Infraction 1/7 scale road racing thread. (T/C,G/T, F1, and Indy)

[Wade Wilson]

Hey Buddies,

New thread dedicated to setups, events, and areas for road racing the 1/7 scale line.

We are not throwing shade at speed runners, at all. The setups are just so vastly different, and the road racing community is so small, it’s difficult to gather info on how to setup these cars to turn, without drifting and burning up expensive tyres.

Anyone who has posted in this interest, please re-post here, or provide a link. I will share my setup sheets in the next couple days, just have to get my stupid scanner working.

Thx!

Wade

 

[LibertyMKiii]

Lately I have been thinking more about making a parking lot car that can carve up some cones.

Interested to see what people come up with. I know a few guys on the forum run infractions around parking lots. I would expect that a GT car or Limitless can generate more downforce and perform better.

I suppose my only contribution would be the VTE 2 setup I did. I was not crazy about the way it handled with the wide rear tires as the car rolled on me when trying to drift it. I think I'd stick with standard GRPs on all 4 corners once I get serious about a parking lot car.

The rear wing is adjustable to tune in more rear downforce. It needs a front splitter and canards to help with the front end.

This is along the lines of what I wanted to do with the Limitless: https://www.thingiverse.com/thing:5202601

 

[Wade Wilson]

Lately I have been thinking more about making a parking lot car that can carve up some cones.

Interested to see what people come up with. I know a few guys on the forum run infractions around parking lots. I would expect that a GT car or Limitless can generate more downforce and perform better.

I suppose my only contribution would be the VTE 2 setup I did. I was not crazy about the way it handled with the wide rear tires as the car rolled on me when trying to drift it. I think I'd stick with standard GRPs on all 4 corners once I get serious about a parking lot car.

The rear wing is adjustable to tune in more rear downforce. It needs a front splitter and canards to help with the front end.
View attachment 211363


This is along the lines of what I wanted to do with the Limitless: https://www.thingiverse.com/thing:5202601

View attachment 211369

Nice!! Splitters are such an important part. I’ll post some of my aero stuff a bit later, but I like the splitter, ramping it like that, and channeling the air over the tyres is a great idea, but you might want to make it more of an air dam without the slots? Maybe? Without a wind tunnel, hard to determine

Raising the rear roll center on the red car will let it drift without catching, drop the rear links to the lower holes on the tower, and raise them on the hub.

Understand the Bernoulli principal is key to designing aero for a track car, helped me a ton. There’s a great write up here on applying it to racing cars:

https://www.catchmentsandcreeks.com.au/docs/Race-Car-Aerodynamics-print.pdf

Wade

 

[LibertyMKiii]

Nice!! Splitters are such an important part. I’ll post some of my aero stuff a bit later, but I like the splitter, ramping it like that, and channeling the air over the tyres is a great idea, but you might want to make it more of an air dam without the slots? Maybe? Without a wind tunnel, hard to determine

Raising the rear roll center on the red car will let it drift without catching, drop the rear links to the lower holes on the tower, and raise them on the hub.

Understand the Bernoulli principal is key to designing aero for a track car, helped me a ton. There’s a great write up here on applying it to racing cars:

https://www.catchmentsandcreeks.com.au/docs/Race-Car-Aerodynamics-print.pdf

Wade

That is a great document but only skims the high level concepts.
You would probably enjoy my ground effect car project https://www.arrmaforum.com/threads/libertys-ground-effect-project-speed-runner.49889/

 

[Wade Wilson]

That is a great document but only skims the high level concepts.
You would probably enjoy my ground effect car project https://www.arrmaforum.com/threads/libertys-ground-effect-project-speed-runner.49889/

That is sick. Absolutely love it!

That splitter design with the ground effect gap is next for me now that I saw it in your write up. Also trying to finalize canards, (upper n lower), for the truck bodies while I wait on a GT and a Limitless to show up…and then paint them when the freaking wind dies down…

Any ideas on the diffuser? I took out the 2nd and 5th vane, I do mount a wing to a buggy wing mount for downforce on the frame.

What’s your diff oil like for the track cars? I’ve got 6S sensored and 8S both running 500k C, 300K F, and 100K rear.

 

[Moirae]

That is sick. Absolutely love it!

That splitter design with the ground effect gap is next for me now that I saw it in your write up. Also trying to finalize canards, (upper n lower), for the truck bodies while I wait on a GT and a Limitless to show up…and then paint them when the freaking wind dies down…

Any ideas on the diffuser? I took out the 2nd and 5th vane, I do mount a wing to a buggy wing mount for downforce on the frame.

What’s your diff oil like for the track cars? I’ve got 6S sensored and 8S both running 500k C, 300K F, and 100K rear.

Higher weights better for this application? I'm thinking about dabbling into this just a little. Bought some cones to setup in a parking lot so the wifey and I can mess around for now lol.

 

[Wade Wilson]

Higher weights better for this application? I'm thinking about dabbling into this just a little. Bought some cones to setup in a parking lot so the wifey and I can mess around for now lol.

In my experience “racing” around parking lot courses with fairly heavy cars, with a LOT of power, the heavier weights seem to perform better. The 6S setup has a XeRun plus ESC and G3 2250 motor combo, with the turbo timing cranked. The 8S setup has a Max 6, with a 1275kv motor from my Xmaxx, and both cars run HV lipos. Seemed to me they could not get the power down, (got a lot of diffing out and twitchy behavior upon acceleration), with lighter diff oil, and not running heavy in the front was under steer city, on power, when exiting turns.

Still experimenting for the best oil combo. If you end up trying the heavier oils, please share your observations!

 

[Surchaufeur]

Wish i had friends to run with

 

[chocwheaton]

That car looks great!!!
This thread is exactly what I'm trying to do with my infraction.

