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Annual THSCC Tech Inspection Day

Yesterday the AP&C garage hosted the Tar Heel Sports Car Club’s annual tech inspection.  The purpose of this event is to give the members a chance to use our facility to perform vital inspections of member’s track cars to ensure that they are safe and ready for the challenges of HPDE, Time Trials, etc.


It is also a great time to see just what these people have for cars and talk to them about their passion.



The staff from THSCC examines all aspects of the mechanical condition of cars that plan to participate in its events.  Helmets are also checked for compliance with safety standards.


Many types of cars show up for these inspections and it is a treat to see them up close and talk to the owners.


Everything from turbocharged Miatas to the latest Corvettes.


All kinds of cars…




From nine in the morning until two in the afternoon the volunteers from THSCC spent their time checking cars that rolled in for their inspections.


AP&C feels its important to support these clubs and their events.  We provide specialty alignments for track day customers.  If you need advice on brakes, suspensions, roll bars, and tires or need our help getting these things installed the correct way we are available to help.  Come see us and find out for yourself.

New direction for a ’71 Lemans

The prior owner of this ’71 LeMans had a particular direction in mind when they installed a 455, added a rear wing, customized the interior, and lowered the car.   The new owner wanted to take the car in a new direction and return to a classic muscle car stance that was closer to a stock ride height.  After all, its no fun dragging your headers on every speed bump.

Whether you are planning to raise or lower your car with a change in springs,  it may help to make some measurements of your current ride height and the springs which are currently installed.  You can measure from the center of the fender lip to the ground at each corner while the car is parked on a flat spot.  You can count the number of coils on the springs and measure the diameter of the coiled wire.  Ideally, removing your current springs will allow you to also measure the free height and consider that as you compare these values to the new springs you are planning to order.

Let’s see how free height, number of coils and wire diameter come together to affect the final result as installed.


The Spring on the left is the Eibach spring I removed from the front – it has a free height of about 13.5″ and a wire diameter of about 17.34mm and 10 turns.   The spring in the middle was listed as the OEM spring for the car, and is almost two inches taller at 15.25″ free height with a wire diameter of about 15.46 mm and also 10 coils.   The spring at the right was an alternate listing for this vehicle and is taller still at 17.25″ free height, with a wire diameter of 16.52 mm and 11 coils.

Initially, I installed the middle spring as our goal was  to add a couple inches to the front to restore the stock ride height.  While the free height was two inches taller that the springs they were going to replace, they were not as stiff due to the smaller coil wire diameter – 15.46mm vs 17.34 mm.   As installed, these easily compressed by the weight of the car and wound up being close to or even lower than the set which they replaced with a fender height to the ground measurement of 23.75″.


So, to get the result we were looking for, we needed a taller spring with more coils and a larger wire diameter that would not compress as much when installed and turned to the third spring which was about 3.75″ taller and had a wire diameter between the stock set and the stiff lowered springs.  The result was a fender to ground clearance of 27.4″ which meant that we had raised the front of the vehicle just over 3″.  Compare the fender to tire relationship between these two photos.


This is closer to the look the new owner is looking for and we expect that this will settle a little over the first 500 miles or so, after which we will recheck the alignment that we performed after the spring install.   While we were doing this job, we noted the upper control arm bushings were badly worn and took the opportunity to swap those out.


Here are a few thoughts if you are swapping out your own springs.  We supported the car on a lift and then used a floor jack to support the lower A arm, separating the upper ball joint after having disconnected the outer tie rod, sway bar end links,  and removed the shock and brake caliper and supported the brake caliper on a hanger.   I recommend use of a safety chain – looping between the A arm and frame and down through the spring out through the shock mounts at the bottom of the A arm.  This will keep the spring from flying out if it pops out of the pocket while you are installing or removing it.  With the tallest set of springs, I needed to use a length of wood 2 X 4 to push the bottom of the coil spring into the pocket in the lower control arm as it was compressed.   When compressing the new spring with the floor jack, you may find that with tall / stiff springs that the car will start to lift off of the supports (jack stands or hoist lift points).   I reduced / countered this by placing another jack under the frame at the opposite corner of the car as close to the end of the car as possible.





