46 PM   #3
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Quote:
Originally Posted by Skynet View Post
Hello guys!!
I have a Xray T2'008 with lipo and brushless. I use a heatsink and fan on the motor and on the speed control. I also use aluminium screws.
The thing is that my car weights to much, about 20g extra than the minimum weight. What shall I do to reduce these 20g?
(I don't like the idea of not using a heatsink and fan on the motor)

All sorts of ideas is welcome, even to trim the chassis if that is necessary
Use
  1. Lightweight body. Use less paint.
  2. Plastic spool instead of multi-diff
  3. Eliminate the ESC fan if running 10.5 or slower
  4. Change Hudy steel turnbuckles to aluminum
  5. Get lighter motor with cooling vents that don't require a fan and heatsink.
  6. Balance car with Lipo angled out before adding weight.
  7. Use lighter and smaller RX (ie Spectrum Micro)
  8. Use lighter and smaller steering servo
  9. Use lightened rear CVD
  10. Use TQ 13 gauge wires instead of 12 gauge. Short as possible.
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Old 12-07-2009, 04:30 PM   #4
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Use a lighter LiPo. The weight between one brand to the next is as much as 45g.

IP5000 40C vs Thunder Power 5000 40c.. The TP is 30g heavier.

Most 2s2p batteries will weigh more then 2s1p since they have 4 soldered cells vs 2.
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Old 12-08-2009, 10:55 AM   #5
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Well, I have the following equipment:

1. Lightweight body. Use less paint. :Good idea
2. Plastic spool instead of multi-diff :I already use this
3. Eliminate the ESC fan if running 10.5 or slower :I'm running 5.5 ...
4. Change Hudy steel turnbuckles to aluminum :Where do I buy these?
5. Get lighter motor with cooling vents that don't require a fan and heatsink. :What is this, where do I by it? I now use LRP X12
6. Balance car with Lipo angled out before adding weight. :This is done.
7. Use lighter and smaller RX (ie Spectrum Micro) :I use Airtronics M11 RX
8. Use lighter and smaller steering servo :I use low profile
9. Use lightened rear CVD :How much weight do I save?
10. Use TQ 13 gauge wires instead of 12 gauge. Short as possible. :Well, is the power delivery as good with 13 gauge as with 12 gauge? :They are extremely short...

The lipo i use is IP 5000, and I think it isn't to heavy
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Old 12-09-2009, 12:59 AM   #6
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Quote:
Originally Posted by Skynet View Post
Well, I have the following equipment:

1. Lightweight body. Use less paint. :Good idea
2. Plastic spool instead of multi-diff :I already use this
3. Eliminate the ESC fan if running 10.5 or slower :I'm running 5.5 ...
4. Change Hudy steel turnbuckles to aluminum :Where do I buy these?
5. Get lighter motor with cooling vents that don't require a fan and heatsink. :What is this, where do I by it? I now use LRP X12
6. Balance car with Lipo angled out before adding weight. :This is done.
7. Use lighter and smaller RX (ie Spectrum Micro) :I use Airtronics M11 RX
8. Use lighter and smaller steering servo :I use low profile
9. Use lightened rear CVD :How much weight do I save?
10. Use TQ 13 gauge wires instead of 12 gauge. Short as possible. :Well, is the power delivery as good with 13 gauge as with 12 gauge? :They are extremely short...

The lipo i use is IP 5000, and I think it isn't to heavy
The speedpassion V3 motors are a bit lighter i believe, but only by a few grams. Also are you using ip30c batteries, if you are, try some 40c's there around 15-20g lighter

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Old 12-09-2009, 02:10 AM   #7
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Quote:
Originally Posted by Skynet View Post
5. Get lighter motor with cooling vents that don't require a fan and heatsink. :What is this, where do I by it? I now use LRP X12
As Yokomo (why is he driving an Xray? ) stated, the Speed Passion v3.0 motors are vented and a teeny bit lighter.

