The time has come. It’s time to add some horsepower to this little beast! Alright, take it easy, killer; it’s just a Chevy Cruze. Sad face.
So, I have been consulting with Brian from Vermont Tuning on a turbo upgrade for my Cruze. He installed a Garrett GT2252 on his and achieved 300 hp, with water/meth and E85. 300 seems like a decent number and should make it more fun to drive, so that’s what I set as an initial target. After a few conversations, he recommended going with either a BorgWarner EFR 6258 or a Garrett GT2056. I had heard good things about the EFR turbos, and I felt I might be able to get a little more out of it over the GT2056, so that’s what I went with.
The next challenge was not only where I was going to mount this thing but also what I was going to mount it to. Unfortunately, no one makes an aftermarket turbo manifold for a Cruze, so I would need to have someone make it for me. I consulted with Piper Motorsport, as they did fabrication work for me on my old race car, and I know they do high-quality work. They were more than happy to help me with the project, so I went ahead and ordered the turbo so we could get started.
After I had the turbo in hand, I drove to Piper Motorsport so we could formulate a plan. To help save me some money, and them some time, they suggested I make a template out of cardboard or something that would show where I wanted the mounting flange for the turbo to be in relation to the mounting surface of the head. In the meantime, they would send the OEM manifold gasket out to have the flange that mounts to the head laser cut out of stainless steel. Once I finish the template, they will use it to make a jig and then weld up the manifold. After they finish the manifold, I can mount the turbo and bring them the car to have the intake pipe, downpipe, and charge pipes fabricated. We had the plan, and now it was time to execute!
I removed the stock turbo/manifold and started working on where I was going to fit the turbo. Because of the water lines, oil line, and oil drain line, it seemed to fit in only one area. It was going to be a very snug fit, and knowing the GT2056 was a little smaller, I really started to question my decision to go with this turbo. It was too late to turn back now, so I went to work on the template.
I decided to make the template out of wood so it would be sturdy enough to mount the turbo in place so I could verify the fitment. I used an old manifold gasket to cut a piece of wood that would mount to the head. Once I drilled the holes for the mounting studs, I attached extensions that I would use to hold the turbo mounting flange in place. Once that was bolted to the head, I held the turbo in place and marked it on the extensions. I then attached a cross brace between the extensions so I could attach the turbo mounting flange. Next, I attached the flange to the turbo, placed it on the template, marked it, removed it from the turbo, then mounted it to the template. After that, I mounted the turbo to verify it was exactly where I wanted it to be, and it was!
With the template completed, I took it to Piper Motorsport so they could start fabricating the manifold. They made the jig and started welding it together. Because of the space constraints, a log-style manifold was going to be the best option. What they came up with was a pretty wild-looking design. It may or may not be the best for flow, but I was happy with it.
Once they finished the manifold, I installed it on the engine along with the turbo and then started assembling the water lines and oil lines. Because of how snug the fit was, I had to order several different hose ends with varying angles to make sure none of the hoses would rub on the radiator fan or anything else. Once I had the correct hose end angles, I measured, assembled, and installed all the lines. Now it was ready to go to Piper Motorsport for the intake, exhaust, and charge piping.
The exhaust was going to be all 3″ to a Borla muffler with dual 2.5″ outlets. I also decided to add a resonator to help deepen the tone and make the sound a little less annoying. I’m old now, so I’m not really into a loud exhaust. If I put an LT1 in it, that would be a different story!
For the charge piping, I stayed with the 2.25″ pipe on the cold side that was previously on the car. On the hot side, I went down to 2″ pipe. Staggering the pipe size is supposed to help maintain flow after the pressure loss created by the intercooler.
The intake tube that was on the car was a K&N Typhoon, and they just modified it to fit the new turbo.
Once Piper Motorsport finished the work, I hauled it back to the garage for the initial start-up, and that turned into a disaster. I made a rookie mistake that cost me big. I made a change to the length of the oil lines for the oil cooler mod I had previously done, and I routed them differently. It was something I should have double or even triple-checked, but somehow the lines got crossed. The outlet got connected to the inlet, and vise versa. The fluid would have probably still flowed through the system, except I had installed a check valve for the Accusump that I added. So, when I started the engine, there was no oil pressure, and the timing chain tensioners, which work off of oil pressure, didn’t tension the chain, and the exhaust cam jumped timing.
Not so bad, I just switch the oil lines back, realign everything, and reset the timing. Well, that requires a special tool kit that I needed to order. So, I got the kit, reset the timing, and thought, I better do a compression check before I attempted to start it again. I did the compression check, and the #2 cylinder was much lower than the others. So, what does that mean? Well, since the exhaust cam was out of alignment with the crankshaft, the piston hit the valves and bent them more than likely.
Everyone makes mistakes, but this was one that I certainly could have avoided. I removed the turbo and hauled the car to the machine shop that did the rebuild so they could check it over and replace whatever needed to be replaced. Fortunately, it was only the exhaust valves on the #2 cylinder. Everything else looked good. They checked all the bearings as well, just to make sure.
After the car was back in the garage, I reinstalled the turbo and everything else. I double-checked the oil lines, that’s right, double-checked! I turned the engine over to make sure it was building pressure and then fired it up. All the pressures looked good, and it sounded good, so I took it out for some light runs to record some data to send to the tuner.
The tuner looked over the data and said things looked good, so he started slowly making adjustments and letting me know where to set the preload for the wastegate actuator. Once we had the preload set, we started data logging runs so he could start tuning and increasing the boost.
Unfortunately, at the top of the RPM range, the engine was hesitating quite a lot. The data showed quite a few misfires on cylinders 3 & 4. I hadn’t changed anything with the injectors or the coils, except disconnecting the wire connectors, so I suspected there might be an issue with the wiring somewhere. So, that is where I am now. It’s going to take a little time to sort through and find the source of the misfires, so stay tuned!
DS
