Experimenting With body and aero.

[Cranky]

So, ive been thinking a lot about aero and how much its contributing these days to these cars. Ive been noticing that guys are shifting the whole tail end of the cars to the right. I had a guy at a track last night that allowed me to string the left side of his car and the quarter panel was over towards the right of the car by 8". On the right side of the car, the quarter was over by that much which means the whole spoiler would be offset to the right?? Has anyone else been doing this? Is this normal for a dirt late model? Im also noticing lots of cars with the body curved on the right side like a snow plow. Are these guys just "getting away with it" or is this fairly normal these days? Im about to make some alterations to my body and if these are legal locations, im going to make some further changes.

[MasterSbilt_Racer]

So, ive been thinking a lot about aero and how much its contributing these days to these cars. Ive been noticing that guys are shifting the whole tail end of the cars to the right. I had a guy at a track last night that allowed me to string the left side of his car and the quarter panel was over towards the right of the car by 8". On the right side of the car, the quarter was over by that much which means the whole spoiler would be offset to the right?? Has anyone else been doing this? Is this normal for a dirt late model? Im also noticing lots of cars with the body curved on the right side like a snow plow. Are these guys just "getting away with it" or is this fairly normal these days? Im about to make some alterations to my body and if these are legal locations, im going to make some further changes.

It's normal. It's not legal. It's a impossible to be competitive and try to load your car in a standard enclosed trailer. This crap needs fixed.

[HuckleberryB4]

I was watching a Lucas Oil Race the other night and noticed this when they showed the cars pacing down the front strectch and the camera was filming head on down the straights. I was amazed at how far the right side is flared from fender to rear of quarter. Then I started looking at mine and realized what MBR said......there is no way I could ever load it in my enclosed. It barely fits as it is.

[JustAddDirt]

If I build the body it will not fit, will it MBR? LOL

[MasterSbilt_Racer]

If I build the body it will not fit, will it MBR? LOL

Nope. And we are still a long ways from meeting Fast 49 dimensions, when it concerns the topic at hand.

[grt74]

there doing what cup did years ago, putting the bodies on offset with the rear to the right

[Rajflyboy]

What’s Ray Cook think of this stuff ?

[Austin34471]

One interesting draw back to putting the body on there crooked is the back of the car hits the wall way sooner than it would have otherwise. If you are running the cushion, or near the wall on the straight away where there is more grip, you will knock the deck out of the car sooner with the back of the body pulled to the right... Bobby pierce would not like this body setup. Always a trade off

[cjsracing]

One interesting draw back to putting the body on there crooked is the back of the car hits the wall way sooner than it would have otherwise. If you are running the cushion, or near the wall on the straight away where there is more grip, you will knock the deck out of the car sooner with the back of the body pulled to the right... Bobby pierce would not like this body setup. Always a trade off

With the new composite quarter panels they don't bend, they just go back to their original position when they are hit.

[MasterSbilt_Racer]

With the new composite quarter panels they don't bend, they just go back to their original position when they are hit.

What about t bars and decking panels?

[billetbirdcage]

What about t bars and decking panels?

What you don't know about the Heavy spring steel T bars and deck metal yet? it's like the heavy LR stuff worth a half second

[CCHIEF]

Had an MB Narrow car back in 1998-99?, body was on pretty skewed. As assembled by Masters. Keith was pretty proud of it......Was a BEAR to put in the box, and you could really see the offset once in there. Isn't a dished door bad aero, flared out at the bottom good?

[billetbirdcage]

Isn't a dished door bad aero, flared out at the bottom good?

That's an argument that has been going on forever and I have never seen any real data that supports one way or the other. The problem is most wind tunnels aren't wide enough to put the car into enough yaw to get accurate data at the true yaw the car sees. Then if they are (know someone that tried) and at a certain yaw, the car slides off the scale pads from the side force and can't get the data.

I don't think people realize how much yaw is actually in the car at times, even with a driver that drives pretty straight. I can say the numbers actually surprised me

[Cranky]

Well I'm glad I started this thread and have received as many responses so far. I'm (not a nice word)(not a nice word)(not a nice word)(not a nice word) sure going to be trying some things with the body now. Will be running primarily on a half mile track so aero definitely comes into play.

