MPH Challenge

[davidemaxx]

i dont remember are you gonna use different tires for the rear? the maxx stockers seem to balloon at speed.

[1979chevy.]

Yeah he's not going to use those, just for mock up.





God answers prayer,pray,believe,NEVER GIVE UP!!!

[davidemaxx]

anything new? update?

[Snook Man]

I did a few test runs while the forum was down and ran into a few issues that need correcting.

I added a few braces to the mockup chassis to stiffen it up, made a temporary engine mount for a .28 and used Kevlar fishing line wrapped in the grooves of a pair of old siped chevron tires to test run this thing.

The 1st issue is the transmission. With the 2:1 spur gear/clutch bell ratio (18/36) I’m hitting 3rd gear way too soon. I will need to find a higher rate spring for the 3rd gear clutch and maybe even the 2nd gear.
I had the same problem when I 1st made the 3 speed with standard gearing but was eventually able to find a spring rate that worked well. With the gears I’m using for this build the primary shaft and clutches are basically spinning almost 2 times faster than they normally would and engaging that much sooner.

2nd issue is the rear suspension and the angle of the rear arms and wheel shafts. Without the body there wasn’t a problem but once I added it the down force compression squats the rear pretty quickly. I will have to stiffen up the spring rate and shock oil.
Since I narrowed the a-arm length, at full compression the angle of the wheel shafts are pretty severe and within just a few runs the shaft joints heated up enough to melt/wear the plastic stock shafts to the point they would have failed within a few more runs.
I’m going to add a spacer block between the chassis and bottom of the bulkheads to reduce the angle at full compression. I need about ¾ inches for the arms to be slightly above parallel with the ground at rest and just slightly below parallel when compressed.
That will make the angle of the rear diff input drive cup pretty severe to the rear dogbone shaft so I plan on removing or modifying the rear diff collar so I can rotate the rear diff input down to reduce the angle.

3rd issue is the body itself. I placed myself to where the rig would pass by me at the fastest speed I could get in the parking lot before I had to let off and apply the brake.
As it approached I could see the body sides and top panel moving pretty violently and a couple of the seams came apart after a few runs.
Without a substantial amount of bracing inside the body I made I just don’t think it will survive very long.
So now I’m going to make a mold out of wood and have a custom body vacuum formed out of standard lexan. I will be able to add more contours that will help add rigidly to the body and end up with a lighter weight body in the long run.
The rear spoiler which is a separate piece and adjustable seemed to work great and with the bracing I already have on it seemed solid and stable.

I have a lot of work to do, but that’s what winter builds are for.

[08kgraves]

trial and error, thats what its all about man. you didnt by chance film this did you?

[Snook Man]

No video, but I did have a gps strapped in it. As far as the numbers I'm going to keep that to myself for now, but I was smiling when I had a look at it. It was more of a mad scientist laugh than a smile

[08kgraves]

awe come on snook, we all know your a mad scientist and are going to reach your goal one way or another in the end. and we all know what that goal is as well. how about this......... did you break 75mph?

[Double G]

It's been a while since I've read the entire thread. Would it be better to use a solid link between the arms and shock tower rather than a shock or would it cause it to bounce too much when it rolls over the imperfections?

[08kgraves]

realistically on a 1:1 dragster they dont have a suspension on them, but with the small scale im thinking the best bet would be just stiffer springs with heavier oil like snook said already. since its kind of hard to make a smooth course for something so small.

[1979chevy.]

Definitely weave some kind of suspension in there, I agree with Graves, run something really stiff.





Life is rough, God is good, let's go.

[Snook Man]

With a high profile tire with some side wall flex, no suspension may work ok but with the wheels and tires I intend to use there will be only about 3/4 inches of high density foam(like an on road car would use)on the wheel. It would probably be too bouncy/stiff to keep good traction without a least some suspension.

[1979chevy.]

How heavy will this thing be approx.?






Life is rough, God is good, let's go.

