My First Crack at Tuning the CX7

[Ian0611]

Hey guys,

I took my first crack at tuning our CX7 tonight. I hope to discuss my tune in more detail very soon but for now I just have a couple quick questions. My CX7 is still completely stock other than a K&N drop-in filter. So my questions are:

1.) What kind of power do you guys typically see on a stock CX7 on the stock tune? The baseline I got on the stock tune seemed pretty low. (See pic below)

2.) How much WGDC does a stock CX7 need to run to hit 1.4 load @ 6K? I'm hitting 1.4@6K but it's taking about 90% WGDC to do it which seems like a lot. Possible boost leak??

Here's the graph. The lowest of the three was on the stock tune. The other two are from my tune.



Obviously I'm happy with the increase in power, but the numbers still seem pretty low. Anyway, let me know what you guys think.

[mituc]

What version your CX7 is? the 244bhp AWD AT or the 260bhp AWD MT?

The numbers seem pretty much ok, it also depends on the altitude you're at to emit any opinions about the WGDC values for a specific load value at a specific RPM.

[Ian0611]

What version your CX7 is? the 244bhp AWD AT or the 260bhp AWD MT?

The numbers seem pretty much ok, it also depends on the altitude you're at to emit any opinions about the WGDC values for a specific load value at a specific RPM.

It's the AWD AT version. My altitude is only about 750 feet.

[mituc]

Ok, then the numbers look perfect.

[Ian0611]

Ok, then the numbers look perfect.

Alright thanks for confirming

[Ian0611]

I'm a little confused by the MAP sensor readings on these cars. According to the MAP sensor I'm hitting a peak of about 30psi (which I know is not true). Is there a way to convert the MAP sensor readings or even the Load numbers to PSI so I can get a better idea of how much boost I'm running and see where the crossover is from vacuum to boost?

[mituc]

The MAP sensor is reading fine. These cars also have a barometric pressure sensor which you can get readings from. The actual boost is MAP-BARO. Usually at sea level the barometric pressure is varying between 99 and 103kPa (14.4-14.9psi). So if your MAP sensor is reading 30PSI then you're actually boosting about, say, 14-14.5PSI.

So MAP is the absolute pressure while boost is relative to the barometric pressure and in my opinion should not be used in the tuning process. 14PSI of boost will get you a certain amount of air at a certain RPM no matter what the barometric pressure is, BUT if the barometric pressure is very low (high altitude or high ambient temperature or both) the turbo will spin like crazy to meet that boost value because the air entering the intake is less dense.
That is one of the reasons there are several limits and sub-unitary multipliers in various tables to keep this under control (Absolute limits -> Overboost protection fuel cut, Boost Control -> Boost limit barometer adjustment and BCS DC Barometer adjustment and possibly others).

So take your mind off of the actual/relative boost. Work with the absolute boost values (MAP).