How to modify your 1.4L turbo Cruze/Sonic

Apr 12, 2019

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 order our tune specifically for 87 octane, and for safety 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.   We can rent or sell you an interface that allows us to remotely tune your vehicle for your mods and octane.

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 have 2.5 and 3 inch options.  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 so hard to silence the turbo. 

Larger Throttle Body: For those of you that would like this, it is available.  The gains are minimal because the air that is flowing into the engine is already compressed, but it will improve throttle response.

Ported Intake Manifold: This is a great next upgrade after the above mods.  Each runner on the stock intake is partially 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.  This is paired well with a new valve cover, that replaces all of the factory PCV components.

Coil Pack: This will supply a stronger spark to your spark plugs for a better fuel burn, plus the stock coil pack is known to corrode and fail.  Great mod paired with a new set of 1 step cooler NGK iridium spark plugs.

Valve Springs/Retainers: You can't 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 they will start to valve float.  Our Sonic picked up 10whp and 700 additional RPMs on the stock cams with our springs, so now it revs over 7000rpm.   

Cams: These are for people that have larger than stock turbos.  There are zero gains on the stock turbo due to the restrictive AR of the turbine housing.  Basically, too much backpressure to support more flow.

Turbo: We offer a complete bolt in V3 Big Wheel Turbo as well.  The factory exhaust housing and wastegate can crack increasing turbo “lag” and can make it so the stock turbo cannot achieve full boost.  The V3 turbo is an improved design that will avoid having that problem again, having a larger AR exhaust manifold to reduce back pressure, heat, and increase flow as well as larger compressor and exhaust wheels.  This turbo spools over 500rpm quicker, carries the powerband out over 500rpm higher, reduces KR, and makes a lot more power than even a brand-new stock OEM turbo.  The next option we offer is our Z04 turbo, it will give 25whp additional over our V3 turbo but just adds a little more lag.

Transmissions and Driveline: Now the next mods can be done at any time and are highly recommended.  For the manual trans guys: Short Shifter, Shifter cable clamp (stiffens shifter feel), Shifter Cable Bushings, Shifter Base Bushings (stiffens shifter feel), and a Limited Slip Differential, Clutch & Flywheel upgrades, and for the manual and auto trans guys: Lower and Upper Transmission Mounts (Lowers the amount of engine/trans movement during launches, and gear changes).

Suspension: Best bang for the buck would be our Sonic Suspension Kit which is GMPP performance struts paired with ZZP lowering springs.  Another option is just our Lowering Springs (for Sonic and Cruze), or a set of Coil overs (we have ZZP and BC options for Sonic and Cruze).  Coil overs  allow you to manually adjust ride height, dampening, as well as swap springs to perfect ride.  Next upgrade we recommend would be our Rear Sway Bar (Sonic only).  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.  Slight oversteer will perform better around corners.  

Brakes: We have a few brake upgrades, we have zinc coated Cross Drilled and Slotted Rotors and upgraded Power Stop Brake Pads, also a 12” Front Brake Kit, Brembo Front Brake Kit, and a Rear Disk Conversion for the guys that didn’t get rotors in their model of Sonic/Cruze.  We also carry Chromoly Control Arms to reduce wheel hop and improve cornering ability by holding the tires in place, not letting the factory bushings flex like the OEM ones do.

Fueling: We also have a few fueling upgrades.  Injectors, we have 42# and 60# injectors for the 1.4.  A simple tune will max the stock injectors.  If you plan on running a larger turbo, we recommend our 42# injectors.  If you plan on running E85, I would recommend our 60# injectors.  The 80s aren’t required until you are running full bolt ons, E85, and a custom very large turbo.

We also 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.  Must be enabled in the tune.  Please note that your fuel system must be capable of supporting your power level and fuel demand.  The stock fuel pump will support full bolt ons, a z04 turbo, and E85, so you won’t need to upgrade that until you are running larger than a z04 turbo on E85.

Forged Pistons/Rods: We only recommend these for builds of over 300whp, or of course if your stock engine is damaged and in need of repair.