Higher reading MAP sensor fitment?
 

My 94 classic MAP sensor runs out of scope when boosting over 1.14 bar.

I read here that the later classics ( 98 on ?? ) can read to 1.8 bar??
And that aftermarket MAP sensors can read to 3 bar, e.g. Apexi MAP sensor.


What is the best one to get / fit, and what is involved in wiring it in - does it need a remap / rescaling to suit the PFC fitted to get the real boost value?

Hope it is a plug and play upgrade for say the Apexi MAP sensor, else it will have to wait with the Z32 until I get to AndyF for a remap!



Thanks

Neil

You can't do it without a rescale, actually not true, you can fit a Cossie 2.5 bar one (minus 1 plus 1.5), it produces a lower output and disables fuel cut, you might not make mapped boost though without a boost controller.

Point is there isn't a direct replacement.

bob

Cheers Bob, what would you say is easiest option then, if I need the rescale at remap time... 98 on MAP or Aftermarket Apexi one for instance??

I already run an external boost controller ( outside of the PFC control ) to significntly above the OEM MAP sensor, and seems to lift boost / fuel cut, and was hoping to get a MAP that could feed accurately to the PFC for better monitoring etc.

Neil

As Bob said, you can rescale the map sensor in the Pre96 ECU, to use a map sensor from an MY97> i.e a 3 bar (1bar minus, 2 bar plus...although 1.8 bar is more realistic).

But not sure if your running a standard ECU or an Apexi PowerFC.
If using the Apexi, then I think the Ecu itself limits you to 1.2bar. So you need to disable Apexi boost control and fit and Apexi AVCR (I think).

Ask Paul @ Zen, I know he's spoken about this before.

Assuming you still running Apexi PFC Neil?

The Apexi only uses the MAP sensor for controlling the boost.. I didn't believe it until I unplugged the MAP sensor on my own car.

The MAF is used to transverse the ecu maps.

You can fit a later MAP sensor but the boost displayed will not be correct.. something like 0.8bar at actual boost of 1.2bar..

Speak to Andy but you would be better to either use a Boost control kit or another form of boost control.. which I think you were already anyway.

Simon

Fine Simon! AndyF didn't think it a problem mapping well above the 1.14 bar limit of the std map sensor with the Apexi PFC fitted and boost controlled by a seperate device - I was even advised by someone that even with the AVC-R I should let each device work independently ...

I think IIRC that the PFC allows 0.1 / 0.2 bar boost above the MAP sensor limit fitted to allow increased boost but if PFC isn't controlling boost then no issue!

My PFC has boost control turned off .. the Hybrid boost controller does a really good job,

So the bottom line is ... I don't need a higher reading boost controller to help / improve the PFC to run the engine .. it's an aesthetic thing for the PFC to DISPLAY the right boost, but not a control thing.

Good, I can drop this idea then!!! I can live with the PFC commander displaying 1.14bar when at 1.6 bar! Boost gauge will do then!

Thanks all

Neil

Exactly Neil.. I have gone one tiny step further and removed the MAP sensor (extra weight) lol

Simon

Might be an idea to fit an Apexi 3 bar map sensor. My reason for saying this is that you would be able to retain an overboost cut in event that something went wrong.
Still not sure how your hybrid boost controller works at 1.6 bar Neil when it reads the OEM map sensor :confused:

Andy

Andy

That was where I was coming from initially, get a MAP sensor that could actually read what the turbo / engine was doing - I know you mapped it last time to 24 psi despite the OEM map sensor maxing out at 1.14 bar, and that worked very well safely.. an over boost cut just above the mapped boost would be OK but could the PFC / Apexi MAP sensor deliver that?

