need4speed Posted March 23, 2014 Share Posted March 23, 2014 Im not sure how these work sooooooo... Is it normal not to be able to blow/suck through the MAP hose when its attached to the sensor? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted March 23, 2014 Share Posted March 23, 2014 Yes, it is a diaphragm measuring pressure. If it breathed it would be a constant vacuum leak to the engine inlet! Quote Link to comment Share on other sites More sharing options...
need4speed Posted March 23, 2014 Author Share Posted March 23, 2014 Phew! Thanks Bowie Quote Link to comment Share on other sites More sharing options...
Laptom Posted March 23, 2014 Share Posted March 23, 2014 Just a follow up question... Had somebody exchanged these with a sensor directly on the inlet manifold and just wired it back to the MS ECU iso the vacuum tube? If so, which are good sensors to use? Thanks, Tom Quote Link to comment Share on other sites More sharing options...
Quagmire Posted March 23, 2014 Share Posted March 23, 2014 Not sure what the benefits of that would be? You still have to run wires back instead of a tube, and you are placing a sensor somewhere hot, oily and full of vibration when it could stay cool, clean and snug in its enclosure? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted March 24, 2014 Share Posted March 24, 2014 Yeah I wouldn't mount on on an engine, especially V8s, they do seem to get fairly hot under the bonnet Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 24, 2014 Share Posted March 24, 2014 People have done it, Microsquirt does this as standard (to keep ECU size down). You have two options: - Pick a sensor that has the same response curve as standard Megasquirt ones (the std one is MPX250, there is a 300 or possibly higher that's used for high-boost applications that's an option in the firmware too) - Pick whatever you want & change the response curve data in the firmware to suit (more faff but quite doable) Quite a few cars have inlet-mounted MAP sensors, TD4 freebie has one, and they're not renowned for going wrong... but I don't really know what you'd gain either? Bruce & Al tested the MS sensor for lag using some stupid length of tube (like a 50m reel!) and found it to be negligible. It's more common to add in some lag/smoothing by sticking a filter in line to smooth out sharp spikes in MAP readings on vehicles with lumpy cams. Quote Link to comment Share on other sites More sharing options...
Chazza Posted March 26, 2014 Share Posted March 26, 2014 Quite a few cars have inlet-mounted MAP sensors, TD4 freebie has one, and they're not renowned for going wrong... but I don't really know what you'd gain either? Bruce & Al tested the MS sensor for lag using some stupid length of tube (like a 50m reel!) and found it to be negligible. It's more common to add in some lag/smoothing by sticking a filter in line to smooth out sharp spikes in MAP readings on vehicles with lumpy cams. I did this on my carburettored Alpine; because it uses DCOE Webbers - which is essentially four carburettors for four cylinders - I used an old fuel filter for the plenum, just before the Megajolt, Cheers Charlie Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted March 26, 2014 Share Posted March 26, 2014 What I meant was.... I'm not sure how robust the MS sensor is, and wouldn't mount THAT one on the inlet manifold. Quote Link to comment Share on other sites More sharing options...
Laptom Posted March 29, 2014 Share Posted March 29, 2014 I can imagine that they could produce robust MAP sensors. They have been producing good MAP sensors for other cars, but it seems that also other sensors are produced which could withstand a RV8 (temperature, TPS, etc). I understand that the regular MS MAP sensor is not robust enough, but the system would be much cleaner in mine opinion when the MAP is on the engine iso in the MS ECU. Why have all the sensors on the engine exept the MAP? Quote Link to comment Share on other sites More sharing options...
Cheesy Posted March 29, 2014 Share Posted March 29, 2014 I can imagine that they could produce robust MAP sensors. They have been producing good MAP sensors for other cars, but it seems that also other sensors are produced which could withstand a RV8 (temperature, TPS, etc). I understand that the regular MS MAP sensor is not robust enough, but the system would be much cleaner in mine opinion when the MAP is on the engine iso in the MS ECU. Why have all the sensors on the engine exept the MAP? You can you would just have to calibrate MS for the sensor. All the ones I have seen are on the fire wall not the actual engine, so I suspect they dont like vibration. There is a tidy little bosch on that I have seen in various Toyotas (7AFE, 4AFE etc). I think the designers logic would have been along the lines of: if it doesnt have to be in a nasty environment we wont put it in one Quote Link to comment Share on other sites More sharing options...
Quagmire Posted March 29, 2014 Share Posted March 29, 2014 Exactly! Also, if it ain't broke, don't fix it! Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.