Losi XX and a donor Kinwald

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jwscab
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Re: Losi XX and a donor Kinwald

Post by jwscab »

Just to throw in a little more info on the 'C' rating. The 'C' is capacity, so if it's a 5000mAh battery, that is 1'C'. 5000mA=5amps. If you can discharge at 20C, that is 100amps. If you can discharge at 60C, that is 300amps. These are instantaneous numbers, and are a measure of the cell and pack construction's internal resistance. So a higher discharge 'C' means more available current to the motor at rated voltage, which should give you more instantaneous power. Most car's will only hit this area for very very brief periods of time, and you probably won't see a difference between 20C and 60C, these numbers only become more apparent as you run hotter motors.

you can think of it as equivalent to the old brushed motor esc FET resistance, where the 'pro' controllers had ridiculously low on-resistance.

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Re: Losi XX and a donor Kinwald

Post by mwg »

DerbyDan wrote:
mwg wrote:I've fitted the LiPo battery and the (friends) brushless 6.5T. I will look to get a more progressive engine/esc soon because I anticipate struggling with this combo. The Losi Xcelerin looks like a good buy.

I have also switched the Kinwald chassis (to save my original plastic XX from any big damage).

I have have a new pair of Yellow Mini Spikes (and medium) foam at the rear!

I will need to find a 18T or 19T pinon to reach the recommended gearing (I have a 84T or 88T spur) of 10.3.

I'll wire it in tomorrow at work and drop a few more photos!
Good work mwg..... will you be running tonight? I'm booked in :wink:
I most certainly will be! Come and find me - be good to meet. I have the yellow body shell today.

I'm looking for you to uphold the XX honor!

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Re: Losi XX and a donor Kinwald

Post by mwg »

jwscab wrote:Just to throw in a little more info on the 'C' rating. The 'C' is capacity, so if it's a 5000mAh battery, that is 1'C'. 5000mA=5amps. If you can discharge at 20C, that is 100amps. If you can discharge at 60C, that is 300amps. These are instantaneous numbers, and are a measure of the cell and pack construction's internal resistance. So a higher discharge 'C' means more available current to the motor at rated voltage, which should give you more instantaneous power. Most car's will only hit this area for very very brief periods of time, and you probably won't see a difference between 20C and 60C, these numbers only become more apparent as you run hotter motors.

you can think of it as equivalent to the old brushed motor esc FET resistance, where the 'pro' controllers had ridiculously low on-resistance.
Thanks - that's interesting.

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Re: Losi XX and a donor Kinwald

Post by mwg »

Thanks for all your help last night Dan! You looked like you were unlucky in the final.

Lots of work still to do on my part!

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Re: Losi XX and a donor Kinwald

Post by DerbyDan »

mwg wrote:Thanks for all your help last night Dan! You looked like you were unlucky in the final.

Lots of work still to do on my part!
Yeah I was a little unlucky with that back-marker :? But without my two stupid mistakes earlier on in the race (which you marshalled one - thank you :) ) I wouldn't have been in that situation, 'C'est la vie' I guess - thats racing :wink: I was pleased with my qualifying position in 10th O/A, considering the dissadvantage of the rear motor layout on that strange grippy Astro-turf surface, I think that if I do the winter series at Moulton I will revert back to my mid-motor CR2.

Was watching you drive in your final - despite the obvious problem of having an over-tight slipper, combined with mental 6.5 BL power... you have obviously still got the skills from you raced before... it really is a very tough surface to run on yet you demonstrated a high level of skill in-between trying to tame the wheelies! :mrgreen: :wink:

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Re: Losi XX and a donor Kinwald

Post by mwg »

Haha! You are too kind.

I'll continue to work on the XX and be back! ;-)

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Re: Losi XX and a donor Kinwald

Post by mwg »

Dan, do you know if a gear cover from an XXX will fit the XX?

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Re: Losi XX and a donor Kinwald

Post by DerbyDan »

mwg wrote:Dan, do you know if a gear cover from an XXX will fit the XX?
I'm afraid it doesn't, however I have an RPM one on my XXX so i'll try & see if it could be adapted to fit the XX motor plate (the RPM covers don't 'lip' over around the plate so would be easier to adapt)

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Re: Losi XX and a donor Kinwald

Post by mwg »

No worries - thanks! The XX RPM covers are hard to come by.

Do you think a 8.5T motor would still be too hot?

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Re: Losi XX and a donor Kinwald

Post by DerbyDan »

I know... I got one with that spares car that I recently got hold of, but the previous owner has cut the bottom out of it... so its not very good for keeping the dirt out :roll: Reproductions of the standard lexan ones are avalaible from TBG (team blue groove) in Canada - i've not tried one, but its an option I guess?

An 8.5 would be what I would get if/when I replace the motor I have now.... its probably 'hotter' than would be ideal at your level at the moment... but it would serve you well as you'd probably never have to buy another for sometime, with a 10.5 you may find that in a year or so time as your driving/results improve, that you want to up the pace, so you would need a new motor. Unless of course you have a timing advance/boost function on your speedo/ESC?

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Re: Losi XX and a donor Kinwald

Post by mwg »

Indeed, a cheap 8.5T might not be a bad idea.

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Re: Losi XX and a donor Kinwald

Post by mwg »

I've gone for a 10.5T!

I'm going to try some staggers at the front. Are you using the standard front wheel width?

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Re: Losi XX and a donor Kinwald

Post by DerbyDan »

mwg wrote:I've gone for a 10.5T!

I'm going to try some staggers at the front. Are you using the standard front wheel width?
Nice one!

You should find the staggers give a bit more steering - but more importantly they should make the car less prone to flipping over if you land a little askew off a jump :wink: These tyres fit a slim front wheel.... which is the standard width of the XX front wheels, so you should be fine. I'm running XXX wheels which on the front are wider but to get the staggers to fit properly i've mounted them on the inside edge of the inner rib of the wheel.... i've then cut off the potruding inner lip up to that rib (if that makes sense?) Some people don't bother to cut this off.

IIRC the spacing of the ribs on the original XX wheels - to the wheel edge is quite tight to get the tyre lip into - which might make it tricky for you for glueing the staggers on as they do have quite an odd side-wall design.

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Re: Losi XX and a donor Kinwald

Post by Caine »

I've had 8.5 in my CR which will go into the one i'm almost finished doing now, it's got plenty of go in it for me.
I went with the cut staggers on mine, most of the guys at club use minipins all round but i find them far to aggressive on the front so i thought the cut staggers would suffice, and i was really pleased with them.

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Re: Losi XX and a donor Kinwald

Post by mwg »

So I made a return to Silverstone last night with my upgrades! For last night, I had:

* 10.5T motor.
* Front staggers.
* Lowered front and rear suspension.
* Significant weight over the front axle (wheel weights).

The end result was a car that is actually drivable! I won the first heat (D)... had a DNS in the second but ultimately can third in the final but second 1/10th. I did break the rear underside chassis plate however.

Now I must practice to find more time!

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