# Hey Blubyu



## Hornet (Dec 1, 2005)

Didn't want to steal Joe's thread.

Here's the formula for finding Cruise or Average RPM.

Gear Ratio X MPH X 336 divided by Tire Diameter = Cruise RPM.

To get MPH you divide your feet per second by 1.478.

Your tire diameter = 0.434"

36 ft per sec = 24.36 MPH

8/18 gears = 2.25 to 1 gear ratio

7/15 gears = 2.14 to 1 gear ratio

2.25 X 24.36 MPH X 336 divided by 0.434 = 42,434 average rpm with the 8/18 gear set-up.

2.14 X 24.36 MPH X 336 divided by 0.434 = 40,359 average rpm with the 7/15 gear set-up

I used a 1 second laptime,as i didn't know how far under it you'd went.
If you have the length of the lane ,and it's more or less then 36 ft,it will slightly change the numbers too.

But that gives you a ballpark idea of your average rpm

Updated numbers.

36.25 track ft divided by .0989 laptime divided by 1.478 = 24.80 MPH

2.25 X 24.80 MPH X 336 divided by 0.434" = 43,200 average RPM

2.14 X 24.80 MPH X 336 divided by 0.434" = 41,088 average RPM


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## Hornet (Dec 1, 2005)

I'm not sure how far you've taken things,but by them numbers you've gone a fair ways,lol:thumbsup:.


If you're going for an all out record,it's worth lightening the rear axle assembly if you haven't already.
Drill out your hubs and crown gear,then send them off to Mark McVittie ,he does rear axle balancing.
It's only worth doing if your going for an all out record,as the hubs do get weaker,the crown gear not so much.

BTW:who's 18 and 15 tooth crown's are you using


http://mmvhoracer.com/Balancing__etc.html


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## blubyu (May 4, 2008)

Using Quicker 18's, JW & Quicker 15's. metal 7 & 8 Quicker. No drill holes,Tyco X2 axles. So if I did the math right 48,000rpm with 8/20 gearing? Could the sweet spot be around 44,000rpm? Yes DRILLING out the gears and rims along with a hollow axle would help,but your right in a race I want it to stay in one pc.


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## blubyu (May 4, 2008)

7/18=49,370rpm. ???


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## Hornet (Dec 1, 2005)

Yup,you got the numbers right.
Remember this is only an average,on the top end of the straights your gonna be well over those RPM numbers
Years ago the drag guys were already up around 135,000 RPM going through the lights
60,000 is about the upper limits of a stock style arm,if the com plates aren't glued.

For a one shot deal,to set a record,it's worth lightening things.Take a look at Slottech's hollow Titanium axles,front and rear too.
It'll be an axle you'll only want to use during qualify'ing or record attempts,as it'll be to light duty for racing
On a car your actually using for racing,these things aren't worth doing,but for that one run at the record,a light weight axle swap might be the ticket,yea baby:thumbsup:.
You guys sound alot like us,and holding the track record,has just about as much status as being the champ,lol

If you can try increasing the room temp a few degrees if it's cool at the tracks surface,sometimes it'll help if your after a track record,lol

Rick C think i should send him some shoes,lol


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## blubyu (May 4, 2008)

Hornet, we have been waiting for a lap under 1 second for years as most cars qualify around 1.11 with some top qualifiers @ 1.05. We still are around those numbers on are flat 28' oval, hoping to get under 1 on that track soon? Seems the cars run faster the colder it is out in the garage?


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## Hornet (Dec 1, 2005)

Those are wicked numbers Blu.

Have you thought about going even taller on the gears for that track.
Brings the RPM down more,and lets the car pull more amps,picks up a little more of the torque factor a DC motor has.
I think you might be getting close to the RPM limits of the Vortec arm,and reliability will start to get shaky.
I bet you're well over 50,000 on the straights.
Are you running big foots,i'm guessing you might be,if you are,try getting your hands on some Slottech Silver brushes,if you haven't tried them.
I always got more speed out of Tony's brushes then Bob's brushes:thumbsup:


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## blubyu (May 4, 2008)

Not a fan of the bigfoots for S/S, but I have been building all my Storms with .008 brush springs for the past 2 years instead of the .006 & .007's.....let me tell you after a good breakin they Rock.... I have been on the pole for every race this season but 1,still have to figure out how to win? (won on the banked oval) I run a salt & pepper.


