theCARhack

Cracking up: E46 Sub-frame issues

2008-11-18T14:58:56Z

There is no doubt that the BMW E46 3 Series line up of cars is great. They are right sized, relatively efficient to operate and have superb all around performance. But there are critical weaknesses in the chassis-- especially in the M3 version-- that need to be addressed. We already reported on the fatigue issues with the front strut tower in an earlier blog entry. This time we will focus on the rear subframe.

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First a little background. The above drawing shows the rear sub frame assembly (sometimes referred to as an axle carrier) for an E46 M3. The differential nests within the box like frame and the suspension attaches to it. Below you see the sub-frame assembly on the car:

The complete sub-frame with attachments removed from the car:

Talking about sub-frame failures is a bit of a misnomer since it is the mounting points on the body that fail, not the sub-frame itself. The sub-frame is bolted to the body at four locations, and isolated by rubber bushings. When torque is sent through the axle and to the wheels, a moment is applied to the sub-frame. The sub-frame is also subjected to impact forces from the road surface (though much of the impact force is directed towards the shock and spring mounts, not the sub-frame). Over time, the forces begin to fatigue the sheet metal of the body.

Below is a photo of the right side front sub-frame mounting point. You can see the outside sheet metal has not only cracked, but chunks have broken off:

Here is a photo of the left rear mounting point failure:

Thanks to road grim that builds up on the chassis and the limited access to the mounting points, it is extremely difficult to spot these types of failures without removing much of the rear suspension or taking out the sub-frame all together. The car from which these photos were taken showed a slight compression on the right side rear which indicated something was wrong-- but it could have just as easily been a bad spring as a sub-frame mounting failure.

The fix is relatively simple, though it is quite involved. After the sub-frame is removed (along with all the suspension, driveline, brakes and gas tank) the mounting areas are inspected. We next grind away the paint and body filler. Simple cracks are first prepped and then welded. We custom cut, form and weld new sheet metal for the areas where metal is missing (as in the above example). As a precaution, we reinforce the mounting areas with extra steel plate and weld. The bare metal is then cleaned, primed and repainted before the sub-frame is re-attached. (A future entry will detail these final steps)

Some of the risk factors are:
Carrying heavy electronic equipment such as aftermarket sub-woofers and amps in the trunk
Installing heavy duty aftermarket sub-frame bushings that do not isolate shocks as well as the softer OEM bushings
Driving regularly on bad roads, particularly washboard dirt roads
Driving the car at track events
Repeated hard launches (launch control on SMG equipped cars)

Operation Touring Car: Part 3, the Weigh In

2008-11-17T19:13:06Z

We finally got around to weighing the Civic Si donor car for our touring car project. It's always a good idea to get some baselines before you begin transforming a car-- be it from stock to slightly modified or from stock to race car.

And the weight of our stock Si is...

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2811 lbs

What a Drag

2008-11-03T14:45:52Z

Sure, as real automotive enthusiasts we like cars that can stop as well as accelerate and turn corners as if on rails-- all in a nicely balanced package. And it’s not always the fastest car that is our favorite. But sometimes a showing of brute force is just plain old fun. Follow the jump and watch a video by Motor Trend having some straight-line merriment with four of the best performance cars currently offered: Corvette ZR1, Nissan GT-R, Ferrari 599 and Porsche GT2. Who will win, and why? AWD vs. rear engine vs. front engined power, you can make an argument for all 4 cars...

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Operation Touring Car: Part 2

2008-10-06T20:28:22Z

A few weeks back we announced that VRPerformance is going racing in SPEED World Challenge Touring Car. It is a daunting exercise that we are nonetheless excited to start. The first step was picking the car.

]]> The car we chose is a new generation Honda Civic Si.

Our decision to go with the Si comes down to three main points, weight, power and handling. The stock Civic is a relatively lightweight car, coming in at well below 3000 lbs. The engine fits the Touring Car size parameters and is well known for its basic robustness. The high revving characteristics of the engine are also well suited for race car duty. And finally, the Civic's suspension geometry is solid and is a great starting point for conversion to heavy duty track use.

Next step: the weigh in.

Agency Power Header Install on E46 M3

2008-10-06T15:52:23Z

We have installed plenty of Super Sprint exhaust components on cars over the years. They make a superbly engineered product with plenty of research and development to back up their performance claims (and price). The biggest down side to Super Sprint is the sometimes sketchy build quality and comparatively high price. There are some good alternatives out there, including the Agency Power units we installed on an E46 M3 recently.