[Zkessler16]

Id have to agree have seen guys pushing the rr quarter out. Thats all fine n dandy but where's theres tack up top you'll be destroying the deck and quarter way sooner. I would be pushing things left b4 I would to the right imo. Seal the right off n get that spoiler as high as possible

[Jking24]

Their are dimensions in the rule book that would pretty much prevent the body's from being so out of wack but they don't check them. I mean when is the last time anybody seen the width at the bottom of the doors checked or the top for that matter

[MasterSbilt_Racer]

Their are dimensions in the rule book that would pretty much prevent the body's from being so out of wack but they don't check them. I mean when is the last time anybody seen the width at the bottom of the doors checked or the top for that matter

That's been the issue for years. Not checking and sometimes even dropping rules. They were checking that straight line on the right side for a while. High point of fender back to rear of rr quarter. Couldn't be more than 1" gap anywhere. At EB, cars were 4" on that measurement.

[Jking24]

That's been the issue for years. Not checking and sometimes even dropping rules. They were checking that straight line on the right side for a while. High point of fender back to rear of rr quarter. Couldn't be more than 1" gap anywhere. At EB, cars were 4" on that measurement.I noticed that aswell and when i mentioned it to Someone they said " oh no it's not from the fender top its from the back of the fender" it definitely didn't used to be

[over4T]

We were looking at a new(ish) full roller, bodyless chassis in the shop the other day and discussing this bent body deal and came up with a couple of ideas.
Considered that if you cut the chassis tubes, from side to side, through the middle and hinged it and mounted an air bag system to let it go back to normal for the trailer you wouldn't have to waste a gallon of WD 40 and plexiglass the trailer walls. The airbags would allow the Pierce-type wall bangers to soften the beatings and help save the quarters and spoilers. Bags also could make for constant adjustment of the deck heights. Ask the lowriders in your area if you need help with this. Some of those guys are very creative with 'bags.
Of course there's a few things that we didn't figure out yet; drive line alignment things, steering problems, things with constantly moving rear tires, the extra batteries weight, educating the driver to about completely change the way to drive and, obviously, a few things we haven't considered yet.
Good old 4m has some bright minds (and some not so much) that can surely figure these out. Guys?

[MasterSbilt_Racer]

I noticed that aswell and when i mentioned it to Someone they said " oh no it's not from the fender top its from the back of the fender" it definitely didn't used to be

I guess someone convinced Francis it was a bad rule.

[TheJet-09]

I got to watch a few of the Florida races online, and the overhead or drone shots really gave a good look at how skewed the nose is on some of these things anymore. They look ridiculous, but I've always been a "form follows function" kind of guy anyway.

[Ltemodel]

We did shift the body over six inches to the right several years ago and it did seem to help a little.
One thing we did find which hurt us was cupping the right side door. Think about it this way, with a cupped door, air will push the car up on the right side top of the door.
The fastest way to run your right side door is to slant it out from the top to the bottom.
This will add downforce and traction.
Shifting the body right will also have another plus. It puts a bigger gap between the front of the left rear tire and the back of the left rear tire. This will create a vacuum and pull air out from under the deck. The spoiler width is the limiting factor that makes this happen. Just don't angle the left rear quarter to create a parachute-like function under the car.

[ZERO25]

With the lr's up in the clouds these days, how much of the aero load is the rr getting?

What happened to the theory that 2 pairs of equally loaded tires made more traction?

[MasterSbilt_Racer]

With the lr's up in the clouds these days, how much of the aero load is the rr getting?

What happened to the theory that 2 pairs of equally loaded tires made more traction?

The rr gets all the mechanical load. That watch spring rf don't take any.

[ZERO25]

Would it not be beneficial to get the rr up in the air, at least some?

[Punisher88]

Would it not be beneficial to get the rr up in the air, at least some?Down the straightaway, yes.

[95shaw]

With the lr's up in the clouds these days, how much of the aero load is the rr getting?

What happened to the theory that 2 pairs of equally loaded tires made more traction?

