VTEC operation on 8th Gen Civic R18A

[buddah51au]

Contrary to most peoples belief the operation of VTEC on the R18A works in an entiely different way to what we have come to expect. On this engine VTEC is on only under light or very light throttle opening and low engine load under 3500rpm. I will copy part of the technical overview on the R18A below.

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. Thus it is a completely different idea from the VTEC implementations of old where VTEC will always open after a certain rpm, irregardless of the driving conditions. This is also the reason why Honda feels it is justified to call this new implementation an i-VTEC implementation, 'i' of course meaning 'intelligent'. This is because the engine/ECU is 'smart' enough to know if conditions are right or not for VTEC to engage. This new mode of operating is clearly illustrated in the 3-dimensional torque-rpm-driving load chart on the left (supplied by Honda). Note the standard torque curve. This is the line right at the top of the chart and VTEC never activates across this torque curve. On the other hand, VTEC opens across a fairly wide range of driving conditions, in the shaded portion inside the torque curve. So if our throttle pedal position or other critical driving conditions are outside the shaded portion, the R18A will not engage VTEC at all.

If anyone would like a copy of technical documents i have downloaded send me a PM with your email address

[aaronng]

http://world.honda.com/HDTV/news/2005-4050705a/index.html

[buddah51au]

That is an old video clip. It is much easier to read the buletins in order to understand they way the engine is designed & once it is understood it is possible to achieve remarkable fuel ecconomy.

[aaronng]

The video is pretty good in explaining how it works.

All VTEC is used for is to allow the R18A to switch between Atkinson and Otto cycle modes for better fuel economy.

[buddah51au]

Yes, the video is good, i am not denying that, but reading technical bulletins is more informative for the mechanically minded.

[aaronng]

Yes, the video is good, i am not denying that, but reading technical bulletins is more informative for the mechanically minded.

That's true... Sending you a PM with my email address. :)

[denot]

hey buddah... is this the same with the K20 - sports model?

[buddah51au]

hey buddah... is this the same with the K20 - sports model?

no, the k20 is different i believe. but i haven't gone into or looked for details on the K20

[denot]

ooo ic... thanks

[buddah51au]

All the information i have was found on The Temple of VTEC Asia......
if you take the time to search that site there is lots of good info. How about a turbo kit now available for the R18A....lol

[buddah51au]

Here is a Technical overview of the JDM Type R...i presume it will be similar to the CTR we get....... http://asia.vtec.net/Engines/FD2K20AR/index.html

[buddah51au]

Here are some more tachnical links for those that are interested....................
R18A.....http://asia.vtec.net/Engines/RiVTEC/index.html..............................
R18A.....http://asia.vtec.net/Engines/R18A/index.html.................................
K20Z.....http://asia.vtec.net/Engines/K20Z/index.html.................................

[aaronng]

All the information i have was found on The Temple of VTEC Asia......
if you take the time to search that site there is lots of good info. How about a turbo kit now available for the R18A....lol

Ahh from there. I've been through all the techical articles on that site already. :)

[Bob san]

All the information i have was found on The Temple of VTEC Asia......
if you take the time to search that site there is lots of good info. How about a turbo kit now available for the R18A....lol

here are some intrestsing links to turbo R18As...

http://www.8thcivic.com/forums/showthread.php?t=52439

http://www.ajperformance.com/product_info.php?cPath=90&products_id=137963

there are also alot of other articles on the r18a turbos but they are on the 8th civic website...

also found an intresting site regarding the r18a

http://www.d-series.org/forums/showthread.php?t=55784

[jcpabc]

I like the video!

[clem]

This will surely dissappoint the fools who claim their 8th gen's

"VTAK JUST KICKED IN Y0!" -_- :thumbdwn:

[markCivicVti]

Someone is a grumpy bums.


I'm actually quite happy with what I've read on the R18a. I'm really hoping a i-vtec indicator product comes to market so that we can see when i-vtec is active - this will show the driver what sort of driving habits guarentee fuel efficient driving.

[buddah51au]

Mark, i you keep a log book of fuel used and kilometers traveled such as i do you will learn over time how to achieve the best ecconomy. It took me quite a while to adapt my driving style to suite this tecnology, but i am now rewarded every week when i fill up.

[aaronng]

Someone is a grumpy bums.


I'm actually quite happy with what I've read on the R18a. I'm really hoping a i-vtec indicator product comes to market so that we can see when i-vtec is active - this will show the driver what sort of driving habits guarentee fuel efficient driving.

Surprisingly, the D15B engine with the 3 stage fuel efficient VTEC had a little green light that came on when you triggered the fuel-saving lean burn mode. When the light was on, you were on your way to 4L/100km.

[buddah51au]

The best consumption i have recorded with the R18A is 577km on 35.45 lts which worked out to 5.8L/100km. Now that i know how this was achieved i am very confident i could improve on it, by how much i dont know, but i think i could get into the low 5L/100km on 1 long section between here and sydney

[Borg]

Mark, i you keep a log book of fuel used and kilometers traveled such as i do you will learn over time how to achieve the best ecconomy. It took me quite a while to adapt my driving style to suite this tecnology, but i am now rewarded every week when i fill up.

Do you have any tips specific to the SOHC i-VTEC engine?

[aaronng]

Use light throttle and medium rpm between 2000-3000rpm. :) Don't use heavy throttle to compensate for too low an RPM like below 2000.

[buddah51au]

Use light throttle and medium rpm between 2000-3000rpm. :) Don't use heavy throttle to compensate for too low an RPM like below 2000.

i second this comment

[dannybubu]

anyone got that turbo or the cat back from http://www.ajperformance.com/product_info.php?products_id=137917 ? i'm interested more so on the catback...not enough money for the turbs yet...haha

[Vvvtec]

NOT TRUE VTEC

such odyssey

[JordanMugen]

Someone is a grumpy bums.


I'm actually quite happy with what I've read on the R18a. I'm really hoping a i-vtec indicator product comes to market so that we can see when i-vtec is active - this will show the driver what sort of driving habits guarentee fuel efficient driving.

Perhaps. :)

Honda does already provide the green status bars on the hatch (that turns blue when not driving economically); and the previous hatch had an "ECO" meter on the right as the yang to the "REV" meter's (shift lights) ying, on the left. The ECO meter is replaced by iVtec indicator on the fn2r model.