New to nitro questions.

[BCbud]

Ok, here I go.

My receiver battery is 1300mA lipo and there is a voltage regulator installed. Approximately what would be the run time be with this battery setup?

New tires, do you true them to a sertan size or just true them to be round or throw them on right out of the box and run them?

The way my car is right now the front wheels are turning faster than the rear. Is this a common setup and will the tire size need to be smaller on the front to compensate for this? What advantage or handling characteristics will this change?

That is all for now but there will be more to follow.

Thanks, Neil.

[Shawn68z]

Ok, here I go.

My receiver battery is 1300mA lipo and there is a voltage regulator installed. Approximately what would be the run time be with this battery setup?

New tires, do you true them to a sertan size or just true them to be round or throw them on right out of the box and run them?

The way my car is right now the front wheels are turning faster than the rear. Is this a common setup and will the tire size need to be smaller on the front to compensate for this? What advantage or handling characteristics will this change?

That is all for now but there will be more to follow.

Thanks, Neil.

1) Depending on your servos and RXer, you should probably expect close to an hour or 1.5 hours  (or more) on that battery. I think I draw about 120Mah per qualifier race (So maybe 7-8 minutes per race)  from my life cell.

2 & 3)   Depends on the tires if you need to cut them. Jacos you need to cut, Matrix already come with the rears 2mm larger.  You will want to start your rears alittle bigger then the front. Two main reason, they tend to wear alittle faster, and it will make your car pushy, which is good for the beginning of the race.   The car will get better and dial itself in during the middle of the race, and get alittle loose towards the end.
 To help with tire wear, its normal to run one of two levels harder in the rear (35F, 38 Rear)  On our track I have been running 32F, and 35R, which works really well for normal club racing, but tries to traction roll on big weekeneds when the grip is up.  For that I have 37F, 40R.   
 Speaking of tire wear. I have found that I have been getting better tire wear with softer tires then the harder compounds when the traction is low (normal weekend stuff.)  When the traction is up, you get hardly any wear at all.

Don't forget to check the ride height before every race.. I forgot to check for the mains (mainly I was to busy with my electric, and Cameron's car), and couldn't drive the car anymore. The chassis kept  bottoming out on the straights...


Shawn.

[Blake]

I really like a 5 shore split.  32/37 or 35/40.  The front and rears wear at the exact same rate that way on my car.  I run the fronts 2mm smaller than the rears.

Ride height is a pain in Nitro because if you start raising your ride height as your tires wear, you'll automatically reduce your droop/uptravel.  This drastically impacts the NT1's corner entry from undrivable oversteer to undrivable push.  This year I set my ride height with plain rims (no foam) to 1mm front and rear.  Then I cut the tires fairly big 62mm/64mm and run them until my ride height is too low (3mm on our track is getting pretty low).  I only adjust the srings to correct tweak, and I only adjust the droop screws if I'm looking to make a handling change.

This is good for cleaning.  Spray it all over the car and then blast it off with 100psi or more.  This is not Isopropyl.  It is "95% Ethanol" when reading the fine print.
http://www1.shoppersdrugmart.ca/en/health-and-pharmacy/everyday-medicines-and-first-aid/first-aid/details/057800059479

Try a Charge/Discharge cycle on that RX battery to get an idea of its true capacity.  I agree with Shawn that a full 1300mAh could do a 90min race with normal servos and properly set endpoints.


Blake

[Shawn68z]

This is good for cleaning.  Spray it all over the car and then blast it off with 100psi or more.  This is not Isopropyl.  It is "95% Ethanol" when reading the fine print.
http://www1.shoppersdrugmart.ca/en/health-and-pharmacy/everyday-medicines-and-first-aid/first-aid/details/057800059479

Matt at NRC has aluminum pressure bottles that you can fill with any liquid, and charge with a bicycle pump or compressor.   Next time I am up that way I will see if he still has some, they would be perfect for this.  Kinda reminds me of the old school "seltzer bottles.. "..


