Project Sipster Part 6
Power to the Peeps
by Dave Coleman
Ok, Power to the Peeps was my original title, but it got changed to something more meaningful, more immediately understandable, and slightly less clever before it was originally published. This story is, for the most part, my original draft, with nothing edited for clarity, logic or truth. Much better that way, if you ask me.
Somewhere in the middle of the LA/Orange Country sprawl there's a forgettable little suburb called Westminster, and in the middle of that burg is a barely noticeable little repair shop called MD Automotive. To the untrained eye, it's a perfectly innocuous place to get your brakes done, but to those in the know, this is a performance mecca. The shop's affable owner, Mark DiBella, has worked on everything from your mom's Camry to Group-B supercars, and yet his willingness to hang out with guys like us means every automotive publication in Southern California has him on speed dial.
When we drop in to use his dyno and camp out for our week-long Diesel tuning adventure, we have to move an NSX, a Skyline GT-R and a 350-hp supercharged, Honda-powered Lotus Exige out of our way just to get to the dyno. We already know the Sipster's old engine made 33 hp and 41 lb-ft of torque and struggled to drag the Sipster to 60 mph in 22 seconds. And we know the new TDI engine we installed 2000 miles ago at CWS Tuning knocked that down to 9.8 seconds. After a few yanks on the dyno, we learn that performance came from our new output of 98 hp and 167 lb-ft of torque.
Tripling our horsepower ain't bad for a week's work, but we've got that 0-60 in 7 seconds goal breathing down our neck. Time to turn the screws.
When Cam Waugh swapped out our simple, mechanically-injected Diesel for our fantastically complex, computer-controlled turbo Diesel, he opened up a world of opportunities for us. The computer controls every relevant tuning parameter on the engine (boost pressure, injection quantity and injection timing for example) and it can be re-programmed right through the diagnostic port. Better yet, we don't have to know what to do with any of these parameters, we just have to be smart enough to handle an e-mail account.
Two weeks ago, in preparation for this adventure, we purchased a box from Bora Parts called the Flashzilla. Now, magically, when we want more power, we just call Mark Malone, the British Columbia-based owner of Diesel Inside, and he e-mails us a file that we can upload to the Flashzilla. Then we plug Flashzilla into the car's diagnostic port and wait a few seconds while the computers talk to each other.
Supposedly, Malone's standard stage-1 tune for our engine is good for 20 more horsepower and a noticeable improvement in fuel economy. That's right, one e-mail and you get both power and fuel economy. We've been around long enough to know when something sounds too good good to be true…
Amazingly, this one isn't. Minutes after recording 98 horses, we e-mail the Sipster and it immediately spins the dyno to the tune of 120 hp and a shocking 239 lb-ft of torque. Two hundred thirty-nine! Flabbergasted, we head out to test the fuel economy claim.
Normally, testing fuel economy means filling your tank, driving somewhere really far away, filling your tank again, and dividing the number of miles you drove by the number of gallons you added. With the kind of fuel economy we're already getting, we'd be back in Canada before we've run through two tankfulls. Instead we got a magic box called Scan Gauge II. It plugs into the diagnostic port, talks to the engine computer and calculates fuel economy as you drive.
When you do the road trip thing, your fuel economy represents an average of all the boring crap you did while you burned those 10 gallons of fuel. Instantaneous fuel economy, on the other hand, only tells you about the boring crap you're doing right this second. If you happen to be accelerating, you might be getting 8 mpg. If you're cruising downhill behind a truck, you might be getting 120 mpg.
If we want to see what kind of difference the Diesel Inside tune made, we need to eliminate every other driving variable and test the car in exactly the same instantaneous condition both with and without the new tune. That means no accelerating, no following trucks, no hills, no headwinds, etc.,
To eliminate wind and trucks, we wait until late at night. To eliminate acceleration and hills, we find a 2-mile stretch of flat public road bisecting the Seal Beach Naval Weapons Station. And in the name of science, we drive back and forth across this flat, dark, boring stretch with the cruise control set on precisely 60.3 mph, 3 times in each direction, and then calculate our average fuel economy from the six runs.
After a night of stalking the weapons depot, the entire Top Gear staff is now on the terrorist watchlist, but our sacrifice revealed a number almost as shocking as the dyno results. The same tune that just got us 22 hp and 72 lb-ft of torque also gained us 5.1 mpg. If the rest of the tuning adventure goes this well, we'll be done tomorrow.
Just a tip for those of you new to the concept of reading: The point in any story where the author states "if all goes well" is precisely the point at which any story, regardless of subject, takes a dramatic turn for the worse. Observe:
This seems like the place where we'd put a picture of the flashzilla box, or the RS232 port mysteriously hacked into our Rabbit's dash, or a fuel map, or something like that. All those pictures have been misplaced. Instead, here's me looking up instructions on how to change diesel injector nozzles. Nothing on a diesel works the way a gas engine guy thinks it should.
