Tech / Tech Articles

Quick Test: Dyno Testing Dorman’s LS6 Intake Manifold

Ask and you shall receive, LS fanatics.

You’ve continued to express a strong demand for the old GM LS6 intake manifold. That’s because the one-piece Nylon intake has always been a quick and dirty upgrade that could bring an instant 15-plus horsepower gain to a hot-rodded LS1. Unfortunately, GM recently stopped producing LS6 intakes—and they’re getting really hard to find.

That’s where Dorman comes in.

Dorman now offers a replacement LS1/LS6 intake manifold that runs just shy of the original LS6 power numbers. It’s a sturdy, good-quality piece that even comes with some extra material around the ports to accommodate some mild porting.

Some of the LS (and even non-LS) forums have taken notice of the Dorman intake and asked for power numbers. So Trick Flow Specialties recently tested the Dorman intake on one of its LS test engines. They also swapped out the intake and tested an original LS6 manifold and a FAST 92mm unit to get a good comparison.

You can see the results below:

Fast v LS6 v Dorman

The Dorman LS6 replacement intake manifold (denoted by the red line) delivered nearly the same power as the original LS6 (blue line). Both the original GM LS6 and Dorman intakes were mated with a 78mm throttle body; the FAST manifold (black line) used a 90mm throttle body for its test. The engine also sported a set of Trick Flow LS cylinder heads, which were being tested.

Dorman says it also has a 90mm LS2 intake in the works that will be a true performance upgrade for the LS1/LS2 manifolds and an improvement on the original LS6, too. The bottom line is less scrambling (and less money) for LS enthusiasts looking for that quick LS6 power upgrade.

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  1. why didnt u test it against the original ls1 intake .. because all i know now is the dorman is a little less than the ls6 .. but i dont know how much better it is than the ls1 … if its just a little better… and depending on the price.. i might not be interested…. but if it was a good bit better than the ls1 and a good price i would be interested…. people with ls6’s dont need to know how much less it is .. ls1 guys need to know how much better it is than ls1 stuff ..

  2. Should have compared it to an LS1 intake..

  3. Agenda driven comparisons like this mean nothing. The whole thing is a fraud designed to advertise Trick Flow heads. I don’t use Trick Flow so I can’t condemn or praise the heads themselves, but it’s obv the company feels it’s necessary to use trickery self promotion to sell products.
    It’s one thing to advertise your products and inform people why your products are superior. But this is an act full of deceitful intent and misinformation.

    The Dorman manifold is not a LS6 replacement manifold. it’s an aftermarket universal fit manifold designed off the LS1 and LS6 parts.

    The truth is all three manifolds LS1,LS6 and Dormans flow within a few percent of each other. we have found some manifolds do make a little more power then others but they are not all LS6 manifolds. Several of the 2000 and up LS1 manifolds were among the best performing.

    These results were confusing at first because the best performing were not always the best on the bench. It wasn’t until we looked at the injector port that we found the answer. sometime in 2000 GM made improvements to the injector port seat and flange resulting in more precise injector angle and elevation.
    The more accurate injector location provides better atomization and more power.
    However were only talking 3-8 horsepower difference on a stock 2002 ls1.

    My suggestion is if you have a 2002 and up manifold keep it. If not then maybe pick up the Dorman or whatever you find reasonably priced.
    Don’t waste your money on the LS6 intake. If it was superior you can bet GM would not have discountinued it.

    Take some time to make sure your injectors are all seated properly, with good o rings and spend your money in different areas. When you approach 450 horsepower then look into the aftermarket performance manifolds.

    It’s a shame this information is not common knowledge among enthusiasts. Money is hard to come by these days.

    • Wow I thought something was wrong with my car but now it makes sense. I put a ls6 manifold on my 2002 Camaro and lost a mile an hour and few hundreds in the quarter mile.
      13:98 with original manifold and 14:02 LS6.

      It sucks that I spent all that cash on ls6 manifold.

      • Yea don’t feel bad Fonze I did it too and slowed mine even more. I kept thinking maybe intake was not sealed correct but I had it on and re checked it twice. It’s bullshit. I’m pissed. I took off better part.

      • Ronster Tuning says:

        I’m willing to bet the weather was different on both of those days as well. Density Altitude or DA for short, plays a big role in performance. For example, 800′-1000′ of DA change would change the car’s time by .1 sec and the same mph.

    • Like a 2000 and up Camaro that came with the ls6 intake manifold. I’m 4 years too late but the know it alls that dont know shit are still around.

    • Finally someone with common sense.

  4. 01-02 LS1 f body cars came with the LS6 intake already on it.

  5. early ls camaros, 2000 to about 2005 cost little and are ready to race after a curry style rear axle change. the cars look good too.

  6. dustin west says:

    they didnt make camaros after 02 until 08 i believe. and 01-02 camaros had a ls6 intake on it already. so you swapped out the same intake for the same intake you had…idiot

    • Dumb fuck they are different manifolds LS1 vs LS6

      • He’s saying that the guy swapped his 2002 Camaro’s intake for an LS6…the 2002 Camaro already came with an LS6 from the factory. 01 and 01 Maros had the LS6 as a stock intake. So yes an LS1 is different from LS6 but the last ones of the 4th gen F bodies had LS6 already. So the guy swapped for the same intake.

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