Modified Masterpiece

By J.G. Pasterjak
Apr 19, 2018 | Chevrolet | Posted in Features | From the Nov. 2015 issue | Never miss an article


That’s the phrase Ron Ver Mulm uses to describe the acceleration of his SCCA E Modified Chevrolet Camaro autocrosser.

The fact that he says it in a delicate, polite Midwestern accent completely belies the weapons-grade ferocity of this single-purpose automobile. But when we give you some of the objective numbers, you realize that no amount of filthy language could possibly do justice to this automobile’s insane performance.

“We’ve measured 1.8 to 1.9 sustained lateral gs, 1.6g braking, and”–wait for it–“1.7 gs for eight-tenths of a second in sustained acceleration.” Those are numbers usually endured by rookie Air Force recruits thrown into some sort of plane crash simulator, but Ron and his wife, Sonya, strap themselves into this rocket voluntarily.

Iowa residents Ron and Sonya are regulars on the Midwest autocross circuit, and they’ve spent almost two decades campaigning a Camaro in the already heavily modified C Prepared class. “But there were a lot of things that we were solving with Band-Aids, and we kind of wanted to take it to the next level,” says Ron. Don’t let the modest tone fool you: Ron’s idea of “next level” is several levels beyond what the typical car owner envisions.

Purpose-Built Performer

“We started with a clean sheet of paper,” Ron explains. “I had all sorts of files with examples of GT1 cars and various race cars that I drew inspiration from, but mostly this is a clean-sheet design.”

The E Modified class is for heavily modified production-based cars or tubeframe silhouette copies of production cars. Those purpose-built machines take a scant 50-pound weight penalty over their production-based counterparts.

“With a GT1 car, the priorities are safety, crash resistance, durability, stiffness and performance, basically in that order,” says Ron. “But with an autocross car, I could reverse that 180 degrees and concentrate on stiffness and performance along with low weight and not have to worry about crumple zones or impact.”

Behind the Curtain

There’s not a single piece of Camaro chassis anywhere in this car, although the dimensions have to meet certain Camarobased standards. That gorgeous fiberglass shell, a replica of a 1970 body, came from a vintage racer who intended to use it in an old IMSA car restoration. However, he went with a reproduction made from his car’s original metal instead. So Ron took the body back to Iowa and set about designing a chassis that would support it.

The most noticeable feature of this Camaro isn’t really noticeable until you peel away that skin. The beating V8 heart, much like the heart in your own body, is offset significantly to one side. The entire engine also lies quite a bit behind the front axle, although still ahead of the midpoint between the front and rear axle line as prescribed by the rules. Still, it sits closer to where a passenger would than it does to its original location.

This placement required a custom-fabricated rear end, offsetting the differential severely to the right. “The driveshafts are something like 16 inches on one side and 34 inches on the other side,” Ron figures. But thanks to the three-link arrangement’s carefully placed forward-connected suspension links, the offset doesn’t place any unusual torque strain on the chassis.

Indeed, one of the areas where the car truly excels, according to Ron, is powering through and out of corners.

“Packaging was a huge consideration in this car,” says Ron. “The only major component that lies outside the wheelbase is the radiator.” The view with the skin off shows most of the large and heavy components situated in or around what would normally be the passenger compartment of this pseudo-Camaro.

“Center of gravity is much lower compared to the CP car. The roll centers are very low, and the polar moment is obviously very low as well,” Ron says. “I’d like to get the engine even further back, but according to drawings, that would run the headers right through the steering wheel.” He chuckles, adding, “So we probably couldn’t do that very well.”

Although he drew some inspiration from more mass-produced GT-style cars, this Camaro truly was an original build. “I taught myself SolidWorks and designed the car in that,” says Ron, with all of the casualness of somebody mentioning what they made themselves for breakfast.

When we pointed out that one does not simply teach himself SolidWorks, Ron clarified, “Well, it took me seven months. I watched a lot of YouTube videos.” When pressed further on how he managed to master such a complex program and design such a complex piece of machinery in such a relatively short amount of time–all with self-training–Ron offered, “I’m a nerd.” Maybe so, but he’s a nerd with a Camaro that all the jocks would envy.

Ron did encounter a few challenges with his design’s extremely low center of gravity. For example, because of the engine’s low placement, he had to cut off a portion of the transmission bell housing so it would properly clear the ground. This also necessitated a “low ground clearance” clutch–basically a very small-diameter, multi-plate unit that feeds power from the engine to the two-speed transmission. Again, to keep the package small and the rotating mass compact, Ron used the third and fourth gear cogs instead of the larger first and second ones. This required the use of an extremely low 7.33:1 rear end.

Great Expectations

Now in the car’s second full year of competition, sorting has gone pretty well. “Out of the box it was basically what we expected it to be. The brake system had to be completely redone, though,” Ron recalls. “We basically swapped over from the CP car, and it didn’t work at all. We were getting all sorts of brake hop, uneven lockup. We just ended up replacing nearly everything except for the front rotors.”

Aside from that, sorting has mostly been a matter of dialing in the suspension to get the most out of the computer-designed chassis. This mostly involved switching to stiffer and stiffer springs until Ron found a package that was amenable to the extremely stiff chassis.

