How to modify your 1.4L turbo Cruze/Sonic
First I would like to start this with these cars are not ok running 87 octane. They are boosted engines, even stock, everyone should be running premium fuel. Now you can run 87 safely with these cars, but to do it safely, I would run the stock tune, but add our complete exhaust and intercooler kit. (read on for more details on these items)
ZZP 1.0 tune: The biggest bang for the buck is our 1.0 Tune. The PCM controls your fueling, timing, boost and when you have an automatic transmission, the shift points and shift firmness. Our tune will completely change the power and feel of your 1.4 liter.
Exhaust: This will free up the flow of the exhaust so the engine can make more power and also expel heat so it actually helps reduce spark knock/preignition/knock retard or “KR”. These cars have a lot of components to the complete exhaust system. First is the O2 Housing/Downpipe, Mid Pipe, then Secondary Cat Section (Cruze only), followed up by the Catback. We offer these pieces individually and in our “Exhaust Package” which is a complete turbo-back exhaust.
Intercooler: These cars come with an intercooler from the factory, but it is restrictive and doesn’t cool very well. We offer an intercooler kit that replaces the factory charge pipes and intercooler core with more high flowing and efficient pieces. This just like exhaust will make more power and lower KR.
Cold Air Intake: The factory airbox is engineered to draw in air, while keeping the turbo whistle quiet. Our air box draws cooler air with less restriction because it is not trying to silence the turbo.
Ported Intake Manifold: This is a great next upgrade after the above mods. Each runner on the stock intake is blocked off, we remove the “wall” and gasket match each runner. Plus the factory intake PCV fails quite often so this way you will have a new intake and new PCV valve.
Valve Springs/Retainers: You cant just keep turning the boost up for more power, at some point you will need to increase the RPM range of the engine. These cars valve float right from the factory a little over 6000rpms, and the more miles that are put on the factory valve springs, the earlier it will start to happen. Our low mileage Sonic picked up 10whp and 700 additional RPMs on the stock cams with our springs, so now it revs over 7000rpm.
Turbo: We offer a complete bolt in Big Wheel Turbo as well. The factory exhaust housing and wastegate can crack increasing turbo “lag”. This is an improved design that will avoid having that problem again, as well as larger compressor and exhaust wheels for more power.
Transmissions and Driveline: Now the next mods can be done at anytime and are highly recommended. Shifter cable clamp (stiffens shifter feel), Shifter Bushings (stiffens shifter feel), Lower and Upper Transmission Mounts (Lowers the amount of engine/trans movement during launches, and gear changes), the Clutch (the stock one has a terrible feel and wont hold very much power) and Flywheel (we sell an aluminum one, this will allow the engine to rev quicker and make more power).
Suspension and Brakes: Best bang for the buck would be our Sonic Suspension Kit which is GMPP performance struts and ZZP lowering springs. Another option is just our Lowering Springs, or a set of Coil Overs. Coil overs have a significantly reduced suspension travel so ride quality is reduced to have a manually adjusted ride height. Next upgrade we recommend would be our Rear Sway Bar. This will stiffen the rear suspension by reducing the body roll in the rear which will promote oversteer instead of the understeer the car comes with. Oversteer will perform better around corners. We have a few brake upgrades, we have zinc coated Cross Drilled and Slotted Rotors and upgraded Power Stop Brake Pads, and we also have a 12” Front Brake Kit and a Rear Disk Conversion.
Fueling: We also have a few fueling upgrades. We offer a Flex Fuel Conversion Kit which is an inline alcohol sensor and wiring harness to pin into your ECM. With this installed and the PCM updated specifically for it, the ECM will adjust fueling and timing based on ethanol percentage. This will allow you to run any mix of E85/gas and the computer will adjust accordingly. Please note that your fuel system must be capable of supporting your power level and fuel demand. We offer 42# injectors as well, however the PCM must be updated specifically for them.