Mod to turbo intake horn

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,580
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Mid Michigan
It's an antisurge inlet. Also, It's the same reason for the resonator they installed (hollow plastic part on top center of the motor hooked to the intake). It's for silencing the whole setup. Some folks like it quiet.

So now the question is, with opening the inlet to 3" to "uncover" the ring, have we now opened ourselves up to surging the turbo that much easier?

Im just asking....I know very very little about this subject.


DS, as for the PnP turbo, yes I did get one from Merchant. Right now Im using it to fab up my new downpipe. Man, is that an interesting project......not.
 

diamondshocks

crash skippy racing
Feb 15, 2009
115
0
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Fargo, NS
www.diamondshocks.com
So now the question is, with opening the inlet to 3" to "uncover" the ring, have we now opened ourselves up to surging the turbo that much easier?

Im just asking....I know very very little about this subject.


DS, as for the PnP turbo, yes I did get one from Merchant. Right now Im using it to fab up my new downpipe. Man, is that an interesting project......not.

i think surging went the other way, much less
 

super diesel

<<<< Under Pressure
So now the question is, with opening the inlet to 3" to "uncover" the ring, have we now opened ourselves up to surging the turbo that much easier?

Im just asking....I know very very little about this subject.

Not at all Tom. It was made in the compressor housing to keep it down. The intake was set up to work as a reentrant intake (reculated back through the intake with this intake horn design from GM). Also to keep the whistle in check for those that didn't want to hear it.

This is how it works as was told to me by a turbo guru.
 
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TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,580
1,833
113
Mid Michigan
Not at all Tom. It was made in the compressor housing to keep it down. The intake was set up to work as a reentrant intake (reculated back through the intake with this intake horn design from GM). Also to keep the whistle in check for those that didn't want to hear it.

This is how it works as was told to me by a turbo guru.

Good deal! Thanks Michael.
 

07DuramaxHD

Diesel newbie
Feb 25, 2009
15
0
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Virginia
I can't help but smile everytime I read a thread like this. It definitely makes me feel proud to know there are plenty of diesel gearheads out there!
 

eds04max

New member
May 7, 2008
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Landis, N.C.
Tom, I removed the groove when I modified the stock IHI..................it created quite a bit of surge while towing...........but it's a wicked turbo on a empty truck!!;)
 

uwyo_dmax

...
Sep 17, 2008
190
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35
Laramie WY
Some things I've been wondering after looking at an LB7 turbo a bit more closely...

What exactly is the "bleed ring" around the turbo inlet for? Why not just make the inlet larger to start with?

Why would GM/IHI/Isuzu make the decision to block the ring with the horn?

Wouldnt pressurizing the air flowing into the closed bleed spaces cause the compressor to "fight" against itself?

Tom are you going to try and remove this ring?
 

DmaxFamilyMan

New member
Feb 20, 2010
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Oregon
SmokeShow, did you get someone to do yours or did you buy one that is already done? I don't have any extra time or the right tools. Please point me in the right direction. Thanks
 

dairymandev

New member
Jun 9, 2011
3
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Pingree Idaho
Hey, I just got and 03 dmax and I was looking around to see some sweet little mods. Do you still machine the intake horns out and trade them for the originals? I would really like to do this mod, I jost don't have the capacity to machine it out, unless I used a dremel or something. Also, Whay is the cp3 reg mod and the suction pump mod you were talking about?
Thank you for your help.
dairymandev
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,637
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Phoenix Az
dunno if you ever got any dyno testing done mike but i totally forgot way back when, i modded my intake horn based off your thread and did some runs before and after. granted there was some time between me making the runs, conditions were better (cooler weather with the modded horn), i had lighter tires on with the modded horn (only by 5lbs each), and it was done on an inertia dyno with 2 3k rollers. Same tuning used through out, no changes other than the horn modd and what i stated above. i was on my race tune on both runs (3100uS). Before the horn modd, i put down 465hp. after the modd i hit 480hp. the horn was cut down via a carbide bit, die grinder, 3" round flapper wheel and i polished the whole inside while i was at it. i attribute the 15 hp gain partly due to nicer weather (first run with stock horn was 105* out, second with modded horn was 85*). So i know its not in the best situations but i think its definitly good for a few HP if anything

I did notice quicker spool up off the line when i lived in Flag (where i first did this). its 7k ft in the air there. Down here in phoenix it really shinned. it definitly added a little more whistle to the turbo.