“I’m also having to recalibrate my driving, as I’m having trouble with corner entry at this point,” Ron admits. “That’s personally, not so much the car. It just gets from corner to corner so quickly. We’ll exit a corner at 30 mph, and in less than a second we can be hitting nearly 70 mph. That takes a whole different mindset.”

Still, our guess is that Ron and Sonya are in this Camaro for the long haul. They spent nearly two decades in C Prepared, where their other car earned them a wall full of national trophies and two championships.

“Ultimately I’d like to see this car have some success,” says Ron. “On paper it really appears to have what it takes to compete, even though E Modified is populated with lots of very small cars. [The Camaro is] physically a lot bigger and quite a bit over the minimum weight, but on paper there should be some situations where we can compete favorably.”

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View comments on the GRM forums
Rubens New Reader
2/19/16 1:54 p.m.

I wish I could see more photos of the engine set up. That is totally new to me.

HunterJP HalfDork
2/19/16 2:15 p.m.

Ron and Sonya are, simply put, amazingly awesome people. This car build is simply an external, material expression of that awesomeness.

Ed Higginbotham
Ed Higginbotham Editorial Assistant
2/19/16 2:40 p.m.

In reply to Rubens :

Here's a shot of the bottom if that helps any.

cmcgregor Reader
2/19/16 2:41 p.m.

That thing is bananas.

In a good way, of course.

Rubens New Reader
2/22/16 9:52 p.m.

In reply to Ed Higginbotham :

Thanks a lot. The pic does help to understand the whole set up a little better. Amazing idea to bring the power train in between the axles... But how is the lateral weight distribution? Isn't the car way heavier on the right side?

Fueled by Caffeine
Fueled by Caffeine MegaDork
2/22/16 10:08 p.m.

Mental in every possible way.

OHSCrifle GRM+ Memberand HalfDork
2/25/16 5:34 p.m.

looks like Loosecannon's MGB - and damn impressive.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
2/25/16 5:46 p.m.

He's totally destroyed the spirit of the Camaro. It's not meant to be an autocrosser, or have the engine beside the driver. The car is ruined.

bentwrench Dork
2/25/16 8:57 p.m.

Look how long the front control arms are!

84FSP HalfDork
2/26/16 3:28 p.m.

That thing is a pure beast. Awesome smells of smoking hoosiers and race fuel.

Indy-Barely Functional-Guy
Indy-Barely Functional-Guy SuperDork
2/24/18 2:39 p.m.

This Car is amazing.  Love the ingenuity that went into it.

Trackmouse UltraDork
2/24/18 4:05 p.m.
Keith Tanner said:

He's totally destroyed the spirit of the Camaro. It's not meant to be an autocrosser, or have the engine beside the driver. The car is ruined.

Yeah, it’s supposed to loose traction and go off track every corner. Lol. 

Suprf1y PowerDork
2/24/18 5:01 p.m.

The look reminds me a lot of 1970's late model stock cars

freetors Reader
2/24/18 7:20 p.m.

I love this car. Not to belittle the build in any way (it's very impressive!) but I wonder why the builder chose the inboard shocks when making them act directly on the control arms would have been a perfect fit. I can think of several advantages to this; less weight, fewer components, and a simpler frame design that would channel forces more efficiently.

john9546 None
4/20/18 9:29 a.m.

Ron and Sonya are wonderful folks.  They bring a lot of "good" to our autocross sport.  Sponsorship helps Too:)  The car is so cool; the sound and the acceleration capability.

KyAllroad (Jeremy)
KyAllroad (Jeremy) PowerDork
4/20/18 2:09 p.m.

If you haven't seen this car in action you owe it to yourself to get to a Tour event where they will be.  It goes like nothing else but is amazingly composed doing it.

FPZguy New Reader
4/20/18 3:03 p.m.

I'm impressed by the creativity and execution of the design.  I would love to see more details.  Well done!!


z31maniac MegaDork
4/20/18 3:10 p.m.

Pure insanity. I love it.

Apexcarver PowerDork
4/20/18 3:32 p.m.
freetors said:

I love this car. Not to belittle the build in any way (it's very impressive!) but I wonder why the builder chose the inboard shocks when making them act directly on the control arms would have been a perfect fit. I can think of several advantages to this; less weight, fewer components, and a simpler frame design that would channel forces more efficiently.

Unsprung weight is the common driving factor.  Especially if you are in a class with a minimum weight you must reach. 


The less weight at the wheels, the better the wheels are able to react to bumps and other displacements and maintain traction.

mazdeuce - Seth
mazdeuce - Seth Mod Squad
4/20/18 4:58 p.m.

Motion ratio might also be a concern with the design. These cars will have little total travel on course and my shock friends tell me that it's very hard to tune a shock that only moves a short distance. Put it through rocker arms and choose your motion ratio and you can change that short distance into 3-5 inches and that makes building and tuning shocks easier. 

JimMurphy New Reader
4/21/18 10:42 a.m.

I have always been very impressed with the craftmanship displayed in this Camaro.  Ron placed very well at last year's Lincoln Nationals - right there with my low budget Jeep.  I keep working on the Jeep in preparation for this year's Nationals.  I have a distinct feeling that both will be in the hunt.


REM None
4/27/18 9:51 a.m.

In reply to mazdeuce, thanks for your insight regarding shock travel/motion ratio.  Makes perfect sense!cool

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