2006 HHR Project

We love it when we have a customer that brings us a project to upgrade their ride.  The owner of this 2006 Chevy HHR was looking for a sportier ride and a little more power, but didn’t want to go crazy and didn’t need it to be a track car.

We spent time listening to what he was hoping to achieve and understand his budget.  We took him to Tire Rack’s web site and showed him some of the options available to him there.  Together we picked out a set of Eibach anti-roll bars along with a fresh set of KYB struts and shock absorbers.  Since the struts were being replaced we knew it would be the perfect time to replace the old strut mounts, bump stops and strut boots.  He wasn’t interested in lowering his HHR so we knew that we could re-use the stock springs.

He took us up on our suggestion to replace the anti-roll bar end links with some made by Moog.  The new ones came with grease fittings, too.  He found that Chevrolet sold an upgrade to the exhaust system that would give him a little more power, but keep a very nice exhaust note.






With the vehicle up on the lift we took a look at the rear where the anti-roll bar would be mounted.  The Eibach kit would be added to and not replace an existing anti-roll bar.  It used factory holes in the rear trailing arms so no new holes would need to be drilled.  A new metal bushing was slid inside the trailing arm and dropped into an existing hole.  This is where the black brackets would be bolted to the arms.



Once they were bolted (loosely) in place the bar was fit in place and then bolted to the two brackets (again loosely).



Once everything was in place and the brackets were adjusted we tightened all the bolts to 65 ft/lbs as required.

Next we removed the rear shocks not only because they were being replaced, but that would lower the rear suspension and allow the installation of the new exhaust system.


The old system was unbolted from the catalytic converter and then cut just in front of the rear suspension.  That made it easy to remove.

The exhaust hangers were lubricated with silicone spray that allowed them to be popped off the chassis hangers as well as the old exhaust system.


The new system came in three sections with a new gasket and two clamps.  We kept it loose as we positioned the pipes and clamps.




When we were certain that the system was lined up properly and that there was clearance everywhere that it was needed, we tightened up the bolts and clamps.

Then the new shocks were installed.


It was time to tackle replacing the front sway bar (aka: anti-roll bar).  That was an involved project as the subframe would need to be lowered and the steering rack temporarily disconnected from the subframe.  The front motor mount bolt would be removed as well as the rear motor mount bolts.


The end links were unbolted from the stock bar and then the clamps holding the stock bar were removed.

With the subframe dropped down the old bar was easy to remove and the new Eibach bar could be positioned in place.  We kept the protective plastic wrap on the bar as long as possible to protect it from nicks and scratches.



The new bushings were coated with grease to ensure that the bar wouldn’t squeak.



Then it was bolted in place and the subframe was reattached.  The steering rack was also bolted back in place.  The end links were bolted loosely to the new bar and it was time to remove the strut assemblies and get them apart so the new struts could be installed in their place.

Removing strut springs can very dangerous and not all spring compressors are created equally.  We use the Strut Tamer Extreme and find it to be safe and effective.  If you have ever changed a set of struts and struggled with the inexpensive clamp on spring compressors available at the part stores and had them slip around to one side of the spring or even pop loose unexpectedly, you will appreciate having a tool like this one.



We installed new strut mounts and bearings along with the new KYB struts.



The end links were bolted up and a complete visual check of all the work was performed to ensure that a quality job had been done.

A new set of tires had been mounted on the wheels so they were bolted on and torqued to the proper specification.

Then the HHR was taken for a test drive to check for any squeaks or rattle that should not be there before it was put on the alignment rack for a check and adjustment.

All this resulted in a fun car made even more enjoyable.  The ride turned out to be comfortable as well as more stable and the exhaust note was perfection.  Chevrolet did a great job engineering the cat-back exhaust.  It added better breathing to the system without torturing the driver with a droning exhaust.  It was sporty and civilized.  Just what the owner was wishing to achieve.

Track Car Project – Part 2

Previously, we talked about building a budget track car that could do double duty as a track car and as a performance oriented daily driver.  In our first installment, we procured an Audi A4 quattro and began repairs, planning our upgrades and ordering parts.

