"best" Map sensor for NA engines / alternative MAP sensors

Specifications, applications, part numbers, and prices for various OEM fuel injection components.

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Dennis_Zx7r
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"best" Map sensor for NA engines / alternative MAP sensors

Post by Dennis_Zx7r »

As I'm currently trying to improve my MAP signal, I'm looking into what might be the best available sensor to chose.
Specs are as follows:
-Naturally aspirated engine, maximum MAP before less than 103kpa. With the new setup (1 sensor per intake port) I expect something less than 100.
-Expected minimum value below 20kpa. Current sensor is limited to 20kpa, bottomed out at. Extrapolation the datalog suggests minimum pressure might be around 15kpa. 20kpa might also work though, as I plan on using overrun fuel cutoff, but 15kpa would still be nice.
-Engine revs >13000Rpm, very light crankshaft. Responsiveness would be a bonus.

From the perspective of sensitivity (mV/kpa) and therefore signal-to-noise, I think it's best to drop the original MPX4250 (20-250kpa) and choose something with around 110kpa @5V.
I first thought of the MPX4115. This sensor would provide a range of 15-115kpa, and I already know it is used sometimes with an MS as its calibration data is available in TunerStudio. I then found the MPX4101 with 15-105
The MPXHZ6130A provides 15-130kpa and seems newer.

Spec sheets aside, can anyone offer experiences with Map sensors other than the MPX4250 with the MS?
I'm not limited to the MPX series or NXP sensors.
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LAV1000
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Re: "best" Map sensor for NA engines / alternative MAP senso

Post by LAV1000 »

The PRT03/04 is used on Ducati motrocycles.
I know it is also used on a Fiat sciecento and other cars equiped with weber marelli ecu's.
On the Ducati's it is used as Barometric sensor.
Maybe get one from a scrapyard and expiriment.
WestfieldMX5
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Re: "best" Map sensor for NA engines / alternative MAP senso

Post by WestfieldMX5 »

MPX5100AP Can do 15-115 as well
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Six_Shooter
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Re: "best" Map sensor for NA engines / alternative MAP senso

Post by Six_Shooter »

Does your engine actually pull vaccum at 15kpa with load or only on rev down from high RPM? If it's only on rev down, then anything more than a few KPA below the lower point where the engine actually runs under load is unnecessary.

According to my datalogging software of my old Delco systm the GM 3 BAR MAP sensor I was using would go as low as 12 KPA, but that took a lot to get the intake vacuum THAT low. lol The 1 BAR MAP sensors used by GM/Delco should have similar lower reaches.
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Dennis_Zx7r
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Re: "best" Map sensor for NA engines / alternative MAP senso

Post by Dennis_Zx7r »

Six_Shooter wrote:Does your engine actually pull vaccum at 15kpa with load or only on rev down from high RPM? If it's only on rev down, then anything more than a few KPA below the lower point where the engine actually runs under load is unnecessary.

According to my datalogging software of my old Delco systm the GM 3 BAR MAP sensor I was using would go as low as 12 KPA, but that took a lot to get the intake vacuum THAT low. lol The 1 BAR MAP sensors used by GM/Delco should have similar lower reaches.
It is only on rev down currently, and only above mid-rpm. In high revs, I can provoke about 25kpa cruising - but this isn't normal operation.
But this is with 4 ITBs connected and averaged, and I'll be taking the individual pressures with one sensor per ITB in the future and therefore expect lower minimal pressures.

However, I've got a good offer for some Mpx6115 (15-115kpa) which makes this an easy decision, as the data sheet and NXPs website suggest these may be just what I was looking for.
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whittlebeast
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Re: "best" Map sensor for NA engines / alternative MAP senso

Post by whittlebeast »

Can you post a big data log off the motor?

Andy
Dennis_Zx7r
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Re: "best" Map sensor for NA engines / alternative MAP senso

Post by Dennis_Zx7r »

This is the most representative of normal operation I can access right now, although somewhat low revs and load. Some introductory turns on the Nürburgring, therefore not including the "provoking" cruising mentioned.
https://dl.dropboxusercontent.com/u/106 ... B2_NBR.msl
Here's a graph showing Map-usage in this file.
Image
Keep in mind the 4 ITBs were coupled via T links to a single sensor and MapAveraging was selected, which means every Map value in the log even near the lower end has the low peak most certainly cut off. I unfortunately never did an experiment with the Map sensor on a single ITB and MapSampling and can't do right now as I'm in the middle of refining my build quite a lot. I'm aware this isn't necessary to get the MS to run fine (not an issue), for the most part I'm experimenting out of curiosity. I'm not hunting for the lowest Map i can get, but as I'll most likely datalog the single cylinders separately in the future (also, just out of curiosity) I like getting as near to the real pressure curve as practically possible.
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whittlebeast
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Re: "best" Map sensor for NA engines / alternative MAP senso

Post by whittlebeast »

Really cool data.

http://www.nbs-stl.com/racecardata/Moto ... 20Data.png

I created a new calculated field called Throttling in MLV HD

I defined it as

[Field.TP]<0?0:10*sqrt([Field.TP])

That is what I came up with after applying filters to the GPS data. Wow is that thing a classic ITB motor to tune.

Andy
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