I was going to upgrade to the BD Twin Turbos so I needed a stronger
more reliable exhaust manifold to replace the stock manifold. My stock manifold was just fine, but the problem that a lot of people have is that after they add a certain amount of power, the stock exhaust manifold will crack. In some situations people are not even adding horsepower and their stock manifolds crack.
The ATS Exhaust manifold is designed with a pulse manifold design which eliminates the problems with shrinking and breaking as well as cracking and gasket issues. The ATS design helps to increase turbo spool up faster with less exhaust backpressure with a slight increase in fuel economy.
The installation that I'm doing is going to be a little bit different than a normal installation because I'm going to be installing twin turbos. It is very important to realize before installing the new manifold, that the manifold must be installed inverted(upside down) to accomidate twins. I did not know this before I reinstalled the new ATS manifold and had to uninstall it as soon as I began the Twin Turbo Install. That cost me more time than I wish to admit.
Here is a picture of the old exhaust manifold that I removed. The first step is to remove your intake and then your turbo. In this case, I removed my Volant aftermarket intake and my BD Power Super B turbo so that I would have a clear shot at changing out this manifold. I also removed the clamp that attaches the 2 metal coolant hoses together that run right along the manifold. This will make the job much easier.
Unbolt all of the bolts attaching your manifold to your block. I would make sure that the last bolt that you remove is easy to get to. In fact you may want to unbolt the manifold from the back to the front. The last bolt or two are always the hardest to remove because of all of the pressure that they have on them.
I really recommend that you purchase a new gasket kit. Make sure that you scuff the outside of the block around the holes with some mild sandpaper. This will help the new gaskets seal better and also help scrape away some of the old exhaust crud that might have got in. I would also vaccum out the holes to make sure that you dont have any dust remaining. They say the little dust wont hurt your turbos, but I like to be extra careful and you might as well because you are there anyways.
Before mounting the manifold, make sure you know wether the outlet is to be facing up or down. If you are changing the manifold and still using a stock or single turbo, have the manifold outlet pointing down. If you are upgrading to the BD Twin Turbos like I was, you need to have the outlet pointing up.
Put one of your bolts in with a gasket hanging on it and install the manifold. After you put in that first bolt and gasket go ahead and install the additional gaskets and bolts one at a time. Make sure not to forget any gaskets and try to line up all the gaskets as best as possible before tightening.
Make sure that all of the bolts are tightened to the installation manual's specs(I lost mine and forgot). Install your turbo and intake in the order that you removed them.
There you go! Your exhaust temps should be cooler, your turbo should spool up faster and you should maybe even see a little glimps of fuel economy increase. I cant really tell what all this did directly for me because I also installed the twin turbos at the same time.