Shawn.

[Falcon]

blake so you use a set of old tires ,just the rims no foam on them. I'm going to try this.great idea

[Shawn68z]

Another approach to tire wear and ride height, is to buy 3-4 sets of tires in the spring, and run them until they are half-down. Then once you have used all 4 sets, setup your car to run them to the rim, and run each of the sets until they are gone. That way, you get to use all foam you paid for, and don't need to true the tires when them come out of the package (if your running matrix.)

 

Cheers,
Shawn.

[BCbud]

Well it looks like X-ray changed the 2 prefix numbers on there shock parts for the NT1 but the NT1 shocks appear to be taken from the T1FK04 so I have a lot of extras there !

I do not know how far I will get but I am going to try and put a factory team setup into my car. The one I have chosen is Paul LeMieux 2010 ROAR Nationals - Winning Setup. It is close to the basic setup with a few changes. Once I have done this I will know how to ajust the car to a point and know what my settings are unlike now, where I have no idea how my car is set up.

Neil.

[Blake]

blake so you use a set of old tires ,just the rims no foam on them. I'm going to try this.great idea

Yeah, I just trued an old set down to the rim.  Try not to touch the plastic. The rims are not perfectly round so you'll have some foam/glue remaining on the rim in certain places.  They should measure exactly 50mm in diameter (with Xceed rims anyway) if you do it perfectly.

Blake

[valk]

I just run t3 style shocks on my nt1. the adjustable rebound thing they tried to do is just too complex for my feeble brain lol. you should ask blake for his setup sheet. his car is definitely the benchmark for our track.

[BCbud]

I just run t3 style shocks on my nt1. the adjustable rebound thing they tried to do is just too complex for my feeble brain lol. you should ask blake for his setup sheet. his car is definitely the benchmark for our track.

After doing the shocks I have confirmed that they are the same as my old T1. Saying that I have too many spare shock parts to change. As for setup, I tried Blakes on my t4 2013 and it was not for me so I tried a couple of factory setups and found one that was good and I am workng on fine tuning that one. What works for one may not work for some one else.

Neil.

Edit: What is this adjustable rebound you are talking about?

[valk]

absolutely Neil. it all comes down to your own personal goals from the cars handling. factory setups will only give you a benchmark to ensure your car works properly, then you tweak to suit.

the adjustable rebound.. there is a plastic bottom cap on my factory shocks that allowed you to adjust rebound by pumping them a certain number of times with the cap open.. i couldn't see that being accurate or repeatable though. they also had a damping adjustment that goes inside the shock and lets you change the hole profile. that i could see using, but i stuck to good old fassion 3 hole t3 shocks. to set rebound i just compress the shock a pre determined amount when inserting the bladder and hold it there as i put the cap on. I use my wire crimps as they seem to give me a fairly re-producable 25% rebound.
  then with a pair of shocks, ill tighten/loosen the cap to get a pair of shocks to rebound the same.

your car seemed to work pretty well the few times i saw it running though. when you had tires on it that is ha.

[BCbud]

the adjustable rebound.. there is a plastic bottom cap on my factory shocks that allowed you to adjust rebound by pumping them a certain number of times with the cap open.. i couldn't see that being accurate or repeatable though. they also had a damping adjustment that goes inside the shock and lets you change the hole profile. that i could see using, but i stuck to good old fassion 3 hole t3 shocks. to set rebound i just compress the shock a pre determined amount when inserting the bladder and hold it there as i put the cap on. I use my wire crimps as they seem to give me a fairly re-producable 25% rebound.
  then with a pair of shocks, ill tighten/loosen the cap to get a pair of shocks to rebound the same.

Are you talking about X-ray shocks as this is that is what I am talking about.

