i was just wondering how restrictive the stock headers for 5.0 gen are compared to aftermarket headers. thanks.

 

The Maxima doesn't come with headers, it comes with exhaust manifolds. Aftermarket headers are less restrictive, which is why they are installed to add power or free up power (however you want to term it). You can find some valuable information in regards to headers just by doing some research on the net by simply searching some of the manufacturer's sites.

 

yes, i just worded it wrong... How much less restrictive are headers over stock exhaust manifolds that 5.0 gen maximas have? can stock manifolds still be used in a turbo setup (will the flow be good)?

 

You may want to consult this link & section in regards to turbo setups and questions.

 

If you run a turbo setup, you'll be producing a higher volume of exhaust gases than you do now. A lot of 5th gen owners leave the stock exhaust manifolds in place and get an aftermarket y-pipe if they plan on staying naturally aspirated, but you're not gonig to be able to do that with a turbo setup. The stock exhaust manifolds on a 5th gen may flow decently for a naturally aspirated car with bolt-ons, but they will not do a good job of handling the increased amount of exhaust output that you'll be pushing with a turbo.

I'm basing this claim on the fact that the 5th gen (VQ30) and the 5.5th gen (VQ35) have roughly the same exhaust manifolds, even though the 5.5th gens have half a liter more displacement. 5th gens respond well to aftermarket y-pipes, and they also respond well to headers, but the gains with replacing the headers vs just replacing the y-pipes aren't as impressive on the 5th gen as one might think. The story is different for 5.5th gens. Since they have higher displacement, they produce more exhaust gas, and they benefit much more than 5th gens from replacing the headers. This demonstrates that while the stock exhaust manifolds flow relatively well for a naturally aspirated VQ30, increasing the engine's displacement by just half a liter will take the stock manifolds to their limit (some would say beyond their limit) from a performance standpoint.

If you turbo your VQ30, it will increase the volume of your exhaust gas as if you had a larger engine under your hood. The stock exhaust manifolds probably won't cut it.

Having said all of that, there is a simpler reason why you probably can't use the stock exhaust manifolds OR aftermarket headers. I've never worked with a turbo setup on a V6 or V8, but my experience with I4 engines tells me that you're going to need a custom-fabricated exhaust manifold to harvest the exhaust gas and run it through the turbo itself. Somebody correct me if I'm wrong, but I think that buying aftermarket headers would be a waste of money if you're going turbo, because you can't use them with a turbo setup anyway. Take a look at some of the aftermarket headers available. They replace everything from the stock exhaust manifolds all the way back through the y-pipe, and they stop at the main cat. Where are you going to bolt a turbo into that?

 

you recerse the y-pipe right after the firewall bank of cylinders joins it and get it to go back under the hood...