Truck intakes, differences between them? (have 2 very different variants).

[MrHorsepowerLSx]

That is a dorman replacement manifold part # 615-183........not OE GM. It costs me $313.46 from my warehouse with no tax!!! It list for $499.99

http://c2c.activant.com/ctoc/index.j...pwBlEUVnlQBQAA

[BRAAP]

You get ready to sell it pm me a price.

If I do I'll PM you first. ;-)

[BRAAP]

That is a dorman replacement manifold part # 615-183........not OE GM.

http://c2c.activant.com/ctoc/index.j...pwBlEUVnlQBQAA

Ah hah... Thank you.

[MrHorsepowerLSx]

No problem case closed lol

[kerrige]

Haha wth? Weird they would do a completely different design like that.

[Mickeymotormount]

Here's one for sale around my way.

http://southjersey.craigslist.org/pts/3570780619.html

[jansen]

If it'll come apart where it could be ported there has to be some performance gain... and it looks better!

[Oldspimp]

Why would dorman take it upon themselves to completely redesign the truck intake? The intakes they make for the GM 3.8L motors are almost identical. Haha It does look good though and I wonder if there is much of a difference in how they perform, maybe more torque from the taller longer runner shape...

[kerrige]

Dorman intake rockauto price: $261.99
ACdelco intake rockauto price: $218.79
So weird to have the knockoff be more expensive, but the design is a little nicer no doubt about that.

[BRAAP]

First off, thank you to all for your help in identifying this intake, that portion is closed. Now, is this Dorman intake an upgrade or not?

DISCLAIMER;
As a professional engine builder/machinist/tuner since the late ‘80’s specializing in custom cylinder head work, from a closer examination I have some theories regarding these intakes, though take it as just that, “theories”, nothing more. Ones advice is only as good as their experience, my experience with both of these intakes regarding their ability to breathe and make power is basically NIL, (do own a ’01 Suburban 5.3 with ugly intake that we have put over 240,000 miles on but not a performance application, my LM7 and LQ4 peered M3 had the car LS1 intake so neither really count), so take my theory with a grain of salt. Hopefully someone will perform actual dyno testing to prove or disprove. (Also have LS1, LS6 and LS3 intakes on hand, only spent time looking over and measuring the OE truck, Dorman truck, and LS6 intake)

Disclaimer out of the way, looking closer at both the ugly OE and pretty Dorman truck intakes a few things stand out. The most obvious is 1) Aesthetics. In the eyes of most, the DORMAN is more attractive. 2) Air flow pattern/direction within the intake itself, and less obvious without looking in the intakes, 3) Plenum designs.

1) Aesthetics. Beauty is in the eye of the beholder, purely subjective. I’m sure there are some that would argue the OE intake is a visual work of art, others would say it looks like a tumor. Regardless, with the hood open and intake cover removed the Dorman has a sculpted design vs the organic, (not sure that describes it) OE intake.

2) The Dorman air flow path is more like the car intakes in that the plenum are routed "over" and outside of the plenum space, OE truck intake runners are routed "under" the plenum space. In looking at the air flow path of the runners alone from elevation view, both look to be decent, no sharp radiuses and the transition into the port of the head is nice and relatively clean, from the perspective the air sees this tract, one continuous curving flow path. Overall runner length appears to be equal between OE truck and Dorman truck. Runner cross section is a little different. Dorman has a bit more cross sectional area vs the OE. Pic below is rendering of the OE truck with chart of the height x width and square area oat those points measured, (using snap gauges and dial caliper, +/- .020"), DORMAN truck and LS6 as measured at head flange and at 1” intervals from the head surface. One thing I find fascinating is the shape of the DORMAN runners compared the FAST car intakes. VERY similar, yet the FAST truck intake runners are more of a straight shot from the head.













3) Plenums. Two totally different approaches to plenum design here. The OE at glance appears to be a convoluted dual stage plenum. I’m sure the engineers have their reasoning for it, my guess is for “aural” reasons like the Helmholtz resonator protrusions addd to the OE intake ducting, again just theorizing here, I have nothing to support this. The OE plenum utilizes a primary and secondary plenum. The primary section is the tube that is essentially the diameter of the Throttle Body ID and runs back approx ¾ the length of the manifold, at the back is a small hole, in the roof of this tubular primary plenum is a slot that feeds the secondary plenum. Found a shop on LS1tech that is taking the UGLY intakes and cutting the top off and their “porting” involves removing the roof of the tube so as to create a single plenum with nice radiused transitions from plenum to runner entry. Dorman plenum is a single huge by large cavernous plenum, generous radiuses on the runner lead-ins, simple. :-)





In summation of my not so humble opinion, for a stock or even mild 4.8-5.3L the OE intake is probably fine, might not realize much gain if any, especially seat of the pants. For performance oriented 6.0L that wants/needs to retain a truck intake I wouldn’t hesitate to go for the DORMAN. For power production it looks like it will outperform the OE intake and hold its own against the FAST car and truck intakes. I don’t think the DORMAN will outperform the FAST intakes but at less than 1/3 the price of the FAST for what could easily be at least 75%+ the gains a FAST delivers, the DORMAN looks to be a viable option.

Now someone please take your 6.0L, optimize fueling and ignition timing, dyno it, swap intakes, optimize again and dyno again and let us know if indeed the DORMAN delivers.


Here are some pics of the UGLY stock, and ported by PeakSpeedShop;








FAST truck intake with the cover removed showing the runners. Note how much straighter they are vs the FAST car intake runners pictured above;




One last bit, the DORMAN is multi piece intake, was gonna take this one apart for pics though the screws under the base are sealed, surrounding plastic is melted around the head of the screws chose not to to retain the factory seal.