Testing Turbo Time USA’s Lightning Bolt Performance VGT Solenoid On A Retrofitted ’13 6.7L Power Stroke
When variable geometry turbochargers hit the diesel market in 2003, it was a giant leap forward. Turbo lag was minimized, drivability increased considerably, transient response was quicker, and emissions standards could more easily be met while also increasing horsepower. However, in both stock and larger VGT applications there has always been room for improvement. One of the key components in Garrett GT37-based variable geometry turbo applications is the VGT solenoid. The solenoid receives its commands from the engine’s computer (i.e. ECM or PCM) and converts that electrical signal into hydraulic work—essentially opening and closing the vanes in the turbine housing according to throttle position.
To improve the performance of a factory VGT, as well as a larger one, Turbo Time USA developed the Lightning Bolt Performance VGT Solenoid. Its internal design works to increase the resistance strength on the vane system to help retain positions at longer rates—the result of which is improved spooling potential and boosted efficiency. With our hands on a ’13 6.7L Power Stroke that was set to receive a ’15-newer Garrett GT37—a turbo that’s larger and known to be laggier than its GT32 SST predecessor—it was the perfect time to put the Lightning Bolt Performance VGT Solenoid through its paces. Join us for the turbo swap, the new VGT solenoid install, and our initial impressions of Turbo Time USA’s drivability-enhancing product.
With the factory turbo mechanically checking out on this ’13 F-250, we pulled it into the shop for its GT37 (’15-newer turbo) retrofit, followed by Lightning Bolt Performance VGT Solenoid testing. First things first, both cooling systems were drained, followed by the removal of the factory air intake system and the turbo boost sensor. After that, all upper intake bolts were broken free and the composite piece was lifted off of the engine.
Both the factory hot-side and cold-side intercooler tubes would be retained in the turbo swap. Here, the hot-side pipe has been disconnected from the failed GT32 SST turbo’s compressor outlet and the water-to-air intercooler’s inlet and is on its way out of the engine bay.
Pulling the factory lower intake, the cast-aluminum piece, was next. But before it could be removed, the OEM crankcase ventilation hose had to be disconnected on the back side of it. Also, notice that the factory under hood fuel filter housing has been removed.
Once all fasteners anchoring the lower intake to the engine were out, it was pulled off of the engine. In order to run a ’15 or newer style GT37 VGT, this piece is replaced with the updated (’15-newer) lower intake. With both the upper and lower intakes out of the way, we went ahead and blocked off the air inlets to the cylinder heads.
As is often the case for the Garrett GT32 SST that came on all ’11-’14 6.7L Power Stroke engines, this unit bit the dust due to over-speed. Thanks to its twin compressor wheels, dual ball bearing center cartridge, and electronic wastegate, the GT32 SST is a neat piece, but its undersized (59mm/64mm) turbine wheel and its tiny 43mm inducer compressor means extreme shaft speed is part of its normal workload. Add in excessive shaft speed (we’re talking 150,000 rpm or more) courtesy of fueling and tuning mods and the GT32 SST is on borrowed time.
Space is very limited between the firewall and turbo on the ’11-newer Fords. To access the V-band nut for the passenger side up-pipe, the truck’s inner fender well had to be removed. In our case, this meant the aftermarket fender flare had to be pulled first.
In most ’15-newer turbo retrofit kits, the corresponding passenger and driver side up-pipes are supplied. Comprehensive kits will also include fresh up-pipe clamps, gaskets, and fasteners. If you’re in the market to add a ’15-newer turbo to your ’11-’14 6.7L Power Stroke, many companies offer an all-inclusive system that makes the upgrade a 100-percent bolt-in solution. And there’s a new one that doesn’t even require replacement of the up pipes.
Here you can see just how tight things are at the back of the engine. Without removing the passenger side inner fender well you have very little chance of successfully loosening the up-pipe on this side of the turbo. As for the driver-side up-pipe, the new unit (which is needed to accommodate the ’15-newer style GT37) would be installed prior to the new turbo being set in place.
With all intercooler and exhaust plumbing disconnected from the factory turbo, the coolant and oil lines were removed, along with the wastegate solenoid harness, which is no longer needed with a GT37 in the equation. From there, all four turbo pedestal bolts (two up front, two in the rear) were broken free using a 13mm socket and the OEM turbo was ready to be pulled.
In this photo, you can see the difference in compressor wheel inducer size between the ’11-’14 VGT (left) and the ’15-newer GT37. It is here that Turbo Time USA’s Lightning Bolt Performance VGT Solenoid becomes a lifesaver for guys who’ve upgraded to a larger VGT but aren’t happy with the newfound lag they have. Even though a slight increase in lag is common anytime you add a larger or heavier (or both) compressor wheel to a turbo, even a VGT, most modified VGTs are marketed as being capable of offering spool-up equal to stock…
Prior to installing the Lightning Bolt Performance VGT Solenoid, we installed the GT37 and all of the supporting parts required to make it work. For those wondering why the ’15-’19 GT37 turbo is more reliable and performance-friendly than the ’11-’14 GT32 SST, the GT37 utilizes a bigger turbine shaft diameter and its larger turbine wheel sees far less rpm at full boost. This means that excessive drive pressure is kept at bay without the need for a wastegate. The GT37’s 61mm compressor wheel inducer is also capable of moving more air up top than the GT32 SST’s 43mm dual compressor arrangement can.
It’s important to note that for our initial testing, a bone-stock GT37 turbo was run. This means it was equipped with an OEM VGT solenoid. You can see the factory VGT solenoid coil and plug here, protruding from where the solenoid sits in the GT37 turbo’s center section.
