No one can deny the impact VW's 1.8T engine had on the aftermarket industry. Before this 20-valve turbocharged unit popped up, VW's powerhouse was the 2.8-liter, 12-valve VR6. Although a great powerplant, it was tough to see huge power gains without an equally huge cash outlay. The 1.8T changed this, making gains easy and affordable.
VW and Audi enthusiasts have a variety of ways to enjoy the 1.8T's turbo goodness; everything from coupes and hatchbacks to sedans and wagons. The 1.8T's first appearance in the MkIV platform happened in 1999, in the New Beetle. The following year saw it introduced into the Jetta/Golf/GTI and Audi TT. Since these cars are nearly 10 years old, the average consumer can use them as reasonable starting points for a great project build. Sifting through the classifieds, it's easy to find MkIVs for under the $10,000. For a budget build, first-year Beetles can be had for around $5,000. There are also a number of MkIV owners whose cars are paid off and are now looking to have some fun with it.
We're using a 2003 Beetle as our starting point. But regardless of platform, the things we are doing can apply to all MkIV 1.8T cars, featuring common modifications any owner can do-without adversely effecting the use of their car as a daily driver-and things we feel any enthusiast would want to do to optimize their MkIV's performance. Most mods here are standalone, meaning they can be done all at once or one at a time. We are also giving special attention to parts replaced through normal wear and tear, showing a performance alternative to a factory replacement.
First up is suspension. The factory went soft on the MkIV suspension and most enthusiasts feel their cars sit way too high. Apparently, someone at VW is convinced Americans like cars that float down the road and we constantly feel the need to pull in over parking blocks. There is a wide variety of suspension systems on the market and an enthusiast can spend anywhere from a few hundred to a few thousand to get the desired effect. Threaded body adjustable coilovers became popular with the MkIV crowd, mainly for the tweakable ride height. But for most people, they are really overkill on the street.
We've chosen a more conservative and less expensive alternative. After trying many different brands (and we have a lot of favorites), when it came down to it, we went with Koni Sport shocks and struts and Eibach Pro-Kit springs. The Koni dampers are five-step, rebound adjustable, allowing us to dial them in to best suit our driving styles. We have also found them to provide excellent damping ability while maintaining a comfortable ride. The Eibach springs dropped the car about an inch and half-not slammed, but noticeably lower than stock. They also provide a good compromise between ride and handling. Bumps are a little more pronounced, but nowhere near harsh. Dive and squat are both reduced and the car feels more eager to turn into corners.
To give the springs a little help in controlling body roll during cornering, we chose Eibach's anti-roll bars. At 22mm in front and 25mm in the rear, they balance out the car nicely and help us keep the tires' contact patches flat on the road.
Since shocks and struts are normal replacement items that usually require attention around 50,000 or 60,000 miles, it makes sense to upgrade at this point. The minimal cost of springs is worth doing, since the labor is already being paid. The anti-roll bars are a nice addition we would recommend, but labor will be more and they can be done later.
The worst thing about the MkIVs' factory tires is how long they last. For the most part, they aren't bad, but with so many good alternatives out there, it's crazy not to try some. While we were doing tires, we also decided to upgrade the wheels. Several MkIV platforms came from the factory with 18-inch wheels and we thought an upgrade was definitely worth the small expense. We started our search at Discount Tire Direct's website. We have also been considering a brake upgrade, so we had questions regarding that and needed technical info on different wheels. We called DTD's order line and got answers immediately, with clearance concerns put quickly to rest. We went for TSW Montage wheels, each weighing 25 pounds for our 18x8 size. Finished in silver centers with a polished lip, they give the car a great look without being too overstated.
For tires, we chose Nitto's new Invo in 225/40. The tread design has always piqued our interest and we have been impressed with its low noise and high grip. They were shipped directly to us from DTD, mounted and balanced on the TSWs. All we had to do was bolt them on.
With the car connected to the ground, our next replacement/upgrade was obviously the braking system. We contacted parts4vws.com, who provided a basic upgrade to 12.3-inch rotors (up front) from the Audi TT and Hawk pads. The larger rotors require a different caliper carrier to move it out to the appropriate position. In the rear, we considered an upgrade to 10.1-inch brakes and calipers from the 337. Looking at the cost-versus-benefit ratio, we decided to stick with 9.1-inch Powerslot rotors and Hawk Pads to match the front.
The MkIV has good brakes to begin with, but when replacing them, the TT front upgrade is a no-brainer. The car stops incredibly, the Hawk pads bite much harder while also being easier to modulate. Even with the stiffer suspension, it's obvious the fronts are still doing the largest share of the stopping. If we were to go any larger at the front, we would consider a rear upgrade, but we're happy with the current set-up. We had the install done by Ron Wood at VW Specialties in Huntington Beach, California. This is a job most enthusiasts can handle in their drive way with basic tools, but Ron got it handled quickly and easily.
This next part may be the most interesting for the average enthusiast.
While we all know suspension and brakes are the most important upgrades, power upgrades are fun. We start with probably the only part that could be considered a real wear-and-tear item. VW's factory diverter valve can best be described as 'economical' (we probably couldn't print the worst things it's been called). We sourced a shiny new aluminum diverter valve from VF Engineering: a piston-type valve with a billet aluminum body that will probably outlast the factory turbo. The factory diaphragm-type diverter is prone to failure and leaking, leading to less-than-factory boost levels and so decreased performance. This is an easy mod that's well worth the expense, even on an otherwise stock engine. After replacing a couple of stock valves, it's nice to have components we know will be dependable.
For those tired of replacing those paper air filters, and looking for more power, we suggest the Eurosport Cool-Flo Intake system. Not only does the intake add power (five to seven hp depending on other mods), it also adds some intake noise. A reusable ITG foam filter is surrounded by a heat shield that keeps hot air away from the intake. Construction and all included hardware is top-notch on Eurosport's pieces.
To get gases flowing out as fast as they get pulled in, we used Eurosport's 2.5-inch downpipe, followed by a 2.5-inch cat-back exhaust. The downpipe utilizes a factory-style flex joint and laser-cut mounting flange to meet up with the turbo. The downpipe is rated at 10 hp and allows the turbo to spool faster. The cat-back system is a full stainless steel performance exhaust that utilizes mandrel-bent tubes and adds an additional eight hp. The sound is great, barely louder than stock at idle and cruising, but most noticeable at wide-open throttle. The sound is deep and a little raspy, not buzzy. You can really hear the turbo spinning on acceleration and the burble on deceleration sounds great.
The final piece we installed was the Eurosport underdrive pulley-a billet aluminum crank pulley that provides a slight underdrive, but is less than half the weight of the stock steel pulley. You don't necessarily pick up power at the crank, but less power is lost between the crank and the wheels. This is another piece that really has no downside.
With just a few well-chosen mods, we have taken our MkIV 1.8T from basic daily driver to a fun canyon-carving machine. The handling is now dialed in, we are putting down about 180 hp to the wheels, it stops well and looks great. For the enthusiast on a budget, the 1.8T is an excellent choice for a project build. For well under the price of a new VW, you can build something unique that fits your personal taste and performs just as well as a brand-new car.