]]> The quality of manufacture of the American made Agency Power headers for the E46 M3 install was excellent. The tubes were flawlessly formed and polished and the welds looked strong. The headers included all the bungs necessary for the pre-cat O2 sensors (post-cat sensors and temperature probe were removed) so no modifications needed to be made. As always we used new OEM gaskets and copper crush nuts at the block end of the headers.

Here is a picture of the headers installed, viewed from the engine compartment:

Here are the two collector pipes attached to the Bora mid-section.

Agency Power is a great, less expensive alternative to Super Sprint if you do not absolutely need every last horsepower.

Operation Touring Car: Part 1

2008-09-18T20:17:52Z

Time to go racing! Welcome to the first of many entries documenting our entry into the SCCA SPEED World Challenge Championship. As our busy summer season winds down, we’ve taken on the task of building a race car with the goal of competing in the Touring Car category of the SPEED World Challenge. Call it a stretch goal. We’re under no delusions as to how expensive and challenging this endeavor will be, but we have the car, the enthusiasm, and hopefully the stamina to see it through to a worthwhile conclusion.

]]> According to the SPEED Challenge website, the purpose of the race series is “to provide teams, manufacturers and aftermarket suppliers a competitive production based race series in which to prove their products.” I would add that we’re taking up this project to prove the design, engineering and building capabilities of VRPerformance; for nothing shows off your strengths and weaknesses more quickly than delving head first into racing.

Regulations for the Touring Car (TC) class allow cars with engines up to 2.8 liters in displacement. Turbo or supercharged engines are permitted if they came that way from the factory. Cars can be front, rear or all wheel drive. They must have been able to seat at least 4 adults when in stock configuration. Convertibles are not allowed. Typical estimated horsepower range is 240 to 290.

Car models racing this season include several Mazda6s, BMW 325s, Acura TSXs and RSXs, Dodge SRT-4s, and even a single VW Jetta diesel. The most successful cars over the last few years have been Realtime Racing prepared Acura Integras and TSXs.

Check back soon to see what car we’ll be using…

How not to do it

2008-09-03T19:44:49Z

Okay, I thought this was too funny not to pass along. We actually run into customers like this every now and again...

7 Worst Ways to Modify Your Car

STi Big Turbo Install

2008-08-26T18:14:53Z

Squeezing more power out of a turbocharged 2.5 liter flat four cylinder engine is as easy as swapping out the original turbo for a bigger one, right? If only it was that simple.

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A good friend of the shop, and great customer, brought in his Subaru STi looking for some more boost. He picked up a rebuilt compressor (turbo unit) and wanted it installed, along with the requisite upsized fuel pump, injectors, intake hose, intercooler and blow off valve. Whenever you start replacing OEM components for larger capacity aftermarket bits, finesse and lots of patience are required. Today's engine bays are so chock full of equipment that it's always tough retro-fitting in new parts-- difficult but not impossible.

The turbo came from Forced Performance:

To get access to all the parts required us to take the intake and intercooler out.

Leaving what can only be described as a mess. The engine bay of a STi is one of the more confusing ones, with lines and tubes and hoses running crisscross. It's very important to keep track of every disconnect you make so that when it's time to put it all back together you don't run into an issue.

The components from Forced Performance were top quality, but we did have to grind, bend and plain old tweak much of the mounting hardware in order to make it all fit. The oil tubes and cooling lines around the compressor were particularly difficult to fit. This is where patience comes in, since we had to install, check, remove, tweak and re-install the turbo unit alone probably a dozen times. We could have settled for good enough and not taken the time to route everything perfectly, but that is not our style. Folks come in to our shop because they know we take the time and go the extra mile to make things right.

For example, here you can see where we had to grind some material away from a bracket in order to make the turbo fit properly.

I called the car's owner a "great customer" because he knew upfront that these jobs are difficult and require a good amount of time to make right. When it was all said and done, the project was a satisfying one for all those who worked on it. The car fired up on the first try, and ran well enough for the customer to take the car to the tuner to get the ECU reprogrammed to match the mechanical upgrades. So beware the next time you see an impeccably clean blue STi on the road-- there are a great many extra ponies under that scooped hood...

Fun at 25 Grand

2008-08-21T14:38:37Z

Car and Driver magazine came calling a while back. They were looking for an unadulterated E46 M3 they could test for an article they were planning. And I happen to own one.

