The new OS MAX 25XZ…Are the mid-size big block engines back?


OS Engines have announced last October 2009 their new “truggy” engine, the OS MAX 25XZ. Since then I’ve searched the web for more information but nothing have been written since the press release in October 2009. Nothing on the www.osengines.com neither. That’s strange but this is not the point of this article.

The OS MAX 25XZ engine is the answer to people who wants an engine with more torque than a .21 engine and a better fuel economy than a .28. If we go back few years. There were many .25, .26 and .27 engines on the market. And suddenly, the trend was .21 and .28 engines only. I’m happy that OS Engines is coming out with a .25 engine. Knowing OS Engines, I’m convinced the OS MAX 25XZ will be a great engine.

By the way, here are the specs

  • Displacement: 0.25 cu in (4.09 cc)
  • Bore: 0.689 in (17.5 mm)
  • Stroke: 0.669 in (17.0 mm)
  • Practical RPM: 4,000-39,000
  • Output: 3.1 hp @ 33,000 rpm
  • Weight: 13.05 oz (370 g)

My question is… Do you think the trend for “mid-size” big block engines is back?

3 Replies to “The new OS MAX 25XZ…Are the mid-size big block engines back?”

  1. I tried my first .25 motor yesterday. I had been running .28 before that. After running the .25 I put my .28 up for sale. .25 was quicker and way better mileage, .25 was easier to drive the car was more responsive faster lap times.

  2. I don’t know if other racers will make the trade down from .28 to .25 but if mileage is a concern they should conceder it. The .25 spool up faster then my .28 did but most mfg are building .21 or .28 and 25 are doing by the way side. I am selling 2 new .28 and will probally never buy another and stick to .25 or .21 these motors make so much power and they are more raceable my 28 can break traction at rolling speed.

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