LiPo & 6.5

[jason]

Any of you that have been running this care to shed any light on the sort of gear ratios you have been running?

Also useful if you could advies on motor and size of track that went with it.

Jason

[jonny123]

I ran a orion vorex 6.5 with orion 3800 lipo for the first time on saturday just gone and it was awesome. Team Orion advise on their site to gear it at 7.5 as a starting point but i thought that sounded a bit high so tryed it at 8.5 and it was way overgeared on a track with a straight about 25m long. I then geared it down to 9.5 and it was awesome. But i still wasnt quite as quick as the 3.5 5cell boys down the straight so i asked Andy M about timing and he told me to advance it 1mm to give me more punch and top end and it made a huge differance i was pretty much as quick as 3.5 5cell down the straight then but i kept advencing the timing 1mm at a time and it just got faster and faster. :cool::D

If ur gonna run mod i'd recomend 6.5 lipo as its loads cheaper than buying loads of 5cell packs and 6.5 is smoother to drive and i found i could put the power down better with 6.5 as i have run 5 cell 3.5 aswell. Although the 6.5 doesnt make that lovely wining sound down the straight like a 3.5 does.
If u play about with timing and gearing i think you could be going as quick as 3.5 with lipo

[John_s]

Really? I didnt expect the new 6.5 lipo thing to keep up with 5 cell. If so thats awesome :)

[Chris ODonoghue]

Jason,
I ran Lipo 6.5 last year throughout the STCC and some club meetings at West Kent.
We've also run them at the KO GP, Maritime (clubmans) and more recently two rounds of Rug Racers.

Motors used:
Speed Passion v1 motor (the black/green off road one)
Speed Passion v2 motor
Hacker

I've had a play with rotors on the speed passion motors and have found that a 12mm rotor in the V1 motor works quite well as it has bags of power but doesn't rev very high.

12.5mm and 13mm rotors work well in the V2 motor, but I've not tried any others in the Hacker yet.

Gearing for outdoors:
Brooklands: 5.49 (Speed Passion v1 motor)
West London: 6.5 ish (Hacker and Speed Passion v2)
Snetterton: 7 ish (Hacker)
Rug Racers: 7.5 (Hacker and Speed Passion v2)
Colchester: 6.8 (Speed Passion v2)
Eastbourne: 7-ish
Maritime: 7.5 ish

I've found a good starting point for outdoors is 6.5-7.0 and a little higher indoors (7.5-8)

as Jonny123 has said they are as quick as a 3.5 5-cell setup in a straight line, perhaps even a bit quicker. The performance through the corners with the extra weight means they are not as agile on the infield.

I averaged 2100mah being used from the trakpower 4900's I was using at the STCC, although Brooklands (huge track) was quite a way off that.

People were using the 3600's without any problems in terms of runtime.

Sorry for the brain dump, but feel free to come back with comments/questions.

[Stefan C]

Hi

I have been running lipo/mod for some time now after switching from 5 cell. I agree with chris, it is about as quick as 5 cell to be honest but just slightly less agile in the corners. Out the corners the punch is also sweet :). I have found 6.5 slightly slower down the straight than 5 cell but i havnt pushed the gearing yet to its limit tbh i could go alot lower if i wanted.

:)

stef

Mirage - HotBodies - Nosram - Edit - Hudy

[steveonamission]

5.5/lipo = 3.5 5 cell straight line speed

6.5/lipo = 4.5/5 cell speed, but out thee corners, its quicker than 3.5/5 cell

This is from my findings at the KOGP.

Handerling charateristics are that lipo mod, isnt as nimble through the corners as 5 cell, mainly due to the weight difference, its not a majour difference, but is noticable.

My gearing was around the 6.6 mark with a nosram 6.5.

Can't really comment alot as i havent run it anywhere else, have been runinng 5 cell.

HTH

Steve

Mirage - Xray - Nosram - Edit - Hudy

[MikeS]

The only reason 5 cell is more nimble is due to the lower minimum weight. Just remember that all LiPo 6.5 mods have been run at 1500g since I introduced the class, but for 2009 STCC has already reduced the minimum weight to 1450g ;)

[steveonamission]

Is it down to just weight though?.......5 cell is positioned in the middle of the car, (if you have a 5 cell chassis)......with lipo the weight is at the back, middle and at the front, so that is still gonna handle differently from 5 cell .....just like running a 6 cell chassis with 5 cell and running the cell forward or at the back. Yes you can add weights here or there, but you still have the lipo weight 1/2 a cell more either side compared with running 5 cell on a 5 cell chassis.

Not bashing it, ive run it and like it, will be interesting to see how the likes of me and Stef do at nats with it, compared to the 5 cell lot.

[MikeS]

I would expect that 5 cell open at 1425g should produce quicker lap times in capable hands than LiPo 6.5 at 1500g! Really has nothing to do with the positioning of the weight as this is not an issue, it is purely and simply the actual lower mass that is having to be accelerated and moved around in changes of direction.