The question behind the story is not that unfamiliar to day dreaming car enthusiasts the world over: what cool car can you get for "x" number of dollars? C&D picked $25,000 for their bogey and then came up with a list of eligible used cars by combing through classified ads and price guides. (Video after the jump)

]]> Twenty-five grand is not a pittance and it can get you any number of fine new cars, such as the Mazda MX-5 or VW GTI they highlight in the article. But, thanks to insipid depreciation, that amount of money opens the door to a great dream garage of fun pre-owned cars.

And while it's depressing to think that just 5 years ago I paid my local BMW dealer close to $60 grand in cash for what is now a used car bargain, I can't really complain-- since, well, I've been enjoying the car for 5 years.

If you have not figured it out yet, I'll take that white M3!

E46 M3 GT Part 2

2008-07-24T14:19:35Z

A few weeks back I posted the first entry in my "M3 GT conversion" series. I mentioned that the next step in my quest to turn my 2003 E46 M3 into a true "Gran Tourismo" is installing new wheels. Well, they are here!

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As you can see I'm continuing my black and white theme with the wheels. The car is now devoid of any chrome jewelry save for the BMW roundels on the hood and trunk (and the headlights and tail lamp turn signals). I have to admit I've been a big fan of black wheels all my life-- they impart a no nonsense functionality and seriousness that chromed or otherwise painted wheels cannot. Race cars wear black wheels.

And more often than not, they are made by Fikse. Made in the USA since 1992, Fikse wheels are of forged modular design. This means the wheels are comprised of three forged pieces, the inner and outer rims and the center disc. All three pieces are forged separately, which provides superior strength to weight characteristics when compared to single piece forged wheels. And cast wheels; well they don't even come close.

I went with the classic 5 spoke pattern of the "Profil 5" series with black anodized finish. The E46 body style or shape is heavy. And the M version is even more muscular looking with its bulging fenders and bulldog stance. Because of this, you need a strong looking wheel, one that follows the theme set by the original design of the car. Thin spoked wheels that look light and airy simply do not fit on an E46 M3 in my opinion.

I also took this opportunity to upsize the tire width a bit-- to better fill in the generous wheel wells. At the front I have 245/40R18 tires on a 8.5 inch rim, at the rear 275/35R18 on a 10 inch rim. I stuck with 18 inch diameter because I'm simply not a big fan of ultra short sidewalls plus the roads in SE Michigan are so bad that I feel safer with a bit of extra distance between the road and the rim. Thanks to the thin cross section of the rim's spokes there is plenty of back spacing available for a future big brake kit.

I swapped the stock lug bolts for wheel studs and black annodized alloy lug nuts (surprising how much lighter the alloy lug nuts are compared to standard steel ones).

So now the "visual" side of the GT transformation is pretty much complete (the lighter weight of the Fikse wheels also reduces unsrpung weight which increases performance several different ways-- so it's not just looks). The next step is to tweak the performance. Stay tuned.

E46 M3 GT part 1

2008-07-04T16:05:16Z

After long and careful consideration I have decided to keep my personal E46 M3. Instead of purchasing a new car I will invest some money in the old M3-- give it a mid-life makeover so to speak. And as great as the car is on the track, I really think the E46 is a better GT car than all out sports car. So my tweaks will take that into consideration. I will not turn the car into a full out track monster (which is not that hard to do, really), instead I will focus on making it a better grand tourer.

]]> Step one: completely and utterly superficial. I replaced the stock chrome bits with all black parts. The car is Alpine white, and as much as I like some chrome "jewelry", I think a black and white theme is pretty darn cool as well (and it will match my all black wheels-- stay tuned).

Turner Motorsports sells a nice set of black kidney grills. They are molded in black and thus will not chip. The satin finish also matches the OEM window surrounds, so you get the impression that the grills are stock.

At the same time I ordered a pair of side grills. Unfortunately they came in a gloss black-- which did not match the new kidney grills or the window surrounds. So I called up a local body shop that I trust to see what can be done. AutoMark Collision specializes in heavy duty repairs of high end automobiles-- plus specialty projects (check this out). Their quality of work is unsurpassed in SE Michigan and they came through again. A quick coat of satin clear coat did the trick and now all the new black bits match.

Stay tuned for more updates!

Front Strut Tower Fatigue on BMWs

2008-06-20T21:03:52Z

This is a note for all of you who run heavier springs on your E36/E46 BMW. We have had a rash of M3s come into the shop with cracked FRONT strut towers lately.