With the new engine, transmission and sway bar mounts in place, we began to work our way forward starting with a new radiator.   As the stock radiator support was trashed, and includes piping to the factory side mount inter-cooler that we will not need, we decided to fabricate a new support from thin wall box tubing.  This will be a foundation for the radiator, AC condenser and new front mount intercooler.


With the new support in place, we installed the radiator and connected the radiator hoses and transmission cooling lines.  Next, we installed the AC condenser which mounts to the radiator.


As we test fit the stock bumper as a guide to determine location of the intercooler, we used the mounting hardware provided by CX Racing.  As we were using a non-factory radiator support, we made our own lower mounts from steel bar stock.  The intercooler kit was pretty good out of the box, but we did need to re-tap several of the threaded bosses.  The silicon hoses and clamps worked well.


First we installed the cold side connections to the throttle body, and made some minor modifications to our support in order to attach the new AC hose which connects the condenser to our new AC compressor.


As we moved over to the pressure side, this was a great time to upgrade the turbocharger and exhaust manifold to make greater use of the increased capacity of the new intercooler.   We removed the stock K03 turbo and cast iron exhaust manifold, along with the stock cat, downpipe and exhaust system.  The system on our car was not stock – it included Borla resonators and mufflers, but the pipes and mufflers were only 2″ diameter.


We will be fabricating our own exhaust with some larger pipe.  There are many good kits available on the market as well.

For this stage, we are moving up to a K04 turbo which includes a larger compressor wheel, and a stainless steel equal length header that has been wrapped to keep the heat in the pipe which will not only benefit the turbo, but will reduce under hood temperatures.


We used Allen head bolts to attach the turbo to the header as the normal hex bolts would have been more difficult to manage, and then installed as a complete assembly.   A new oil pressure line will be needed for several reasons.  First, there is mechanical interference with the header.  Secondly, we want to keep the oil as cool as possible, so routing it away from the pipes is a benefit.  Lastly, a new pressure line is recommended with installation of a replacement turbo.  If we weren’t replacing the line for the first two reasons, removing it and flushing it with solvent and compressed air would be a minimum precaution.


With the new turbo and header in place, we continued the installation of the coolant feed and return lines,  oil drain back line and turbo brace.



We removed the factory air cleaner box and are installing a new reinforced silicon intake hose that will connect the mass airflow sensor and less restrictive air filter.   This will require some further work with tube and clamps to plumb in the check valve for crankcase vent, re-circulation valve and electronic boost control.

We’ve ordered all new front end control arms and steering components, along with a set of H & R coil overs and Hotchkis front and rear sway bars.   These have all arrived, so in our next installments we will tackle the suspension and fabricate a new down pipe and exhaust system.


Track car project – Part 1

We thought it would be a lot of fun to build an affordable HPDE/track-day car that could also double as a spirited daily driver.   We also thought it would be fun for our readers to be able to follow along and watch our project progress to a track day finale.

We chose one that would reflect what we see with many of our customers who have dual use cars of this type.  We looked for a car that would accommodate a range of drivers comfortably, retain key amenities like air conditioning and a full interior to allow the vehicle to be driven comfortably to the track or to function as a second car when needed.  We felt it should be mid-sized,  turbo charged, and preferably all-wheel-drive (AWD) for more predictable traction and handling under a wide range of weather and surface conditions.  We also felt that a passenger (or instructor) should fit comfortably, and the car should have ample storage for tools, gear, and maybe even the occasional bag of groceries.  With all that in mind we set our sights on finding an affordable Audi A4.

A search of local classifieds netted a number of Audi A4 B5 or early B6 models that are inexpensive, and enjoy a wide range of aftermarket options that can improve acceleration, handling, braking, safety and reliability.


Our project car was previously involved in a minor off road event that damaged the bumper cover, radiator, AC condenser, side mount inter-cooler, and several engine and transmission mounts.   Since we planned to change out many of these items in the process of the build, this was a limited concern to us.  That meant that we purchased it at a bargain price to boot!   Others of you out there might want to start with an undamaged vehicle for slightly more money and have less things to return to undamaged condition.

