BangShift.com member Bob Holmes, along with his teammates competes in the NASA American Iron road racing series. The team competes with a Mustang, but not in the configuration you’d expect. These guys went the road less traveled and run a turbocharged four-cylinder Mustang SVO engine. After getting the car back together the team needed to tune it and get a baseline setup that they could then tweak at the track. Enter BangShift.com member and tuning guy Scott “DieselGeek” Clark and you’ve got a match.
Scott got together with Bob in California and together they spent some time on the dyno rollers getting the car ready for battle. See below for Bob’s rundown of the car, and underneath that, video of the snotty little four-banger screaming away on the chassis dyno. The car is totally bitchin’ with big fender flares, and it’s Gulf blue paint.
Here’s what Bob told us about the car:
The car uses a turbo charged 2.3 liter (140 ci) Ford SOHC engine that was used in Mustang SVOs, Merkur XR4Ti, and Thunderbird Turbo Coupes manufactured during the mid to late ‘80s. Jack Roush used a derivative of the engine to win three Trans Am and three IMSA titles and the Huber family has used it to win several Drag Week competitions.
This particular example will be used in both sprint and endurance road racing competitions. Set up to run in the NASA’s American Iron Class, it has to meet strict horsepower/torque to weight caps. Given that the car itself was built to allow the team to run at a low weight, the struggle has been to decrease the power of the engine, a rather curious twist to the normal desire to get as much power and torque out of an engine. Out of the box, the engine made far more horsepower and torque than allowed in class, so efforts have been focused on lowering power while maintaining a broad power curve.
In its current configuration it has an almost stock bottom end. Crower rods paired with a 10/10 stock crank and 30 over stock replacement forged pistons, with a 9:1 CR. The topside is where all the power is made. Bo Christman at Bo-port Racing Heads (http://www.bo-port.com/) was tasked with porting, installing big valves, flow testing and installing his 2.1 cam into a stock iron head. This “Stage 3” head can easily provide the airflow necessary to meet the power requirements. In addition Bo ported and matched the intake to complement the head. A huge intercooler cools the intake charge before it enters a stock 58mm SVO throttle body.
The exhaust side is relatively pedestrian. The team started with a T3/T4 hybrid that was abandoned when it experienced compressor surge at the low power levels that the series requires. In its place is a stock SVO T3 turbo feed by a “40Bob” log style weld-el exhaust manifold . The turbo perfectly matches the needs of the engine for its 3,000 to 6,000 rpm operating range. Looks like Ford knew what they were doing! However, if additional power is needed in the future the turbo will need to be replaced, its operating at its maximum efficiency.
This has been a long term effort for Grabaldi Racing. The car is owned by Bob Holmes and Geoff Velguth. It couldn’t have gotten this far without the help of Roger Henry and wiring, rewiring and overall electronic wizard Scott Courtney. Without Scott’s ballsy ripping out of all the existing wiring and starting over, the car would still be plagued by electrical gremlins. Mike Tolle of Tolle Fab in Ranch Cordoval CA did the cage work and critical fab work. Cliff Duvall at Turbo-Power provided the rebuilt turbos, Bo provided the horsepower. A really big thanks to the members of SVO COP for their continued support and critical advice during the build, this set of SVO owners’ encouragement was invaluable when the urge to sell the Blue Bitch Mustang was strong.
http://www.youtube.com/watch?v=qjA9qzFbeWM
