apexi vtec controller on a honda conversion

anyone got one? Do you notice much difference

never heard of it… what is it?

If you have a look on www.civictype-r.co.uk (you may have to register) there are a few posts about these. A lot of people would recommend a Hondata chip over the vtec controller as you can re-map it, change the rpm the vtec engages, increase the rev limiter etc.

Hope this helps!!


is that not effectively what the apexi unit does? It will be interesting to see the many modifications suited to these honda engines now taking place in the elises/exiges. I also wonder how long before we see a honda Spoon engine (11000rpm!!) in an elise for track use

randy - A’PEX introduces the first digital fuel computer that combines fuel computer functions with a VTEC engagement controller. The V-AFC features a user-definable, eight-point, adjustable fuel curve that can be set in 500 RPM increments. The range of fuel adjustment is +/- 50% at each of the user-defined setting points. The Fuel Adjustment function considers wide/narrow throttle and low/high camshaft settings, from which four different fuel maps are created (wide-low, wide-high, narrow-low, narrow-high). The integrated VTEC Controller adjusts the point at which the engine switches from the Lo to Hi cam during acceleration, as well as when the engine switches from the Hi to Lo cam during deceleration.

Mine has a variable vtec change point anyway. Changes anywhere between 4200 and 5200ish depending on how you are driving. Needless to say it’ pretty rare for mine to change anywhere after 4200 .

I was actually toying with getting an Apexi when I had my Type-R. After doing much research I have found that more people recommend the Hondata over the Apexi. They state that a vtec controller is merely an optimiser and to get any real power gains you need to change the ECU. Unfortunately I never got round to getting either of these as some scrotes trashed my car!!

Look on the bright side Tom - this means someone can fit another K20 in a Lotus

Yep, one persons loss is someone elses gain!! (is that right or am I getting muddled?)

Anyway, shame I didn’t have my lotus at the time as i’m currently saving up for the honda conversion!! it’s going to be worth the wait though!!

The A’PEXi VAFC (like the SAFC I have currently) is limited by two main problems.

Firstly, the ‘remapping’ only allows piecemeal alteration of the AFM voltage that the ECU ‘sees’ based on RPM. There is no alteration of the timing possible.

Secondly, this method indirectly changes the timing the ECU applies, sometimes potentially detrimentally. This is because the timing value the ECU applies is affected by the load, which is calculated partly using the AFM voltage.

TBH, in this application, as long as it’s set up by someone who really knows what they’re doing, I reckon the difference would be minimal.