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## blubyu (May 4, 2008)

8/18 works better than a 8/20, unless your running a Panther (the other car I'm trying to beat) seems the panther guy's can pull a 9 with a 22 or 20 with .458-.456 rears and by your numbers there around 50,000rpm?


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## blubyu (May 4, 2008)

Next race is back at the Banked oval looking to break the 924 lap total for 5min. Are biggest problem is the hobby fading out this track would draw 15+ racers back in the day for a friday night race now were happy with 8??


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## Hornet (Dec 1, 2005)

Have you ever tried 8 /15,it would bring your revs down a bit more,and the 15 tooth crown should be lighter then the 18,although it won't apply as much leverage to the axle,if it's a whole lot smaller in diameter ,but it's lighter weight might offset the leverage factor.
Have you tried a 9T pinion.

If you're allowed bigfoots,it might be worth experimenting a bit more with them.
I know alot of guys swear by the small brushes,but in theory the bigfoots work better,and i've always got more speed from the bigger brushes.

The way to get good speed with the bigger brushes is wear them out first in a beater car,honestly,lol.
When they're about 1/2 wore-out,is when they really start to work good.
Then use either a Slottech Hi Temp .009" (hard to get),or try Bob's .009 or .010" Big Foot springs.
I know,i got rocks in my head,lol.
But brush bounce is a killer in our hobby,especially at your RPM levels.
And the principle behind the big spring light brush is the same as a wheel on your car,the lighter the weight,the easier it is to control the bounce.
If you tune by ear or use a dyno,the amount of pressure on the com will actually be less,as this combo will usually always rpm slightly higher on the dyno.

Here's a link to some of my brush theory from a few years back.

http://ho-tips.net/showthread.php?tid=241

Try it out ,and see if it works for you,it does for most of our guys.

If you want to try out a pair of my custom Storm shoes,PM me your addy.The only thing is the shoe's will only work real good on the bigger barreled cars,my homemade bender is only set-up for big barrels
There's a few guys who've had my shoes,and i've never had any negative feedback from any of them,so if you want to try a pair out,let me know.
Rick


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## blubyu (May 4, 2008)

Tried the 8/15 seems not to pull as hard,9 tooth never seems to workout on the storm but fine for the panther (might be those big motor mags?). Yes there is alot of speed in the shoes and how you tweak them,as well as new shoes. I also like my brushes broke in real good,if you seen them they would have as much area as a bigfoot,plus when you turn the rear wheels by hand you feel like there is no tension very smooth.


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## Hornet (Dec 1, 2005)

Which motor mags are you using,the newer round back's or the old square backs.

The old square backs will give you a bit more torque then the round back motor mags will.

Sometimes a guy gets in a rut,and it's hard to change,lol.

My theory has always been,if i've been working the same set-up or combo for awhile,and seem to have hit a brickwall for getting more speed from it,it's time to change the combo up,lol:thumbsup:
You'll never get faster,if you don't experiment,lol:thumbsup:

I'm just throwing ideas out for you to try,if you haven't already tried them:thumbsup:

If you do decide to experiment some more with the bigger barrels,let me know,and i'll send you some shoes to try as part of your experiment.
Rick


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## blubyu (May 4, 2008)

Running the radius motor mags,with the newest ones seem to be the ticket! You can't beat little bit more mag sticking down when you see the ride height going through the banking? Have to try a square motor mag with a 9 tooth (need to fine my best set??).I started trying the t-jet crown (15) because that panther had the 2 best lanes white and red as it could motor up top. As far as shoes I'm good on them thanks anyway! Remember it's the SHOES!


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## Hornet (Dec 1, 2005)

I think in your case the older P3/early Scorpion motor mags,might work a little better,more torque :thumbsup:

You make the statement your small brushes have the same footprint as the bigger brushes,if that's the case,watch your brushes for mushrooming,once they start to mushroom,they don't slide in the barrels like they should,just something to keep your eye on.

I only make the shoe offer usually once
Rick


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## Hornet (Dec 1, 2005)

Just a heads up,"Don't" do the pinion and motor mag swap at the same time. 