The Hybrid boost controller ( I spoke to Hybrid about this as it does not lift fuel cut on all cars - mainly fails to work on UK cars ) draws a little current (voltage? ) from the signal wire to take its readings and adjust the boost, and this "resets" the boost cut control to just above the boost setting on the controller - effectively fuel cut defender / remover. It is an electronic boost controller and fast acting 3 port boost control solenoid, but works to the setting dialed in NOT the ECU / MAP readings, so lifts / removes the fuel cut, apparently. It is not advertised as a feature of the Hydrid EBC, as it was not particularly designed in but is known to exist / work. A seperate Hybrid MAP sensor to feed the EBC was in development, but I have yet to try it or hear of any outcomes ( this uses own MAP sensor to feed signal to EBC and does not tap into ECU wiring from oem MAP sensor ).

There is always the risk of serious over boost if the wastegate / EBC hose fails or some one over adjusts the EBC settings.

Overall, I doubt a higher reading MAP sensor would restore the overboost fuel cut whilst the Hybrid EBC is installed.
Would an Apexi AVC-R allow the high boost I run ( 1.65 bar / 24 psi ) and still give emerency protection??

Further Q / thought, how long will it last / how efficient is the TD05 at this high boost?

Two ways you can do it,
1- fit an apexi pressure sensor (£100 ish) and control the boost from the ECU via the oem 3 port at anything up to 2.2 bar. This retains the overboost cut at 0.2-0.25 bar above setpoint.
2 -fit an AVCR, this allows full profiling of the boost which is ideal if you want to run 1.6 bar midrange and taper out at the top for compressor efficiency reasons. It also has individual gear dependant wastegate offsets to improve acceleration through the gears (which gets confused if you run it in a rolling road !)

Andy

This is an issue I also need to sort out for my PFC too.

I want to map it for running above 1.1bar (89 RS Legacy) but surely all of these options mentioned besides the proper boost control kit (not sure about the AVCR in terms of how & if it interacts with a PFC) mean that whilst you will be able to run above 1.1bar and not get fuel cut, the map sites being read would be the same ones as at 1.1bar.

Sorry if I've missed something about how that is got around (been a long day!) but surely at higher boost levels it's even more critical to have the map sites containing the correct info being accessed, or do you just compromise the settings at 1.1bar on the pressure axis so that they will cope all the way up to the limit you're aiming for?

no because the PFC doesn't used the MAP sensor to traverse the map sites..
MAF is used.

Simon

Of course! How stupid of me as I did already know that but was being dim.
Mine gets to P level 15 at around 1.3 bar - does that map row sound about right for that sort of boost level?

So in that case as I control the boost on mine with a dawes type device the only thing really to gain from fitting a boost control kit or AVCR is that I can exercise more tailored control over the boost characteristics?

The other thing I was curious about is what units are used for the boost figures logged by datalogit? My recorded figures range from -500 to 120 or so but I've no idea if they are actual units or just some arbitrary figure. Any way they translate to psi or bar?

Thanks Simon

Jim

they are measuring in KPA.. 100 is 1bar.

boost control kit doesn't allow tailoring of the boost curve.. just 4 boost settings selectable on the controller and the actual boost on the monitor / datalogit.. but as Andy says just the Apexi MAP sensor and your 3port will do the same..

AVC-R will allow tailoring of the boost curve.

Simon

Oh and as to row 15 it varies from car to car, maf to maf but 15 is about the normal.. mine at 1.3bar is in row 16.

Ace - thanks for clearing that up Simon. :)

There's actually an apexi map sensor on Ebay at the moment and I'd get it but I think it said it was for an S14 nissan or something so probably isn't suitable.

At least I'm clear on all that now anyway. Much obliged.

I would imagine.. but don't quote me on it, that the Apexi sensors are the same..

Simon

Cheers - I doubt I'll bother as I was mainly concerned about the right areas of the map being read and now I don't need to worry so much I'll wait til funds are a little more 'liquid'! :eek:

Got the AVC-R / 3 bar MAP kit now to go on, ideally ready for the mapping session!

Can we turn off the gear settings when on rolling road ?

Neil

Yes but ideally you need to run it with the correct duty offset in relation to loading otherwise you will not get a representative boost profile on the rollers.

Andy