I adjusted my wastegate to yield the 14.5 psi measurement and I would have to take issue with your statement of the stock IP settings not yielding any benefit over 12.0 psi.

I have tested this system to see if the overboost circuit was working and IIRC, it activated at about 15.5 to 16.0 psi. The performance from the car at 15.0 psi, before the overboost protection activated, was phenomenal.

I have the ALDA backed out CCW all the way and have changed the shim thicknesses under it slightly, although I cannot recal exactly which way I went without my notes.

Either way, I drive this car over 100+ miles day (round trip) to work with 14.5 psi of boost recorded at WOT. I have very little smoke, even at WOT (certainly normal opacity for a 617.950) and the car has V8 performance.

My last two tanks of fuel, keeping engine rpm at or below 3000 rpm, have netted 28.6 mpg...I am still shooting for the elusive 30 mpg figure on a consistent basis. I am hoping a future change to a 2.47:1 will get me in the ballpark.

Forced Induction:

I am not trying to be argumentative or discredit you. Here is how I approach things: If theory agrees with results, accept theory. If results disprove theory, adopt results. In the case of my 617.950, the IP has never been touched and the fact is, regardless of theory, the car wil absolutely fly when you increase the boost, even above the 12.0 psi figure you quoted.

I may not be able to explain to you why, all I do know is the results are outstanding...Robert

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Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership