Boost setting (demister switch)
 

For the life of me I can’t get it to switch between the 2.

I’ve tried everything, foot to the floor with a single tap, foot to the floor with a double tap. 4th gear, 5th gear and so on.

I thought at one point that it did change because I thought I was getting a different noise whilst under boost but there wa no difference, I got the VBOX out and the times were the same and the noise under boost seemed to disappear.

My mapper checked it on Friday and we were getting 1.44 bar but the setting obviously went back to low after the ecu was reset (changing rpm limit) and I can’t get it back to high.

What the fook is going on?

What is the correct method?

I’ve ordered a boost gauge so that I’ll know for sure what’s going on.

if its ecutek turn on ignition without the engine running, press and hold accelerator pedal fully to the floor and press the demist button once. turn ignition off release the pedal and then start up and go test. you should obviously feel the difference in pull if its switched over.

The difference we felt in the car on Friday was massively different, if it weren’t for resetting the ecu after the rpm limit change then it would’ve been still in high and I’d have left it there.

I did try “ignition on, throttle to floor and press the button” but that was the other day, I’ll maybe try it again and see what happens.

thats all there should be to it wull. i do it if i ever put the car in the garage so any joyriding mechanic doesnt get full power out of it and it works everytime. it does revert to the lower map if you do an ecu reset as ive also plugged in my laptop to data log etc and it always goes to low boost setting if i reset the ecu.

And it never changes back unless you either do the “ignition on, foot to the floor and demister” or “ecu reset”??.......I started to think (when I thought it had changed) that maybe it went back to low setting on its own accord, almost as if it was a set time that it stayed in high. It’s stressing me out, hate the farkin thing :lol1:

should only do it if you do the method above yes, or as you say on an ecu reset or battery disconnection as well im sure.

Went out again, I stuck the scan tool on as I wondered if I was actually getting 100% throttle.

I was only getting 97/98% because of the mat, so I moved it and started getting 100%.....

So I tried the ignition on, full throttle and double tap. Headed out and no difference, whilst out I kept trying as above and it never changed. I was talking to a mate yesterday who had the same set up on his 03 sti and when he did it you’d feel the difference immediately as the boost would go from actuator pressure to the higher setting.

That’s a frickin balls mate working maps from
Demister switch is lazy mapping imo
Actually wouldn’t mind on the demister but the sequence you have to do to get high boost map is a joke should be able to just flick a switch why so complicated
Hope you get it sorted soon

It’s a pain, I’m use to the set up on the Evo which is Profec spec 2 solenoid and a simple press of mode will switch between low and high.

It’ll be better once the boost gauge is fitted so I can then see the actual boost pressure and peak, then there’s no guessing “did that feel faster”.....

lazy mapping? nothing of the sort. its taking advantage of a system thats already in place to switch the map and it works perfectly well. it works even when driving, just select 5th gear when trundling along and floor it and press the demister switch and it changes to high boost. i meant to ask wull was anything done under the bonnet at the time? maybe check all the boost pipes etc in case 1 has popped off? edited to say dont double tap wull! 1 tap to change, maybe you are changing twice and putting it back to low boost if your double tapping! just a thought :wonder:

I have tried everything though, i was under the impression that it was single tap up until last night when I read otherwise. But up until then I had always been doing it “foot to the floor, single tap”......

Even when I went out there the now I tried both single tap and double tap, at least a dozen times and nothing.

I’ll have a look and double check all the hoses, we were messing around but tbh after the last run when it made 1.6 bar tapering off to 1.44 we never went back under the bonnet, just the reset after lowering the rpm limit.

Would the scan tool (Autel 419) that I have show WG duty?

should only need a single tap but the ECU has to see 100% throttle and it has to see the switch being pressed. Also the demister has to be off first - if it's not working with ignition on / engine off, 100% throttle then turn defogger on then the ECU isn't getting the signal to switch. Either the ECU isn't seeing 100% throttle or the demister pin to the ECU isn't putting in a signal.

Mapper should be able to log both items and confirm the map switch conditions have been met.

Boost gauge arrived today so I got that fitted after work.

Good news is the boost settings are changing when I do the demister switch trick, will only go to 0.8bar on the lower setting and will hit 1.3 bar on the higher setting.

Bad news is it doesn’t make that boost until late on, I believe that’s why I never really noticed the demister switch changing the boost setting, you don’t get that real surge of power kick up the arse like you should do.

Getting it checked again on Saturday so fingers crossed this will be the last, hopefully get boost coming on strong early and making decent power.

nice one wull, sounds like its a map tweak thats needed to bring in the boost earlier. mine hits 1.5 bar peak (vf35) then tails off to around 1.3 nearing the redline for safety. if its andy looking at the map he will sort it. he,s done both my cars in the past and they have been spot on.