on my truck i cannot hear any turbo whistle. it has a new vac pump because the old one was shot and new vac lines. the only way i can hear it is if i put my head next to the hood and have someone play with the throttle a little. why is this?




p.s. i am thinkin about gettin a pinnacle 4" exhaust to give it a little rumble and let it breathe. how much louder is this? (a sound clip would be awesome:D)

You may have difficulty hearing your turbo at idle. It is best heard while going down the road. Go through the diagnostics and make sure your turbo is working. Go here for information on that. (http://dieselplace.com/forum/showthread.php?t=39368)

With a bigger exhaust, sans soot trap, and higher than stock boost levels (put in gauges first), you should hear the turbo spool right off idle.

even while going down the road i cant hear anything. i thought i read a thread about a turbo muffler or something? any info?

After installing my exhaust I like to go fora ride with the customer and un the passengers window down so they can hear the turbo whistle reflect off of parked cars and buildings...

Your '96 has the square filter in it right? IIRC, 97 is when they went to the round air filter with the 'turbo muffler' on the turbo inlet hose.

If I'm wrong, and you do have the round filter, then you should see a plastic tube about 1½" dia. sticking out of the turbo inlet. somebody was saying they removed it and put a freeze plug in its place.

To hear the turbo whistle you have to install a bigger exhaust and remove the soot trap. I have a 3" mandrel bent down pipe and 4" with straight thru muffler. With light throttle you can hear a noticeable whistle from idle to about 1600 rpms then exhaust tone covers it and engine noise up. A little more throttle and harder acceration will cover up the whislte though.

I did hear significant whistle when I was driving over to the muffler shop with only the factory downpipe and no exhaust pipe (that really was a fun ride). It sounded good and was not too too loud like that. With 4" pipe its louder than stock but not bad. Its hard to tell someone about the noise level but here is my try: my truck with new exhaust is quieter than a V8 CJ Jeep with headers and side pipes (round mufflers that exit in front of rear tire). It does drone a little at highway speeds though. I can go through a really good drive through but on most I have to turn truck off to order.

To get more whistle you can open up the air box (with big holes or use an aftermarket box) and maybe try a K&N or similar element. (But you then suck in hot under hood air and thats another discussion). The 6.5 is not really an air hog so it won't ever be real real loud.

To hear the turbo whistle you have to install a bigger exhaust and remove the soot trap. I have a 3" mandrel bent down pipe and 4" with straight thru muffler. With light throttle you can hear a noticeable whistle from idle to about 1600 rpms then exhaust tone covers it and engine noise up. A little more throttle and harder acceration will cover up the whislte though.



I get the opposite. It's noticable at idle with a change in pitch off idle to 2200, then the whistle picks up a notch and sounds like air blowing at 10-15 psi.

Interesting QM I bet the boost level makes a big difference ( I am stock what maybe 3-6lbs not sure (don't laugh I can't afford guages yet) BUT more so maybe our muffler differences is the key?? Mine is a straight through design but it has little standouts in the flow like little hills that are hollow on the exit side. It has a deep throaty rumble and grumble tone that I think covers up the whistle at higher RPM (~ 1600 -1700 +). Are you running straight pipe? I would think with straight pipe you would get a lot more whislte especially with more boost and not necessarily loudness ( the turbo muffles the exhaust pretty good). Man straight down pipe sounded like a big rig but that was exiting much closer to the turbo too?????

I can make out a turbo noise sitting at idle, and when you drop it in gear and/or turn the AC on, it even kicks up a notch.

No kitty, more whistle. :) Makes the bus sound great. Took the guts out for a Cat "decoy" and you can hear the turbo. Pop on the high idle switch, and you can hear it.