new sensors needed when supercharging / turboing a 304?

[4x4sandman]

Hello.

Im ready to screw an STA side mount supercharger to my VG ute with a 5ltr in it. It is pullied for about 12psi so I intend to add a blow off valve to regulate boost to 9psi to keep the tears inside my eyes.

I have my pcm hacking modded 808 in and working with 12p, that works with my windows surface 1, thanks vl400 for sorting me out with the nvram and usb bits.

Ive read up a fair bit and I know I need a 2 bar map sensor and a wide band o2 sensor. Are there any other sensors I need to upgrade?. Can anyone please advise me what ones to get, and where?

Also, I guess jamming lots more duel and air into my donk will leave me highly susceptible to detonation, should I fit a knock sensor? Is much involved in finding and installing the knock board into the 808? Can I fake a knock device somewhere else on the system?

Apologies for any repeated questions, I've tried to ask everything now to keep this info in one spot for future searches on doing this mod.

Thanks, Laurie.

[Holden202T]

you'll more than likely need larger injectors too.

[TdracerTd]

When you say Blow off valve, do you mean the piston type like what they use on turbo engines? I have done this myself, but not for boost regulation, rather to relieve pressure when the throttle closes suddenly as well as to take load off the blower when idling. More useful would be a bypass valve (Butterfly and Diaphragm) As with a blow off valve it is either open or closed which makes transitional throttle control almost impossible. On the dyno I was unable to hold the manifold pressure steady anywhere between about 80 and 130 Kpa.

Just a heads up. Hope it helps

[4x4sandman]

Thanks 202. I have a set of 40lb bosch injectors and a bigger fuel pump, so fuel will be ok.

TD I did mean blow off valve, piston type, the one that sneezes, but from what you say that will need a rethink going on your experiences on the dyno. A bypass you say, that would work and it will keep the air inside where its meant to be... thanks for the tip, you possibly saved me weeks.. I suppose I wouldn't need a blow off valve for closed throttle as the air pressure will essentially reverse back through to the air filter.

Thanks for the tips.

[TdracerTd]

If you are chasing a nice little modular bypass valve, bmw can supply one which is in use on the Mini Cooper that should fit the bill nicely.

[kojab]

Definitely fit a knock sensor. You will need to get a V8 HSV memcal.

[4x4sandman]

Righto boys, good info. Nice looking bypass on that beema.

Hsv memcal and knock sensor is on the way.

I have been reading up lots on the o2 sensor, nb, wb, when they work, why and how and I think I have that down, except... why does the 808 need to see the wb's as an analog signal? TBH I dont understand what other way it (PCM) will read a signal, its a voltage that goes up and down, right? Why are people selling boxes that turn the signal into something else?

Map sensors, AFAICS I could use a 3 bar map sensor on a 8 - 10 psi engine and this would just spread the available options on the ve table over a wider pressure range, so the differences on the table would be a bit wide to cover the wider area.... yeah? no?

Thanks, once again.

[Dylan]

A digital input wouldn't work with a 0 5 volt signal. A digital input would work with 0 or 5 volt but woud not process 3.63 volts as xx.xx afr.

Or have I misread your quetion? Wideband controller's conversation the current generated by the wideband sensor into a use able 0 to 5 volt reading.

[pman92]

A wideband 02 sensor is useless unless it has a controller. The measurement of AFR is determined from 'pump cell' current, with corrections for temperature. The controllers job is to monitor the sensing element and control the pump current and output a voltage for the measured AFR. The PCM can only see voltage, not current. Late model PCMs have the controller built in, the 808 has no such capability. So we have to use an external controller. Is that what your asking?

You could use a 3 bar map sensor but the top third of the VE/spark tables etc would never get used on a 10psi engine. You would be better off using a 2 bar sensor as the accuracy of the reading would increase, as you have the whole 0-5v for that 2 bar your using. Instead of only having say 0-3.4v you operate in, and 3.5-5v never getting used.

Correct me if I'm wrong.

[4x4sandman]

Yep, all questions answered.

re the 3 bar map, yep thats what I asked and suspected, it would work but the extra range would be a wasted, ok, got it.

In the mean time I found this page to explain how the sensors work; http://www.aa1car.com/library/wraf.htm

I now understand better. Man this stuff is deep!

Can anyone suggest a controller that works with the 808?