A few months ago I bought a 1992 Cheyenne C2500 TD with 5-speed manual trans. It has the L65 engine with mechanical fuel injection. The odometer shows 089,200 miles.
The engine seems to be underpowered, and I don't feel any turbo surge like I'm used to feeling on other turbocharged vehicles, nor do I hear any turbo whine. Fuel economy is good, averaging 20-22 MPG unloaded, and the engine runs and idles smoothly (I also recently replaced the air and fuel filters). But the damn thing seems underpowered, and accelerates with about as much gusto as my old 1983 non-turbo 6.2 diesel K5 Blazer, which was pretty lame. Unfortunately, I don't have access to another like vehicle with which to compare performance.
My questions are these;
1. Are you supposed to be able to feel the surge when the turbo boosts?
2. Does it whine loud enough to hear?
3. Is there any way of checking the turbo to see if its properly hooked up and working?
Thanks in advance for any suggestions...

Read this, it will show you how the turbo works and what parts to check.

www.dieselplace.com/forum/showthread.php?t=39368

Does it smoke. black? If not its probably working. You can put a boost gauge on it to check. You really cant hear the turbo to well on these trucks, just barely ever so often when everything is just right, not like the newer diesel pickups.

I'd leave it alone if it isn't blowing black smoke, as the fuel mileage is good, you might let the magic out.

Check all your vacuum tubes, make sure there are no leaks or frayed tubes.

92 is not a vacuum system for wastegate. Unless there's been some changin' under the hood. Spring wastegate in 92. Plug into the computer with scan tool of some sort, or hook up a boost gauge to the manifold. You'd have to drill and tap that into place. Those two would be about the best way of getting data on the subject.

Clogged soot trap, leaking intake and exhaust manifold, dirty air filter, etc, will hinder boost building too.

Turbo should be heard to some degree... sometimes better with window down in town...

92 should not have a kitty (soot trap) but does have mechanical wastegate controller....and is easily converted to a Turbo Master type setup where you can adjust manually or you could just buy the Turbo Master.

You probably will not hear the turbo until you open up the exhaust and/or intake.

Mine is 3.5 inch straight pipe (no muffler)out the right rear, at around 1800 rpm's she whistles pretty good, especially when letting off the throttle to shift gears....it's nothing compared to the turbos on the newer trucks.

Thanks to zman17, midniteplowboy, jmjnet, knkreb, and odlaw, for taking the time to respond to my questions.
I would still like to know if you can feel a surge in acceleration when the turbo kicks in, because I don't get any with mine...

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1992 Chevy Cheyenne C2500HD, L65, 5-speed, std. cab, bone stock, 89K mi.

My setup is the same as yours. No surge with turbo.

These are not gassers. The turbo only packs more air into the cylinders so more fuel can be burned. If you aren't smokin black, the turbo is working.

Spend the 50 bucks and put a boost gauge in and know what your turbo is doing.

BTW, what is your rear end ratio?

I noticed the same thing on mine, but it must have been working while pulling a heavy horse trailer, uphill passing other cars. I could never hear the sweet sound like the new ones.

The GM-x series turbos are smaller than what they should be. They are wastegated, and slightly small for the application for quick spool up. So, you may not notice the "surge" because she's already turning... in fact it'll start to dump boost via wastegate.

x2. It's a 6.5 not a dmax. It's not going to throw you back in the seat. Not a whole lot of power difference than a 6.2. I 've owned both and yes there is some but not neck snapping like my old powerjoke.

No sudden burst of power...but without boost acceleration is kinda boggy and slow