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And I Said I'd NEVER go Turbo
We did it again. Yet ANOTHER thing I said we'd NEVER do.

Yet here we are building a turbocharged combo for 2013.

This will be a mild combo by anybody's standards. The goal here is not to set records, but simply to run on a class index ET of 10.60. I chose this goal because primarily, it is run on a .4 Pro Tree. Secondarily because I did NOT want to run quicker than 10 seconds flat at this time because of the extra certified equipment and licensing fees that come with it.

It is a small header, small turbo, blowing through a single throttle body with mechanical injection using mostly Hilborn parts, and running on methanol.

This all came about because as late as 2009, we had a race winning combination. That year, we won the Bakersfield March Meet. We consider this to be the “Holy Grail” of our racing career.  Also, we were typically in the top three in points in a couple of the other series run at Famoso, and we were winning at VW BugIn and Drag Day events and doing pretty well in VW PRA competition as well.

For some reason, I had the hankerin’ to re-do the back half of the car after that season. I wasn’t really satisfied with the U-Jointed conversion swing axles that allowed the use of a type 2 trans. It changed to IRS, coil-overs, and big tires. (See related links at the bottom of the page)

Upon completion, the car worked really REALLY well. So well, it was no longer possible to slow down the vehicle’s reaction to be able to compete on the .5 pro tree in use at Famoso’s two series, ANRA and WCHRA in the 11.60 index class. And that’s what led to where we are today.

After trying various schemes to tame her down enough, and not having any success, I became extremely frustrated. Going down on first round redlights time after time, kinda does that. Frustrated enough to sell the car. After a few false starts, I finally pulled the pin and put it up for sale. Most likely at the worst possible time. Economic conditions in both the US and Europe were not good. We got not a single inquiry.

While out to dinner one Friday night, my wife Cindy said she wished we could keep it. I said I did too, but the way it acts, it’s no longer competitive. I told her I needed to be competitive for it to be fun.

“How can we make it competitive again?”
“We’d have to run it in a pro tree class with a .4 tree, because that’s where it works. That would mean stepping it up to D/Gas. It would take a Pat Downs Pro Stock motor (a VW "Pro Stock" motor is about 2.7 liters, and makes about 360 hp normally aspirated and operates at 10,000 rpm) to get that car to run those times and I wouldn’t want the maintenance issues with something as high strung as that.”
Then she says, “How about going turbo?”

And here we are!

And so, construction begins.

It starts with a T3/T4 hybrid turbo, and some exhaust flanges from CB Performance (see related links below). After trying a few different header tube configurations, I settled on an "Over the Top" arrangement. The header tubes are high enough to where the intake tract can go below, and NOTHING will have to be relocated. Still plenty of room for the decklid to shut without anything being too close. The first tube, #2, had to clear the alternator, so it was the first to be built. The others have a less obstructive path. The upside is that the tubes are within a couple inches of one another in length, and the firing order is right. I know it's not super critical, but that's the way worked out. I think once complete, it will look super bitchin' too!

First was to get some head pipes made up along with selecting bends out of the collector to make sure everything clears the body work. Once satisfied with that, I yanked the motor and fitted up the rest of the tubes.

Also received from Marty Staggs at TurboSmart (See related links below) is the Comp-Gate 40. That is plugged into the collector on the right side when facing the pulley side of the motor.

I first used a straight piece of tubing to plumb the waste gate into the collector at about a 60° angle. Better than a 90° but not the best. Marty suggested using a bend to "sweep" it out. So, I changed it out.

The discharge of the turbo we have chosen is 2" in diameter. The throttle body is 2.75" with an outside diameter of 3.25". Since this will be a "blow thru" configuration, a provision for a Blow-Off valve is needed between the turbo discharge and the throttle blade. So an adapter was carved out of a piece of 3.5" solid aluminum bar stock. The BOV attaches to that.

With the intake portion of the system finalized, the assembly was sent to Quillen Motorsports, a specialist in turbo mechanical injection systems, to have the fuel system set up. Quillen does mostly "BigCar" Pro Mod systems and is a leader in the field. I am very pleased with the way it is set up. There is enough "overbuild" to the fuel system to support up to 650hp. There are no plans to push it that far. But I won't say "Never!"

The entire assembly is a very compact set-up. The exhaust pipes are pretty "snakey," but it all fits and it fits under the decklid. It's pretty close to other components in some areas, so I will wrap it with kevlar tape where it comes in close proximity to vital parts like the alternator, plug wires and fuel lines.

It will also complicate any major servicing. I kinda doubt we'll be doing and engine removals at the track. Although after a few rounds of removal and reinstallation in the process of fitting everything, it appears as though the motor can drop out without removing the intake. So, maybe it won't be all that bad.

The motor also required some changes. A lowering of compression ratio and a slightly smaller cam. The CR dropped for 14-1 to slightly less than 10-1, and the cam changed from CBs 2298 to their 2289 - about four degrees less duration and about .025" less lift. The lowering of the compression ratio was done by selling my existing heads to a fellow VW racer and installing new heads with a larger combustion chamber. Gearing in the trans has also being changed. It'll be good for up to 140mph, so there's plenty of room to grow. But at the target ET range in the mid ten second zone, trap rpm will be well under 7000 rpm.

Since the clutch we had was "just enough" for the power level we had with the previous combo, a heavier clutch was needed. Since I already had the "J&G" Style McLeod 8" race clutch, I simply opted for a pressure plate hat with a stronger diaphragm. This proved to be somewhat problematic. After installation, it wouldn't release. Component flex coupled with an improper initial set-up was the culprit. After some changes, plenty of swear words and many hours of trial and error, and along with help from my son Mark, we finally got it working. This won't be the final solution to the clutch, but it got us to the track. After a few runs getting things dialed in, I'm learning to live with it.

Now that it's complete, it acts like a whole 'nuther car. I didn't expect it to blow right past the 10.60 index for D/Gas and knock on the 9 second zone!! So far, the best ET has been 10.20 at about 135mph. This with a seven pound spring in the waste-gate. While running 9 second ETs would fun, at least for a while, I don't want to go there yet. So we will tone 'er tone for the time being, and focus on getting some round wins.

At this point, only detail and clean-up work remains. Items such as refinishing the engine bay....again. Other things as well. wiring for turbo controls, an improved oil containment tray, and exhaust sytem refinements.

All in due time!

 

The final installation into the car. Click on the photo to see it full size. Decklid still closes, and there's no funky lookin' exhaust stickin' out the back!


See you at the races!

 

Related Links....

Swing axle to IRS Conversion

TurboSmart

CB Performance

The beginning of header building. First is to make a pipe to get around the alternator (click on the photos for full size images)

Next is make some head pipes that will clear the body work

Then with the motor out, build the rest of the pipes, piece by piece

Once this step is complete, the waste gate tube will be built onto the collector

In the photo above, the waste gate is mocked up using a straight section of tube. It was changed to a bend to improve the "angle of attack." (below)

The Blow of valve will attach to the tapered adapter between the turbo discharge and the throttle body.

In the photo above, the intake manifold is beginning to be built.

The intake manifold complete with plumbing (Above), and the whole enchilada below for final trial fitting. It's a nice compact assembly.