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2.4L Street Stroker Torque Monster Build

6K views 67 replies 15 participants last post by  GThound 
After my intake manifold modifications and explorations, I completed my MODERNIZE Opel Fuel Injection System build.

That EFI system running on the Holley Terminator X ECU platform is installed on my 1971 Opel GT and the car is running great! The current engine is a 2.0 liter CR 1980’s built engine block with the big valve head and autocross CR150 cam. The injection build got so many things right and achieved its goal to unlock the engines potential.

The next phase of my Opel’s journey is to achieve the following;
  • more torque (target 180 ft lbs)
  • more horsepower (target 180 hp)
  • Wide power band
  • Snappy throttle response (maintain)
  • idles at < 900 RPM (maintain)
  • Runs on pump gas (93 octane)
  • Super reliable (maintain)
  • Makes me smile when I drive it
Sorry, I may have missed where you're at now on HP & Torque, if you're looking to move up to 180/180. Can you tell me where you are now, or point me to the comment/thread?
 
"All that said, if I can find pistons that have a 21 mm pin and the right compression height, I say let them drive the bore diameter. Else, what is on the larger but still safe side? 96 mm? I believe the Chevy 305 pistons in the original Bob Legere 2.4 build article were 3.766” diameter Chevy 305 pistons = 95.65 mm."

JMHO. If I were going this far with a build (and I have) I would not knock myself out looking for off the shelf pistons. Custom pistons are not that expensive (especially on a 4 banger).
When I built the engine in my 83 745i, I ordered custom pistons, as well as a custom camshaft (not saying you need a custom camshaft). That way you can dial in everything to optimum; pin height, compression height, CR, etc.
When I went from 2.0l to 2.2l I got custom pistons direct from Wiseco; looks like $706 in 2018, with every feature I could want (e.g. slippery coating on the skirt, desired CR...). What impressed me was how well the support guy helped me through the process of spec'ing what I wanted to get; I thought it was going to be nightmare for an Opel, but turned out to be easy. So, I definitely agree with LB.
 
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