Compound turbos are 2 differently sized turbos working together to create quick spooling power throughout the entire rpm range. The power range you desire is determined by what size turbos you use.
HOW DO COMPOUND TURBOS WORK?
Compound turbos first produce a large volume of air supplied by the "big turbo" or low pressure turbo which is typically an s400 frame turbo, ie: Borg Warner S475 or S480. Then feeding the air into the intake of the "smaller turbo" or high pressure turbo which can be the factory hx35/he351, Borg Warner s300 or s400 for street applications. The smaller turbo will then "compound" or compress that large volume into a high pressure air supply to feed the engine. This is where the twin turbo design gets the classification of "compound twin turbo's". On the hot side, the exhaust gas exit's the manifold and first enters the high pressure turbo, then travels through the hot pipe into the low pressure turbo and out the exhaust. This creates a low rpm spool with high rpm power. Compound turbos are great for daily driving, towing, and racing, they really can do it all.
WHAT SIZE TURBOS DO I NEED?
That depends on how much power you want to make, at what rpm you want the twin turbos to spool and what the truck is used for. If you take a look at our products page we list different sized compound kits for different uses with info about each setup. For sub 600hp applications we typically recommend the stock turbo with an S475, for 600-850hp an s300/s400 combo, and 850+ an s400/s400 for added reliability.
WILL MY STAINLESS DIESEL 5 BLADE, BORG WARNER, INDUSTRIAL INJECTION TURBO ETC I CURRENTLY HAVE WORK WITH AN EVILFAB KIT?
Yes, if you do not see your exact option listed please call or email so we know what turbo you currently have to ensure you receive the correct twin turbo kit the first time.
CAN I USE MY STEED SPEED, STAINLESS DIESEL, RONIN, PDI OR CAST 3 PIECE MANIFOLD I CURRENTLY HAVE?
Steed Speed manifolds work best with an EvilFab compound kit or 2nd gen swap. Please verify what you will be using if not purchasing a manifold from EvilFab.
DOES MY COMPOUND TURBO KIT COME WITH A WARRANTY?
Yes, all turbo kits come with a 1 year limited warranty.