Couple this with the 75g lower weight but only 0.7V-0.9V lower voltage rather than 1.5V (compared to 6 cell) - using typical average voltages. There is a greater drop in motor power between 3.5 and 6.5 ;)

However, running 6.5 at 1450g is going to bring them closer than they are now. Just a shame the AGM did not lower the 6.5 class weight to 1450g, even though I did point out this difference.......... :)

[Chris ODonoghue]

something for next year maybe ? :)

[GWESTY]

will be interesting to see how the likes of me and Stef do at nats with it, compared to the 5 cell lot.[/QUOTE]



im planning on running this at nats also , hopefully it will warm up soon (and b dry ) so i can try it !

[Steve Cann]

That at the IC venues Li-Po/6.5 will be the equal of 5cell if not actually have the upper hand...

[steveonamission]

im planning on running this at nats also , hopefully it will warm up soon (and b dry ) so i can try it !.

Nice one

See you trackside.

[Chris ODonoghue]

im planning on running this at nats also , hopefully it will warm up soon (and b dry ) so i can try it !


try it in the snow like we did last year at West London :)

[Steve Cann]

something for next year maybe ? :)



I favour 10.5 @ 1350grms... Would be plenty quick enough as well as 'nimble'... Would be more confident of being able to scrutinise properly... Which was a major point raised at the AGM about policing eligibilty of 6.5 motors...

Plus, most importantly, there would be a greater chance of electric venues hosting Nationals rather than the series mostly plying its trade at IC venues...

[MikeS]

Sorry, but I really do question the "objections" that were raised over the so called "policing" of 6.5's. The motors on the EB list are NOT listed specifically on their wind, they are just another modified wind motor. There is no difference between a 3.5, 4.5, 5.5, 6.5, 7.5 etc...... if the base motor has been approved then all the winds are approved! There are already at least 10 different specific 6.5T motors listed!!!!!

[Steve Cann]

It was 'actively' discussed was it not!

Think after a couple or so meetings we'll know wether the 'concerns' were well placed or not...

I'm sure you'll agree though [hopefully] it was correct to raise the points sooner rather than later...

[MikeS]

Steve, exactly what 'concerns', as I said there at the meeting, there are 6.5T motors already on the EB list, so exactly what is the 'valid' concern that seems to be aimed at just the 6.5 since like all the other listed AND approved winds it is the same. I questioned it then as I still do now and still have no answer ;)

[MattW]

6.5 will need to be policed, otherwise, what is to stop someone running 5.5 with LiPo. Because you quite rightly point out Mike, there is no obvious difference in appearance between the motors in the range of that majority of modifieds.

[MikeS]

Right, so no different to how it was with 12T brushed mods when we ran them then....... ;)

[MattW]

Correct, (ish). We had 2 methods of checking those. Firstly they were generally marked on the armature with their wind and manufacture (although this was only ever and EFRA rule and not a BRCA one), and we knew what the inductance should be and hence could check that.

Hence, we need a method of checking 6.5's. IMHO anyway.

[Mark Christopher]

quick question

when you ran 12t you could anoly alter brushes and springs

6.5 wind motor, would changing the rotor have a bigger effect on performance than brushes/springs on a brushed motor?

[mr4man]

well it does in off road so i can imagine will be greater in a lighter t/c.
Tbh i think the real issue will be stopping people overcharging lipos a method i dont advocate and needs to be stamped out.

[Oliver]

Some interesting discussion here....

RE checking of 6.5-turn motors, inductance testing can still be used, I'm sure all the manufacturers would be happy to supply the value of their 6.5-turn versions (which could be added to the EB list?) - As Mike said, no difference (or harder!) than when we had a 12 turn limit!

Going to be very interesting to see how the two stack up against each other during the year.

[mr4man]

Another thought i dont think run time will be an issue so maybe the rotor change will not give such an advantage as it does in other classes.

[Chris ODonoghue]

I'm most interested to see how it fares in the hands of capable 5-cell mod drivers or good pro stock drivers making the move up... of which I am neither :D

[Bonny85]

I'm most interested to see how it fares in the hands of capable 5-cell mod drivers or good pro stock drivers making the move up... of which I am neither :D

i think for someone moving up from pro stock it will be perfect, not too fast that it makes the car undriveable and still allowing people to use there lipo cells, due to the lipo cells as well and the fact it will not be pushing speed controllers or motors I think 6.5/lipo is the perfect club racing combo

however put it in the hands of the likes of an elliot harper or andy moore and i do not think it will even get close to 5 cell mod at any track, i would go as far as to say it will not even get close if they were run at the same weight limit, ie a 3.5 vs 6.5 motor

[Steve Cann]

Steve, exactly what 'concerns',



Firstly it wasn't me that raised the 'concerns' but 'seasoned' National competitors...

