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Formula 500 Setup

Formula 500 Setup

Postby Petawawarace » June 10th, 2005, 9:30 am

Hey everyone i figured i'd set up a forum for building the formula 500 sleds. First off, what size would be best suited for radius rods on the right side. I'm making them from aluminum and i was thinking that 5/8 should be big enough...if not please someone let me know.
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Formula 500 Setup

Postby jhooper/HRE » June 13th, 2005, 2:56 am

Jeff,
5/8" is fine for the tie rods but I would use 3/4" minimum for the radius rods and IF you are a little hard on things you may want 7/8" on the lower right radius rod. I would use 7/16" steel adjustable rod ends on upper radius rods and 1/2" on bottom, if you use left hand thread on one end of each rod it makes adjusting much easier.
You will need to drill out the holes in the strut to fit these larger rod ends.
While you have the struts off for drilling, this is a good time to brace the R.H. one, there are various ways of doing this, the critical area is at the top of the radius rod bracket where it is welded to the spindle tube. You should at least clean the paint out of this area and weld it more solidly, it wouldn't hurt to add a gusset.
When a race sled enters the corner the force tries to push the Right ski under the bellypan, this is what we must brace against.

Since we are on the subject of front ends lets talk about skis and carbides. I would use the minimum length alum. racing skis {I believe it's 14"} and I will use the wider style on the left {available from WAHL Bros.}.
I will use 7/16"-20 gr. 8 bolts to attach to spindle and I will make sure my 6" carbide is centered under this bolt.

Preparing your carbides will be the MOST CRITICAL thing on your sled, always use a gauge {available from WAHL} and make the carbide angle perfect, "CLOSE ENOUGH" will not win you many races.
I would also grind down the steel in front and behind the carbide until the groove is about gone, this will also be very critical when you only have 6" of sharp carbide to work with.
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Formula 500 Setup

Postby jhooper/HRE » June 20th, 2005, 2:40 am

Since I am not a Polaris guru, maybe one of you who is, could supply us with part numbers for the H.D. sway bar assy., it would also be handy to know which years and models they came on. Thanks, John H.
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Formula 500 Setup

Postby Jamon » June 20th, 2005, 11:06 am

The HD sway bar was available on all XCR from at least 94 to 96, maybe also 93 but not sure. just take a look at www.partsland.com , all the OEM parts are there... Jason.
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Formula 500 Setup

Postby jhooper/HRE » June 23rd, 2005, 3:26 am

I have had a few calls about removing items from the chassis, you will be allowed to remove all the brackets that held the fuel tank, oil tank, air box, hood, belly pan and bumpers.
You will not be allowed to perform surgery on the sled, this means no cutting or drilling holes for lightening purposes, we will not allow racers to spend time or money to excessively lighten these sleds and add ballast wherever they want.
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Formula 500 Setup

Postby jhooper/HRE » June 27th, 2005, 9:56 am

For all you racers looking to save a few $$ when setting up any ice oval sled, I would suggest making your own stud backing plates, I have been making them out of 1.25" x .125 thick aluminum flat stock, grade 6061-T6.
You just need to cut this material into pieces slightly less than 2" long then drill 2 - 1/4" dia. holes aprox. 1.25 inches apart, try to keep the hole pattern consistent {it makes everything easier}.
When you are installing make sure the plate is resting against the track bar to keep it from flexing in the rubber under acceleration.
It is very common for new guys to get confused and have the plate against the wrong side of the track bar.
Make sure your drill is cutting the right size, if the hole is any larger than .255" the T-nut will pull into it and you will never have proper tightening.
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Formula 500 Setup

Postby Petawawarace » June 28th, 2005, 11:18 am

Just a few questions for anyone out the with the answers......i know john had been talking about running the wider ski on the inside, i was wondering where the best place to get both sets of skis would be....i have another friend building a sled, and we are going to buy a set of wide skis and a set of the narrow ones. as well, this question is more for john, but can i run a replacement camoplast track?...There are tracks that are a direct replacement for oem, but made by camoplast.....that are cheaper than the one you have listed in the rules...thanks everyone, and i'm sure i will have more questions
Jeff
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Formula 500 Setup

Postby jhooper/HRE » June 29th, 2005, 4:26 am

Jeff, The skis you need are available from Wahl Bros. 1-218-782-2295, you just need to tell them you want the same thing Terry was using on his Champ sled, there is a standard Alum. ice oval ski for the right and a wider one for the left.
If you are going to replace the track you will need to use the low profile Camoplast racing track, it comes with the tall clips already on it, if you figure the expense of buying and installing these tall clips on a standard track it makes more sense to buy the track already setup for racing.
If your stock track is nearly new you could use it but you MUST install tall clips on every bar on the right side to prevent derailing and excessive hi-fax wear.
There is a couple disadvantages with the stock track, most are a taller profile which needs longer studs, these have a tendency to bend your alum. plates more and pull the T-nuts thru the track.
The stock track is not as strong as the Camoplast, which allows the entire stud/plate assy. to bend over under a load, this can hurt the holeshot and cornering. John H.
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Formula 500 Setup

Postby Petawawarace » June 29th, 2005, 3:56 pm

I am very quickly addin alot of cost to building my sled.....not that its more than what you said john, its just more than i expected with my very tight budget....two rules i would like some clairification on are the exhaust rule and the sway bar rule....from previous dicussions i'm assuming that we can do what we want with the sway bar so long as it goes through the same chassis holes and the same spots on the skis , correct? can we make our own swaybar? and how the hell do you get the stock one out without damage? and i uderstand the cutting of the exhaust at the after muffler....im just wondering where the after muffler starts.....is it as soon as it starts to go straight and stay the same dia? thanks....Jeff
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Formula 500 Setup

Postby jhooper/HRE » June 30th, 2005, 5:27 am

Jeff, Now your seeing first hand why we really need a class like this, if you were trying to build a competitive Sprint your cost would be 5 to 10 times higher. If you want to have the very best {fully prepared} 106" Track for a Sprint you would have close to $2000us in just materials and it takes 1 guy aprox. 40 hrs. to complete {just ask George Samson}.

To remove the stock sway bar you will need to remove 1 strut then drill out the 3 rivets holding the plastic sway bar bushings to the chassis, this should give you enough clearance to snake it out of there. Yes you can use ANY swaybar but it must fit in the stock location thru the chassis, you can also use any bushings and connecting linkages but it might be best to just find a HD swaybar off a little later XCR.

For the pipe mod. I would use a cutting torch, MAKE CERTAIN THERE IS NO GASOLINE OR FUMES IN PIPE. Cut off the after-muffler by cutting completely AROUND the muffler aprox. 8" from the back end, DO NOT CUT STRAIGHT THRU, you would cut off the back half of the tuned pipe inside. After you take this piece off it is easy to see where the remaining piece needs to be removed,{aprox. 12.5" from the back of the original muffler}, just be careful not to cut into the tuned pipe.
There is also a 35mm i.d. internal stinger pipe which should be removed by cutting {with a hacksaw} the tail end of the tuned pipe {right beside the weld}. The outlet hole in the tuned pipe will now be aprox. 38mm, this is much too large but you should leave this alone until I test one on the dyno. The size will need to be reduced a bunch, a change of 1mm in diameter at this point will make a noticeable difference, if it is 1mm too small it may be fast for 1 or 2 laps but will heat fade, if it is 1mm too large the engine may take 1 or 2 laps before it starts to run fast, if the size is off by 2mm on an engine like this it will never be fast. Another thing I will test is to see if there is any difference between extending the stock rear cone angle down to meet the proper size stinger or simply using a square shoulder reducer. John H.
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