I think I figured how to post a pic. This is a pic of the outlet pipes. Hard to tell but the rusty one is smaller at this end which is bizarre since it has the larger inlet tubes.

Great question. Anyone?????

Looking at your pics again I think you're right. Which one do you think has the better flow and/or sound? Smaller inlets/larger outlet like the one you have or larger inlet/smaller outlet? Or at this point have we beat a potentially meaningless difference to death?

It is all about exhaust tuning which is why you would find different parameters among pipes from the same VQ family but different variants.

Not to complicate matters, but if you take a picture (with flash) of the merge collectors, I bet that you will find slightly different design on the 3 "HR" ypipes....

If the one that looks the HR G35 has roughly 2" inlets and anywhere above a 2.35" outlet - I'd go with it. It has the improved flow design and inlet/outlet diameters that have been proven to work. This should be very close to the 350z HR Y pipe, both cars have the VQ35HR engine.

I have the G37 Y on right now and I'd like to compare it with a 350z HR before I recommend it to others. It has improved the low end, and upshifts smoother. It also downshifts with less effort, I don't have to mash into the throttle to get it to drop down like I had to with my stock DE pipe. But I am wondering how substantial my top end sacrifice was due to the smaller inlets.

I found a 350z HR y pipe and I should have it within the next few weeks. I won't be doing a dyno, but I'll be able to directly compare the G37 Y to the 350Z HR. I'll post my results

Keep us posted

Thanks. My y pipe came off an 07 Z and was worth the 20 mile trip to pickup too. As for the name, I always thought it was known as the Y pipe. If you can search for the service manual, you can find out the actual technical name.

Otherwise they should know what you're talking about when you call your local parts person @ the dealer if you chose to go that route

alright cool ill get that one, basically an HR Y pipe.. hopefully it would fit on an 06 revup (i assume the exhaust parts are still the same as non revups)

I believe the exhausts are exactly the same.

Looking inside the 3 I have, they are quite different.

That's my thinking as well, and let us know your results.

All of these exhaust parts bolt up together. If you have 3 different Y pipes, you can swap them out at your leisure and see which one works out best.

wish i could find one of these fricken HR y-pipes for a decent price

dang who would of new that there are so many Y pipes.

im guessing as one stated before, its maybe due to the design of the factory exahust set up.

i enjoy my hr ypipe from the 07z i got it from. now combined with mrev2/spacer and exhaust, my car feels incrediable.

I paid 100 for mine....keep searching. The person I bought it from had just installed a Borla true dual shortly before so I lucked out.

Keep your eyes peeled...deals show up all the time

-Mike

actually i just got pmed from a guy on the z forum saying if i wanted to buy his hr ypipe. i think he got me mixed up with someone else, cause i already have one.

well i went to Glendale Nissan and asked them for a HR Y pipe they quoted me 435....