[valk]

xray 308330 bodied shocks are what im talking about. if the bottom cap of your shocks have plastic caps these are prob the ones you have. if aluminum caps on bottom, they are the more standard xray shocks. the black bottom ones have a process to pump in rebound. I didn't like it and went with the more traditional shock that has been on all the nt1 revisions since.
Is all im saying. seems like you have it sorted out though so it doesn't even matter =)

[Shawn68z]

Why have  a shock with rebound at all?    Shocks are for dampening, and should not have an effect on your wheel rates. 


Shawn.

[BCbud]

I always try to build my shocks with little to no rebound.

One thing I noticed in my limmited run time is it was not easy to slowly apply the throttle out of a corner, does anyone use expo on there transmitters?

Neil.

[Shawn68z]

I always try to build my shocks with little to no rebound.

One thing I noticed in my limmited run time is it was not easy to slowly apply the throttle out of a corner, does anyone use expo on there transmitters?

Neil.

Nope not me. Alot of how the feels out of the corner can be changed with clutch and gearing adjustments.

Shawn.

[valk]

it all comes down to feeling the throttle. you could practice just getting enough throttle into it to engage the clutch.

i dont run any expo now, but i did when i was first starting out with mod cars. you more or less blip the throttle between corners and let the car roll where it needs to go.

as for rebound, for carpet you don't want any rebound but its commonly accepted that most outdoor tracks unless they are SUPER smooth concrete prefer a small amount of rebound.

[Blake]

I always try to build my shocks with little to no rebound.

One thing I noticed in my limmited run time is it was not easy to slowly apply the throttle out of a corner, does anyone use expo on there transmitters?

Neil.

I use some Expo on the throttle to try to gain a little more feel/control in the low ranges.  Your clutch setting can override any Expo setting though if it's really late to engage.

Blake

[Shawn68z]

I always try to build my shocks with little to no rebound.

One thing I noticed in my limmited run time is it was not easy to slowly apply the throttle out of a corner, does anyone use expo on there transmitters?

Neil.

I use some Expo on the throttle to try to gain a little more feel/control in the low ranges.  Your clutch setting can override any Expo setting though if it's really late to engage.

Blake

Late to engage? You mean maximizing the engines power curve right?

Shawn.

[valk]

or burning gears.. whichever way you wanna look at it heh.

[Shawn68z]

or burning gears.. whichever way you wanna look at it heh.

Na... The only time I have ever blown a gear because of the clutch was because of the clutch gap was to large, and allowed the clutch to slip.  The high rpm engagement is hard on the thrust bearing though.....  Just don't have that gap to big and it will be fine...


Shawn.

[valk]

yea i went through three thrusts before i figured out my nt1 clutch. the one im using is actually broken.. the cage is broken, but it still thrusts so leaving it the frack alone til i get a replacement.
high engagement can be tough to handle though. lites up the tires too easily. i personally like the clutch to come on soon, so you can roll onto the throttle gently and get the full rpm range of use.
of course depends on the shoe you are using as well.

[Tom]

One thing I noticed in my limmited run time is it was not easy to slowly apply the throttle out of a corner, does anyone use expo on there transmitters?

Yep.

[Tom]

The power dissipated by the clutch when slipping is proportional to the square of the RPM. So, a higher engagement point means more temperature in your clutch, which increases the likelihood of melting gears.

[Shawn68z]

The power dissipated by the clutch when slipping is proportional to the square of the RPM. So, a higher engagement point means more temperature in your clutch, which increases the likelihood of melting gears.

Its a linear relationship.   If your clutch is slipping enough to make the gears blow, its because the gap is set wrong and cant fully engage, when my clutch has been set for a high engagement point, I have never blown a gear, but it can be a handfull when the traction is low....(Definitely had a hard time with it in last weeks race!).  If the track has high enough traction, it can definitely be worth it to have the clutch engage at a higher rpm, esp if you have a tall set of gears on.


 HEAT (watts)  =  TORQUE (lb.-in.)   X   SLIP RPM   X   0.012

Shawn.

[Tom]

It appears you're right in that it is a linear relationship.

That does not change the conclusion though that an engagement point that is too high will generate damaging temperatures.

