So swapping an S turbo to a JCW turbo requires the JCW MAF as well? Hadn't thought of that.

 

Negative. The system will calculate flow from pressure and RPM. It is possible to swap JCW sensors on MCS. I've done this before on custom tunes but not on Manic.

 

Which JCW sensors are different from the S? Are they straight swap, or require a retune?

 

MAP and MAF sensors are different between the MCS and JCW. MAF is not important from a performance perspective but the MAP sensors are. Changing these requires updating tables in the ECU. Swapping out any of the above without recalibrating will trigger errors.

 

Thanks for answering all the questions! So anyone with a burned out S turbo and manic tune cannot "correctly" upgrade their turbo to a JCW, get reflashed and everything work like if their car was a JCW to begin with? When you put in a bigger custom turbo the ECU uses pressure/RPM as well? If this isn't ideal, it's "good enough"?

 

Not at all. You can absolutely upgrade to a JCW or larger turbo on an MCS with a Manic tune and it will operate correctly. That's what the Stage 3 reflash is for. The turbo profile, lamda, timing tables and PID control for the turbo are all adjusted to take advantage of the extra flow potential and spool characteristics of a larger turbo.

On the MCS however the MAP sensors are 2.5 bar units which will register 255 kPa of manifold pressure. This correlates to 1.55 bar of boost but they will actually read a smidge higher which is what makes the 1.6 bar tunes feasible on the MCS. To go higher than that you really need JCW MAP sensors in my opinion. Once the MAF sensor and MAP sensors are maxed out the ECU has no way to know with 100% certainty how much air is entering the engine. The original 1.5 bar fuel cut that so many tuners ran into on the MCS was designed that way for just that reason.

Is it possible to go higher than that on the MCS with original sensors and make big power. Yep, disable the subroutine for boost related fuel cut completely and run off of defined tables knowing what turbo is being used. Doing it this way eliminates several features designed into our ECU. Temperature and altitude compensation become more problematic but at least it makes it possible.

If however you swap the MAP sensors for JCW you can raise the fuel cut as high as 2.2 bar and the ECU is able to accurately measure air entering the engine. The 2.2 bar limit is used for safety. The JCW MAP sensors should be able to routinely read 2.5 bar of boost but some report erratic figures after 2.2 bar for some reason.

 

Good explanation! To support this, here's a brief summary of my build --- my MAP and MAF sensors are all OEM for MCS, not JCW. My AP custom tune was done for a big Garrett but Jeff wouldn't go for more than about 25PSI boost. When I switched from AP to Manic's stage 4, Nick provided maps for my specific Garrett model --- up to and sometimes a brief surge over 30 (slightly more than 2 bars).

Working in my power range, 360+WHP, there's hardly any max boost for more than a few seconds, and that's typically on a dyno. That kind of performance on local streets is prohibitive. It's available when I want it, but I've mellowed quite a bit since my build started --- late 2010. Also note that my home turf is about 4500' elevation, and there's occasional trips thru the Sierra Nevada mountains. It's even scarier when I take it to sea level! Disclaimer --- this description is to be read as "past tense" --- the car is currently torn down. After spending my kids inheritance on mods, I need to spend a bit more on the spouse and family-related ventures, so it's gonna be awhile before I'm back on the road with it.

 

What plugs are you running ?

 

If your question is for me, I'm running NGK-4962 --- heat range 9.

 

Nope I was asking the thread starter

 

Resurrecting this thread! So now that the weather is cooler and dry in my characteristically tropical environment (high is <80 deg F) I play with my stage 2 map C. The rest of the year I run map B. I noticed that if I run map C for a while, then go back to map B, it feels like I still have a little "residual" power from map C, at the top of 6th gear (I have an an auto) gently accelerating at highway speed without causing a downshift, possibly from timing? Does switching to map C, or another map in general, reset either or both of the short/long term timing adaptations? Or other parameter?