Safari buggy + Rotary engine, now converting to S2000 engine

[PhillipM]

It is using MAP as load, there's a touch of delay I think given the volume of air in the inlet tract.

[stevieturbo]

not quite following what the problem is ?

you seem to use map2 for when vetec is on ? This accounts for fuel/spark changes ?

But you want to vary when vtec engages or something ?

[PhillipM]

No, at the moment it just uses AUX5 - 12v+ out - to engage vtec, so there's no MAP2 switching or anything available. It's just mapped in the main map at the point it switches.
Problem is with some hysteresis on the AUX5 output you have to ramp the fuel in early - and you can't change the timing until it's 100% that VTEC will be on so you get a bit of a flat spot, as the high cam on VTEC needs a few more degrees of timing advance.
The car drops right into that on a gearchange sometimes so it's a bit of a pita.

I smoothed it out as much as I can but I'm just going to rewire it through a solid state relay over winter, using the AUX3/VTEC output instead, so I can have it on MAP2 any time the output is on, plus use the enrichment on switching to smooth the switch itself.
My only issue is I'm unsure if I can use input hysteresis on AUX3 if it's being used in its alternate VTEC mode, since there's switch points in the VTEC/Cam Control menu that look like they'd override the normal AUX3 settings.

I need to have hysteresis on the output there as on the rough terrain RPM's can quite easily be skipping up and down a few hundred rpms or even more as the grip/tyre slip changes around - you don't get smooth acceleration through the rpms even at full throttle.
Obviously having the VTEC valve trigger on and off half a dozen times, even single time you pull through the engagement area wouldn't be too good, so I've been running 2-300rpm of hysteresis on the output.

And if it's on MAP2 rather than mapped in the main map I can shuffle VTEC around to stop any gearchanges dropping right on it anyway to help a bit, as it wouldn't need the mapping altering bar the engagment RPM's shifting a few hundred either way, so I can do it on the day with a quick tweak, depending on the course.

[stevieturbo]

So tune no Vtec Yo on MAP1, all load sites.

Tune Vtec Yo on MAP 2, entirely as much as possible, all load sites

Activate Map2 via the Vtec solenoid trigger itself.

[PhillipM]

Yes that's entirely what I intend to do, I'm just wondering if I can use hysterisis on the Vtec output when it's selected as a VTEC output rather than AUX3.

You can do that for one input on the AUX3 page, but since when it's used on the VTEC output there's no hysteresis option on the CAM/VTEC page, just the RPM and throttle setting separate to the AUX3 settings, what I'm wondering is if the hysteresis setting no longer works when it's in VTEC mode - because it looks like it would override anything set in the AUX3 page.

If I don't have hysteresis on that output it's likely to try to actuate the Vtec solonoid a dozen times as the car accelerates through that area, instead of just once, I'd rather not have the solonoid or the valve pins dancing around every time

Or are you meaning wire the output to the ALS/MAP2 switch input to trigger MAP2?
Would work yes I can see that - seems a messy way of doing it, when the option is there normally though.

[stevieturbo]

Yes, I mean use the actual vtec triggering of the solenoid to externally supply MAP2 with it's input.

Lots of things should be easy to do internally....but they aren't

But that way you will always be on the correct map for vtec engaged or not.

[Alex DTA]

The VTEC output has a hysteresis of 150 RPM.
The AUX3 settings are not used if VTEC is on.

Switching to map 2 when the VTEC is switched will stop the flat spots, as the map will be correct at all times.

You don't need to wire in a separate switch, if that's what Steve's suggesting.
There's a built in option to switch to map 2 on VTEC, in the VTEC settings.

[PhillipM]

Yep, that's what I was intending to use Alex, I just wanted to make sure there was some hysterisis because of the amount the revs bounce around with slip and grip all the time, I didnt want it thrashing the output on and off - 150 might be enough, I'll try it first and see.