Sluggish 91.5 Dodge P/U
Hi Nick,
I don't know if this will help you, or not, but my 91. 5 W-250 was a "lead-sled" until I fixed it. As you probably know, Dodge made quite a few changes in the 91. 5. They went from an 18sqcm turbo housing to a 21 sqcm housing. The "21" lasted only a year because of so many complaints regarding unacceptable turbo lag. They called them, affectionately, the "dog diesels".
I went to a 16sqcm housing, which, can be purchased for about $150. 00. It made a world of difference. Really woke the truck up.
Previous to that, I had turned the power screw in, twice. First time, by the dealer after my complaints about low power. That cost me over $100. 00 with a dyno run to determine that the power was just one HP over the minimum point at which they would have had to turn it up on their dime. That helped just a little bit. Entering a freeway, you noticed slightly more acceleration.
The second time, I had Chuck's Speed Center, in Phoenix, mill off part of the limiting band on the screw so that it could be turned in even further. That, also, helped just slightly. None of these two mods had anywhere near the effect that the 16sqcm turbo had.
Later, I heard about Diesel Performance Center, Inc. , 4014 West Van Buren St. , Phoenix, AZ. 85009, 602-269-5043. They told me that they could "re-calibrate" my pump, off the truck on a machine dedicated to that pump. That made a BIG difference. Equal to what the 16sqcm turbo housing did. Quite a bit more smoke but, lots more power. The trucks really fun to drive, now.
Before these mods, my maximum boost was 15 lbs. , on a 30 lb. Isspro guage. With a K&N filter in the stock housing, I could slam the needle against the limiting post (30lb. ) on the boost guage. Don't really know what the actual boost was but, probably in the 35lb. range.
I have since removed the K&N and gone back to stock, paper element filters due to the K&N letting way too much dirt in. The boost has suffered a bit. Maximum boost, now, is 25 lbs. The trucks performance still feels good, though.
Anyway, I hope some of this helps you out.
Joe F. (Buffalo)