Project Corn Star: Building Boost With The Lingenfelter LNC-2000

Someone asked me the other day what it was exactly that I disliked about electric cars so much. It’s not that I don’t like them, though I’m a big proponent of internal combustion, it’s more the fact that electric vehicles lack the visceral experience that a car propelled by harnessing small, rapid explosions has to offer.

For me, the more noises a car makes, the better – given that it’s not just broken and clattering its brains out, obviously. That was a big bonus when we decided to go turbo with Project Corn Star. While that’s not the only reason – after all, you’d have to be crazy to base your power adder decision on sound alone – it didn’t hurt that our PT7675 turbo from Precision, combined with our Huron Speed turbo kit would have Corn Star making some pretty fun noises while it was on its way to massive amounts of power.

Fun noises aside, we are getting to the point with our Corn Star build that she’s just about ready to hit the track. But before that happens, we still have a few things that need to be addressed; namely, how would we build boost at the line with our six-speed car. Well, that’s where Lingenfelter and the LNC-2000 launch controller come in. And, as an added bonus, it will add quite the ruckus to our already cacophonous build.

The Dilemma

In case you aren’t already up to speed on the troubles of launching a turbocharged six-speed car at the track, allow us to enlighten you. Unlike an automatic vehicle, there is no way in a car with a manual transmission to put a load on the engine and bring up boost before launching it. In an automatic vehicle, you can simply hold the brake and throttle at the same time, a technique known as brake boosting, which will put a load on the engine and help to spool the turbo and thus build boost for the launch. This process is amplified when used in conjunction with a trans brake.

Here you can see everything that comes with the box including extension wires for all of the inputs and outputs as well as the Velcro tape and sheet metal screws.

In a six-speed car, this just isn’t an option. So, what do you do? You get a two-step, that’s what. Or, you go one step further, and you get a launch controller like the one we received from Lingenfelter for Project Corn Star. You may have already heard of a two-step and chances are likely that if you’re reading this, you are well versed with what they sound like. But what is the difference between a standard two-step and a launch controller like the LNC-2000? For the answer to that question, we turned to Justin Galvan, a production engineer at Lingenfelter Performance Engineering.

Function

“A two-step can be used as a launch controller, yet a launch controller is not necessarily a two-step,” Galvan explained. “A two-step is simply a rev limiter with two stops. On a two-step, the lower rev limiter can be used for launch control or as a burnout rev limiter. The second rev limiter can be used as an upper rev limiter. A launch controller, on the other hand, is used to provide a consistent launch RPM off the line in drag racing and other standing start applications.”

In essence, the LNC-2000 isn’t necessarily a two-step as it has only one setting for RPM limiting. This is usually the RPM at which you plan to launch your car. It doesn’t have an upper RPM limiter and is thus not exactly a true two-step. However, what it lacks in RPM limiting capability it more than makes up for with other functionality that is hard to find on other launch controllers or even full-on two-steps.

You can see that the box has two adjustable inputs. One to determine what RPM the limiter will be set to, and the other for how much timing the box is pulling when prompted. The top two switches determine RPM. To select 4,500 rpm, you would set the lower switch to 4 and the upper switch to 5. At the bottom, the left switch determines how much timing is being pulled when engaged while the right switch determines how aggressively that timing is pulled out –it’s also known as a ramp rate.

The LNC-2000 is well known in the nitrous world for its ability to retard ignition timing after it’s given an input signal. This is ideal for nitrous cars that don’t want to upload a different tune every time they crack the bottle open. With the LNC-2000, you can simply wire it so that when the nitrous system is armed, it tells the controller to pull a certain amount of timing (selectable from 0-15 degrees) across the board. This way, you get the best of both worlds. You get an RPM limiter for launching the vehicle and you also can run on your naturally-aspirated tune while you spray the house down without the need to upload a custom tune.

And while that’s all fine and well for nitrous builds, what are the benefits for turbo cars? “Retarding the timing allows more of the fuel to burn in the exhaust. This allows more energy from the fuel burn to reach the turbo compared to an application where the spark timing is not retarded,” Galvan explained. Basically, what happens in a turbo application is that when you pull to the line and the system is activated, the rev limiting function stops the engine at the predetermined RPM. However, since the throttle is typically wide open when this happens, a flood of fuel and air passes into the engine. Since the timing is being retarded to impede the engine from revving any further than its settings, not all of the air and fuel entering the combustion chamber is being burnt. Thus, a large amount of fuel enters the exhaust.

Unlike other two-steps, the LNC 2000 functions by controlling ignition timing as opposed to fueling events. This is much safer in racing applications as cutting fuel in nitrous or forced induction applications can cause a catastrophic lean condition and can quickly turn your engine into expensive shrapnel pretty quickly.

