http://www.badasscars.com/index.cfm/...100/prd100.htm
Are roller cams better? The answer is yes. Less friction, wear, faster lift rates. We know that 2017 has higher HP, but how about torque curve across the range?
http://www.badasscars.com/index.cfm/...100/prd100.htm
Are roller cams better? The answer is yes. Less friction, wear, faster lift rates. We know that 2017 has higher HP, but how about torque curve across the range?
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View my fuel log 2015 Mirage DE 1.2 manual: 46.4 mpg (US) ... 19.7 km/L ... 5.1 L/100 km ... 55.7 mpg (Imp)
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View my fuel log 2015 Mirage ES 1.2 manual: 49.6 mpg (US) ... 21.1 km/L ... 4.7 L/100 km ... 59.5 mpg (Imp)
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View my fuel log 2015 Mirage DE 1.2 manual: 46.4 mpg (US) ... 19.7 km/L ... 5.1 L/100 km ... 55.7 mpg (Imp)
I was impressed that Mitsu added a roller cam to this motor. The 2017 will have 4 more hp. People laugh when they hear that number but for a small motor that was rated at 74hp this is slightly more than a 5% increase in hp. Not bad at all.
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View my fuel log 2015 Mirage ES 1.2 automatic: 40.5 mpg (US) ... 17.2 km/L ... 5.8 L/100 km ... 48.6 mpg (Imp)
davidricardo86 (02-19-2016),kerc (12-11-2015)
There are also much lower frictional losses with roller cams. Easy way to make some HP without reworking the engine too much.
Wow. It already has MIVEC. I didn't know Mitsubishi changed the cam profile. Well, that's great news. I don't think I heard that in the press release.
Go MIVEC! (And higher cam profiles!)
MITSUBISHI The Mechanism of the New MIVECTiming is continuously independently controlled to provide four optimized engine-operating modes:
- Under most conditions, to ensure highest fuel efficiency, valve overlap is increased to reduce pumping losses. The exhaust valve opening timing is retarded for higher expansion ratio, enhancing fuel economy.
- When maximum power is demanded (high engine speed and load), intake valve closing timing is retarded to synchronize the intake air pulsations for larger air volume.
- Under low-speed, high load, MIVEC ensures optimal torque delivery with the intake valve closing timing advanced to ensure sufficient air volume. At the same time, the exhaust valve opening timing is retarded to provide a higher expansion ratio and improved efficiency.
- At idle, valve overlap is eliminated to stabilize combustion.
I like to watch the video in slow-motion.
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View my fuel log 2015 Mirage ES 1.2 manual: 49.6 mpg (US) ... 21.1 km/L ... 4.7 L/100 km ... 59.5 mpg (Imp)
When I got behind the wheel I was fairly impressed fow flexible and usabi torque is on 3A92 especially under 2k.
It is interesting to see how roller cam improve on it. HP ratings are great but most of the time engine is below 4k, so changes to that have more impact on drivability. Rollers allow faster valve opening/closing, so potentially better breathing, less overlap, higher effective compression ratio. That could also improve MPG.
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View my fuel log 2015 Mirage DE 1.2 manual: 46.4 mpg (US) ... 19.7 km/L ... 5.1 L/100 km ... 55.7 mpg (Imp)
It's one of the things that sold me on the Mirage was the 3A92. It's a high quality engine that Mitsubishi has obviously put a fair amount of $$ into designing. Timing chain, MIVEC, multi-cam and high compression still able to run on regular octane fuel. Now with the addition of a roller cam and a more hp. Pretty darn impressive. Although the Mirage isn't perfect of course (suspension and rear axle alignment), I haven't read of ANYONE having any major mechanical issues with the engine. Go to any other forums on subcompacts and there are many tales of woe with engines.
Last edited by inuvik; 11-30-2015 at 05:38 PM.
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View my fuel log 2015 Mirage ES 1.2 automatic: 40.5 mpg (US) ... 17.2 km/L ... 5.8 L/100 km ... 48.6 mpg (Imp)
To give a real world example of the positive effects of a roller cam, consider this;
Roller cams, since they decrease friction, also increase longevity. A friend of mine had built a pretty crazy OHV pushrod V6 motor. He first went with a traditional cam, and after a single highway run of 160 miles, a couple of cam lobes had already worn down (300 lb/inch valve springs put a LOT of force on it). After a swap to roller lifters, he no longer had problems with the cam wearing down, even with 20 psi of boost, 300 lb/inch valve springs, and a rev limit of 8200 rpm that was touched quit often at the track.
Certified holder of useless car knowledge.
Now my questions are if the current motor can be rebuilt to run roller cams? Will it require a full head swap? How about ECU mapping to accommodate the possible cam profile changes?