Reverse i-VTEC on R18A engine. Gen8 must read

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04-01-2008, 10:09 AM

Gene J

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Reverse i-VTEC on R18A engine. Gen8 must read

Since this topic has not been discussed here that I know of, I thought you allmight like to know thatthe gen8 (2006 and up) R18A motor in the non-SI Civics is a reverse VTEC. The hot cams are the non-VTEC cams and when the VTEC kicks in it is the economy cams.

Here is a link to the article and a quote from it below:

http://asia.vtec.net/Engines/RiVTEC/index.html

Quote:

So the new SOHC i-VTEC implementation is an entirely new implementation, quite unlike those already in use. Under normal driving conditions, the R18A runs on its normal set of cam-lobes which in a completely reversed role, Honda calls the 'hot-cams'. So VTEC-off on the R18A means it can be considered to be running high cams. When the right conditions are acheived for fuel economy, VTEC engages the 2nd set, the 'low' or 'economy' cams. Thus VTEC-on on the R18A means it is running low cams. More importantly is VTEC engages the low-cams only if the right conditions for fuel economy are acheived. If they are never acheived, like when we are driving aggressively for the whole trip for e.g., VTEC will never open on the R18A

04-01-2008, 02:52 PM

civic_burns_all

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RE: i-VTEC on R18A engine

so what good does that doo?

04-01-2008, 05:30 PM

cyberx32

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RE: i-VTEC on R18A engine

Thats pretty cool

04-01-2008, 05:32 PM

cyberx32

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RE: i-VTEC on R18A engine

Quote:

ORIGINAL: civic_burns_all

so what good does that doo?

lol did you not read? it means the engine is always aggresive with the drive by wire, but if your just coasting and pressing lightly below 3500 rpms, the vtec engages but instead of being faster, it engages economy mode

04-01-2008, 07:37 PM

06Si

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RE: i-VTEC on R18A engine

That is pretty cool, kinda like V6 and 8 closing half of thier cylinders when power is not needed. The first four cyl. that I heard of with a feature like that.

04-10-2008, 08:50 PM

Gene J

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RE: i-VTEC on R18A engine

This is a thread that should not be buried so quick. If you own a Gen8 DX-LX-EX, this applies to your car. If you want better mileage then please read this article carefully.

04-10-2008, 09:40 PM

Masonn

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RE: i-VTEC on R18A engine

I think this is pretty cool. I didn't expect it to be this way... I thought it would have been the other way around... [&:]

04-23-2008, 10:48 AM

Gene J

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RE: i-VTEC on R18A engine

After reading through the article several times, I decided to change my style of driving from shifting up at the lowest RPM to using the minimum throttle. I now generally shift up at about 2K+ and make sure I never stomp on the gas pedal. The last tank (70% highway) was a whopping 39.8 MPG (407 miles on 10.23 gals). I shall continue to monitor my gas usage.

One thing I did notice, is that I can now feel the VTEC kick in (out actually)at 3500 RPM, where I couldn't before. The computer obviously remembers I normally use low throttle.