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13
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3answers
3k views

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 ...
5
votes
3answers
1k views

Cylinder 1 and 4 has low compresion, after engine has been redone

I have a Opel Corsa 1999 B type. We had a mechanic redo the engine about 4 months ago, but this week it just does not want to start. Today had other mechanic look at the engine, and did a quick ...
3
votes
1answer
413 views

Low compression and will not ignite after broken camshaft pin and replaced head and gasket

My 95 Geo Metro Lsi 1.0L had a blown head gasket. I replaced the gasket and drove the car for approximately 120 miles before it started spitting and sputtering. Then it died just before I got home. I ...
3
votes
1answer
90 views

Corsa Sport (2007) low compression cylinders 2 & 4

I have been having trouble with my Corsa. It sometimes just cuts out or does not want to start at random times. I have had the car serviced, I have had the starter motor replaced & am now having ...
2
votes
2answers
195 views

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 ...
2
votes
2answers
670 views

Motorcycle 125cc question about PISTON condition and battery

Last year I bought a 125cc bike Modenas brand, most likely unknown to you. It is a moped. http://www.modenas.com.my/v2motorcycle.asp?id=70 It can go as fast as 110 km/h enough for the city and not ...
2
votes
2answers
23 views

Could this be the result of bad compression?

I've had a bunch of problems with my truck (2000 Ford Ranger) and I've been hoping to sell it. Most recently, I was driving it and the heater control valve snapped. I drove it home and replaced the ...
1
vote
3answers
247 views

Mondeo 04 TDCI bent conrod - worth fixing?

I have a 2004 Mondeo 2.0 TDCI which has issues when starting from cold: lots of white smoke and rough idling until it warms up. Had it tested at several garages, who both diagnosed low compression in ...
1
vote
1answer
49 views

Strokes during compression test?

Just wondering what the general consensus out there for the amount of times the vehicle turns over during a compression test? I have heard anywhere from 5-8, and personally crank 7. What is the ...
1
vote
1answer
1k views

Does a warped engine block affect compression test?

Check other questions, and did not see an answer. Backstory: Driving around, discovered pin hole in radiator. Chose to drive home, since I was at my exit, and I lived right there. Blew head gasket. ...
1
vote
0answers
26 views

Is it wise to use engine compression to help slow down a car to prolong brake life? [duplicate]

I have a 2010 Mercedes C-300 with six speed standard transmission. I'm wondering if it is wise to downshift to get engine compression to help slow down the vehicle when stopping to lessen brake wear? ...
0
votes
1answer
187 views

How much Octane Fuel does Honda CBR 250R (India Version) needs? 91 or 93?

Honda CBR250R STD 2013 Model's manual state that fuel(petrol) used should be 91 or more. Seems like they have defined the minimum threshold of RON than stating the optimum RON for the given bike. ...
0
votes
3answers
178 views

Typical Stock Boost Values

For an engine that is boosted out of the factory, what are typical maximum and average boost values? Are they conservative in the 5-6 PSI range or do they get more aggressive getting up to 10-15 PSI? ...