As you can see here on the left, the harness simply plugs in between the coil packs and the vehicle's wiring harness using factory connectors. On the right, here you can see the trigger wires as well as several connections that allow the LNC to perform other functions. It even includes a plug for a map sensor which you can use to boost reference the controller's timing retard capabilities.

When this raw fuel hits the hot exhaust or turbine wheel of the turbo, it ignites releasing energy rapidly into the exhaust stream. This causes the turbo to spin faster than it normally would and thus allows a six-speed car to build boost without placing a mechanical load on the drivetrain. This event is then multiplied when the LNC-2000’s timing retard function is activated. This essentially retards the timing even further at the predetermined RPM point and at every RPM on the way to that point.

The result is not just boost building, it typically sounds like a machine gun going off as the unburnt fuel rapidly ignites on the hot exhaust components. Not only is it one of the coolest sounds you will ever hear emitted by a vehicle, but the result is also much quicker elapsed times at the track.

With Great Power Comes Great Responsibility

With a two-step or launch controller installed, it is admittedly tempting to use it all the time to show off to your friends, startle passersby, or roast marshmallows (since it typically causes turbo cars to shoot flames), but there is also something you’ll want to be aware of when using one. Like many race-specific components, the capabilities offered by a launch controller can shorten the life of components.

Above, the box comes listed what each individual wire is designated for. The box comes with complete instructions for installation in almost any application, a precision screwdriver for making changes to the box, and several resistor wires that would be used if you want the box to automatically deactivate once it detects that the car is rolling.

While the rapid expansion of gases in the exhaust caused by the unburnt fuel igniting will help you build boost, it also isn’t the easiest thing in the world on the turbo. As you can imagine, with the sound of those machine-gun-like bursts there are associated pressure waves with each “backfire.” This can be hard on components nearest to these shock wave, particularly the turbocharger.

“It is possible for a launch controller to be harmful to a turbo,” Galvan said. “When the vehicle is revving against the RPM limit, the spark is disabled in the cylinders which allow raw fuel to spill into the exhaust. Once the spark is enabled again, the fuel can ignite in the exhaust causing an explosion (backfire). For this reason, we do not recommend operating the engine with the LNC limiter active for extended periods of time.”

Though it may be a bit harder on the turbocharger, responsible use of the launch controller will still give you long turbo life. Plus, you didn’t build your racecar to live forever, did you? When it comes right down to it at the end of the day, if you are going to drag race any car with a turbo and a manual transmission, a launch controller or two-step is an absolute must.

Snap Crackle Pop

With the benefits far outweighing any risk, we were ready to set to work on installing our LNC-2000 in Project Corn Star. If you’re not that comfortable with wiring, and you’re worried that this may be something you can’t tackle, you should know that the wiring is fairly straightforward and is outlined in exquisite detail in the instructions provided by Lingenfelter. In fact, they give you wiring diagrams for just about every scenario you could possibly ever need including nitrous, turbo, nitrous with roll control, nitrous with several different nitrous controllers, etc. If you just take your time, even the novice mechanic should be able to install one of Lingenfelter’s LNC-2000 launch controllers in an afternoon.

We laid out the harness and box to determine the best mounting location. This position, close to the vacuum distribution block, seemed perfect. Especially if we wanted to boost reference our timing retard further down the line.

The first decision for us was where to mount the control box. Obviously, you want to be able to access it easily as this will be where you set your limiter and the amount of ignition timing you want to be pulled when the retard circuit is activated. Also, you want to be able to see the LEDs on the box that indicate when it is powered and functioning. With that in mind, we chose to mount our box on the driver’s side strut tower.

This allowed us to route all of the wires cleanly, and since we already had an opening in the firewall, it allowed us to run all of our necessary wires straight into the cockpit. The box comes with both hook and loop tape (Velcro) or metal screws to mount the box. We selected the screws and drilled four 3/16-inch holes in the strut tower using the box as a template as we went. With the box securely mounted, we routed the main harness that plugs into the coils back toward the firewall behind the brake booster.

As you can see on the right, this mounting position allowed us to cleanly route all of the wires back toward the firewall and behind the brake booster for a clean install. Compare that to the left.

How the box interfaces with the ignition coils is a plug-and-play affair. The harnesses from the box tees into the original wiring harness of the coils. The harness from the car that normally would plug into the coils is plugged into the new harness and the new harness is then plugged into the coils. This allows the LNC-2000 to intercept the signal being sent by the PCM and modify it to retard the timing. This was arguably the easiest part of the job and the harness provided by Lingenfelter looks factory and is easy to route cleanly.

The LNC controller plugs in between the coils and wiring harness using factory connectors for a very clean install.

