Porsche 944 Turbo Part 6: Gauges, Better Intercooling And Heat Shielding

I'm the type that likes to know what's going on with my car water and oil temperatures, boost pressure, air in the tires...everything.

The 951 came equipped with boost and water temp gauges from the factory. The boost gauge seems fairly accurate, indicating exactly at 1 Bar (meaning atmospheric pressure, or 0 psi of boost) when the engine is off. However, it's difficult to tell exactly how much boost is being produced. Between 1 and 2 bar there are three lines, each of which represents one-third bar, but they aren't whole numbers when you do the math.

The water temperature gauge is a little less than the "idiot" gauges you see in most cars today. The needle actually moves away from the middle without needing a fluctuation of nearly 80*F to do so. There is no oil temperature gauge, and even though the Turbo is equipped with a factory oil cooler, I would like to see what's going on in that area, too.

I'd already decided on three gauges: oil temperature, water temperature and boost pressure. For the oil and water temperature gauges, SPA Technique came to mind. I've used SPA gauges before, on Project M3, and can't say enough good things about them. SPA also was awarded one of european car's "Select Gear" awards last year (ec 12/03).

SPA's dual digital gauge (#DG203) houses both water and oil temperatures readouts, leaving room for another gauge. Using a red control button, the driver can choose from 15 different menu items for custom functions, including brightness, color, units preferences, peak resets and resolution. A quick press of the button will instantly display peak values.

For the boost readout, I wanted a sweeping dial because it's easier to read, and AutoMeter has a huge assortment of these types of gauges. I looked into its Sport Comp line and found a new electronic boost gauge with peak recall and warning light features.

Now that I had two gauges, where to put them? I'm not a big fan of the A-pillar gauge setup, so I decided to mount them in the center console, in place of the sunglass holder. Lindsey Racing offers a gauge holder that goes right in, and it comes with room for one, two or three gauges. If you select one hole, you're left with enough room to mount a MAF controller or boost controller. I opted for the three-gauge cutout, which meant I had to choose one more gauge.

Since I knew I'd be testing more things like an intercooler upgrade and water injection, I chose another AutoMeter reaout, this time its Two-channel intake temperature gauge. I took all three gauges and the gauge panel to Precision Motion, where technician Garcia Holloway performed the install. The oil and water temp gauge sensors were mounted at the oil pan and on the hard coolant line, respectively. The boost gauge reads off a vacuum line, and the intake temperature probes were placed at the air filter and inside the intake manifold. The Autometer temperature probes for the intake temp gauge are fairly long, so placing the unit on top of the intake manifold wasn't going to work because the hood would hit it when shut. Instead, I found the excuse to have Garcia remove the intake manifold and drill the sensor into the rear of the intake's underside. This way it would be reading off the hottest possible point in the intake manifold, right over the turbo.

The excuse for removing the intake manifold was to send it off to Extrude Hone for a thorough clean-up of the inside. Extrude Hone specializes in putting parts through an AFM (Abrasive Flow Machining) process so that the insides are as smooth as a baby's butt for optimum flow. The firm will extrude hone anything from intake manifolds, turbo housings and cylinder heads to mega-expensive aircraft and medical equipment.

With the intake manifold out, there was room to reach the turbocharger. Using a thermal wrapping and a turbo heat shield from Performance Techniques, I covered the turbocharger and wrapped the pipe going to the turbo as well as the turbo downpipe in the effort to keep heat from rising up and affecting the intake temperatures.

The intake manifold arrived and was reinstalled. I was now ready to test the car using the new gauges, and I noticed a couple of interesting points. First, when the factory water temp gauge goes from the halfway point to the two-thirds marker, there's no need to be alarmed--it takes only an 8- to 10*F difference for that to happen, right when it reaches about 193*F. Second, when cruising, the intake temperature at the air filter can go up to about 25- to 30*F over ambient, translating into an intercooled charge temp of about 35- to 40*F over ambient inside the manifold, which still isn't bad (I'll soon test the difference on the track).

Lindsey Racing sells a few neat products to significantly cool the intake charge. Its Stage 1 intercooler upgrade, reported to flow 18% better than the stock unit, is designed for lightly modified 951s. It features a new inlet tank, because the factory's tapered design is very restrictive. The Stage 2 intercooler upgrade is designed more for the higher horsepower and race 951s which need the additional airflow. According to Lindsey, this time the end tank on the outlet side is removed and the intercooler is modified internally for even greater flow, which can't be seen in the photos. I opted for Lindsey's Stage 2 upgrade to get the most out of the car. After all, better cooling means greater longevity, especially with a larger turbo like the Kokeln unit in this car.

Since the intercooler relies on airflow to cool the intake charge, I also ordered Lindsey's Stage 5 header panel and cool-air headlight intake duct. Both units, which come primered and ready to paint, are designed to flow greatly increasted airflow to the intercooler and air filter, yielding lower intake temperatures and more horsepower at speed. Because the header panel is easier to install with the removal of the front bumper cover, I opted to have the bumper cover repainted as well, since it was showing a little oxidation on the upper portion. Lucio Serrano of L&S Custom products beautifully painted the pieces and left me with a new-looking front end.

Back at Precision Motion, care had to be taken when mounting the fiberglass pieces, but the result was astonishing. The space inside the Stage 5 header panel--called this because it's needed in order to fit Lindsey's "Big Boy" Stage 5, Spearco-cored, custom-made intercooler--was filled in nicely by the Stage 2 intercooler inside it, giving off an obvious hint of business meant. The headlight air duct cover, also a good fit, finished off the new look. Its functionality, however, is the main reason for being there.

With the AutoMeter air temperature gauge installed, it was time to test the difference in air temps. The openings of the cool-air headlight duct are about an inch away from the air filter, so, as you might have imagined, the air temperature at the air filter was ambient at speed. As long as the car is rolling, I can pretty much use this probe to read the outside air temperature if I care to know it.

The more important test was the difference in air temperature inside the intake manifold. Amazingly enough, thanks to the intercooler and increased surface area exposed to airflow, the intake charge was sustained at no more than 10- to 15*F over ambient, even after repeated, wide-open throttle blasts. That's easily as good as your average, normally aspirated vehicle, if not better!

In addition to the added airflow for better top-end power, when the car is moving the Lindsey components have shown to be good for an overall reduction of about 20- to 25*F over the stock setup inside the intake manifold. I don't know about you, but I can definitely feel a difference in a car's performance when the days are cooler by this much, especially in a turbocharged vehicle. Equally as important, I know my engine is loving it, delivering better performance and better gas mileage and, hopefully, greater longevity.

Installers:Precision Motion
Estimated Time:14.5 hours shop labor @ $90/hour = $1,305
Upgrade Costs:
•Extrude Hone manifold: $400
•Thermal wraps and heat shield: $49
•Auto Meter boost gauge: $65
•Auto Meter intake gauge: $299
•SPA dual digital gauge: $229
•Lindsey Stage 2 intercooler: $575
•Lindsey Stage 5 header panel: $250
•Lindsey Headlight duct: $80
•Lindsey three-gauge panel: $43
•L&S paint and labor: $400
Total: $3,646