It's only a new car so o don't have any info to provide yet.

I have converted it to be single battery and so far it's good. Acceleration seems a bit better.

Is hard to judge though, especially since I'm new to on road.

View attachment 211542

 

[Wade Wilson]

The Vette and Biddy look great! I have a Biddy ready for paint, prob go with Red/Black or Black/Yellow. High visibility is nice:

Anyone looking to shorten the wheelbase, the Tekno SCT 410.3 rear arms will do the trick. A lot of Tekno 2.0 or 48.3 kit can replace the Arrma gear, sways, endlinks, shocks/standoffs, rear arms/hubs, CVDs, wheel hubs, servo saver post and bearings, diff cross braces, (when used with the Arrma aluminum diff case), steering and camber link ends, droop screws, diff couplers, diff outdrives, “C” block to adjust rear toe and anti-squat, hinge pins, and a few other bits.

IMHO, the Tekno stuff is a bit better quality. Or, I’m an asshat, lol…

Did some tuning and setup today, hope to get some testing in tomorrow.

 

[chocwheaton]

I'll be trying out grp s7 tyres tomorrow. Hoping to get longer like that the silver hoons.

Something I'm also playing with is 4S vs 6S. My current feeling is that for road racing, unless it's a really big track with a long straight, 4S gives better control, and gives more range of trigger travel. With 6s i tend to stay in the first 1/3rd of the throttle. With 4s it's 2/3s, with the occasional full throttle for a second or two on a straight section.

 

[jondilly1974]

I would think a heavier car wouldn’t make a better racer. You want light and powerful, but enough downforce to keep traction. That’s what Liberty is trying to correctly say above. That weight works against you in turns as it multiplies quickly. Also in acceleration that weight will reduce the effectiveness of the power you have on hand, either creating heat or reducing runtime. Those can be worked around too, but usually by adding more weight. It’s a never ending cycle. Much easier to cut weight and add downforce. Venturi effects and airfoils are the best ways I’ve seen. Another is using active vacuum, but that only works until the seal breaks and then all hell breaks loose.

 

[LibertyMKiii]

I wonder if the EXB LSD Diffs might work good for a dedicated track car? I know in 1:1 cars LSD diffs perform best....

For this application you want as light as possible with as much downforce/wings as possible. Think pikes peak race cars.

I think the Delta Plastiks Prototype body may be the closest things we have. It comes with a large front splitter integrated in the body, but it would need to be re-enforced. I believe that is the one I would use for a track car and modify it.

Example from one of the best painters in the RC world https://www.arrmaforum.com/threads/1-7-deltaplastiks-“prototype-“-body.47459/

 

[chocwheaton]

I had my first run with the GRP slicks S7 (medium hard compound) and the first thing I'll say, is if you want grip, get GRP's and don't worry about Hoons anymore.

These hard compound GRPs have way more grip than the white HOONS. Not just a little more...way more!

I can't imagine how well the soft GRP's would grip like.

So I'm going to stick with GRP's from now on for my car park racing.

I am still intending to get a set of the solid rubber slip on's that WestOz RC has been testing, for when I just feel like drifting around and having fun that way...without breaking the bank on HOONS.

 

[Moirae]

I had my first run with the GRP slicks S7 (medium hard compound) and the first thing I'll say, is if you want grip, get GRP's and don't worry about Hoons anymore.

These hard compound GRPs have way more grip than the white HOONS. Not just a little more...way more!

I can't imagine how well the soft GRP's would grip like.

So I'm going to stick with GRP's from now on for my car park racing.

I am still intending to get a set of the solid rubber slip on's that WestOz RC has been testing, for when I just feel like drifting around and having fun that way...without breaking the bank on HOONS.

Funny you mention this because I just tried the new GRPS on my limitless, I have XM4 soft medium and they have so much more grip than I anticipated. I'm used to using hoons and i couldn't even swing the car around the same way I'm used to. It started going on two wheels whenever I tried to do it and that NEVER happened on hoons.

 

[chocwheaton]

Yes I had a lot less sliding and had to re-learn how to turn the car too!

On 4S with these grippier tyres, I could not make the car power slide properly, which is still easy using the hoons.

I had a lot less understeer too which was good for manoeuvring around cones.

 

[Surchaufeur]

How does grps last longer than hoons?

 

[jondilly1974]

How does grps last longer than hoons?

Because they aren’t made of chalk

 

[LibertyMKiii]

I had my first run with the GRP slicks S7 (medium hard compound) and the first thing I'll say, is if you want grip, get GRP's and don't worry about Hoons anymore.

These hard compound GRPs have way more grip than the white HOONS. Not just a little more...way more!

I can't imagine how well the soft GRP's would grip like.

So I'm going to stick with GRP's from now on for my car park racing.

I am still intending to get a set of the solid rubber slip on's that WestOz RC has been testing, for when I just feel like drifting around and having fun that way...without breaking the bank on HOONS.

It is funny how many times I recommend GRPs and people often come back saying.... No I am ok with Hoons
GRPs are really good and the new series are so much better than last years model. So glad they fixed the tire and wheel balance issues.

 

[rotauq]

My ultra light 4S 1/8 Serpent GT-E on it's original tires will beat any 1/7 on a (medium sized) road circuit.

Weight is the biggest enemy. Drifting and powerslides looks cool but they are slow. It's all about perfect racing lines, being in control all the time. Not saying aero isn't important, but that's finetuning... Use a centerdiff and don't go to heavy on diff oil weight.

These 'medium' compound Serpent tires are much softer and grippier than GRP S1's and won't like 100+mph speeds, but they will corner like crazy. https://www.serpent.com/xcart/cart.php?target=product&product_id=10546