Our project build will be performed in multiple installments focusing on upgrades to the engine, suspension, brakes, wheels & tires.  The body and interior mods are expected to include some carbon fiber panels, roll bar (or semi-roll cage), seats and harnesses.  We want our approach to reflect the journey an enthusiast might go through as they build their own dual-purpose track car.  Suspension, engine, and brake components often need to be updated in stages as improvements in other areas such as power create an imbalance in the factory equation.  For example,  significant power increases will dramatically increase  speed entering a corner, resulting in the need for improved grip from the suspension and tires, and larger brakes to slow things down and dissipate the heat effectively to avoid brake fade or warped rotors and may overpower other drive train components like the factory clutch.

For our initial work, we are disassembling, assessing damaged and worn out components, then ordering replacements  along with our first round of upgrades to the suspension and engine.  After raising the car on a lift, we  removed the bumper cover and bumper assembly, the damaged AC compressor, condenser, radiator, headlights and various mounts and sub assemblies.  This gave us a list of things to consider for upgrades as well as replacements.  This also gave us a view of vehicle components and structure that is not usually seen.


The damaged side mount inter-cooler and piping were removed, along with the cross pipe and radiator mounts.  The oil pan needed to be replaced along with several engine, transmission and sub-frame mounts.


Note the shattered aluminum mount – this provides the the driver side mount points for engine mounts, anti-sway bar, and connection to body and sub-frame.  The damaged loop of tubing provided minimal factory cooling for the power steering system.  This will be replaced by a dedicated cooler as the build progresses.

A used replacement bracket was sourced for less than $30 online.

new bracket

The driver side transmission mount bracket was also replaced for about $20.  There are a number of websites that sell used parts from salvage vehicles.  This was the most cost effective way to source these parts.   We also replaced the associated bushings and mounts with new pieces as these were readily available from our parts suppliers.  For many of you an alternative would be a pull-it-yourself auto recycling yard such as LKQ.

Note the blue numbering indicating the inventory numbers from the salvage vehicle this bracket was removed from. When inspecting a used vehicle for purchase, look for these type of tell tale numbers which can alert you to parts that may have been replaced as the result of an accident or complete failure (as with engines, transmissions, differentials).

trans bracket

The oil pan had a hole in it and needed replacement.  With the oil pan removed, it is an opportunity to visually inspect for any other issues including signs of sludge and carbon build up, and ensure to the oil pickup screen is clean and undamaged.

bottom end audi

This was also a good time for a bit of research as we consider engine mods once the initial restorative work is done and we have a baseline to work from .  We found a helpful resource in Integrated Engineering’s website, covering the variations in the five valve 1.8L VW / Audi engines.   For now we will keep the stock bottom end, but if we want to increase power significantly while maintaining reliability, it may be time to build a fresh engine with stronger rods,  and hardware.


With the new oil pan in place, we’ll take a break and be on the lookout for the UPS and Fedex trucks. Our upgraded suspension parts are starting to arrive, so in Part 2 of the project, we will begin our upgrades – focusing on the new coil over suspension, larger sway bars, new control arms and tie rod ends. Stay tuned!





Cryo treated drilled rotor upgrade for C5 Z06 Corvette

The drilled rotors on this C5 Z06 had nearly 100,000 miles on them and having survived two pad changes worth of wear and prior turnings were now down well below the min 30.60 mm (1.205 inches) thickness on the front.   Time for new rotors along with fresh pads.


For daily street / performance driving, we went with a set of Stop Tech Cryo treated rotors and Akebono pads.  The rotors are cross drilled and each hole is counter sunk to reduce risk of cracking at the holes.  The rotors are pre-conditioned over a 24 hour period by cooling them to -300F and then warming them to normal temperature and then heating them to +300F and then cooling them again.  This process permanently changes the structure of the metal improving durability including abrasion resistance, and improves dimensional stability and resistance to warping.



Cryo treatments are increasingly finding their way into many race applications and commonly used on cranks, rods, heads ,valve springs, gears and rotors.  If you track your car or are looking for additional performance and longevity from your brakes, ask us about pricing and availability of cryo treated rotors during your next pad and rotor service.   A variety of standard, slotted, cross drilled versions are available from several leading suppliers.