[Shawn68z]

It appears you're right in that it is a linear relationship.

That does not change the conclusion though that an engagement point that is too high will generate damaging temperatures.

Before or after the gears explode, belts break, and bearings are smashed thru the clutch bell?    The only time the clutch bell is going to get hot enough to melt a gear is if the gap is set wrong. The engagement point will not make enough heat, but a high engagement point is definately harder on all the drive line components, esp the belts, thrust bearing, and con-rod.  Your more likely to snap something, or strip a belt before anything melts.   But saying all that, its still another adjustment that can be used to set the car up for maximum acceleration based on the amount of grip available.

Sorry for hijacking your thread Neil, but here is some clutch info.   There is lots out there.

http://www.bukupower.com/ClutchTuning2.aspx



Cheers,
Shawn.

[BCbud]

OK more questions, I am looking at RC Mushroom for both the header to motor and header to pipe gaskets. They list the following for my OS motor.

http://www.rc-mushroom.com/product_info.php/zeppin-racing-gasket-pcs-novarbsirioosstsorion-p-10198
http://www.rc-mushroom.com/product_info.php/zeppin-racing-gasket-pcs-novarbsirioosstsorion-p-10199
http://www.rc-mushroom.com/product_info.php/zeppin-racing-gasket-pcs-novarbsirioosstsorion-p-10197

Are these all header to motor gaskets? There is no discription or size given. I would assume that they are header to moter gaskets because it is for a specific motor. If that is the case where do I find the header to pipe gaskets?

Thanks Neil.

[Blake]

Hey Neil,

Those *appear* to be motor-header gaskets.  Finding replacements for your header-pipe connection is tough.  I have used .21 motor-header gaskets in the past but they seem slightly too small.  I'd like to find a source for proper replacement header-pipe gaskets.

Blake

[Shawn68z]

Niel, I have various types. I will bring them next race, and figure out what you need. I normally use .21 like Blake mentioned, but again there are different types and sizes.   If you want to try them before race day then send me a pm and we can meet up for coffee.


Shawn.

[BCbud]

Niel, I have various types. I will bring them next race, and figure out what you need. I normally use .21 like Blake mentioned, but again there are different types and sizes.   If you want to try them before race day then send me a pm and we can meet up for coffee.


Shawn.

Thanks but I am ok for now, I was just looking to get some as a needed consumable part.

Neil.

[BCbud]

I might need to buy a pair of front tires from anyone that may have a new or used pair that they can spare. The 2 pair I have are fairly bent up.

Thanks, Neil.

[Blake]

I might need to buy a pair of front tires from anyone that may have a new or used pair that they can spare. The 2 pair I have are fairly bent up.

Thanks, Neil.

Hi Neil,

I have a bunch of used tires you can look through.  None are huge - but will probably get you by.

Blake

[BCbud]

First off I would like to thank everyone for ther input and help at the track while I learn about this class.

Ok if with a 5 shore split the tire wear is the same front and rear, why not run the front with no overdrive and cut the front and rear tires the same diameter?

Neil.

[Shawn68z]

First off I would like to thank everyone for ther input and help at the track while I learn about this class.

Ok if with a 5 shore split the tire wear is the same front and rear, why not run the front with no overdrive and cut the front and rear tires the same diameter?

Neil.

Makes it easier to drive the cars out of the corner.  The front end is Pulling the rear of the car so you don't get loose when on the power.

I did find this explaination as well.

http://www.rctech.net/forum/7768633-post3.html


Shawn.

[BCbud]

First off I would like to thank everyone for ther input and help at the track while I learn about this class.

Ok if with a 5 shore split the tire wear is the same front and rear, why not run the front with no overdrive and cut the front and rear tires the same diameter?

Neil.

Makes it easier to drive the cars out of the corner.  The front end is Pulling the rear of the car so you don't get loose when on the power.

I did find this explaination as well.

http://www.rctech.net/forum/7768633-post3.html


Shawn.

