There's another thread floating around in the ECUFLash forum with a couple of us questioning the "spike" numbers being reported by the JDM MAP sensor. I'm also on Cali 91, and the JDM MAP says that I'm boosting 28(!!!) psi at peak torque with no negative timing tapering down to 21psi by redline. While I still doubt that I'm actually able to get away with that much boost, I haven't yet taken the sensor and put it on another car that's using an alternative MAP sensor for boost reporting.

Now, there's the other question of pressure spikes reaching the JDM MAP sensor inside the manifold that don't make it out to the FPR (where most people tap their boost gauges)...so I'm at a loss as to what's actually happening.

 

damet..installed the gauge..but I put in the wrong one..its a vacuum gauge. Found the one that reads positive pressure..will install today

 

I have no doubt in my mind that the manifold spike is REAL. I have logged it multiple times. Infact, I re-installed my GMMAP sensor simply to re-confirm my findings.

Below is a 4th gear log all the way to redline. The red trace is the JDMMAP and the grean trace is the GMMAP. Notice the spikes in the JDMMAP and notice the fact that the JDMMAP reads higher in almost all instances. That is why you need to smooth the JDMMAP to reduce the imapce of the manifold pressure spikes. Most of the time I smooth by 0.25 seconds, but sometimes I hav e to smooth bu 0.41 seconds to get a close match between the JDMMAP and GMMAP.

What I would like to do is log your car with my GMMAP and your JDMMAP @ the same time. This way we can see if your 28 psi reading is real or not. I do not know when we can do this since I am unable to attend the LB meets due to my Tuesday night work schedule.

 

Your data shows the GMMAP reading about 0.75 to 1.25 psi lower, on average, than the JDMMAP across the rpm range, whether under boost or vacuum. Your data also shows the JDMMAP to have slightly more noise than the GMMAP.

Pd1 is talking about something different than what you are talking about. Pd1 is seeing 28 psi at peak spool when he thinks it may be something closer to 23-24 psi.

You seem to be equating noise to "spikey" data while Pd1's spike is a very high boost value at peak spool.

With that said, it would be great if you could go out there and log Pd1's car with your GMMAP so that this could be brought to a close. I've bench tested my personal JDMMAP sensor against lab grade pressure gauges and found the agreement to be within 1 psi. My JDMMAP sensor correlates perfectly with my stock boost gauge. I've also put Pd1's JDMMAP sensor in my car and gotten the exact same readings from his sensor that I get from mine. What I would like to see of you is that you bench test your GMMAP against a calibrated reference like I have with the JDMMAP.

 

Note that I only quoted the section of text where Pd1 is talking about the manifold pressure spikes. The manifold pressure spikes are real and they tend be higher and more pronounced the hihfer the rpm is as you can no doubt see from the posted chart. There are no such spikes on the high end with the GMMAP map sensor since the hose from the fpr T to the sensor acts as a damper of the pressure spikes that Klaus told us about.
I am not. That is why I only quoted a section of text where Pd1 mentions the manifold pressure spikes. What Pd1 is experiencing is not the pressure spikes that I am talking about. It might be his logging set-up that is causing the problem.
I will do that whenwever Pd1 and I have the time. I want to log both his JDMMAP and my GMMAP with LM1/LMA2 w/o have the dat go through the ECU. All I need is to get the signal from the yellow ECU pin MAP sensor wire and attach the wire to the LMA2. The GMMAP already has a wire that hooks to the LMA2.
I do not have access to bench test. I could contact Innovate and see if they would do it for me. I will see if any of my close friends have access to bench testing.

 

I see nothing in your data that correlates with what Pd1 is talking about. Pd1 is seeing a relatively smooth 28 psi peak over a range of data points (where he expects to see 23-24 psi), not a series of saw teeth with no "average" deviation in the gap between the GMMAP reading and the JDMMAP reading.

I understand the damping effect that a rubber hose between a MAP sensor and the manifold can have on the reading that the MAP sensor takes. Its not rocket science. There is no doubt that the placement of the JDM MAP sensor leads to a more raw signal. I personally think that this signal is more representative of the actual boost conditions than a MAP sensor isolated from the mani by a hose. You can talk all day about pressure transients and such in the manifold, but when it comes down to it, the curve of the JDMMAP always exactly follows the trend line of the load curve, which tells me that the JDMMAP is on the money.

Its not that hard to build a bench test system. You could build it from 1/4" copper tubing and compression fittings at your local hardware store. You can hook up your GMMAP and your JDMMAP so the same manifold, and then pressurize it with a bike pump. Take the readings from your LMA-1 and make a chart. If you want, I'll do it for you. I've got laboratory volt meters and power supplies available to take direct measurements from the sensor outputs without any filtering.

 

Let me repeat for the millionth time, Pd1 talked about two things. ONE of them were the spikes in the JDMMAP that come from the intake manifold. I WAS NOT TRYING TO ADDRESS HIS 28 PSI ISSUE. I DO NOT KNOW WHY HE IS EXPERIENCING THAT. That is why I quoted him when he mentioned the spikes. I did NOT quote his entire post.
Think whatever you want to think, but people who are way smarter than you and me have weighed in on the subject, ie, Klaus, and I trust his judgement since he has way more experience with these issues than either of us. The best place to T for a MAP sensor is from the FPR and placing the MAP sensor away from the manifold reduces pressure spikes. Placing the MAP sensor in the manifold and taking the signal from there is second best. That is why you have to smooth the trace to reduce the spikes. As you said, it is not rocket science.

