My 2008 Speed Competition Car

[fasterthanspeed]

I know you guys were hoping for pictures but none yet. Im hoping to get some for you guys tonight if I finish modifying the chassis and making some new motor mounts.
My New car will consist of:
Serpent Impulse
Rossi Maranello as usual
some smaller lighter airplane servos
A futaba gy401 Gyro
Itll be geared to do about 120 at 40k rpm
Itll be using a Futaba 3PK fasst radio system
Im hoping to also get my hands on some capped tires from bsr racing.
I found this one body by serpent I plan on running.
http://www.serpent.com/product/170016/description/
I hope to have this close to running by the end of next week as there isnt a whole lot of custom work.

[fasterthanspeed]

Well the motor is mounted after about 2 hours of working ohn the mill. I do have a small dilemma though. The brake rotor is hitting the flywheel. So ill have it put on a lathe and get made smaller. So all ineed to do is have made a solid diff, some new layshfts, re gear, make a new upper deck, and electronics and ill be driving it!
Sorry that I didnt get you guys any pics tonight. My camera is dead and have no batteries. So ill try to get some pics even if that means using my cellphone camera.

[wqqdster]

Is a single engine going to be enough to pull that gearing? Somewhere on this board someone figured out that it took 3 or 4 hp to get a car to that speed.

Show us some pics as you progress

Gary O

[fasterthanspeed]

Ive been talking to several people out in the miami florida area where basically all they do is speed runs. Theyve seen Super Nitro RS4s going 107+mph. And it was a single engine and it really wasnt a top notch motor from what I heard. If it doesnt work Ill have plenty of time this year to complete it.

And Ill show some pics shortly. Just need to go pic up some batteries for my camera

[fasterthanspeed]

Here are the pics i promised you guys!
http://i120.photobucket.com/albums/o187/speedchallenger/DSC01227.jpg
http://i120.photobucket.com/albums/o187/speedchallenger/DSC01226.jpg
http://i120.photobucket.com/albums/o187/speedchallenger/DSC01225.jpg

[fasterthanspeed]

116 veiws and only 1 reply? I need suggestions. Positive and negative feed back would be nice to.

[wqqdster]

I like that big ol' engine in that frame. looks cool!

What is your gearing going to be? Is what you have there tall enough? If not it'll move the engine away from the rotor and solve your interference problem.

There is a slight reduction between the rear jack shaft pulley and the diff pulley (1.5 : 1?) and your pinion to spur looks like about 3:1 so that's about 4:1 overall. I can't remember exactly what I calced the 2.5" wheel rpm at 100 mph to be, something like 14-16K rpm which means your engine needs to hit about 52K for 100mph. Check my math before you change anything!!!!!!

[ajlovering12345]

Feedback as asked!

If your going to run a Lola shell you need to change the bumper. It will be lighter also.

If your using 4wd make sure you get the gearing right so the overdrive to the front is about 1% Change the wheel diameters to get this right.

Calc the top speed for 35,000 rpm. Realistically you will get between 32 and 35K rpm.

Apart from that it looks great!

Cheers

[fasterthanspeed]

The gars on there now are just the stock ones. The front diff and front pulley will stay stock and i have some 500k oil in the front diff. I plan to just gear the side pulleys differently. I already have the new pulleys.
I plan to go to my friends machine shop this saturday. Ill be getting some longer lay shafts made a solid rear diff and this 1 part for the breaks.
And thanx for replying lol.

[fasterthanspeed]

Well today I thought of an idea. Im going to mount the back of the body to the hubs not the rear of the whole car.
Thisll allow me to run softer suspension and better downforce so less drag. The force will be applied directly to the wheels and the force wont be exspelled thrhough the springs.Thus making the car faster and have better handling. And itll be able to take bumps better as the springs wont be compressed and softer springs will be used. Im also going to find a way to do it to the front of the car.

[fasterthanspeed]

Well here is the floating rear diff. I know its not the prettiest thing uve ever seen.lol. but itll get the job done. I still need to make a front one.Which is what ill probably do tomorrow.
http://i120.photobucket.com/albums/o187/speedchallenger/DSC01230.jpg
http://i120.photobucket.com/albums/o187/speedchallenger/DSC01229.jpg
Tell me whatchya think!

[ajlovering12345]

You should use CF for the bracing, it will be lighter

Cheers

[wqqdster]

I hate to be Mr. Nay-sayer, but I think there are some flaws in your design. Full scale cars are a good reference for scale designs so if you don’t see it on the big ones, there’s a reason.

The whole idea of suspension is to keep the tires in contact with the pavement as much as possible. In the case of our cars, the instant the tires lose contact with the pavement they slow down, just a wee bit, but they do slow. Keeping the unsprung weight as low as possible assists the suspension in keeping that contact. That’s why companies spend millions to develop magnesium wheels and aluminum/titanium suspension pieces. By attaching the wing and all of the mounting hardware directly to the hubs you have increased the unsprung weight by that amount, actually decreasing the handling of the car.

“The force will be applied directly to the wheels and the force wont be exspelled thrhough the springs.” Any down force applied to the car is already applied to the wheels. The springs don’t expel any energy, rather they store the energy when compressed, release it when stretched and transfer it directly when stable. If you put your car on a scale and put a one ounce weight on the wing (down force), that exact weight will be transferred through the springs to the wheels and scale.

“Thisll allow me to run softer suspension and better downforce so less drag” I’m not sure how these are connected, but for most pavement racing we want the stiffest suspension we can get away with. Soft springs allow the wheels to move farther when they hit a bump, allowing the tire to lose contact.

