Power drops on track when hot
 

Posting the link to this discussion I'm already having on the Miata.net boards because it might end up being a tuning or sensor issue to solve and you guys have a lot of experience in this. Running a MS1 in the car with a M45 Sebring intercooled setup.

Having issues making power based upon my straight line observations when the ambient temps warm up and the car runs hotter. Don't know if it's a heat soak issue, hardware not being adequate, tuning (pulling timing/fuel due to heat) issue. Also don't know what is safe to change from the tuning side, still want to protect the motor.

Any advice on what I can look into, information I can provide? Thanks guys.

Down on power when track day heats up - MX-5 Miata Forum

You need to log data. 99% sure you're dealing with a heat soaked intercooler. Data will reveal the truth.

Will do, any way I can simulate without being on track to expedite the logs? Not a streetable car anymore so that limits me.

Also, I just downloaded MSDroid and am going to try and use it for display purposes only but can I datalog with it if I wanted? Thinking that might be easier than having a laptop strapped into my passenger seat on track :)

So I tried to connect to my ECU with MSDroid on my Galaxy Nexus and it didn't work. It's an MS1 built by Brian, guess technically it's a DIYPNP or whatever the generic various is called.

Any ideas? Really want to use MSDroid for data logging my issues. Do I need to setup the phone in a certain way to connect? I was trying to use the USB connection, no bluetooth.

Got MSDroid working. Just needed the right OTG cable and it popped right up. Log to come next weekend.

How much timing are u pulling per degree?

triple88a: Going to answer your question the next time I get to the car and am able to look up the settings. Car is stored not at my house.

So I was out at the track this Saturday and will post the log as soon as I have a chance. But basically the MAT consistently went up from about 100F at the pits to a max of 160F on track. Ambient was approx 80F. Car makes 9psi at max boost on an M45.

Changes from last track day:
1. A little more ducting to intercooler specifically. Basically put up a plastic side piece from the inlet to the intercooler on both side. Directed the air a little more.
2. Wrapped the IAT sensor in insulation.

Observations:
1. Car felt noticeably better in straight line speed. Was passing Miata's of known lower HP's and kept up with a Spec Boxster on the straights through a whole session. (how fast are those Boxsters? haha)
2. Intercooler was cool to the touch within 2 minutes of getting into pits. I could touch it with no gloves and it felt pretty much ambient. Don't know if this is an indicator of anything.

See attached log. There is some sitting in the pits and a brief trip back into the hot pits to start but you can see the MAT's climbing towards the end of the session. What does this tell me? Is 160F high?low?normal?

Two things:
1. Your MAP values look like they are half what they should be. Double check that you have the correct type of MAP sensor selected. This will obviously wreak some havoc with speed-density control.

2. It does look like you're heat soaking. Bigger and/or more efficient intercooler and/or ducting will help. Making sure you are injesting cold air rather than radiator pre-heated air will help also.

Thanks for taking a look hornetball, really appreciate it.

I'm pretty dense when it comes to the MS. To check the MAP sensor can you guide me to what needs to be selected? I'm running an MS1 (pretty old school by current standards).

If you go to <Basic Settings> ==> <Engine Constants 1> ==> <MAP Type> there will be a dropdown menu. You probably have the 115kPa setting selected which is incorrect for a boosted engine. Most MS's are built with 250kPa sensors, although some people use the 400kPa if they expect to use a bunch of boost. To be sure, you should look at the actual part number of the MAP sensor inside the MS.

Be advised that when you make the change, you'll need to retune fuel as you will be running extremely rich.

And if I'm on the right setting but have the numbers as they are in my log, what does that mean?

I ask because the tuner that setup the MS in the first place is very experienced with Miata's and Megasquirt. I would be surprised if a setting seemingly so basic was incorrect.

It would mean there's a problem with the sensor. But a problem that severe would result in a poorly running car -- if it even ran.

I don't think this is the case based on your AFR's. People do make mistakes. If you find the wrong sensor selected, you might want to bring that up with your tuner before making any changes -- maybe he had a reason for doing it (although it means that you are degading the accuracy the sensor can deliver).

Understood, thanks hornetball. I will check out the setting next time I have a chance and give the tuner a call if it's not correct. Then report back, hopefully the helps my situation.

Bumping my old thread, finally checked the ECU and it's using a 250kPa sensor. At least based on what Tunerstudio is telling me.