How to Build a B20 VTEC Part 10: Air and Fuel Delivery, VTEC Oil Feed, and Coolant Lines
Installing an intake manifold and fuel rail / injectors on a b20v is the same as any other VTEC head. The main things to be mindful of are matching the intake manifold to the head (ex: GSR head requires a GSR intake) and that longer intake manifold studs may be necessary when using an aftermarket manifold, or thicker gasket.
Intake Manifold And Throttle Body
Parts wise, I’m running a Skunk2 intake manifold with a 68mm Blox throttle body.
The MAP, IACV, TPS, and IAT sensors are all oem. The intake manifold studs were swapped for 1320 extended studs because the Skunk2 intake has a thicker flange than the oem manifold and several of the nuts were getting less than a thread or two of engagement with OEM length studs.
Fuel Delivery
The stock 240cc injectors weren’t going to cut it so I swapped them out for a set of RC Engineering 440s. They’re nice because they drop right in and work with the OEM connectors.
I also upgraded my fuel pressure regulator because the car this engine will be going in has a Walbro 255 fuel pump and I’ve read that the stock fuel pressure regulator can struggle to keep up with it.
The fuel rail upgrade was mostly done for bling. The stock fuel rail would have been more than sufficient but I didn’t have one on hand so I figured I may as well spend a bit extra for an aftermarket unit.
Part numbers
- AEM 25-100BK fuel rail
- AEM 25-300BK fuel pressure regulator
- (4) RC engineering SL9-440 fuel inectors
- Russel 670840 6AN ORB**
**The car this engine is going into has a 6AN fuel supply line so the ORB adapter allows it to hook right up.
VTEC Oil Supply Line and Coolant Lines
Now’s a good time to wrap up any work on the backside of the block like installing the oil filter sandwich and oil supply line since the engine is basically ready to drop in the car. I had already installed the oil filter sandwich on my block but I had to loosen it up and rotate it counter-clockwise because the oil pressure sender unit for my aftermarket gauge was so close to the water pipe that the connector wouldn’t fit.
Make sure the oil line fittings are good and tight.
Lastly, I hooked up the three small coolant lines on the block. I’m opting to delete the coolant lines that run to the throttle body and IACV so I used a 5/16" tee fitting to join all three coolant lines together.