Most owners of ’11-’14 6.7L Power Strokes who perform a ’15 turbo swap notice that the GT37 is laggier than the smaller GT32 SST. Our case was no different, with initial driving impressions indicating we’d lost a little low-rpm responsiveness (although the truck definitely pulled harder up top). It’s situations exactly like this where the Lightning Bolt Performance VGT Solenoid makes so much sense. You get your GT32-like spool up back, as well as a quicker transient response. It’s the best of both worlds, a quick low-end response that’s common with a smaller VGT and you still get that big kick in the rear performance higher up in RPM that big VGTs are known for.
After checking the installation of the new up-pipes and two-piece downpipe, we torqued the turbo pedestal bolts, installed the new coolant line, and began reinstalling the intercooler tubing. And because we removed the fuel filter housing under the hood during the turbo install, it (along with all of its corresponding lines) was reinstalled.
Dimensionally, the Turbo Time USA and factory VGT solenoids are the same. By that, we mean the section that sits within the turbocharger’s center section, which entails a closed side, an open side, a drain to pan provision, and an oil supply provision.
Internally, the Lightning Bolt Performance VGT Solenoid is very different from the OEM version. Newly designed and machined components are contained within, along with a finned outer casing to help shed heat and keep the solenoid coil cool. Notice here that we installed Turbo Time USA’s R-type solenoid. We’ll delve into the differences between the R-type and S-type later on.
On the Garrett GT37, the VGT solenoid is secured via a bracket that uses a single retaining bolt. The retaining bolt can be removed using an 8mm, 12-point socket. When pulling the solenoid from its bore, outward as well as side-to-side movement is required to break the seals of the solenoid O-rings free.
Installing the Lightning Bolt Performance VGT Solenoid was as straightforward as any install gets. After submerging the internal portion of the solenoid in fresh engine oil (to adequately lubricate the series of O-rings), it was slowly installed in the center section of the turbo until seated.
Each Lightning Bolt Performance VGT Solenoid comes with a new hold-down bracket, along with a new, stainless Allen bolt and the required spacer. We’ll note that until the bolt that retains the hold-down bracket is torqued to spec, the solenoid will tend to want to push back out. This is no different from a stock VGT solenoid. For a bit of insurance, it pays to coat the retaining bolt’s threads with anti-seize.
Justifying the Lightning Bolt Performance VGT Solenoid’s $420 price point comes easy when you consider all of the performance advantages it offers over a factory solenoid. For starters, the quicker actuation means a turbo that comes up on boost sooner, which (as we’ve already stated) is a huge deal for truck owners that upgraded to larger VGTs and weren’t expecting the added lag that came along with it. But beyond its ability to improve spool up and increase low-end torque, the Lightning Bolt Performance VGT Solenoid also enhances exhaust brake functionality (where applicable), providing noticeably stronger braking power. Add in the fact that the Lightning Bolt Performance VGT Solenoid brings more peak boost to the table (an increase of 5 to 12 percent), contributes to cleaner exhaust, and is an emissions-friendly modification and these units practically sell themselves.
Two styles of Turbo Time USA’s Lightning Bolt Performance VGT Solenoid are available: Type-S and Type-R. What’s the difference? The Type-S solenoid is intended for stock trucks, tuned trucks, and/or tuned trucks with an upgraded VGT. It is specifically calibrated to retain a stronger resistance rating on the vane system and eliminates the lagginess of the factory VGT’s response time, as well as the lag inherent in larger variable geometry turbos. The Type-R unit is designed for trucks with fuel system mods and an upgraded VGT. It is calibrated with a lower vane resistance rating than the Type-S in order to compensate for the increased load produced by performance-modified trucks (those with injector upgrades that have either stock or upgraded turbos).
The Lightning Bolt Performance VGT Solenoid is available for various Garrett VGTs based on the GT37 platform. It works on the VGT aboard the 2003-2007 6.0L Power Stroke, the 2004.5-2016 Duramax—which includes LLY, LBZ, LMM, and LML engines—and GT37-equipped 2015 to 2019 6.7L Power Strokes. It is not applicable with the GT32 SST on the ’11-’14 6.7L Power Stroke, hence our reason for testing it on our GT37-swapped ’13 F-250 in this article.
After-Install, Initial Impressions
After loading a new tune to let the computer know it had a different turbo, and that it’d be seeing boost much sooner than usual (had we installed the Lightning Bolt Performance Actuator on a factory-installed turbo, all that would be needed tune-wise would be an allocation for the boost coming on sooner than normal and nothing more), we fired up the 6.7 and went for a drive. The boost came on significantly quicker than it did even with the factory-installed smaller turbo. The power application was strong and smooth. EGT seems a bit lower but we can’t say for sure since this isn’t exactly an apples-to-apples test (new turbo..). EGTs are definitely not higher than before which is something we were worried about since the actuator is by the very nature of how the turbo works, increasing back pressure to create a boost. MPGs are now up by one too with this tuning. All these things we expected to see. Quicker on the power usually means less fuel. What we were very pleasantly surprised by is how smooth everything went. Install was extremely simple, and the truck just ran great right out of the gate. No tune adjustments or method of driving adjustments were necessary, it just had more usable power lower in the RPM range.
On The Dyno
As proof that the Lightning Bolt Performance VGT Solenoid makes a difference in not only drivability but in both horsepower and torque, Turbo Time USA conducted independent chassis dyno testing by a third-party performance facility pitting its solenoid against an OEM unit. Using the same truck on the same dyno and running the same test each time, its test mule made 448-rwhp at 3,500 rpm and 757 lb-ft of torque at 2,444 rpm with the factory VGT solenoid in the mix. After swapping to the Lightning Bolt Performance VGT Solenoid, the numbers jumped to 458-rwhp and 788 lb-ft at the same engine speeds.
Turbo Time USA