I used to have a Mercury Topaz and I've always wondered...what the heck is this "high swirl compression" engine that it has? How is this different then a normally aspirated engine?

Yr/Mfg: 1992 Mercury
Model: Topaz GS
Body: 4D Sedan Compact car
Engine: 2.3L L4 HSC-SMFI
Fuel: Gasoline
Driveline: Front-wheel Drive
Aspiration: High Swirl Combustion Country Mfg.: Canada

The only thing I could find not related to disel engines was:

What your engine requires to operate knock-free, is referred to as the Octane Number Requirement (ONR). The ONR for an engine is affected by design factors and real world conditions. Engineers must balance performance, economy and environmental concerns in their design. Compression ratio, ignition timing, air/fuel ratios, temperatures and combustion chamber design all have an affect on the ONR. Compression ratio has the most significant impact on the ONR and engine efficiency. The higher the compression ratio, the higher the ONR and combustion efficiency. Retarded timing, rich or lean air/fuel ratios, lower combustion temperatures and high swirl combustion chambers all work to reduce an engine's ONR.

 

Many of the multivalve engines these days are optimized to provide high fuel/air mixture. I think Porsche or BMW was recently bragging about their combustion chamber design in this manner. You didnt mention how many valves/cylinder your Topaz was. I've also seen some writing on the use of eliptical valves to increase fuel mixture efficiency.

 

I have one of them fancy new-fangled toilets. I believe it is also a "high-swirl" design.

The Topaz connection should be obvious.



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Regards,
Gordon

'99 Red Lightning
Johnny Lightning Superchip
Johnny Lighting Stage II Ram Air Kit (coming soon)
Century Tonneau

 

I'm not sure how many valves the engine had...

Baddog --> That analogy was perfect! Thats about as good as that car was! Thing had more warranty repair done to it then any car my family has owned, including a new engine at one point. I was VERY glad to see it go. I just feel bad for the person that bought it from the dealer we traded it in to.