Aluminum intake manifold

  • I have been waiting months for an intake manifold, and getting jerked around. This has led to me doing research and I wanted to post what I have found.


    Please look at this pic, which shows a $900 manifold (no powdercoat)




    Now, here is a manifold that is also for an ecotec, but the log is facing the other direction. It cost $595. It is only oriented the other way because it is for a cobalt.



    Here is a kit, which cost $450 as shown.



    I removed my stock manifold, and have been taking measurements while waiting for my aluminum manifold to arrive. I have lost confidence in actually receiving my manifold, and am motivated to push forward anyway.


    In regard to the second pic I posted ($595 manifold), I am thinking about calling this company and asking them to look into making a Slingshot manifold. I see no reason they can't easily orient the log any way they wish. It almost seems like it is possible that the person I ordered my manifold from doesn't actually make them. They could have done exactly what I am thinking of doing, and are charging hundreds more on top of that. I better not find that to be the case. Proverbial heads will roll.


    In regard to the last pic, if I can't have one made, I am prepared to make one myself. I have been a machinist for 30 years, and I have full confidence I can make it happen with help from my co-workers. I have learned that the volume of the log needs to be equivalent to the volume of the engine at a minimum. I run a supercharger so I am sure I have a lot more math to do. If I take it so far as to make the manifold myself, I am also prepared to do what I have to. If I need to make more than one before I get it right, I will.

  • Oomp, I have some things on order from various companies. I'm with you on the frustration but it may not be because anyone is dragging their feet. In my experience with various manufactures it's an accumulation of supply chain complications due to corona virous that is simply out of the control of many distributors. For me, at least it's cold, snowy and the roads are filled with salt & brine. I look at it this way, at least the order is in the system and hopefully as items are manufactured I'll be first in line.


    Good luck, and I'll bet you with you experience you could make a great product!

  • Educate me, what is the aluminum manifold supposed to do?

    The Hahn version was originally designed for drag racing so that you could add a second fuel rail and get more fuel with big turbos, adapted to the Slingshot to help do the same thing as work around for adding a different ECU


    The Fab Factory version was part of their Turbo set up which was designed to help increase flow .


    I can tell you from experience and Dave@DDMWorks can chime in with more detail that the stock manifold has the best flow / much better than any of the after market versions

    The more people I meet

    The more I love my Dog!

  • The Hahn intake on my stock engine just increased the power band from 3,200 to 5,200 rpm to 3,200 to around 6,200-64,000 rpm

    Holy cow, 64,000 RPM is amazing, I bet the engine sounds amazing!! ;)


    Like MACAWS mentioned, we have tested the Fab Factory intake manifold a couple times and finally had the chance to test the Hahn intake manifold on the dyno. So far, everytime we go back to the stock plastic intake manifold, we gain power at the rear wheel. The problem with the 2 intake manifolds seems to be with the #1 cylinder runner closest to the throttle body. Although air is very light, it does still have mass and as the air comes in through the throttle body, it has a hard time making the 90 degree turn toward the #1 cylinder runner. This decreases the amount of air going into the #1 cylinder relative to the other cylinders, which basically means less power out of the engine. There are also the issue of tuned length of the runners and not matching the RPM range that the rest of the engine is running at, etc.


    We looked at doing a really cool intake manifold many years, but to really get good flow equally into all the cylinders is pretty tricky. Believe it or not the engineers at GM did a really good job with the stock plastic intake manifold. It is plastic, so it is naturally very smooth on the inside, it also has almost perfect distribution to all 4 cylinders based on CFD testing (Computational Fluid Dynamics) we did on the stock manifold.


    So from everything we have tested, the stock manifold is not great looking, but we have not see anything that tests better on the dyno. The aftermarket intake manifolds look really cool, but gain no power, if anything they typically lose power at the wheel.


    If someone has one that they want to test, let me know, we are happy to do more testing on it.


    Dave

  • I am guessing that second picture is of the Turbo Tech Racing intake manifold, I thought they did some reverse intake manifolds for the Kappa (Pontiac Solstice/ Saturn Sky) owners several years ago, so they might be open to doing it again.

  • Dave, thank you for the explanation. Yes, the picture is a Turbo Tech Racing manifold. Based off your description of the airflow characteristics, I would assume that cylinder 4 must suffer with the TTR. So, can I assume it would show the same loss of power?


    I didn't expect a big power increase with the aftermarket manifold. If it made no more power, but looked good, I was OK with that. I just wanted to add the icing on the cake so to speak, and button up my engine compartment. A loss of power sucks.


    I guess I should have sought out more information before I got into this. If I would have came across a thread and found this loss of power info, I would not have went forward.

  • Sounds like an intake manifold that feeds air into the center/side of the manifold instead of one end would do a better job distributing the air to each chamber. The only problem with the Slingshot would be fitting the center/side feed over the frame rails on the driver's side, although I haven't really tried to measure clearances in that area.

  • We've done a lot of testing on the aftermarket intake manifolds for Cobalts. NONE of them ever gain power. Most lose a little power. That is the main reason we've never made one.

    ZZPerformance EST 2000 - Go Fast Not Broke

  • Sounds like an intake manifold that feeds air into the center/side of the manifold instead of one end would do a better job distributing the air to each chamber. The only problem with the Slingshot would be fitting the center/side feed over the frame rails on the driver's side, although I haven't really tried to measure clearances in that area.

    The ones like the new 2.0L engine have work pretty well. It feeds from underneath and up into the plenum, the 2.0L Ecotec intake manifold for the turbo engines also does the same thing and has excellent air distribution also.


    There are some ways to get the intake manifolds with forward facing throttle body openings to work well, it just requires more room for the radius into cylinder #1 and different runner lengths/plenum volume. There are also some cool ways to do it that were used in Formula 1 turbo days and rally engines, but those are a little more complex ;)

  • Can we conclude that the only reason to go to an aluminum manifold is when boost levels are too high for the plastic manifold to safely contain?

    If they get that high you will need a different motor

    I think both rabtech and Kyle D have been in the +20lb range without blowing one up.

    But I am sure they can jump in to confirm or deny that fact

    The more people I meet

    The more I love my Dog!