If you want a Diesel to make more power, you just have to squirt in more fuel. If you've never tuned an engine before, this is the most obvious thing in the world. But if you're used to tuning gas engines, this is the most preposterously naive and wrong-headed thing we've said in at least two paragraphs. Diesels, it seems, are a bit different.
Malone says our current tune is giving us all the power we can make with the stock fuel injectors, so he sends us a bigger set. At least we think that's what he says. After 2 hours turning wrenches, we're giddily expecting another 15 hp. Instead we get exactly the same power, but we've lost 40 lb-ft of torque. Worse, there's black smoke belching out the tailpipe and the horrible noises coming from under the hood sound slightly different from the horrible noises we've grown used to.
Some poor Canadian insect dodged every bar on the grille and managed to snake past the radiator at 80 mph only to splat into the engine and fall down an injector hole to get crispy fried for the next 2,000 miles. Sucks to be a bug.
We poke and prod, we e-mail, we stump both the Marks, and finally, we make the right phone call. Scott Russell runs BioChoppers Mobile TDI repair. BioChoppers because he makes motorcycles that run on biodiesel, Mobile TDI repair because he's been working on nothing but TDIs for the last 5 years and will come to your house and fix yours right there in your driveway. Since we're homeless and have no driveway, we clatter and smoke over to his driveway, a few suburbs away in Whittier.
Over the following 16 hours, Scott and Jared check every common failure mode and replace countless questionable parts, including the fuel filter we replaced just a week ago that is now clogged with rust... again. Finally, at 2:30 in the morning, Scott replaces the diesel injection pump. It's an act of desperation; TDI injection pumps never fail, but it's the only thing left. Turns out it's the right thing. TDI injection pumps never fail because they never have to try and suck 239 lb-ft of Diesel through a rust-filled filter. To celebrate, Jared goes to sleep in Scott's driveway.
Back on the dyno the next day, the torque is back, but those 15 hp we were expecting haven't materialized. We're up 4 hp, to 124, and one lb-ft of torque, to 240. Turns out Malone didn't send us the big injectors we were expecting (part number PP520), he sent us more efficient ones (PP357) that he recommends for people trying to do crazy things like squeeze 70 mpg out of TDI-powered Rabbits.
But wait, we might need that extra 15 hp to hit our 7-second goal! To find out, we head back to the weapons depot. To tell the slightly embarrassing truth, we didn't have any way of accurately measuring our 0-60 time last week when we supposedly recorded a 9.8-second 0-60 run. We actually recorded that time with a stopwatch, the inaccurate speedometer, and our trusty 160-lb intern riding shotgun and adding ballast.
On the drive down from Canada, Jared noticed that when the speed readout on his Navigon navigation system said 60 mph, his Canadian speedometer read 109 kilometers per hour (if the gears and tires were the right size, it should have read 97 kph), so during the acceleration test, he'd yell "stop" as soon as he saw 109 swing past, and sometime later Chris would stop the stopwatch. Between Jared's reaction time at the launch, his reaction time seeing 109, and Chris's reaction time pushing the button, there's no telling what the 0-60 really was.
This time we send the ballast back to New York, take the luggage, spare tire, and week-old banana out of the car, and stick a G-Tech to the windshield. The G-Tech measures 0-60 automatically using a precise, 3-axis accelerometer. No speedo error, no reaction time, just real data.
Launching is easy. Bring the revs to about 1500 rpm, step on the right pedal, lift off the left pedal, and turn the tires to smoke. Second gear lays a satisfying set of stripes, too, but when the G-Tech finally beeps, it says 7.8 seconds. Two shifts and a lot of wheelspin are dramatic, but not that fast. Refining his launch technique for less wheelspin and speeding up his shifts, Jared knocks the time down to 7.5, but no less.
Then the epiphany: We have 240 lb-ft of torque, why don't we launch in second gear? Doing so will save the time we normally waste shifting from first to second, and might even waste less time smoking the tires. It works! First try and the time drops to 7.09 seconds. A little more practice and we'll have it.
Second try. Jared brings the revs to a cacophonous 4000 rpm, releases the clutch, lays 25 feet of black stripes, grabs third gear and… the plastic zip tie holding the metal zip tie holding the shifter cable in place finally decides we're done testing. We broke the cheap Volkswagen shifter cable bracket last time we tried 0-60 testing and the chain of zip ties was the only fix we could come up with short of replacing the entire (expensive) shifter cable assembly.
No more than 30 seconds elapse between a stop along the fence separating public road from the Navy weapons cache before the MPs arrive and politely inform us that we will very much be rounding down our 0-60 results to 7.0 and proceeding on our way stuck in third gear.
Yes Sir!
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