Yep so I read, very tedious. When you did your HR OEMs any fitment issue\pipe touch on driverside steering linkage?

 

they do not touch anything. on my 05 G35 Sedan I did have to remove the steering link to install them, once installed they do not touch at all. lots of clearance. put on the oem heat sheilds too so under hood temps would not go up.

 

Interesting support from popularhotrodding.com


Exhaust Systems
Rule number one when it comes to exhaust systems for nitrous-equipped cars is that the system should not look like a cork. When the nitrous comes into play, it creates a lot more exhaust volume. If the system has a small amount of unwanted backpressure (and all backpressure in an exhaust system is unwanted), it can more than double when even a moderate nitrous system is activated. One example is a test on a stock 5.0 Mustang where a 125hp nitrous system, which increased rear-wheel horsepower by 102, pushed the backpressure up by 280 percent. With a baseline output of 221 rear-wheel horsepower off-the-bottle and 323 on, the stock cat and muffler were replaced with high-flow items. This pushed the output to 227 rear-wheel horsepower without nitrous, and 341 with it. With the nitrous on, the higher-flowing cat and mufflers were worth 19 more horsepower at the wheels.


Now let's talk about headers. First, header size is critical to the performance of a street motor when the nitrous is not in action.


If the headers are too big, performance suffers measurably at the bottom end (not good for an automatic with a tight street-style converter), and may not redeem itself by the time peak power rpm is reached. But when the nitrous is introduced, the previously optimal exhaust is now too small. A typical 350 Chevy making between 350 and 425 hp is best on a 1 5/8-inch primary header. At around 475 hp, a 1 3/4-inch header is ideal. Injecting 125 hp into even a 350-horse engine is going to move the header requirement to 1.75-inch diameter for best results. The big question is, at what point should the header size be stepped up, and when? First ask yourself what is most important: power with the nitrous on, or off? If it is nitrous-on, then the exhaust pipe needs to get larger by about .125 inch more than the primary diameter for every 150 hp of nitrous optimal without the nitrous.


Read more: http://www.popularhotrodding.com/tec...#ixzz2J0cu7AZV

 

I wonder what the runner size of the stock headers are comepared to the PPE or OBX long tubes?

 

I have the crappy DE log manifolds+HFC on there now, going to Swain Tech coated HR OEM equal lengths+TP....so for me I am sure I will get some whp under N2O conditions and slight bump NA despite the restrictive 240 cam as I will be more free flowing.

HR Headers (on VQ35HR cam\VVT) to LTH might really magnify gain under spray as those do good under NA conditions alone tuned, but I have yet to find a dyno sheet of those under N2O conditions.