ozzie-crawl

i am looking for some advice from guys running drag cars,i have just started a build. not your usual drag car ???
it will be running a 1/8 scale mug-en rear end minus the suspension on a carbon/alloy frame,as its not being built for competition so no rules, power will be a leopard 4074 2000kv
on 6s then maybe 8s.
body will be a cut down (slammed) short course shell as the rear is fairly wide (255mm- 10")
chassis is around 480mm (18 3/4") long,75mm (3") wide by 4mm thick high grade carbon fibre that will have alloy reinforcement.a large rear wing will also be added.
i have a set of rj speed front rims/tyres coming plus a wheelie bar,steering blocks etc
My questions. is there a formula/calculation as far as rear track width compared to front track ?,most seem the front track is some what narrower then the rear.
should the front have some sort of suspension at all ?
what sort of speed can the rj speed (Oring type) front wheels take ?

here is a few (crappy phone) shots so far
any advice would be appreciated

ziggy12345

Hi

I run the same setup as this with a 1/10th scale rear end. You should keep the suspension and also install a diff. These are hard to come by for 1/8th cars thats why I went to 1/10th. Also the car will need little torsional stiffness. To do this I dispence with the normal flat chassis layout and join the back to the front with some angle aluminium. This give the car linear stiffness (up and down flex) but little tortional stiffness (you can twist the chassis easy)

This is how 1/12th cars are able to be stable with only 2wd as the back is seperate from the front and has a very loose diff.

I use normal 1/10th wheels at the front cut in half, In fact more than half as they are only 10mm wide and rounded

Are you going to use an electric motor?

Cheers

Brent Davis

O.K., I'll try and answer your question rather than ramble on things that weren't asked.

With Top Fuel and Funny cars, the front tires are narrower than the rears because of the extended chassis mostly but if you built a Pro-Mod or Pro Stock car, the front tires are mostly wider than the rears because of the shorter wheelbase. The stability is ALOT better that way for the short cars. You need to know what car you are building first to determine what the front should be and I will add that your rears are waaaaayy too wide but that is because you are using that Mugen rear end setup.

The front o-rings have been on my car and stay on in the 88 MPH ranges. What you will HAVE to do is put superglue on the o-rings or they WILL come off no doubt.

I too built my own Funny car drag racer that has a 14" wheelbase, Novarossi Kanagaroo with a custom home built rear end and has been a best of 1.55 ET and a best pass of 88.2 MPH unofficially. The official World track record is 1.56 @ 82 MPH so I am in the hunt.

Good luck man.

ozzie-crawl

brent thanks for your reply
i am not up on the drag terms but see it being between a pro stock-pro mod setup.
i realise the rear tyres are going to be much wider than a normal drag car,but being i dont have to follow any rules i am hoping the wider tyres will give me better traction and stability.
i will be chasing more top end speed than fast ET,s
any advice is much appreciated

Brent Davis

Look here at my old thread of a build.

http://www.rcuniverse.com/forum/m_9306490/tm.htm

ozzie-crawl

thanks for the link,they are some very nice custom jobs
i done a little more today,motor mount semi bolted in and some alloy T rails cut out. the T section alloy will have some holes drilled threw to lighten it up a bit,they will also hold
the front alloy axle
for got to mention this is a budget build (out of work [&o]) so using what i have around the work shop.
my tools consist of a 30 year old 4" grinder and a $20 battery drill (low speed is busted) so progress is rather slow

ozzie-crawl

holes drilled for front axle