IraPatterson

Hey Everyone,
I am out of college for the semester so I hope that I can make it here a little more often... With it being Christmas and all I have no money, however, I have been itching to work on my truck and I just have a couple of quick questions.

Would it be worth it to somehow by-pass the silencer ring on the turbo intake? I do realize that it would have a lot more under the hood whine (which is fine by me). I just always thought that that silencer ring would stop or slow down a lot of air going into the turbo. I do realize that I would be better off swapping my entire intake housing for one off an 89 or 90 (unless somebody knows a trick that I don‘t), I am just curios about the airflow for now. Also, if it WOULD call for better airflow (if you by passed or did not have the silencer ring), would it be better to have 4” tubing and neck it down at the turbo, or neck it down at the box and have 3” tubing running to the turbo?

My next question is with the air intake tube going from the filter to the turbo, what would be better? A straight shot with small bends (Like this: https://www.dieseltruckresource.com/...d.php?t=115802) or a longer, sweeping bend similar to the factory tube. I was looking through my gold dredging stuff and found a scrap piece of 4” suction hose (the clear hose with white, spiraling reinforcements; completely smooth on the inside but rippled on the outside) and that is what got me thinking. My factory hose ripped so I need to replace it anyway, but I also noticed that it has many places for air to be trapped (the inside of the reinforcement ridges).

One last thing, then I promise to let you go. Would there be any advantage to increasing the size of the tubing going too and from the intercooler? Keep in mind; I am just talking about the tubing from the turbo to the intercooler, and from the intercooler to the intake. My thought, is that if you had bigger tubing in these areas, it would slow down the airflow allowing the air to cool off more before it entered the engine.

Thank you so much for all your help. Everybody here has helped me immensely since I have joined and I truly appreciate it.

gman07

No silencer rings on these trucks; that started in '94.

I don't think you'd see much advantage going to 3" piping without upgrading the intercooler as well.

G1625S

Yup, no silencer ring to remove on our old trucks IMHO, upgrading the intercooler piping would be negated by the fact that it necks back down to 2.5'' at the intercooler itself...The intake piping you in the thread you linked to is pretty common and works fine at many power levels. Where the bends are and how severe they are I think is splitting hairs--look at a second gen intake tube and you'll see a bend!

IraPatterson

Then how come my Dad's 89 has a 3" opening on the turbo intake, and my truck has a 4" opening on the turbo intake? Also, the turbo whine on my Dad's pickup is MUCH louder. Maybe I am calling it the wrong thing then, but my truck as a 4" inlet on the turbo intake. The actual opening to the impeller is only 3" and the 1/2" diameter around that is just aluminum. My Dad's truck just has a 3" inlet straight into the turbo impeller and nothing else.

Thanks again for all your help.

Micaiahfied

i've got one of each, you will hear the 89's called a "baby h1c" and the 91.5 and later are just h1c. you shouldn't hear any more "whine" with his.

dpuckett

Your dad's probably has the 18cm housing, while your 92 came stock with a 21cm housing. Add to the equation more fuel from his 89 (78 vs74mm/ stroke at full throtle), shorter wheelbase if you have a club cab, and you will have a little more whine from the turbo.

Putting on a "baby" H1C would be taking a step backwards for you- your impelar is 54mm, the 89 is 50.

Daniel

IraPatterson

Thanks for the information. My truck did indeed have a 21cfm exhaust housing when I got it, but I already replaced that with a 18cfm when I rebuilt my turbo.

I truly appreciate all the help and information.