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Chevy Small-Block - Two Timing With Turbos

Can Your Chevy Small-Block Make Over 1,000 Hp? It Can. Here's How.

Mike Harrington Aug 6, 2007
Sucp_0707_01_z Chevy_small_block Chevy_small_block 2/33

When people achieve power, they often want more. For extreme examples, think of history's many tyrants. For less extreme examples, think about hot rodders. While it's true that we hot rodders are slightly less deviant that the Napoleons of the world, we are fairly consumed with increasing our power-horsepower that is.

A little power under the hood leads to ambitions of more, much more. (Insert evil laugh here.) After the first grab and taste for horsepower, there's no choice but to become a local tyrant at the dragstrip or on the street.

For those who lust for domination, Gale Banks Engineering has taken the small-block Chevy and given it more power than any reasonable person could want. Perfect! When it comes to musclecars, are any of us horsepower junkies truly reasonable? Banks' twin turbo-powered small-block Chevys have the capability of producing up to 1,100 horses at the flywheel.

Super Chevy magazine hasn't run many turbo builds, so let's take a kindergartner's view of what a turbo system is and what it does. We all know that the more fuel and air that enters the cylinder and gets burned, the more power an engine is capable of producing. Unlike a supercharger, which derives its energy from a series of pulleys that are directly connected to the engine's crankshaft, turbos use exhaust gasses to spin their turbines. Being connected to the engine's crank means there's an amount of parasitic energy taken from the engine to power the supercharger. Why a twin turbo? Banks Engineering uses two moderate sized turbos for the express purpose of creating more boost pressure from the engine's exhaust pressure, eliminating much of the turbo lag ... and it just looks darn cool, too.

Banks Engineering has several turnkey twin turbo engines that it builds, ranging from 700 hp to 1,100 hp. We asked Banks engine builder Mauricio Lindoro what the difference was between the different turbo-powered engines and the horsepower numbers. Mauricio informed us all the engines are built to the same exacting standards; the difference lies in the valvetrain selection, i.e., cam profile, lifters, springs, etc. The rest is intercooled vs. non-intercooled, fuel octane ratings and the amount of boost that's stuffed into the engine.

Let's not fool ourselves. We all know that creating serious horsepower requires serious money. One of these Banks Engineering 6.0L (374 ci) twin turbo turnkey engines runs just shy of $40,000. That may be out of reach for a majority of us (editors included), but it still makes for amazing eye candy to see a small-block push the 1,000hp mark. Even tyrants have an eye for beauty. (Kim Jong Il's hairdo and wardrobe notwithstanding.)

Sucp_0707_02_z Chevy_small_block Main_iron_block 3/33

Each build starts with a Dart 4-bolt main iron block. And from there the Dart block is further bored and machined to the tolerances set by the engine builders blueprint. For this application, the bore is 4.125-in. and the stroke 3.50-in.

Sucp_0707_06_z Chevy_small_block Dart_block 4/33

After machining and cleaning, the Dart block is painted black or red and ready for assembly.

Sucp_0707_03_z Chevy_small_block Freeze_plugs 5/33

The freeze plugs are not just pressed in and left there. Each plug is also riveted once it's in place.

Sucp_0707_04_z Chevy_small_block Crankshaft 6/33

As good as the Scat crankshaft is, the cranks are also machined and mic'd according to the build sheet.

Sucp_0707_05_z Chevy_small_block Cranks 7/33

The oil galleys on the crank are also chamfered and de-burred according to spec. This enhances oil flow as it returns to the pan.

Sucp_0707_07_z Chevy_small_block Main_caps 8/33

The main caps are measured and honed checking for the right size between the crank journal and block.

Sucp_0707_08_z Chevy_small_block Crank_installment 9/33

Once all the chamfering, de-burring and honing is done, the crank is ready for install.

Sucp_0707_09_z Chevy_small_block Arp_bolts 10/33

Only ARP bolts are used in the build-up of this small-block.

Sucp_0707_10_z Chevy_small_block Surface_roughness_meter 11/33

This is a surface roughness meter. After each cylinder in the block is bored, honed and smoothed, the surface roughness meter measures the surface of each cylinder and then gives a print out of what it detects. If the numbers fall within an acceptable range, the block is good to go.

Sucp_0707_12_z Chevy_small_block Centerline_method 12/33

The most common way to verify that the cam is installed correctly is via the intake centerline method. At the risk of over-generalizing, we'll just say that this measures the crankshaft angle where the cam's intake lobe reaches maximum lift. Install a lifter into cylinder number one's intake lifter bore, and mount the Powerhouse Products fixture so that the dial indicator's tip touches the lifter. Every part of this fixture must be secure and tight for accuracy, and the dial indicator's stem needs to be parallel to lifter travel. Zero the dial indicator at maximum lifter travel out of its bore.

