1/2 Scale Dirt Sprint Car!

[Paul Lopus]

Hello Everyone. I thought I would show you guys what I've been up to over the past year or so. If you would like any information on the cars, you can check out this website www.mpminc.net click on the 1/2 scale icon. Kits will be available soon.

[big maestro]

Yea, I requested some info for those cars a while back. How much is a kit going to cost?

[vectrex]

this is 1/2 scale ???? isnt it too small ?

[Marccom]

that is never scale 1/2.
1/4 Cars are round about 1 to 1,3m long...this car is not longer.
And the width ist not more than 0,7m, too.
To imagine the scale is simple:
Imagine how much cars you have to put in a row to show the length of an original 1/1.
When I see the pictures, i think you need more than two.
Greets
Marc

[Mike Casey]

I believe they scaled it off a full size car. Most 1/4 scale cars have a 25" wheelbase. Pretty much any standard full size car or truck like a toyota, viper or whatever has right around a 100" wheelbase. In 1/4 scale 1" equals 4" of the full size car.

[Belfiore28]

i can vouch for SuperModifieds on wheel base, regardless what the rules state ...90" to 96" is most comon think our rules say we can be from 88"to a 100" sprint cars are about the same

[Belfiore28]

i just checked on the specs at thier site .
the Dirt modified that they offer i was suprized to find in the specs that that car wieghts 195 lbs .
wow seems like alot less of a power to weight ratio compared to a 1/4 scale

[Marccom]

I believe they scaled it off a full size car. Most 1/4 scale cars have a 25" wheelbase. Pretty much any standard full size car or truck like a toyota, viper or whatever has right around a 100" wheelbase. In 1/4 scale 1" equals 4" of the full size car.

Yes, i think you`re right.
Normally the wheelbase is always the base for scale calculatings.
But sometimes is this difficult and not very exact.
This Type of car like above it is very difficult, I think - when i´m looking right - the wheelbase is not more than 25".
For 1/4 i know two valid wheelbases: 610mm (~24") [DWA f.e.] and 640mm (~25") [yankee f.e.]
Greets
Marc

[big maestro]

If you scale it out by the size of the rims then it looks like it would have around 32-34 inches to me. But that is just my obsevations. LOL Either way these things are kick ass no matter what scale they are calling them. I just wish someone would tell me how much they are going to cost. I think a dirt latemodel this size would be over the top.......

[bobjeffreson]

You're dead right big maestro...they are certainly "kick arse" machines, not matter what scale!
As a racer of 1/4 scale sprintcars, here in Sydney Australia, I think they are just amazing! Maybe slightly under-powered, but nonetheless, a wonderful R/C speedway racecar.
People down here are amazed when they see my 1/4 scale sprinter...the comments are unprintable on a family site...LOL...
How would they go with these larger versions?

[big maestro]

I hope there not way out in left field with pricing on these things so I can buy one. Hopefully they will let us know on here how much they are going to cost. hint hint

[Lovedr]

I called and they said I think something like $3000 for the sprint car without an engine and wheels and hubs. they are not selling a complete kit because of liability issues. I think the frames look great. also, they are not currently making the dirt car because there is more demand for the sprint car. I tried to talk them into making a stock car. now that would be cool.

[Paul Lopus]

Ok guys, here’s the story right from the horses mouth. My main obsession is building Hot Rods (Full size), but I’ve been a dirt racing fan for a lot of years. Always thought radio control stuff was cool, but the cars were never real enough for me. Electric motors? Are you kidding? At least the nitro cars made smoke, but not real at all. The quarter scale cars came close, especially with that quick change rearend. Beautiful stuff! I remember wanting the edelbrock sprinter so bad I could taste it. So I’m sitting in the grandstands one night, and I’m thinking, you know, a quarter scale servo could easily pull on a throttle cable attached to a 5 H.P. Briggs engine. I’m an old go kart racer so I know the go kart hardware pretty good. The real problem is with the steering and the brakes. About 4 years ago, we started building the dirt modified. A friend of mine races these cars. He let us take many measurements of his frame and body. The only thing I could not make was the tires. The Burris tire company makes a perfect looking grooved dirt tire, very similar to the full size tires. I bought the biggest Burris dirt tire they make. 12 inches tall by 6 inches wide. The full size tire measured 30 inches tall. Divide 30 by 12, for a factor of 2.5. I took every dimension off the full size car and divided it by 2.5. It worked great. About 2 years ago, we decided to build the sprint car. Same thing – measured a full size car. The right rear tire on a sprint car is approx 32 inches tall. 32 divided by 12 is 2.66. Took all the sprint car dimensions and divided by 2.66. I was really happy with the way the way the cars look as far as proportions. On a full size sprinter, the right rear tire is a monster, and that’s just the way our cars look. There it is guys. They are actually between ½ and 1/3 scale. I opted for the ½ scale. Is the glass half empty or half full? The dirt modified is 38 inches wide, 24 inches tall, and 6’6’’ long and weighs about 195 pounds. The wheelbase is 45 inches. The sprint car is 35 inches wide, 40 inches tall, and 5 feet long and weighs about 145 pounds. The wheelbase is 32 ½ inches. As for being underpowered, how much money do you want to spend? A box stock 5 H.P. Briggs engine cost $400. You can use a cheap $25 centrifugal clutch to do the job. You could install a bored and stroked, full race alcohol burning racing go kart engine, but the cost just went up to $2000. You’ll need a $250 oil bath clutch now too. Speaking of cost, here’s the answer. I was gonna build 15 sprint cars to get a good idea of the costs involved. Most of the interest was in the sprint cars. It would be too much to do the dirt modified also. I didn’t want to end up with 15 sprint cars in my garage (as cool as that might be). If I couldn’t sell them, so I decided to go with 5 cars to start with. Many jigs and fixtures later, we have those 5 cars 90% completed. We are an aerospace CNC machine shop and we are so busy with our “normal” work load, that I can’t find the time to finish these cars. But by building 5, I have a pretty good grasp on what it takes –and it ain’t cheap! We have been advised to sell the car as a kit because of liability reasons. The kit price on one of these 5 cars is $3,200. Wow! And you still have to buy an engine, wheels, tires, hubs, clutch, transmitter and some small misc. pcs. The wheels, tires and hubs alone will cost approx. $400. All go kart racing stuff. Being in the machine shop business, I am fully aware that the more you make of something, the cheaper the item gets, up to a point. But these cars are way too much work to take a chance on building 50 or 100. I have guys calling and emailing me that I need to build a Nextel Cup Stock Car or a dirt late model. I can just imagine what these cars would cost. The buck and mold for the body would cost unbelievable. Yeah – people tell me there are bodies already out there. I’ve seen some of these bodies and the scale features are not that accurate. Again – you have to start with the tires and build the car around that. These bodies are built for kids go karts. Everybody cringes at the $3,200 price of the sprint car. These cup cars would probably be in the range of $4,500 to $5,500, just guessing. Moral of this story- as the cars get bigger, so does the cost. To those who think these costs are ridiculous, try it yourself. I told you how. Go thru all the problems, research, building jigs and fixtures, debugging, making the parts, and you’ll have a pretty good idea of what it takes. Well, that’s my story. Thanks for your comments and remember – if you haven’t got dirt in your beer, you’re not at a real race - Paul

[alloyparts]

Thanks for the full blown story Paul.
I give you props for doing what you have done, I dont think the price is that far out either. If you look around it will cost you that to own a Edelbrock sprint as well.
Thanks for posting the info
Fred