Compressor Efficiency Problem

Killerbee

Got Honey?
No. I helped Thomas.:rofl:He wanted to use pink.

Here is the old and new air slug design. I pulled every fluid flow trick in the arsenal, given space constraints. Larry, you will appreciate the flairing of the PCV and resonator ports. There is a contingent piece that eliminates the PCV in lieu of a water (or propane or nitrous) injection port.

The 100 degree bend/constriction goes from 5.4 in^2 to 10 in^2, basically cutting velocity in half, and smoothing the turbulence inducing bend.

The new design fits well in the confined space. Removes 75-85% of the restriction acording to modeling predictions (been correct thus far).

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SBCNX20

Junior Member
Aug 7, 2006
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When are they shipping? I want one!!! Are you going to make a pcv/ resonator deleted version?
 
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LarryJewell

Back with his honey :)
Jan 21, 2007
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I will have to make a decision, I'm only doing this once. What would be more important, a resonator delete model, or with the res?

LBZ, not sure about your question. If you mean release agent, I use paste wax.

I think you need to delete the resonater as well as deleting the pcv inlets :D
 

Killerbee

Got Honey?
In the present redesign, there should be almost no flow interuption with the flaring of the res port, and the larger diameter of flow area.

The tooling costs for this is enormous and I don't think there are that many people going to twins to make it feasible to produce without the res port. Like myself, I think most people want to keep the res, I'm a noise hound.
 

LBZ

Super Moderator
Staff member
Jul 2, 2007
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B.C.
Nevermind KB, I looked at a pic and thought you had the inside coated with something but it was just a pic with the plug in it!!

I like the idea of plugging all of the holes but leaving everything to appear stock on the outside to keep the dealer from asking questions.
 

TNRGreene

Kicked to the Curb
Sep 2, 2006
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Bradenton, Florida
I am keeping yours intact, I found it interesting that is was hand honed from the factory. I have spotted no other ones so far that were like yours. It is good evidence that GM knew this was a problem. I am writing articles for a mag now, and a photo of it will get into the article next year.
That is interesting, It had only been off 1 time & that was for a FPR install & it never left my shop :)
 

Ruralgas

New member
Nov 23, 2007
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Compressor Efficiency

Hello Killerbee:
I measured my tube and found that at the narrowest point (the sharp bend) mine measured 2.489". A measurement near the end that couples to the turbo measured 2.804" and at the inlet end (just before the reasonator port) measured 2.775".
After doing some grinding and hand sanding I got the 2.489" opened up to 2.755". That's a .266" increase. The 2.804" got opened up to 2.900" and the 2.775" got opened up to 2.825".
Someone had a question as to how much material you can remove and the 2.489" to 2.775" is the most you can go. I went through and ended up with a little hole, however some JB Weld and some sanding and it's good again.
The other two areas were more just clean-up so I wouldn't be worried about going through.
Next is to reroute the PCV as my turbo vanes had oil on them and a small puddle of oil at the bottom. Plus the extra heat from the engine going into the turbo can't be of much benefit for the inlet air.
Unfortunately I won't find out how this will work as winter is here and the truck won't be going outside until next summer/RV season.
I have all winter to play with it.
As for everyone else, thanks for all the info and keep more of it coming. This is very informative reading/discussions.
 

Killerbee

Got Honey?
Good deal, that quarter inch goes far.

The new piece opens everything up to 3.2-3.3". The added curvature reduces the "minor loss coefficient" in the overall loss equation.

The modeling suggests you have removed 30-40% of the restriction loss with your DIY effort. For zero cost, that is hard to beat. I don't think there is any other DIY mod that compares to the benefits you will enjoy, and as I keep hinting at, it will most benefit the heavy load tow people.

I expect an 80-90% reduction when finished.
 

LarryJewell

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Jan 21, 2007
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Will enlarging the mouth help any at all, since there is a good size lip around the mouth for the clamp, some more material can be removed here as well, I didn't see any merit in doing it, but if it will gain some more airflow, i'll get the dremel back out.
 

LarryJewell

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Jan 21, 2007
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I actually have a spare now to play with, I figured I would see just how far i could push it. I have a log of before, and a log of the 1st try, we'll see what happens with the 2nd try, give me a few weeks and i'll report back....:)
 

Ruralgas

New member
Nov 23, 2007
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Compressor efficiency

Hello Killerbee:
Looking at my tube and after JB welding the little hole a person made, I think that there is an opportunity to JB Weld the area in the sharp bend (doing this on the outside of the tube) and then grinding out the sharp angle on the inside. Looking at mine I think I could get probably another 1/4" out of that sharp bend. It would probably change the 90 degree bend to a more gradual 70 or 80 degrees? This would have to help smooth out the flow?
It wouldn't interfere with the screw clamp, done correctly.
Years ago we used to do that with cylinder head intake and exhaust ports.
Do you think this would be worth pursuing? I'll sure give it a try to see what measurments and curve I can come up with.
Thanks and I'll be waiting for your reply.
Garry