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Questions tagged [compression]

One of the four internal combustion engine strokes necessary for the complete combustion process to occur. The compression stroke compresses an air fuel mixture and prepares for it ignition by spark.

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29 votes
3 answers

Static vs. Effective compression: Why does higher effective compression not require higher octane gas?

Background I've been trying to do a lot of research on boost lately because I'm planning on running a moderate turbo setup on my daily/light-duty-autox car in the future. I'm trying to get into the ...
Annath's user avatar
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11 votes
3 answers

What do these compression figures mean

This is a follow up question to What are the causes of fluctuating intake manifold vacuum I have a 2005 Honda CBR600 F4i which suffers from occasional hesitation at low rpm when accelerating. After ...
Ian Oakes's user avatar
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4 votes
1 answer

How Many Times to Crank During a Compression Test

I've read a number of different recommendations on how many times to cranks the engine during a compression test. I've read those that say to crank until you reach a stable reading. In the book, ...
Robert S. Barnes's user avatar
4 votes
1 answer

Do Compression Rings and Oil Ring Wear at the Same Rate?

Is it possible that the oil control rings might be worn to the point that you're burning significant amounts of oil, but the compression rings still be good? Or do they typically wear out together ...
Robert S. Barnes's user avatar
2 votes
1 answer

Leakdown Test | EJ205 on Engine Stand and replaced all Valves

I have my EJ205 out of my 2003 WRX. I pulled the engine in the first place to troubleshoot a 90% pressure loss in Cylinder 4 (measured via a leakdown test with the Engine still in the car). The ...
Joe's user avatar
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