]]> Cars with stock suspension seem to be unaffected, but those with aftermarket suspensions-- particularly those with Ground Control camber/caster plates-- are prone to cracking between the stud holes (cracks already chamfered):

If the cracks have not propagated too far, the fix is relatively simple. First step is to remove the front suspension and clean up the area:

Chamfer the cracks and weld:

Grind and clean:

Repaint and then put it all back together again:

Next time you're under the hood of your BMW E36 or E46 3 Series, take a look for the telltale signs of cracked paint around stud slots and/or under the strut tower brace end caps. If you see any cracking, get it fixed as soon as you can.

The Care and Feeding of Your Coil-overs

2008-06-20T20:30:31Z

Height adjustable suspensions have become quite popular of late-- even to folks who do not track their cars. Often referred to by the blanket term "coil-overs", height adjustable suspensions allow the owner to set and change the ride height of the vehicle for any of a number of reasons: to corner balance for the track, winter/summer ride height changes or just to fine tune the "look". But as high tech as some of these kits are, they do need yearly maintenance.

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It is a good idea to exercise those spring perches at least once a year. The spring perch is the ring the spring sits on. On a strut suspension as pictured above, the shock tube is threaded and the spring encapsulates the tube and sits on a two rings, one is the actual perch and the other is a locking ring. Once a season you should take the wheels off, clean up the threads and move the perches up and down. It’s also a good idea to apply a little anti-seize compound to the threads. By moving perches periodically and making sure everything is clean, you will lesson the risk of the parts seizing together. We've had cases at the shop where we have had to cut off the spring perch and replace it with a new one just to adjust the height. A little preventive maintenance can save lots of grief in the long run.

E30 M3 Rebuild: Differential

2008-06-02T17:15:21Z

We began this project car with a clear focus on improving the performance of the suspension and the brakes, since the engine already had a thorough going over by another shop a few years back. The one speed area of the performance equation we decided to improve right from the start was changing the gear set in the differential. The biggest bang for the buck is not in adding power to the E30 engine, but changing how the exisiting power gets to the ground. This is espcially important at the track, where this car will consume most of its gas.

]]> Speaking with many E30 M3 experts around the country, we settled on what was considered by almost everyone we spoke with as the best track driving gear ratio for the differential: 4.45. We had E30 expert-- and differential builder extraordinaire-- Ben Thongsai out of Chicago craft the new unit for us. He built up the diff with the aforementioned 4.45 gear-set, 4 clutch limited slip with 50% lock-up. We also had him install the M Coupe cover which has bigger cooling vanes, again with an eye to track use.

Hard to tell what this is, thanks to all the rust, dirt and oil, but here's the original differential still in the car:

Here we have the old one out, sitting next to the beautiful new unit:

A close-up showing the M Coupe cooling fins:

The new differential, installed:

The First 1

2008-06-01T20:18:10Z

The BMW 1 Series has only been showing up on people's driveways in the States for a few months now and already there are enthusiasts ready and willing to fine tune it. A great performance car straight out of the box, it none-the-less comes with the compromises every modern car has. We've talked about this often enough: in order to satisfy the government's regulators, insurance lobbies, and the average consumer, new cars are "sanitized for our protection."

]]> The owner of this particular 135i decided to tweak his car before the break-in process was complete, arguing that you might as well make the car what you want it to be right from the start. Our kind of guy. The biggest item on his list of things to do was eliminate the well documented understeering characteristic that pretty much plagues every new car these days (according to the lawyers, understeer handling is much easier to deal with-- and thus safer-- for most average drivers). He already had specially tuned sway bars installed before he came to our shop; and now he wanted us to install a complete Variant 2 KW brand coil-over suspension to further button down the handling.

First introduced on the E60 5 Series cars, the front suspension of the 1 similarly utilizes a complex multi-link front suspension with standard strut dampers. The photo below shows the front hub assembly removed and suspension partially disassembled (note the stock 6 piston brake caliper cradled on the red towel):

Here you can see the KW front strut assembly installed:

While it looks pretty complex-- and make no mistake it is-- we've done enough of these BMW suspension swaps to know the tricks to do it properly without damaging any of the ball joints and links.

The rear suspension is typically easier to work on because there is no steering gear to get in the way. But, it still takes time and the proper tools. The entire trunk needs to be de-trimmed to get to the upper shock mounts. And-- again to do it properly-- we used a special spring compressor to get the stock springs out:

Here you can see the KW suspension installed (note the polished stainless steel damper and the height adjustable spring perch in purple):

We're big fans of KW suspensions, and this kit did not disappoint. The welds looked great, the hardware was top notch, and everything fit as it was supposed to. To start things off, we set the ride height about one half inch lower than stock. The springs will settle some and when the customer comes in for an alignment we can tweak the height.