You introduce to many variables at once,and you'll have no idea of what's doing what:thumbsup:

Try the mags with your existing combo first,as they're easy,then try adding in the gear swap.
Do one test at a time

Another thing is,if you aren't already doing it,i'd have my rear axle assemblies set-up so i can swap them in and out using the differant pinions.
Probably means you'll have to do some crown gear modify'ing and trimming,and that'll mean you'll need a bunch of spacers.
Trim everything to fit your biggest gears,then throw enough spacers on the axle between the back of the crown gear and the inside edge of the tire to accomodate the differant combinations of gears.
This way to swap differant axles onto differant pinions,all you have to do is slide the required amount of spacers over for that particular pinion.

Always try to keep the variables to a bare mininimum when you're testing new ideas,and that includes the room temperature,start documenting it during tests,as differant room temps will skewer your test results


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## blubyu (May 4, 2008)

Hornet, you must of been looking in my tackle box......I have a ton of setups ready to go. I know I don't have the same area as a bigfoot but after breakin and a race or 2 there radiused well. I'll try the square mags and see?


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## Hornet (Dec 1, 2005)

I figure the numbers you're running,you pretty well got things figured out,but just checking in case,lol:thumbsup:

Rick


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## slotking (May 27, 2008)

interesting thread.
have you tried playing with a panther or t1?
I love the torque the motor mags provide.

The other benefit is the shoes, using ricks shoe bending, I can always get a panther or t1 with super soft shoe pressure and and still maintain speed.

No matter what, the storm always seem to need more shoe tension than the slottech cars that seems to allow me to turn faster than the storm.
just my experience on plastic track. routed tracks is a different thing


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## Hornet (Dec 1, 2005)

The only thing i could ever come up on the T cars being able to run less tension was the travel factor,they carry and need less travel then a Storm
But yea you could always run less shoe tension on Tony's cars then Bob's.


I was hoping he'd pick up a little more torque if he had a good set of the old square backed motor mags for his Storm,i don't know if they'll match the Cat mags for torque,but they'll get him closer in torque then the radius backed mags will.

Blu,i don't now if you ever seen this,but here's some brush testing i did awhile back,all my tests are on Wizzard cars.
Bottom of post 1 might interest you,it's a vortec arm test,and also post 4 might interest you,it has the differances between a salt and pepper brush set-up to a full silver brush set-up

http://ho-tips.net/showthread.php?tid=1125


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## blubyu (May 4, 2008)

Guess I'm cheap? Silver is a bit faster (much better then the very first silvers) or set in my ways (just because it's new and costs more it's better?). Try and setup a square mag tomorrow for next Fridays race(8/18-15) as soon as I finish the 2 fray cars I'm building,have my watchmaker tools out........Let you know how the big mags are. T-1 ran okay on the banking but the Panther just won't go away (panther,storm show). Funny as it is the heaviest chassis by far? Flex can hurt your speed on the Banking. Fresh tires are a must, Lawbreakers were on the record car it also won the race with record high totals with perfect segments in more than one!


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## Hornet (Dec 1, 2005)

PM your addy,i'll make you up a parcel with some modified bigfoot barrels and shoes,plus i'll throw in a set of Slottech Silvers for you and a pair of .010" brush springs.It'll give you enough to slightly change up your existing combo.
Have you got good square back mags Blu.
I'm thinking your stuck in a rut lad,you been listening to the bulletin boards to much,but we'll get you changing,lol:thumbsup:
Rick


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## brownie374 (Nov 21, 2007)

blubyu said:


> Guess I'm cheap? Silver is a bit faster (much better then the very first silvers) or set in my ways (just because it's new and costs more it's better?). Try and setup a square mag tomorrow for next Fridays race(8/18-15) as soon as I finish the 2 fray cars I'm building,have my watchmaker tools out........Let you know how the big mags are. T-1 ran okay on the banking but the Panther just won't go away (panther,storm show). Funny as it is the heaviest chassis by far? Flex can hurt your speed on the Banking. Fresh tires are a must, Lawbreakers were on the record car it also won the race with record high totals with perfect segments in more than one!


Hey Jeremy where ya running the tjets?


