Mike Mann's turbo street terror!

Mike Mann built a turbo charged '65 Corsa street machine that he drove for several years now, he wrote this article about it. There are some photos of it on Gary Aube's site here.

Mike's Build.

The engine is a 65 140 that was completly gone through and runs Otto's TB-30 cam, oil pan, spacer, and oil pump. The pistons are .060 TRWs (weak spot) with approximately 70% of the top milled off to lower the c/r and decrease pinging. I use Total Seal pro rings which really do the job. The 140 heads have deeper and thicker valve seats installed by Moby Dick racing. The combustion chambers have been reworked also. The heads cc'd out at 8 to 1 c/r. I figure at 20 pounds of boost the engine is seeing 11-13 c/r. All of the valve train has been modified or replaced. Maximum rpm is 7200 which with the turbo is ample.

The turbo is a b-flow with a e-flow compressor. 110 exhaust manifolds were used to keep the exhaust flow velocity high and keep the turbo lag down. At 3200 rpm(70/80mph) there is no lag, just acceleration when you floor it. A wastegate is used to keep the pressure at 15 pounds for normal street use. Seems sufficient to keep up with traffic. A Porsche 911 turbo by-pass valve is also used (provides a flow of air through the turbo even though the throttle plates are closed. This will reduce vane breakage on the compressor wheel and also reduces turbo lag time when making shifts.)

Water injection is turned on automatically at 4 pounds of boost using a Hobbs pressure switch. An Air Sensors electronic fuel injection system that was designed for small block chevys was adapted to a center mount four barrel manifold. The FI is a throttle body type with 4 injectors, high pressure fuel pump (an in tank Chevy Vega pump primes it), air mass sensor and the electronic control unit. The ECU has individual adjustments for idle, accelerator pump, air/fuel mixture (a/f) load, choke and "limp home" (in case of air mass sensor signal loss) modes. As the turbo draws more air through the air mass sensor, the sensor signals the ECU to tell the injectors to deliver more fuel which maintains the correct a/f ratio whether on boost or not.

The intercooler uses a honey-combed transmission cooler for the core which was selected because of it's ability to disperse heat. The body of the intercooler was made by gas welding 5 pieces of aluminun together and hammering the beads down which results in a seamless and functional piece of hardware. The intertercooler is air to water which results in more temperature drop without the large size required by air/air intercoolers. The intercooler was flow tested on a flow bench at 1,000 cfm which matches the injection.

The ignition system used is a turbo distributor, Allison photocell and race coil, DALE's advance/retard canister and spark plug wires from Seth Emerson. Timing is set at 20 degrees advance.

The suspension is modified with h.d. coils cut 1 turn, adjustable shocks, 1 inch sway bars, Crown lowering bracket, 205 and 225/60-14 tires on 7 inch rims, quick steering box and tele steering column which I put a Momo wheel on. Wherever possible urethane bushings are used. Power front disc brakes were installed also. Stock brakes weren't enough.

A sub trunk has been built into the trunk containing the Madaza rotary oil cooler, GM a/c evaporator which serves as the radiator for the intercooler, water pump, a/c condensor and a electric fan for use in traffic if the need ever arises. The sub trunk has it's own door to seal it shut. Slots cut in the lower valance panel allows the air to enter and after passing through everything it exits out through louvers on the trunk floor. Going to and from Utah to the national convention in Ontario, Calif. with the outside temp. well above 100, crusing at 75/80 mph, the oil temperature never exceeded 220 degrees.

The air conditioning system comprises of stock interior pieces, Sankyo 508 compressor and an early condensor. A Hobbs switch turns the a/c off at 6 pounds of boost.

The interior of the car has Nissan air inflatable bucket seats, center console which houses various gauges, switches to control the choke, water pump and electric fan. A thirty pound boost gague is mounted on top of the dash. The stock tach has been replaced with a Sun 8,000 rpm one.

With 3.27:1 gears (makes the turbo pull harder) and 250/300 horsepower available, the cars crusing speed is limited only by my ability to pay for the tickets. 70 mph is 3,000 rpm and redline is 7200 so top end should be fairly high. On the trip to Calif I averaged 18mpg which was acceptable for the amount of fun I had driving the car. the license plate is Utah CORVAIR.

If anyone has questions please e-mail me.

Mike Mann