Sucp_0707_11_z Chevy_small_block Piston_rings 13/33

All piston rings are end gapped and de-burred, then test fit into their corresponding cylinders.

Sucp_0707_13_z Chevy_small_block Connecting_rods 14/33

At a separate workstation, the connecting rods are also being cleaned and de-burred.

Sucp_0707_14_z Chevy_small_block Wrist_pin 15/33

Every wrist pin is measured to fit the piston and rod.

Sucp_0707_15_z Chevy_small_block Measure_piston 16/33

The same measuring goes for the piston as well. Nothing on this build is left to chance and nothing is assumed no matter the quality of the said part. Banks engine builders follow the blueprint, then measure and record the numbers of each fitting.

Sucp_0707_16_z Chevy_small_block Bolt_measuring_tool 17/33

Another tool employed by the engine builder is this rod bolt free length tool. Essentially this measures the length of the bolt before torque is applied.

Sucp_0707_17_z Chevy_small_block Connecting_rod_bolt 18/33

After the connecting rod bolt is torqued into place, the bolt length is measured again to check how much it may have stretched. Serious engine builders like those at Banks are almost more concerned with bolt-stretch numbers than torque numbers.

Sucp_0707_18_z Chevy_small_block Dart_aluminum_cilinder_head 19/33

Dart aluminum cylinder heads that are cast specifically for Banks Engineering with custom CNC'd combustion chambers and exhaust ports are used in every turbo engine build. The cylinder heads receive the same precise degree of measuring as everything else in the build. Every combustion chamber is measured for an accurate displacement of cubic centimeters (cc). These heads feature 2.060-inch intake valves, 1.600-inch exhaust valves and 78.8cc chambers. Compression is a boost-friendly 8.3:1.

Sucp_0707_20_z Chevy_small_block Valvespring 20/33

Prior to install, each valvespring is pressure tested to make sure the right spring load is used for the right horsepower engine.

Sucp_0707_21_z Chevy_small_block Check_valve 21/33

Each valve is checked and measured for travel and spring height.

Sucp_0707_23_z Chevy_small_block Adjustable_cam 22/33

A Cloyes adjustable cam sprocket is used on all the Banks engines. The really neat thing about these is the fact that they do just what they say. Setting the timing on the cam has never been easier.

Sucp_0707_33_z Chevy_small_block Engine 23/33

The bottom half of the engine is now completely assembled and the rest of the engine build accelerates from this point on.

Sucp_0707_34_z Chevy_small_block Measured 24/33

Before the lifters are put in the lifter bore the lifters are also measured and recorded.

Sucp_0707_35_z Chevy_small_block Measured 25/33

Sucp_0707_27_z Chevy_small_block Assigned_specific_location 26/33

After measurement, each lifter is assigned a specific location in the block.

Sucp_0707_25_z Chevy_small_block Install 27/33

Sucp_0707_26_z Chevy_small_block Cast 28/33

The custom cast Dart heads are next on the blueprint, then the lifters, pushrods and rocker arms.

Sucp_0707_28_z Chevy_small_block Polished_intake 29/33

Banks uses an ACCEL Pro Ram polished aluminum intake that has been port matched to the heads.

Sucp_0707_29_z Chevy_small_block Turbo_charger 30/33

Here's what the build is all about. The turbocharger and exhaust manifold are all built in-house, making quality control easy to manage. The turbo's wastegates are the only things not made at Banks.

Sucp_0707_30_z Chevy_small_block Turbo_units_installed 31/33

After the turbo units are installed, the Vintage Air serpentine system, compressor, hardlines, fuel lines, etc., are installed during the next hour. In the interest of space, we won't show every photo of every part involved in this build.

Sucp_0707_31_z Chevy_small_block Twin_turbo 32/33

The moment of truth: somewhere underneath all these wires and tubes lies the twin turbo 1,000-plus horsepower small-block. The long tubes you see coming out the front are for the intercooler. Once the engine is hooked to the dyno, Banks' techies spent a decent amount of time mapping and tuning the EFI system. Every fuel injector is examined and monitored. After breaking in the engine, the spark plugs are removed and each cylinder is examined with a microscopic camera to check the valves, pistons, etc.

Sucp_0707_32_z Chevy_small_block Test 33/33

Afterward, a few more break-in pulls were made while Super Chevy was there with its camera. While we didn't witness the small-block reach its peak of 1,100 hp (work continued on the EFI programming after our deadline) we did see it make 911 hp at just 5,785 rpm with 827 lb-ft of torque to match. That just might be enough speed to fill your shorts. Even though these engines may be out of reach of most budgets, they are still being built, sold and installed into Chevrolets around the globe. This particular engine is destined to make its way to Australia where a '69 Camaro is waiting for it.



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