02-07-2008, 09:54 AM
Join Date: Oct 2007
Location: Louisville, KY
Total Cats: 0
MS dealing with higher intake temps
Being that I am running a coldside MP62 SC, my intake temp sensor is mounted in the manifold about 8in from the blower outlet. I am currently seeing temps reaching 240*F+, but I don't have the WI working yet.
I don't know how much the WI will drop the temps, but I am guessing that I will be >100*F being that I am measuring the air in the intake manifold.
After searching here, it appears that most of you are registering intake temps <100*F.
I will only be spraying water when the car is above 4psi of boost. I am assuming that I will still see higher MATs when not in boost.
I found this statement on another forum. The poster is running a coldside MP62 like me with MSPNP. Do you think I am going to have trouble getting a good tune on my car with the standard correction tables.
Does anybody have any experience with a situation like this? At what temperature do the standard tables deviate?
"As for observations.. The MS IAT correction tables seem to assume a n/a setup that would not see the extremes of manifold intake temps that you can easily attain with a non-intercooled FFS coldside. Remember, I have no E-cool and have not yet installed my water-injection setup. When the FFS manifold heatsoaks, the MS IAT tables apply a little too much negative fuel correction, causing some lean conditions. In my car, this manifested itself as pinging under load during the onset of boost, primarily between 3k and 4k rpms. If I tuned for the heatsoaked condition, I'd be extremely rich when the motor was cool.
The solution is either to stop that IAT sensor from heatsoaking, or modify the MS IAT correction tables. I modified the tables, and recompiled the MS firmware. It seems to have mostly addressed the issue, although not entirely. I believe that the WI will quell remaining heatsoak issues, but for now I'm just careful not to lug the motor when it's heatsoaked. The 'lean when heatsoaked' problem can also manifest itself as a lean idle, causing oscillation of RPMs around the target idle. The MS has pretty sophisticated (and touchy) idle control, and there are a few tricks that you can use to tune out this condition also. And modifying the IAT tables probably helps there too. After several weeks of occasional fiddling, I have finally gotten my idle as stable as it was when running the MS prior to the FFS coldside installation. I'd say idle quality is about 90% of what it was stock."