With the box mounted and spliced into our coil harness, the rest of the install was a matter of running two wires, our yellow wire, which activates the controller for our designated launch RPM, and the orange wire, which when energized tells the box to pull the pre-designated amount of timing. We could simply wire the activation circuits to switches that we manually activate from the cockpit, but we wanted something a little more seamless. After all, we will have enough to think about while staging and launching the car, we didn’t need to add more complexity to our lives unnecessarily. That’s why we chose to activate our launch controller with the clutch pedal.

With the car set up this way, every time the clutch pedal is depressed and the car hits the predesignated RPM the launch controller will activate. This is ideal for us as there is hardly a scenario where we would want to be able to free rev the car past say 4,000 rpm without wanting to launch it. If we just wanted to rev the car just to rev the car, we can put it in neutral, let the clutch out and rev to our heart’s content. However, to get it functioning in this manner, we did have to splice the clutch pedal position sensor wiring. This sounds more complex than it really is.

The yellow wire is run through the firewall using the provided quick disconnect wire. Once through the firewall, the clutch pedal switch pigtail (above) is cut and the purple wire is spliced into the yellow wire we just ran.

Lingenfelter gives you the step-by-step instructions to wire it in this manner. In essence, we had to run a 12-volt supply wire to the input side of the clutch switch. This is normally a grounded circuit but we need to switch it over to provide 12 volts to our controller when the pedal is depressed. We started by clipping off the pigtail that plugs into the clutch switch, giving ourselves roughly 3-4 inches of wiring to work with. Once this was accomplished, we provided one side of the switch with 12 volts which came from a bus bar we used to wire our wideband, fuel pressure, and boost controller gauges. The other side of the switch was then wired directly to the yellow wire that activates the launch controller. With this wiring completed, we needed to make sure the clutch switch (which acts as the neutral safety switch in a manual) was getting the ground it needed to ensure the car couldn’t start without the clutch pedal being depressed.

Once the pigtail is cut, the yellow wire leading to the controller is spliced into the green wire while the purple wire is spliced into a 12-volt source that we ran from a bus bar that gives power to our aftermarket gauges.

For that, we had to wire in a relay. The power wire that runs to the LNC-2000 now was teed off to provide the power for the pull circuit of the relay while the corresponding opposite side of the relay was wired to a good ground. This means that anytime the clutch pedal is depressed, the relay will be powered and shut. Our two wires that originally ran to our clutch pedal switch are then wired to the terminals on the other circuit of the relay. This ensures that they function just as they would if they were still tied directly into the clutch pedal switch.

Left, our clutch pedal switch is plugged back in. Right, we tee off power from our yellow activation circuit to our relay. With the oppsite side of the circuit grounded, any time the pedal is depressed, this circuit goes live and pulls the relay shut. This then closes the circuit for the original clutch pedal switch wires that now are complete any time the pedal is press, just like the factory configuration.

With that, our launch controller was ready to be tested. We fired the car up, held in the clutch pedal, and brought the car to 4,000 rpm (where we had the limiter set). Sure enough, the car hit 4,000 rpm and stopped as the limiter started popping. Since we now knew the box was functioning, it was time to wire up our timing retard which is the orange wire. For us, this was a simple task as we once again teed it into the yellow wire that sends a 12-volt signal to our box and tells it to activate. We simply teed the orange wire into the yellow wire to ensure that any time the launch controller is active, so is the timing retard function.

We could have wired it to a momentary switch in the cockpit to allow us to determine for ourselves when the timing retard function happens, but for simplicity’s sake, this is the route we chose. There were very few scenarios that we could imagine wanting the RPM limiter active without the timing retard function being active as well.

We set our RPM to 4,500. Of course, we will have to tinker with it at the track to get Corn Star’s launch RPM just right, but this is a good starting place. We set the timing retard feature to 5 degrees.

With it all wired up, we gave it a test and boy were we happy. The rapid machine-gun-like noise Project Corn Star emitted was music to our ears, to say the least. And that wasn’t even the best part. The car will now build 6 psi of boost (which is our wastegate spring pressure) while sitting still. This means we’ll be able to launch the car under boost when she’s ready to hit the track.

The way we went about installing our LNC-2000 was fairly straightforward and will work great with many combinations. But be aware, this box has very sophisticated capabilities that allow it to interface with other controllers, turn accessories on or off depending on your inputs, and can even be wired to deactivate the timing retard once it detects the vehicle is moving forward.

Corn Star is getting awfully close to being ready for full-time track duties and with her making all of the right noises, we are more stoked than ever to get her there. So, to answer any question about why I prefer internal combustion over electric, I would just have to say that a launch controller is worth a thousand words.

Stay tuned as we beef up the rearend on Project Corn Star next!

Article Sources

About the author

Chase Christensen

Chase Christensen hails from Salt Lake City, and grew up around high-performance GM vehicles. He took possession of his very first F-body— an ’86 Trans Am— at the age of 13 and has been wrenching ever since.
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