I installed these motors in my T3 US and EU specs. I am hoping to have some fun! Maybe blow one of the motors up, but have me some fun!!
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Old 12-09-2009, 03:01 AM   #8
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How about:

Why the hell are you bothered about 20g ? I'd keep it this way, this way you'll never have any issues with the car being found underweight.
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Old 12-09-2009, 04:22 AM   #9
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Quote:
Originally Posted by TRF415boy View Post
How about:

Why the hell are you bothered about 20g ? I'd keep it this way, this way you'll never have any issues with the car being found underweight.
Here's one for the mathemeticians: Assuming no wheelspin, how much slower is a 5.5 powered car that is 20g heavier over a typical 20-30metre straight or a complete lap if you like???
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Old 12-09-2009, 04:42 AM   #10
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Quote:
Originally Posted by TRF415boy View Post
How about:

Why the hell are you bothered about 20g ? I'd keep it this way, this way you'll never have any issues with the car being found underweight.
This is exactly right, I generally run my car about 40g overweight in 17.5 and have no problems running towards the front of the pack at my local track.
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Old 12-09-2009, 06:42 AM   #11
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At our big meeting last year we had the minimum set to 1400g, the winner of 13.5 class (where arguably less weight really does matter!) had a car that weighed 1490g!

My own car weigh's 1385g without any motor heatsink etc. but I do use TP lipo's.

GM motors have alot of cooling holes, I've always wondered about the effectiveness of motor heatsinks as the main sources of heat are inside the can. You are cooling the outside a lot but surely this must have a limited effect to the rotor and winding temp

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Old 12-09-2009, 08:41 AM   #12
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Nah, heatsinks are exactly that: things that sink heat. They work by increasing the surface area of the body that is heating up, so heat is more effectively dissipated. As long as you can't put one on the rotor, the outside of the motor is next best thing.

But I agree, 20grams overweight is nothing to lose sleep over. Remember, the lighter you go by going to aluminium turnbuckles, etc, the less durable the car is so the higher the risk you won't finish that race if you have a crash. And to finish first, blah, blah, you know the drill.

One thing I wouldn't do is replace steel turnbuckles with aluminium. Aluminium is not strong enough (I know!). If you really have to do it, go titanium (Lunsford make some top quality turnbuckles and I think they're ratehr cheap). They're light as aluminium and stronger than steel, so you double your gain. Truth is, any titanium item you buy, it's forever. I keep all the titanium bits when I change cars and over time I've built quite a collection. This would probably give you about 10 grams or less saved if you replaced all the turnbuckles on the car, so you'd still have a safety margin weight wise. But as I said before, I don't think you'll get any faster by losing 20 grams.

I run my car about 20 grams overweight and it's not slowing me down at all.

One more thign about aluminium screws. They have a bad habit of corroding in the bulkheads and it's not funny to pull them out. The tighter they are, the higher the risk that they're not coming out. Not to mention how easy it is to strip their heads. Use some weak threadlocker as a sealant to avoid any trace of water creeping in. Even better, avoid using them. I personally prefer to chuck them away and use either steel or titanium (without going overboard with the budget). I even replace aluminium pivot balls with brass or steel if I can for the same reason.
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Old 12-09-2009, 08:55 AM   #13
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You can go with light weight axels and rear aluminum drive shafts, remove the uperdeck support posts, shorten your wires just to name a few.
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Old 12-09-2009, 09:21 AM   #14
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Heavier car means more heat build up in your electronics. It makes your motor/ESC to work harder to make the car move.
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Old 12-09-2009, 09:44 AM   #15
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Quote:
Originally Posted by Jochim_18 View Post
Heavier car means more heat build up in your electronics. It makes your motor/ESC to work harder to make the car move.
I agree in principle, but here we are talking about 20g, less than 1.5% of the car total weight.

OTH adding 100g to the car in the right places might make the car more stable, better balanced, give more traction and the guy would become unbeatable?
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