[2010450x]

I think he said somewhere it was like 7lbs. Could be wrong though

[davidemaxx]

so did you atleast break 75? 80?

[1979chevy.]

Give it up guys, he's not telling






Life is rough, God is good, let's go.

[Nitronaught]

Short stiff springs, heavy oil to match. With this, pretty sure you want as little shock travel as possible but a little probably would help with the terrain.....

Looking forward to seeing this go further, and if anyone can do it... I'm pretty sure Snook can....

[1979chevy.]

If Snook can't do it, ain't nobody gonna be able to





Life rough, God is good, let's go.

[08kgraves]

[QUOTE=1979chevy.;4991486]Give it up guys, he's not telling

but i wanna know lol

[1979chevy.]

[QUOTE=08kgraves;4991515]

but i wanna know lol

Haha same here man, so do I.



Life is rough, God is good, let's go.

[mike-susieq1]

i would say with his setup he could have seen more than 65 for sure just look at it and he has done alot so far to it.

[Snook Man]

More changes.

After the test runs I made I saw that this thing has some really good potential to go fast. I started looking at the ISC rules and regulations and found that the only thing I needed to do to fall within the rules of the IC open class was to narrow the rear width to under 11.81 inches.

I made another rear end that totals 11.5 inches from the ends of the stub axles just in case I ever wanted to challenge the record which is 117.56 MPH. That would be a tall task, but you never know
Depending on the wheels I use that should keep me within the rules and still allow just enough for body clearance of the tires. I can’t cut the a-arms down any more or there will not be much left to screw the pivot balls into. I’m comfortable where they are now but any more taken off of the lower arm would weaken it in the pivot ball thread area.

I also was able to use a dogbone and drive cup setup for the wheel shafts. I don’t need or want much articulation of the rear suspension (probably only 2 inches total, 1 inch up/1 inch down from horizontal) so this setup should hold up rather well.

I’m probably the only person that ever wanted a narrow rear width on a Tmaxx suspension.
Now I have to make some stubby rear toe links...





Maybe I'll make a 12th scale TMaxx some day

[Tankdg]

I am thinking a single leaf spring that mounts to the lower shocks mounts and rest on the bottom of the bulk heads. It would control jounce and rebound all at once.

[Snook Man]

It would be hard to control the bounce a leaf type spring would have without shock absorbers.
Plus I need to limit the suspension travel and a pair of shocks/springs would be easiest way.

[08kgraves]

yeah wit a stock style shock you could easily just play with the spring and oil thickness then put fuel tubeing both inside and out around the shaft for the limiters.

[Snook Man]

More changes:

After getting a quote for the price of 2 custom foam tires mounted on pair of custom cut wheels (I supply the wheels) I have decided to go in a different direction. I could not see paying the high price for just a set of mounted foams.

Seeing how the XO-1 tires are rated for 100+mph I have decided to use them (should be available from the chop shops soon).
The problem that creates is the difference in gearing that will be needed to make up for the smaller diameter tires.
I was planning on using 6inch diameter tires, the XO-1 tires are 4.29inches in diameter.
The difference in theoretical speed between them with the same gearing is approx 28mph.

To gain that speed back I would need some massive clutch bells or a much smaller spur gear.
The clutch bells would need to be 1/8 scale mod 1 26T which are not common even if they exist somewhere.
I figured the spur would be the easiest to change to a smaller tooth count. After some calculations using common 17 or 18t clutch bells the spur would need to be 22T to get the correct ratio.
So how do I mount a little 22T spur on a slipper clutch??? I didn’t

Seeing how it will only be run on smooth pavement and I’m not going for a fast ET, I really don’t see the need for a slipper.
With the slipper removed I rummaged through 100’s of gears looking for a simple solution to mount a gear to the transmission input shaft.
I found an RRP aluminum reverse primary gear that I had already modified previously for an input shaft 2nd gear set. All I had to do was install the pin in the input shaft, slide the gear on the shaft to engage the pin and use a nylock nut to secure the gear.
It will also allow me more room around the spur for the 3 geared Idler block needed to change the rotation of the engine output to the spur gear.

