Infraction Finally made it!!

[Flames77]

Wow man, I just read through this whole thread. Crazy impressive. Most of the technical discussions were totally Greek to me. I’ve always wanted to build up a dedicated speed runner, but I’ve found absolutely nowhere that I could run it. I don’t even have an on road car at all for the same reason. I’ll just live vicariously through @Flames77 , @LibertyMKiii , and @jondilly1974 Especially now that I’ve realized just how much ignorance I’d have to be relieved of to jump down this particular rabbit hole. Crazy, man. Nice work, all of you!

That’s awesome man! I’m so glad you enjoyed this thread thus far.

It has been quite the journey for sure. I have learned soooo much from these two. When I first started speed running, like many others I thought it would be easy. Boy was I wrong!

It is very technical as you have read. And to me that makes my accomplishments so far even more exciting.

Please stay tuned for more!

I need to update my setup as of right now. And hope to get a pass in this coming weekend. Been either busy or the weather wasn’t permitting to do a pass lately.

 

[LibertyMKiii]

Just to add a little discussion on foams...

Talking with James - he told me that the foams as they come full height can be a little unstable from the foam flexing. Highly recommends truing them down. I know not everyone has a tire truer and they are ridiculous priced tools.... so you could just hold the back of the truck and wear them down some.
Another method is flip the car up-side-down and use a block of wood and sand paper. (be careful as it can suck that block/paper out of your hand.)

Another tip I have heard is rounding the fronts slightly at the corners of the tire makes them less "over sensitive" in the steering and grabbing groves in the road. Might be worth a shot!

Reducing the tire size will help them fit in the body, as will rounding the corners, and reduce chunking.

Just remember as the tire diameter goes down you will need to change gears to compensate. Keeping good data/notes helps a lot in this area.
example:
2mm diameter reduction = x mph lost. 1 tooth up pinion = x mph gain or 1 tooth down on the spur = x mph gain.....

Good luck!

 

[Dan B.]

Appreciate the shout-out.
I don't have a road good for over 100mph within 1hr of me, which is why you don't see me posting speed run videos lately.
I do have a high speed build going on, but it will only see the pavement of the airport. ( if I can pull that off one day... )

Still love the hobby and always looking to help others. This speed side of the hobby was full of secrets and frustration when I began. I has since gotten better with the addition of people like Raz on YouTube. Many people would try speed running with a bad setup, crash, and quit! Crashes still happen, but good advice/proven setups really a person starting out avoid the big mistakes.

Once you get to 150+ there are still some big secrets.... and it requires being handy, making your own parts, and understanding aerodynamics.

So, if you had to lay down some serious odds for cresting the 200mph barrier, I’m guessing that they wouldn’t necessarily favor the inimitable K. Talbot with the sole philosophy of “MORE POWER!!”
I love Kevin Talbot, but I guess my money is on y’all. Good luck. Your aeroformed carbon tubs are “ABSOLUTELY EPIC!!!” Seriously.

 

[LibertyMKiii]

So, if you had to lay down some serious odds for cresting the 200mph barrier, I’m guessing that they wouldn’t necessarily favor the inimitable K. Talbot with the sole philosophy of “MORE POWER!!”
I love Kevin Talbot, but I guess my money is on y’all. Good luck. Your aeroformed carbon tubs are “ABSOLUTELY EPIC!!!” Seriously.

Thank you!

We all have seen these cars accelerate from 0-130+ in 6 to 10 seconds. That alone is simply amazing to think about.
Power is not the issue to solve for. Air resistance / Aerodynamics is the solution to the problem.

 

[Flames77]

Just to add a little discussion on foams...

Talking with James - he told me that the foams as they come full height can be a little unstable from the foam flexing. Highly recommends truing them down. I know not everyone has a tire truer and they are ridiculous priced tools.... so you could just hold the back of the truck and wear them down some.
Another method is flip the car up-side-down and use a block of wood and sand paper. (be careful as it can suck that block/paper out of your hand.)

Another tip I have heard is rounding the fronts slightly at the corners of the tire makes them less "over sensitive" in the steering and grabbing groves in the road. Might be worth a shot!

Reducing the tire size will help them fit in the body, as will rounding the corners, and reduce chunking.

Just remember as the tire diameter goes down you will need to change gears to compensate. Keeping good data/notes helps a lot in this area.
example:
2mm diameter reduction = x mph lost. 1 tooth up pinion = x mph gain or 1 tooth down on the spur = x mph gain.....

Good luck!

Yeah I looked into one of those tire truers and just can’t justify the price at all. It’s insane how high those things are. So I was like ok maybe I’ll just pick up a table top lathe from Harbor Freight. Umm nope those things are around $700! So yeah that’s out the equation.

I may try and figure out a way to shave them down some how. Or may just run them.

The only tricky part I’ve found in running them is the start. After I’m well in a run they seem pretty stable. And I do turn my steering dual rate way down before I start a pass.

I appreciate you sharing this information @LibertyMKiii !!

I have been working on some canards for it. Got a set 3D printed that I’m fixing to install. We shall see how that works out.

 

[Flames77]

Ok so a little update on what I plan on running tomorrow.

Xlx2 with my 1717-1650kv Castle setup
34t spool
30t pinion- up two teeth from since the start of this thread
2-CNHL 70C 6000mah 4s lipos
1-Venom 3s 1300mah (for motor fans)
BSR Double pink foams

I have added 3D printed canards to try out and hope it helps keep that front end planted.

Enjoy guys! Fingers crossed for some good numbers and a new PB.