But are you not eliminating that by cutting the front tiers smaller?

Neil.

[Blake]

First off I would like to thank everyone for ther input and help at the track while I learn about this class.

Ok if with a 5 shore split the tire wear is the same front and rear, why not run the front with no overdrive and cut the front and rear tires the same diameter?

Neil.

Hey Neil,

It's a good question - I would think your suggestion is valid.  All other things equal, it would seem that the car would behave the same with the overdrive pulley and 2mm smaller front tires as it would with the equal drive pulley and equal sized tires.

The difference might come down to getting more steering with the larger front tire setup.

Blake

[valk]

I think craig explained it to me best. with the 2mm split, as you race for 20 minutes or more, your start the race with the car a little pushy and as the rear tires wear down closer to the size of the fronts, it loostens up and by the end of the race has slight oversteer.

over 5 minutes you could easily run the tires the same size f/r with no overdrive, but over longer periods the rears just wear out faster. maybe with a center dif we could run tires the same size over long periods?

[Shawn68z]

First off I would like to thank everyone for ther input and help at the track while I learn about this class.

Ok if with a 5 shore split the tire wear is the same front and rear, why not run the front with no overdrive and cut the front and rear tires the same diameter?

Neil.

Makes it easier to drive the cars out of the corner.  The front end is Pulling the rear of the car so you don't get loose when on the power.

I did find this explaination as well.

http://www.rctech.net/forum/7768633-post3.html


Shawn.

But are you not eliminating that by cutting the front tiers smaller?

Neil.

Yes, by making the fronts smaller, and the rear bigger at the beginning of the race the drivetrain will be neutral. (Or atleast close) Until the rears wear down during the race, then it goes back to an overdrive situation again.  I really dont know the OD for the Serpernt, but if the car either gets to loose from small rears (to much overdrive), then its time for a harder rear tire.  The most important thing I learned was to never have the rear tires drive the car. (Underdrive) It will make it almost impossible to control out of the corner, and it will push so much going into a corner you probably wont make the turn.

Even the overdrive ratio would change as the our diameter of the wheel changes too.   A big front with a 2mm larger rear will have a different ratio then a small front with a small rear that is 2mm larger..  When I get home from work I had a spreadsheet that calculated overdrive/underdrive. I will post it for you to play with.

Shawn.

[BCbud]

Thanks for the replies. Another thing that is happening is the left rear tire is coning smaller on the out side and bigger on the inside. I have put the car on my setup station and the static camber is the same on both rear tires at 3.5* and I can not see any  visible damage or play in the suspension, any  suggestions?

Thanks, Neil.

[valk]

Maybe droop? An excessive amount will let the car lean a ton of weight to the outside in sweepers. Your car seemed to have a ton of traction there last I saw. 3-4mm down in the back, 2.5-3 in the front I believe is what you want.

[Shawn68z]

Thanks for the replies. Another thing that is happening is the left rear tire is coning smaller on the out side and bigger on the inside. I have put the car on my setup station and the static camber is the same on both rear tires at 3.5* and I can not see any  visible damage or play in the suspension, any  suggestions?

Thanks, Neil.

Yep. Its your Dynamic Camber.    You need to shorten the upper link on the rear suspension.   This might involve changing the angle of it (Which causes your roll center to shift.), but you need more "Camber Rise" as Hudy calls it. Page 29 of the Xray NT1 Setup Book.

Basically when the car is in the sweeper, and the suspension is compressed the car doesn't have enough camber, and its not keeping the wheel flat, so you get coning, in the wrong direction.    Ideally you would want no static camber, and all dynamic camber, but in slow corners the car is not going fast enough to compress the suspension and that's when its good to have alittle static camber.

Shawn.

[Shawn68z]

Here is the program for the Overdrive. Its for a 720, but you can change the gear ratios on the picture and play with the numbers. Calcs the overdrive/underdrive, for any size of tire.  Neat to play with.


Shawn.

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