I knew when I modified that reverse primary gear I would eventually use it for something





Now I will need to re-think the rear suspension with the smaller diameter tires it never ends

[08kgraves]

snook have you read the last word in the title lately? lol you can do it though man. we all know it.

[Snook Man]

It’s really not about the initial challenge to me anymore. I’m pretty confident I can bust 100 sooner or later, but I want to have/make a rig capable of doing it routinely and to see just how fast I can ultimately make it go.

[stallion 63]

Enough with the teasing already!Show us some vids...

[mike-susieq1]

It’s really not about the initial challenge to me anymore. I’m pretty confident I can bust 100 sooner or later, but I want to have/make a rig capable of doing it routinely and to see just how fast I can ultimately make it go.

I would say with what you have created already you can more likely build something to reach around 125mph give or take a few more like a few more than that. when its done i'll be ready to see the vid of it going 100mph.

[2010450x]

Keep up the good work Snook. I can't wait to see this thing fly by at 125.

[Tev364]

was just thinking have you thought about a front scoop at the front of the body at the nose with a channel that shoots air into the carbs? i know you said you dont want to get too drastic but i know you said you want it to continue to work. the small channels dont have to be big and you can make them out of plastic tubes kinda like straws.

heres a crude picture of the situation

[08kgraves]

hahahaha, nice fluxcapacitor tev

[Double G]

I took the picture as this: the red represented the car and its course, the arrows are trees and the flux capacitor as the explosion and I thought, that's not nice.
Then I looked further and saw what it really was. Me --->

[Tev364]

[QUOTE=Double G;4997452]I took the picture as this: the red represented the car and its course, the arrows are trees and the flux capacitor as the explosion and I thought, that's not nice.
Then I looked further and saw what it really was. Me ---> [/QUOTE

LOL HILARIOUS! i added the flux just for fun but i was just thinking about ventilation without much added drag and better handling like a front spliter but im also wondering if it will add lift and flip the rig like gymnastics on the high bar!

[ian-slash]

Any progress?

[Snook Man]

I’ve been busy with the holidays but did get started on the idler block between the clutch bell(s) and spur gear.
I’ve been experimenting with different types of gears and bearings to see which will work best. Since the mesh between the 3 idler gears will be non adjustable the shaft spread pattern is critical and the holes must be exact. It took me 2 attempts to get it as perfect as I think it should be and the gears spin nice and smooth with just enough lash.
I’m going to order some new gears and flanged ceramic bearings for the finished version.





The radius cutouts in the front plate are for clearance of the clutch bell(s)
The rear pate will attach to the aluminum transmission mount/chassis brace and the bottom of the unit will have a 6mm thick aluminum bar that attaches to the front and rear plate and can be secured to the chassis.

The idler block and transmission mounts/chassis braces will bolt together as a unit and attach to the chassis plate and rear bulkheads. The transmission will drop into the mount and attach with through bolts through the chassis.
Slotted holes on the idler block back plate and bottom plate will allow for some adjustment of the top idler gear and spur.



I also figured out a way to add a 4th gear in the transmission if needed

That extra space is all I need to add the gears needed for a 4 speed. I’ll save that idea for a rainy day.

[spencer_lee1993]

Hey snook, I like the tranny design, I have been thinking about your intake design and how their have been lots of suggestions of possibilities, what if you left the top completely closed, or as closed as you could get it and created an intake off the bottom of the chassis, kinda like what is used in the X-01. Many high performance vehicles use this to cool the brakes on vehicles, they use tubes to channel the air directly at the brakes. You could use a tube to channel the air right at the filter.....just another suggestion. to keep the body more aerodynamic

[ToXiC MeRv]

Snook....You are Insane! 4th gear? thats crazy! I have no doubts that you will be able to reach "atleast" 100mph if not more.

[naturalstrike]

nice snook

[davidemaxx]

i really want to see him with a rainy day right about now! a four speed would be insane! i want to see it soooo bad!