You have reason to believe what you believe and I have reason to believe what I believe. Agree to disagree and leave it at that

I will probbly take the GMMAP sensor to Innovate and have them test it for me. I am not interested in building a bench test myself.

 

Turns out my boost spikes were 100% real. Was able to replicate them on the dyno today with the map sensor, the JDM map, and the pressure sensor I have installed. After my "fix" of the boost maps I was still hitting 26psish, figured out the problem, now im down to what it should be (23-24psi)

JDM map reads 23-24psi now as well.

I guess the evo IXs really do like boost, I may throw back on the "broken" boost map , just add 100 oct

 

nj, why you always so angry?

 

Hi mrfred, I'm currently using JDM map sensor but it is an evo 7 which can only read up to around 2.2psi as u've mentioned. Not sure if your JDM EVOIX map sensor would work on JDM EVO7 yet?

Thanks!!

 

As long as its the same physical dimensions, it will work. Can you post up a picture of the one on your car?

 

ROFL...seriously....

nj..you need to step back from the keyboard and take a deep breath sometimes. We are all in here to learn, it doesnt help when you are always in here angry and barking at us all like you are supreme all knowing ecuflash/jdm map sensor user man

 

Dude,

I am not angry. I just do not like it when people present partial or incomplete data.

For example, you just posted this statement about your testing:

"Turns out my boost spikes were 100% real. Was able to replicate them on the dyno today with the map sensor, the JDM map, and the pressure sensor I have installed. After my "fix" of the boost maps I was still hitting 26psish, figured out the problem, now im down to what it should be (23-24psi)"

1. You did not present the data to us to judge the accuracy of said claim.
2. How were these three sensors logged? Did you use the same logger? Did you use three different loggers? Does the logger smoothe the data or not?
3. What type of map sensor does this dyno use? Is it properly calibrated? Did you test it with the ignition on and engine off to see how close to zero it is?
4. What is the pressure sensor that you had installed? Is it properly calibrated?
5. And finally, mrfred's favorite question, did you bench test them?

All these questions need to be answered. When mrfred asks me a question, I dod my best to answer him. I present the data for all to see. I list my calibration method. I go and install my GMMAP sensor to get him the igintion-on-engine-off number. And I do multiple re-tests to make sure that what I got before is repeatable.

I am not angry at you, nor do I hate you. I just dislike incomplete data. That is all.

 

Sorry I cant always furnish as many complete logs as you. But I just share what I learned/experiences

1. I didnt have a method to log all three on the same logger. Nor was it my aim to present data for you to "judge the accuracy". My main concern was to get my car running properly and savely, not fully convince you that I was experiencing real measurable boost spikes
2. 1 via the Mustang dynos SW, 1 via evo scan, and the 3rd simply by eye (its a digital gauge)
3. Its a mustang dyno, so I'm sure its a GM map or equivalent. The MD I was on is very similar to Razorlabs MD, so perhaps he can share what the exact map sensor is
4. The pressure sensor I have installed is a semi-conductor grade digital pressure switch. If I use them on the job to monitor gas pressure for semi-conductor process control, I trust them to be accurate enough on my car. There is no calibration for this except to 0 it at atmosphere. The gauge is a ISE40 series SMC digital pressure switch,accurate to .1psi

I trust myself and the adjustments made. By changing the WGDC, me and my tuner were able to smooth out the boost spikes and get the boost curve under control. I was putting down 300ftlbs on this dyno, which is on par with other cars with peak boost of 23-24psi. Bryan can attest to this as well

Again, my post was to see if there was any issue with the map sensor itself, not to prove anything to you or anyone else. I really wasnt trying to brag about how much boost the car was taking. I do believe it reads maybe .5psi or so high, but definately not 1-4psi.

 

This is one of the most important qualification steps for any sensor, and in the past, you have blown off the question. You have to stop taking pot-shots at people. This isn't the first one you've taken at me. You're not making any friends. And desipite what you probably think, your posts can be extremely antagonizing.

Bottom line here is that as I predicted in the beginning, the JDM MAP sensor was right on the money in measuring the boost level of UCB's Evo. Your first quote on this issue was, "So if you spiking to 28 psi, that is more than likely noise. Evoscan reports data as is and does not allow you to smooth out the noise from the boost." Your second quote was, "He is in CA and if he is running 91 octane, then there is no way in hell that the car is boosting to 28 psi." You finally said, "Hell would freeze over before an Evo will hit 27.5 psi on 91 pisstane and not knock. You will have to run negative timing numbers and be pig rich to do that. And even then it will knock."

If you look at his log where he is reaching 28 psi, you will see that there is no knock at that boost level: UCB's log with no knock at 28 psi

You were 100% wrong on each of your statements. I suggest that next time you think more carefully about what you post. You're not doing anyone any favors with your posts.