Everyone gets hung up on loading the tires equally.
Ideal situation is for the tires to produce the correct amount of traction at the correct point in the corner.

For arguments sake, Set your car up with a single crazy wheel on the front.
Using loading on the tires on your solid, staggered axle to vary traction, complete a lap around the track.
Use the current theory of making the LR nearly solid thru loading of the bars and heavy compression on the shock.

Just food for thought.

[MasterSbilt_Racer]

Everyone gets hung up on loading the tires equally.
Ideal situation is for the tires to produce the correct amount of traction at the correct point in the corner.

For arguments sake, Set your car up with a single crazy wheel on the front.
Using loading on the tires on your solid, staggered axle to vary traction, complete a lap around the track.
Use the current theory of making the LR nearly solid thru loading of the bars and heavy compression on the shock.

Just food for thought.
I'm not going to argue about over damping LR, but the suspension is less rigid now than at anytime since big hike setups started

[95shaw]

Not going to argue that either.

The premise is that with both tires equally loaded on a staggered, solid axle, the car will turn toward the smaller tire, in an arc described by the difference in circumference and the distance between them.

To travel in a straight line, one of the tires must slip. Most likely the least loaded tire.

[ZERO25]

Not going to argue that either.

The premise is that with both tires equally loaded on a staggered, solid axle, the car will turn toward the smaller tire, in an arc described by the difference in circumference and the distance between them.

To travel in a straight line, one of the tires must slip. Most likely the least loaded tire.


Thats not the concept. Its two pair of equally loaded tires (lefts vs rights) makes more traction.

[95shaw]

Thats not the concept. Its two pair of equally loaded tires (lefts vs rights) makes more traction.

I don't see that happening anywhere on a lap with the current cars. Least of all in the corner, where the most traction is needed.

We know that to utilize our stagger to most effect, the rear tires must be equally loaded. We want that to happen in the corner.
At that point, g forces are high, removing weight from the lf thru the center of gravity. At some point in the corner, the lf extends to the end of travel, ie tether. The most weight on the lf occurs at turn in.
Not seeing spoiler in the air counteracting all of that.

[potts5]

Would a dish style roof made out of sheet metal with like a 3/4 lip on the back help you or hurt you

[Jim11h]

Ask a winged sprint car

[MasterSbilt_Racer]

Would a dish style roof made out of sheet metal with like a 3/4 lip on the back help you or hurt you

Air that goes over the roof does not reach the spoiler. Hopefully, that's hint enough...

[ZERO25]

Air that goes over the roof does not reach the spoiler. Hopefully, that's hint enough...

My buddy said, many years ago, they found some slight downforce by putting a 1 1/2 " rounded strip (downward) on the back of the roof. Ive always done that since then, but dont know now if it helps.

[MasterSbilt_Racer]

My buddy said, many years ago, they found some slight downforce by putting a 1 1/2 " rounded strip (downward) on the back of the roof. Ive always done that since then, but dont know now if it helps.

Years ago, we had a convex roof, mounted level, it may have worked. Now, it's flat, mounted with 4" of rake and dynamically gains 5 more inches.

[Cranky]

At your next practice session or hot lap session and you want to truly see where the air is flowing on your car. Sprinkle baby powder on the hood, deck, roof, nose etc. Run two or three hot laps and come in. You can then see how the air affected the baby powder on your car, where the most downforce is due to the higher amount of powder being in certain locations. Its an easy and homemade real time wind tunnel. It really works.

[Raceready]

At your next practice session or hot lap session and you want to truly see where the air is flowing on your car. Sprinkle baby powder on the hood, deck, roof, nose etc. Run two or three hot laps and come in. You can then see how the air affected the baby powder on your car, where the most downforce is due to the higher amount of powder being in certain locations. Its an easy and homemade real time wind tunnel. It really works.I've been to a couple of notorius dust bowl tracks back in the day before there was an internet to complain on and the tracks never would keep the track moist because fans thought it was just a normal thing and they would show up week after week ... On these places the dust was so heavy that one could watch where the dust was going under the lights. the rear spoiler would kick a dust cloud up a few feet up before it spun in a rooster tail.