Intermittent check engine – P0120 on BMW 528i

OBD II self diagnostic trouble codes have made it easier to understand and troubleshoot issues in 1996 and newer vehicles. However, intermittent codes that occur randomly over varying periods of time can be more difficult to conclusively pin down as the code given may or may not be directly caused by the component indicated.

In this particular case with a 1999 BMW 528i sport wagon, the check engine light and underlying P0120 code was being set at various intervals.  This symptom could occur immediately upon startup, or after extended drives which made the process of resetting the code and then reproducing the code again, a someone time consuming process.

IMG_20160624_120142580The accompanying symptoms were sluggish performance and a shutter when the accelerator was pressed.   The code indicated a problem with the throttle position sensor which tells the car’s computer how much throttle input is being given.

Often, the throttle position sensor is attached to the throttle body and may be replaced separately.   In this particular case, and increasingly more often in newer drive by wire vehicles, the entire throttle body must be replaced as a complete assembly.

It is possible that cleaning the throttle body to remove carbon build up around the throttle plate could resolve some symptoms that occur at idle and could be a could low cost first step, especially if the sensor cannot be replaced independently. This particular throttle body had been previously cleaned .


Oil cooler upgrade improves 370z track readiness

This 2015 370z sees some track day events and the owner noted that oil temperatures had been creeping up a bit and wanted to add an oil cooler to improve reliability and endurance at the track.   As with many performance oriented vehicles, the factory included an oil cooler which makes use of engine coolant.  This helps stabilize oil temps, and can also help to get oil up to the proper temperature sooner under cold weather conditions, but under sustained performance driving this adds additional heat to the cooling system that is already being taxed.

Adding an external oil cooler helps keep things under control.  Since the car will be driven year round, the owner opted for a thermostatically controlled cooler that allows cooling flow after a preset temperature.  This lets the oil come up to temperature sooner and compliments the factory system by maintaining the adaptability of the system to deal with a range of weather and driving conditions.

In consideration of the owner’s desire for a high quality cooler that would work under a range of conditions, and offer long term durability, we sourced the components from Z1 Motorsports and opted for the mid sized 25 row cooler with several upgrades including a Setrab core, a thermostatic adapter, and braided stainless lines with an outer protective wrap.

The installation was very straightforward, but required dis-assembly of the front bumper cover and assorted components to easily mount the cooler and route the lines properly.

2016-06-01 12.02.30

The cooler core arrived with several well designed brackets that allowed placement in a location the factory had intended, and had already provided lower mounting locations for.  The holes in the cooler bracket aligned well with only the right side requiring a bit of elongation for a perfect fit.  The hose were routed, and the protective covers added additional insurance against chaffing.   We elected to add some additional protective material over the hoses where they pass through the sheet metal of the radiator support and the passenger inner fender.


Under the car, the thermostatic adapter installs between the filter and the existing coolant based oil heat exchanger.  This is a perfect time for a fresh filter and oil change, and the cooler core must be pre-filled with oil as it holds a significant amount (over a quart).  Space is tight, and this will make future oil changes a bit more challenging.


After the install and warm up, oil temps were stable at approximately 160 degrees and would rise to 170 during driving.  We will update with results after a day at the track…

Amazing Customer Fabricated Turbo Miata

As noted in our last post, it was great to host the triangle miata club at Automotive Performance & Chassis for a spec alignment and corner balance clinic featuring a track prepped Miata.   I really enjoyed the day, and a high point for me was the opportunity to check out all the amazing work that the club members had done on their own cars!   Something drew me to Mike Gordeev’s wicked Miata.

A quick look under the hood confirmed that this was no stock Miata!  The turbo gave that away, yet it was all the details that drew me into a deeper discussion with Mike.  He explained the long radiator hose that re-routed coolant to the rear of the cylinder head to ensure better cooling, and how this necessitated relocation of the coils.   I noted that his strut bracing looked like a custom fabrication – it was.  A Mike original.  From there, Mike outlined more of his fabrication – the roll bar, the exhaust system, all the turbo plumbing, including the trick custom header.

