Interesting look at Stage 1 + SF vs. Stage 1 + MSCAI2 maps, similarities and differences

[bast525]

So I know that Cobb seemed like they put more time and effort into their SF maps, and why wouldn't they... it's their intake. I figure some good info could be learned by seeing what they did differently between the SF map and the MSCAI map, and just looking at the SF map overall. And I did see some interesting differences, but I don't pretend to understand the differences that I found.

First and foremost, the MAF Tables. The Stage 1 + MSCAI2 MAF tables (as well as the MAF tables for many of the other maps, SF and MSCAI maps) are the same as stock. Meaning your ECU will have to correct a LOT on this map/intake combo. Expect high combined LTFT+STFT's (looking at LTFT's is not enough... LOG!!). I know my car was adding as much as 13% fuel at the point right before switching into Open Loop.

Stage 1 + SF raises all of the MAF Table values by 12% over stock. Very close to the total adjustment I saw noted above running the MSCAI, so this makes sense. Afterall, the increase in airflow between the two intakes should be similar enough, compared to stock (much as some people don't want to think the two are even in the same league).

So then I look at the load tables. Now... so far I thought that I (and others) had had it figured out... if you increase MAF table values, power will drop off, and you need to increase Load Table values to compensate. Right?? Okay, so I compare the Throttle Req. Load X Gear tables between the two maps, fully expecting that the load values on the SF map must be higher than on the MSCAI map, as the MAF values on the SF map are much higher, yet they target roughly the same amount of boost (within 1 psi). 1+1=2 right?

But this is not at all what I found! Instead, I found a confusing mix of variation between the two maps in each gear:

1st: SF and MSCAI load tables are the same
2nd: SF load tables are significantly higher
3rd: MSCAI load tables are a bit higher
4th: SF load tables peak higher, but taper back down to roughly same as MSCAI after that
5th and 6th: MSCAI tables are MUCH higher

So... yeah, I'm confused. I looked at most of the other tables that would affect boost, but didn't see much if any difference anywhere else. Even looking at fuel, timing, etc., most of the tables were the same over very close. Even the differences in the load tables that I listed above, really, they were mostly pretty close. Odd considering the drastically different MAF tables.

Yet, I have found that when I run a Stage 1 + SF map on my car, which has an MSCAI, I will run much lower boost than what is called for by the boost targets. I also found (like many did) that when I increased MAF table values to compensate for LTFT's, that my boost and power fell off, until I made adjustments to the Throttle Req. Load X Gear tables to compensate.

I know that these cars are all different and who knows what was going on with the 'test car' for each of these maps... there could be 50 variables that affected how these tunes came out. I still thought that it would be worth looking at for anyone trying to figure out the correlation between MAF Tables and Load Tables. It makes me feel like I am VERY far from understanding exactly what needs to be done to get this car running exactly the way I want it.

[evidence]

Exactly why Cobb had so much trouble... Cars are so different and respond quite differently. This is the preferred way to tune boost though. On many maps MAF and load are the only tables changed, and they are both quite different, so while there are more factors most of them have not been touched.

Also the MAF curve probably isn't a straight 12% across the board, this causes some variance in the load tables per gear so 2 maps will not match up trying to use a straight % even if the curve looks similar.

Also you can tell Cobb didn't put 'too much' work into the OTS maps, just enough to get them working and try to make power past 6000 it seems. The maps are all over the place and have no consistency.

[jlefebvre123]

So with say a proper pro tune there is tons of power that can be available from this car?

[dread]

not really.

[seniorgeek]

OK, I have been following you guys and looking at my maps from the DH and I see many variances. I need to do much more studying and comparing maps but it seems that all MS3 are pretty close but their is enough variances between cars that you start with the basics from Cobb or whoever and then move on your own until optimized based upon what you are trying to accomplish. You have to give credit to the engineers that designed the ECM and the programming that was done to get what we have called 'stock'.

As always, there is always room for improvement.