I know that article is written by an expert and we all know detonation is bad but it doesn't seem to make a whole lot of sense to me - pre-spark ignition isn't detonation but post-spark ignition is detonation ? two flame fronts are bad (err twin spark engines anyone ?)

 

I had no idea that I have a club dedicated to me and so many followers and fans, I'm a little embarrassed..

 

Basically what is bad is when the fuel burns at an excessive rate putting massive pressure on the piston.

Call it what you will (Pinking, detonation etc etc), but you get to a point when the fuel no longer burns, it explodes (which is still burning yes yes) releasing more energy at a much faster rate.

The best analogy is the difference between pushing against an object and punching it. You can push it all day with LOTS of force, but the second you start punching it, things break (Object or your hand).

 

like the humble Honda Jazz, I fell over when I saw what the dealer charged for plugs, till I realised there were eight of them.

 

VTEC engagement point is by design to go lean then to a different AFR to give a feeling of vtec has engaged, people who have their cars tuned will always comment that vtec engagement is smoother when tuned (it should be lowered), the cam engagement point is not optimal nor is the AFR because of the above point, by nature of the engine it will always go lean for a split second because of the increasing flow.

AFR in the 14's for such a short period of time will not cause any damage NA wise.

Contary to popular belief the CAT has the biggest effect on an effective lowered vtec point not the manifold.

I always recommend intake, exhaust and manifold.

IME/IMO the stock airbox can be improved although not by a massive amount.

 

OK

It shows I have some learning to do with engine tuning

 

Hi, I have fitted all what Liam has except the manifold, am I still running risk of running to lean or is it all down to manifold. I have a k&n fipk tegiwa decat and scorpion exhaust. Cheers.

 

Basically as I thought provided I avoid WOT (most of the time) and as long as I check plugs etc. I should be ok, since I have only had the mods on for a couple of weeks.

Cheers

 

Sorry to thread crash but where can you get AFR stats? Is this only from tuners/dyno's? I don't suppose it is something that can be accessed via OBD2?

 

Having now started looking into this and reading up on my VAFCII in detail and what it does or is capable of doing depending on the car it is plugged into, the OEM setting for WOT is set at 52% and that is what the ECU looks for as well as the correct rev range for VTEC to engage (if I am understanding what I have read as being correct, based in the manual that APEXi provide).

My initial understanding of it before doing some reading was that WOT and the ECU interpretation of that is at 100% throttle. However, having looked through the settings on my VAFCII, the only things that have been adjusted are the VTEC changeover point and the WOT % is set at 50%. I have no idea whether APEXi have used 52% as an example for a stock map or not but basically with my VAFCII plugged in, if I squeeze the throttle beyond 50% and I'm at 4700rpm or higher VTEC will engage and its at that engagement point where the car runs lean momentarily.

If you apply the same theory to the stock map then 52% throttle at 6250rpm is where your car would run lean momentarily as it is changing cam profile by engaging VTEC.

I'm a bit confused about it myself but I'm sure Ultra Nexus, S2konroids or someone else with lots of knowledge will come along and shed some more light on the situation shortly.


The readings will be from a wideband o2 sensor using a dyno so it'll only be available through a rolling road.