In summary it was felt that there wasn't currently [at time of AGM] a viable method of testing BL to confirm motor was actually as stated (6.5)... This was considered necessary when a class is limited by motor wind as was the case when 'Modified' class was restricted to 12t... When this was the case a 're-calibrated' [adjusted to suit purpose] meter was used... During the period I used the meter at Nationals etc I personally only found one motor that failed test... The result of test was protested and armature was un-wound [in front of competitor] and was one turn short. Which was what meter indicated it would be! Think majority of competitors were 'comfortable' with results of the meter test and used to have their motors/armatures checked prior to use... Not saying test was 110% guaranteed but was, I feel, fit for purpose...

I'm sure the section committee/EB are seeking ways/methods of trackside checking BL and I'm sure if a viable method can be found they'll be using/applying it... I await with interest...

[MikeS]

Sorry Steve, that comment wasn't "aimed" at you specifically, and I think both you and others have now answered the way forward as well.

[MattW]

Inductance testing was generally considered fairly reliable for 12 turn. However, there were some issues. If my memory serves me correctly, the stack thickness on which the arm was wound had a drastic effect on inductance. I have had motors "fail" when in the can, but when taken out of the can and checked directly on the windings found to be fine - tight, but fine.

This brings me onto the next point - and i genuinely don't have an answer to this point, hence i'm raising it. The magnetic field effected the results of the brushed motor test (or did it - was it the brush gear? - don't know) hence they often needed taking out of the can. So, will rotor size effect the results of a b/l test?? I believe it will. Will there be an overlap in results - i.e x wind with small rotor could also be the same as y wind with big rotor? If so, that possibly rules inductance testing out. I'm sure there are other ways, maybe resistance, i'm not sure. There is i believe a lot of work required to produce a proper testing method that is usable in the time frame given.

[Stefan C]

Will it be allowed to add bigger/smaller diameter rotors to the 6.5 can? i had the feeling it would be,

Onto scruitineering, some kind of mark that the scruitineer can only add and what cant be removed or copied. Barcodes on cans and rotors would be the best thing to use but then theres the problem of having a scanner and relevent software. just an idea:)

[Oliver]

This brings me onto the next point - and i genuinely don't have an answer to this point, hence i'm raising it. The magnetic field effected the results of the brushed motor test (or did it - was it the brush gear? - don't know) hence they often needed taking out of the can. So, will rotor size effect the results of a b/l test?? I believe it will. Will there be an overlap in results - i.e x wind with small rotor could also be the same as y wind with big rotor?

Often with brushed motors you can get an inaccurate reading through the brush gear. In that respect, the same motor could have a slight variance in readings due to the brushes, brush position etc.

So, simplified, a BL motor does not have this issue.

But, yes you are correct, changing the size of the rotor (or even the composition) will affect the inductance reading, similar to changing the stack on a brushed motor. A 'true' correct reading (on a BL motor) would be obtained by removing the rotor from the motor and then taking the measurement across two poles.

I'm unsure of the overlap: I've played with inductance readings of some BL motors (10.5 and 13.5s)... for example the reading on a Novak 10.5 is very different to that of their 13.5 (as you would expected)... but obviously this is with constant rotor size. I will try taking readings with different sized rotors when I get a chance - unless someone else does before me and posts results here!

[Phil C]

however put it in the hands of the likes of an elliot harper or andy moore and i do not think it will even get close to 5 cell mod at any track, i would go as far as to say it will not even get close if they were run at the same weight limit, ie a 3.5 vs 6.5 motor

I have been thinking the same since the 6.5/lipo class was introduced, however I will be testing the two options back to back as soon as the weather is reasonable. I assume that after the testing I will be heavily favouring the 5 cell option:)

[Chris ODonoghue]

As I've said, I'm nowhere near a top driver in terms of ability, but I ran both 5-cell mod and 6.5 lipo last year as way of comparison.

6.5 won out for me, so I'm interested to see how it goes for some drivers who are more "seasoned" than myself :)

[Chris ODonoghue]

Correct, (ish). We had 2 methods of checking those. Firstly they were generally marked on the armature with their wind and manufacture (although this was only ever and EFRA rule and not a BRCA one), and we knew what the inductance should be and hence could check that.

Hence, we need a method of checking 6.5's. IMHO anyway.


After taking a few different 6.5's apart for cleaning/re-oiling... the stacks i've seen are marked. Not sure if every one is done, just the ones I've seen so far.

[GWESTY]

i think for someone moving up from pro stock it will be perfect, not too fast that it makes the car undriveable and still allowing people to use there lipo cells, due to the lipo cells as well and the fact it will not be pushing speed controllers or motors I think 6.5/lipo is the perfect club racing combo

however put it in the hands of the likes of an elliot harper or andy moore and i do not think it will even get close to 5 cell mod at any track, i would go as far as to say it will not even get close if they were run at the same weight limit, ie a 3.5 vs 6.5 motor

hi , i managed to get out and test the 6.5lipo option today at a sunny aldershot . ive gotta say im very impressed with the speed of the motor and i didnt dump at 4.30-5 mins ! car was fast enough to be place on p4 at aldershot national ! not bad for my 1st day testing !!!