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2016-04-24 09.59.13

And what was this?  That looks like a Honda intake manifold?  Sure enough, Mike used a Honda intake and fabricated a new flanges to bolt onto the Miata head, and to correctly clock the Miata throttle body.  This brought us to the topic of his great looking TIG welds and where he got the flanges.  I learned that he had machined them himself, and I began to realize the level of talent out there in the clubs!

Mike graciously tolerated all my questions and was good enough to oblige an interview and passed along a few additional photos…

Mark:  Mike, what was your first self fabricated part on this Miata?

Mike: A rollbar. Sitting in the car realizing that if something were to happen, my head was the closest thing to a rollbar that the car had. That had to change. Coincidentally, I was just finished building a tube bender for a friend to use on his Jeep projects and I decided to break in the bender by using it to make my rollbar prior to handing the bender over to him.

Mark:  Out of all the things you made, which pieces are you most proud of, and why?

Mike: I am most proud that I have been able to largely re-engineer many of the most essential power train systems such that they perform as good or better than what the Mazda engineers produced. I am proud when something I make is mistaken for a factory part.

ChathamCNC miata engine bay.

Mark : Clearly you have gone well beyond bolt-ons and have a real vision for this car.  What are your goals for this car?

Mike: The goal for this car is simple: bang for the buck power. I think I’ll be happy with 300whp, which on paper should give it slightly better power-to-weight than a c6 ‘vette. I have a turbo that will get me there sitting on my bench. The Miata is generally regarded as a cheap, unassuming, and generally slow car. With the added power it’s definitely fun to surprise a Mustang driver or two.

ChathamCNC Miata

Mark:  I’m very impressed with your welding – you seem to do exceptional work with aluminum, stainless and mild steel.  What kind of equipment do you use?   What do you find most challenging to weld?

Mike: All of my welding is done using an old Thermal Arc 300 GTSW; an early industrial grade inverter TIG welder. I am trained in MIG and TIG, but prefer TIG over MIG as it lets me really focus on the quality of the weld. Welding as a skill is 10% knowledge and 90% practice. Every metal welds uniquely and so the hardest challenge is welding a metal on, which I am relatively out of practice. Often I will have a long period of work focusing on one metal and once it’s time to get back into another metal it will take me a little time to readjust my technique and way of thinking. In terms of pure difficulty, once you get a feel for each metal, none are any more difficult than any other, just different.

Exhaust manifold TIG welds.

Mark:  The fabricated intake is really great.   I understand you milled out your own flanges for the mount to the head and to adapt the Miata throttle body to the Honda intake (and fix the clocking).  What did you use to mill this?

Mike: All of my milling work is done on my CNC mill. The CNC allows me to make complex parts, the thought of which would have made my head spin when I was turning dials on a manual milling machine. This machine in itself was an early project I designed and built a few years back.

ChathamCNC machined intake port block-off plate with integrated throttle cable mount.

ChathamCNC machined control link for vintage remote control truck.

Mark:  So you built your own custom CNC mill?   Why not buy a used commercial CNC mill?  Did you just want the extra challenge of building your own custom tools?

Mike: It all started out with seeing what was available and then saying, “I can make that.” I had a very well equipped machine shop at my disposal at the time so I went from an idea to a functioning mill within a few months. At the time I started building my mill, I didn’t have any real use for it. I was basically building it for the sake of building it. I was a manual machinist and had no experience in CNC. Luckily the things that make a manual machine good also apply to a CNC machine, so I designed the CNC with my manual machine experience in mind.

CNC milling machine construction

CNC milling machine initial assembly.

CNC Milling machine.

CNC milling machine cutting chips!

Mark:  So what other kinds of custom machining work do you do?  What kinds of projects do you most want to take on?

Mike: I also do manual lathe turning work. Having welding, milling, and turning capabilities allows me to handle 95% of the projects imaginable. I am a mechanical design engineer by day and I offer that experience to my machining clients if they request it.

I generally enjoy doing prototyping and custom work. Small production run and one-offs. I generally favor work which aligns with my personal interests, so custom automotive and motorcycle work is always welcome! Keeping machining enjoyable is very important to me. Custom work allows me to do this.

ChathamCNC fabricated single carb conversion manifold for a 1976 Kawasaki KZ400.

If you would like to learn more about Mike, visit his site at http://www.chathamcnc.com/