 

[Dan B.]

Canards look great, like they should have always been there. Good luck man, and drive safe!

 

[N.Mango]

Congrats! Not a speed run guy but like seeing you guys hIt your PB!!!

 

[Flames77]

Canards look great, like they should have always been there. Good luck man, and drive safe!

Thanks @Dan B. It’s a bit breezy out but we are still gonna give it a shot.

Congrats! Not a speed run guy but like seeing you guys hIt your PB!!!

Thank you @N.Mango It’s quite the rush let me tell you. By the end of the run my heart is just a beating and I’m breathing heavily!

 

[Flames77]

Ok so todays outing wasn’t successful at all. I continue to have steering issues.

I have tried everything. It’s pulls right under acceleration and then left while braking. I have checked my diffs for broken pins/gears. Nothing. The chassis sits level too and my suspension is equal all the way around. Servo horn is tight as well. I’m lost at this point.

I’m running a Hexfly 25kg servo (because that’s all I had laying around after the factory one died) could that be my issue here?? Any suggested upgraded servos

This is the one thing thats keeping me from progressing and I’m itching to get it sorted out. @jondilly1974 @LibertyMKiii or anyone else wanna chime in with their input.

Thank you guys! Happy Sunday. Be safe out there.

 

[LibertyMKiii]

Jon may have some ideas as I want to say he was dealing with this at one point? Maybe not...

I had this same thing happening with a different car (4tec 2.0) and it was the suspension flexing and adding toe angle one way during acceleration and the other way during braking. Double check the arms and hubs joints are tight and shimmed as needed...

 

[jondilly1974]

Ok so todays outing wasn’t successful at all. I continue to have steering issues.

I have tried everything. It’s pulls right under acceleration and then left while braking. I have checked my diffs for broken pins/gears. Nothing. The chassis sits level too and my suspension is equal all the way around. Servo horn is tight as well. I’m lost at this point.

I’m running a Hexfly 25kg servo (because that’s all I had laying around after the factory one died) could that be my issue here?? Any suggested upgraded servos

This is the one thing thats keeping me from progressing and I’m itching to get it sorted out. @jondilly1974 @LibertyMKiii or anyone else wanna chime in with their input.

Thank you guys! Happy Sunday. Be safe out there.

Something is loose somewhere. A wollowed out a-arm at the hinge pin, a shock with more travel, something. That’s assuming you’re absolutely positive (as you said) that the diffs are perfect. You can swap the diffs front to rear to see if that changes anything. I know you’re not a noob, so I will assume you’re diffs are as good as you claim. Then check all your spacers on the front upper a-arms and ensure they’re equal and no slop. Make sure pivot balls are slop free and not binding. Check for bad bearings in hubs. Etc.

 

[Dan B.]

If you check @jondilly1974 and @LibertyMKiii lists above and still find no joy I’ve also experienced similar issues with traction/stability control causing this. Maybe try reducing it a couple of clicks, and make sure the radio steering perimeters, trim and expo, are proper. I typically run no traction control on any of my 4wd rigs, but I’m not speedrunning at a level anywhere near you guys, so just pure speculation on my part.

 

[Flames77]

Jon may have some ideas as I want to say he was dealing with this at one point? Maybe not...

I had this same thing happening with a different car (4tec 2.0) and it was the suspension flexing and adding toe angle one way during acceleration and the other way during braking. Double check the arms and hubs joints are tight and shimmed as needed...

I watched your video awhile back on lining up the front end which was very helpful. You mentioned something about some scales. Would that be helpful in this situation?

 

[Flames77]

Something is loose somewhere. A wollowed out a-arm at the hinge pin, a shock with more travel, something. That’s assuming you’re absolutely positive (as you said) that the diffs are perfect. You can swap the diffs front to rear to see if that changes anything. I know you’re not a noob, so I will assume you’re diffs are as good as you claim. Then check all your spacers on the front upper a-arms and ensure they’re equal and no slop. Make sure pivot balls are slop free and not binding. Check for bad bearings in hubs. Etc.

The diffs are good. I went through both of those. That was the first thing I did. As far as the bearings I just took those off and cleaned and oiled them. Pivot balls were nice and snug (not tight or binding) But I do have some slight play in my left upper control arm. I may order a set and swap it out.

 

[LibertyMKiii]

It has to be the arms fitment.
Make sure after installing the new ones that they are shimmed real tight (all the shims on the rear side I believe is the way to go?)

 

[Flames77]

It has to be the arms fitment.
Make sure after installing the new ones that they are shimmed real tight (all the shims on the rear side I believe is the way to go?)

Will do. And yeah they go on the backside. I appreciate the feedback

 

[jondilly1974]

I have my shims 50/50 on the top front arms. But you really don’t want any travel anyways, so I get them as tight as possible.

 

[Flames77]

I have my shims 50/50 on the top front arms. But you really don’t want any travel anyways, so I get them as tight as possible.

Ok. Thanks Jon. I’m gonna go over everything once more and swap out that arm. I appreciate the input.

I’ve been waiting on your next speed run video! Can’t wait til you post some more up. Are you still drag racing your infraction?

 

[jondilly1974]

Ok. Thanks Jon. I’m gonna go over everything once more and swap out that arm. I appreciate the input.

I’ve been waiting on your next speed run video! Can’t wait til you post some more up. Are you still drag racing your infraction?

I have not been able to do anything the last week. Had a family commitment that has sidelined all RC work. Might be done for the year as weather turned quickly here.