Lastly, with the tires constantly moving up and down your wing will be following that movement and your down force will be changing with that movement, increasing as it move up, decreasing as it moves down. A wing mounted on a stable base (like the frame or body) will provide stable down force. Years ago the rear wing on pan cars was mounted to the rear pod, effectively doing the same thing you are. Now they are mounted to the body, lessening the unsprung weight and allowing for more consistent down force.

Believe me, if it worked better you’d see it on Formula One and Indy cars, but you don’t. Keep thinking outside the box though! You’ll learn from every experiment.:D

[fasterthanspeed]

Hmm I never rally thought of it that way. I took the design off of 1/8th scale onroad vehicles. And researched that it makes it have better handling at high speeds.I have a question for you then, why do the 1/8 onroads have it then. Its attached the same way as an 1/8 onroad.

Hey aj Ill be making everything thats g10 and some other parts later down the road out of carbon fiber. I just dont want to waste it as I already have. Once I get the car perfected Ill be making some carbon fiber parts.

[wqqdster]

I'll check that out and get back to ya! Do you have a site that I can look at?

[wqqdster]

http://www.mugenseiki.com/menueefi.htm

:oThis site show exactly what you're talking about except they are mounting the whole body to the rear hubs.:huh::huh: I have no idea why they do that but there must be something to it!

[lttakas]

hmm looks realy good how much power and rpm are you geting out of that engine?i am also working on a speed car my self i have a super nitro rs4 that needs a realy big motor to power the tall gear ratio in myn

[DrKnow65]

Any "ram air" ideas for the motor?

Does two speeds help for a high speed rig? I would think that the extra drag/rotating mass in the drivetran would get tossed? For that matter is there a handling bonus to 4wd in a strait line?

A gyro? used to help it go straight?

[fasterthanspeed]

Actually 1/4 mile isnt to long of a track to run. So yes a 2 speed is required. 4wd helps out alot. I am also following all the high speed cars. Most of the 100+ cars are 4wd. Using a gyro is like having a perfectly setup car with no crsswinds side hills etc.
I just finished putting in solid diffs all around.

[balang_479]

still going for nitro...., looks good, much more basic, i think the main problem of all these land speed cars is that people try to make them complicated. Simple like Nick Cases ENTC3 is the key.... thumbsup

[fasterthanspeed]

lol yup im still going with nitro i need a challenge. I dont wanna just stick a big motor and a big lipo in a car and put a large pinion and go 100+. I want a challenge of tuning the engine, choosing different gearing etc...
Not saying eletric is easy by any means. I just want a little bit more of a challenge.
I think ill do a lot better this year as i will be having much more time to get all the bugs out of the car and tune it to optimum performance!

[Jev]

wqqdster I think you will find that most full size racing it is prohibited to attach aero downforce parts to unsprung parts.

The reason unsprung weight is bad is that it prevents the suspension from reacting as quickly as it otherwise would and it will have more momentum.

The trouble with high downforce pushing onto the sprung part of the chassis is that as the speed increases the loading on the springs also increases. This effectivly means you are running a heavier car and the springs that were fine for running at 20mph are nowhere near stiff enough for 80mph.

Hope this helps :)

[GordonFreeman]

I like the 1/8 scale wing to hub idea. Good Job.

[MiamizFinest]

Nice how the project is comeing along FINALLY i was able to make it to this site

[rccardude04]

The reason the body is mounted to the hubs is that at a certain speed, the body will produce enough downforce to bottom out the chassis. Then you have no suspension. I'd leave it the way it is. The amount of force coming from the body pressing down will far outweigh any more unsprung weight you will gain.
-Eric

[ironoutlaw]

what engine are you using , i think you are on the right track probualy alot of fine tunning but that is half or 3/4 the fun keep it up

[fasterthanspeed]

Its an AXE Rossi Maranello, modded by tnt mods.

Tnax for the compliments.

[fasterthanspeed]

Small Update:
I sent a design of the upperdeck to my friend to cnc mill an upper deck for me.
I got the whole drivetrain system complete. I found some pulleys that i used so i wouldnt have to reaplace the layshafts.
One guy at the lhs is giving me a .21 RB concepts boat pipe as a regular 1/8 pipe wont fit. Im hoping to have it all setup except for the upper deck by monday.
ill get some pix after i get the exhaust system tomorrow.

[fasterthanspeed]

http://i120.photobucket.com/albums/o187/speedchallenger/DSC01239.jpg
http://i120.photobucket.com/albums/o187/speedchallenger/DSC01238.jpg
http://i120.photobucket.com/albums/o187/speedchallenger/DSC01237-1.jpg

[ajlovering12345]

The engine is huge! Nice job on the car Brian, it looks Ace!

We should have a few cars over 100 this year.

[Figit090]

lookin' good!

[fasterthanspeed]

Will i finally started it today. I was having issues though. I need to go out and buy some more glowplugs and clean out the engine as i havent started it in a while.

[ajlovering12345]

The marrinelo is not an easy engine to tune at the best of times. What %fuel are you using? I would go for 30% with 0.8mm head clearance and a No 8 plug.

Cheers

[fasterthanspeed]

Just got back from the hobby shop. Picked up some .3mm shims some novarossi short glowplugs #8. Im about to put a pipe on with a silencer so my mom doesnt get as upset lolz. Ill let you all know how it goes in a little bit!

[bozla]

When and where is this year competiton being held - is there going to be one again this year?

[fasterthanspeed]

Well it runs great now. i still have it running pretty rich. Sounds awsome even with the silenced pipe. My radio system isnt working for some reason. I get power to the servos but no messages r getting to them. Its a 3pk radio system.