Cheap Turbos From eBay On A 350 Small Block Engine - Cheap Ebay Turbos

Here is the wastegate as seen from the exhaust side. Note the small size of the door on the right that is connected to the actuator pushrod. All the boost needs to exit through this small port. Didn't happen.

Here is the wastegate as seen from the exhaust side. Note the small size of the door on th

The Manifolds
The exhaust manifolds were only $99.90. They used all the parts that were advertised, such as a 1/2-inch flange and mandrel bends, were made of stainless steel, and included gaskets and hardware. That is the upside. The downside is the generic design. The primary tubes neck down into a 2.5-inch collector before the flange, and the wastegate port is small and mounted at an inefficient 90-degree angle to the exhaust flow. On the '55, Toki had to move the master cylinder to a floor design to clear the turbine housing. We're thinking it might fit a Chevelle that still uses the factory jam-jar nonpower brakes, but don't plan on installing these manifolds on your Corvette. For $99, it's worth trying on anything. You can always cut and paste as needed.

Carb
Eric Solomon at Westside only did a couple of things to the Holley 850 double-pumper to get it ready. First, he swapped the brass floats for nitrophyl so the boost pressure wouldn't crush them. The next step was to mill off the choke horn and epoxy the small oval-shaped hole that feeds the choke rod to the top of the carburetor. The last step was to drill out the power valve channel restrictors on the carburetor. He used the large vacuum port at the back of the carburetor to operate the blow-off valve and left everything else alone. The fuel curve was stable at the power levels we saw in the test.

The headers weren't designed to fit any particular car, so you are going to need a trial fit. The 90-degree turn from the collector to the wastegate tube and the small cross-sectional area where the collector meets the T3 flange are both bad for airflow. The good news: the thick flanges, plenty of reinforcement braces, and a low, low price.

The headers weren't designed to fit any particular car, so you are going to need a trial f

The Baseline 437 RWHP/489 LB-FT
We've stated previously that the small internal wastegates aren't capable of venting enough boost and subsequently risk overboosting the engine. After several safety runs to get the carb jetting and timing set, we made a full pass. The turbos began to make boost at 3,000 rpm and kept climbing to a maximum of 16 pounds. The '55 made 437 rwhp at 5,000 and 489 lb-ft at 4,500 rpm.

Those boost numbers may seem like a good thing, but they're not. Too much boost forces the boost-referenced regulator to add equal amounts of fuel pressure, stressing the system. It also required us to back down the timing to 18 degrees total, a move that kills power and driveability completely. That much boost without enough fuel to feed it and not enough octane to prevent detonation is the fast way to blowing up everything.

The floating-bush journal bearing in the turbo is cooled and lubricated with engine oil. On the small-block Chevy, there are two, sometimes three options. Solomon used a gallery port behind the water pump with a T to feed both turbos pressurized oil. You can also use the port at the rear of the block or by the oil filter.

The floating-bush journal bearing in the turbo is cooled and lubricated with engine oil. O

Another problem with an inadequate wastegate is the overspeeding of the turbo itself. We're going to argue that buying inexpensive turbos and spinning them to their maximum speed is asking for trouble. Since the untouched baseline for these turbos spins them hard, we're going to say that part of the reputation for flying parts and flameouts comes from too much rpm, so the first thing we did was slow them down and keep the engine below 6,000 rpm.

Sadly, if you look at this in terms of the system as a whole and the ultra cheapness of the parts, it was a failure. The only way to make this base system work is to run race gas and virtually no timing and risk overspinning the turbos and destroying the engine. The combo is also going to create a lot of exhaust temperature and crappy driveability.

This is the oil inlet side that feeds the bearing. More expensive turbos use a ball bearing for longer life and better performance.

This is the oil inlet side that feeds the bearing. More expensive turbos use a ball bearin

Wastegates 442 RWHP/445 LB-FT
The fix cost us $600 for a pair of good wastegates. We wired the integral wastegates closed and added a pair of TurboSmart Ultra-Gate 58 wastegates to control the boost. We were looking for 6 to 8 pounds from the turbos, so Marty Staggs from TurboSmart USA supplied a 7-pound spring. On the next run, we were able to add 5 degrees of timing to a conservative 23 degrees, and we saw a decrease in boost to about 10 pounds, allowing us to run the engine to 5,800 rpm. We made almost the same power with less boost. The relatively small size of the wastegate tube and the way it was welded perpendicular to the exhaust primary still prevented us from properly venting all the boost. The 2.5-inch exhaust pipe from the back of the turbine also was too small, causing backpressure that was holding the wastegate valve closed.