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## blubyu (May 4, 2008)

Dan's Race I think? Now I just need some dbl flanged rims for a narrow Stockcar,sold off all my t-jet stuff. Now adding 1 of each from a friends collection and building him 2, and I keep 1 each,not bad? Missed you guy's 2 weeks ago @ PL HOBBIES? Drove by on are way out to the other Rick's series race, they were closed.....hope they have above rims? Hope to get out and try my jets against you Pro's. First I need to get my banked cars ready for this Friday.........HAPPY NEW YEAR!!


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## brownie374 (Nov 21, 2007)

There is a race tomorrow at ALS in Beecher.


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## blubyu (May 4, 2008)

Saw that,but I have so much to do before I can Play.........have tires & rims glue on waiting 24hrs before assembly,that's for tomorrow. Would love to check out his track along with yours!!!


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## brownie374 (Nov 21, 2007)

If you want to come and race there will always be loaners if I am there.I will make sure you know when my next race is.


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## Hornet (Dec 1, 2005)

You're probably aware of this,but when you swap the motor mags out,you'll want to have a couple differant sizes of front and rear tires ready to go.
The square motor backs unless heavily grooved ,won't have the same rail attraction and clearance as the radius back mags do,and there's a good chance you'll need to go slightly taller on your set-up.
At the speeds you guys are running,you're probably slammed right onto the rails,with not much wiggle room for clearance.
Just a heads up,that's all:thumbsup:


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## blubyu (May 4, 2008)

.370+ in front and .434 in the rear.


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## Hornet (Dec 1, 2005)

I don't normally reconmend tire sizes,but you should be tall enough on the front with 370.
Your best tuning aid is your "ears"
Try to get the car on the track by itself,and then listen to it,a low noisy car is a bear to drive as it'll stick in the corners and be very inconsitent,what you want is just a whisper of noise,and a glide through the corners.
You can sharpie mark the bottom of the car too,but remember "1" high rail skewers the marker test,but the marker test and your ears combined work,and will give you you're best set-up.

I usually shoot for a dead even wear pattern across both motor and traction mags,but that's what works for my driving style.
Set the car up for your driving style and what you're comfortable with,not what you hear on BB's,hard to get a Bulletin Board to drive the car,you are the driver,so experiment.
Personally though and this isn't normally my style,but i think you could come down slightly on the front and go up just a hair on the back,level the car out a little more,"but" i've never been on a full banked tri-oval,and you're set-up might be the best for your style.
All i usually try to do is get guys to experiment,even if i pee them off,lol.
At least this way,you've tried differant ideas,some will work ,some won't,but you don't know if you don't try them for yourself.
To many guys take what they hear on a Bulletin Board as the gospel truth and believe that's the only way to set-up a car,"Wrong",the only way to set a car up,is find what works for you and your driving style,and that means you gotta go out on a limb and do some of your own experimenting.
Some guys have enough talent they can pick up any car and drive it faster then most,they have the ability to match their driving style to the car,but they are few and far between.
For the majority of us Joe Schmo drivers,we're better off matching the car to our driving style,instead of matching our driving style to the car
Rick


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## blubyu (May 4, 2008)

.360 is normal for the front,but the newer motor mags and soft chassis I was nicking the fronts of the motor mags. No way was I going to chip them so I went up to .370 and the car still handled like a dream with lots of roll/coast.The rear you need to be down still to stick in the turns. So I run it up in front instead of level across.


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## Hornet (Dec 1, 2005)

If the mags work like i hope they do for you,you should only see a Panther in the mirror

That statement should bring on a flurry of replies from Mike,lol:thumbsup::wave:


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## blubyu (May 4, 2008)

Hornet, had little time to build a square mag.doing tires instead. Saw the panther in my mirror anyways....took pole 1.012,ran 962 laps to panthers 936 laps. Ran 8/18,lawbreakers .434 rears(4 race on tires!) handled. Thought I was in trouble with the panther clicking off some .984 laps in practice!!!


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## Hornet (Dec 1, 2005)

LOL,awrighty,way to go:thumbsup:.
26 lap lead,that's outstanding.
The Kitty fell off a bit from qualifying,you must of pressured him,lol

If you want to try out a set of my modified bigfoot barrels/adjusters (slotted barrels and drilled out adjuster screws),let me know.
I'll send you some shoes to try out if you want.The shoes work,i've never had a pair come back yet,with anybody bitching about them
Rick


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## Hornet (Dec 1, 2005)

Blu,what are you running for a guide-pin?
Rick


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