How restrictive is the stock midpipe
 

I did a lot of searching but couldn't find a good answer so I am putting it up for discussion. I know Nameless decided to only go with an axle back because they didnt find much gains in the mid pipe but what are others results?

Would it be smarter to save money and just go with an axle back and then save for a front pipe/over pipe? Has anyone gone from an axle back to a cat back and noticed any gains?

Thoughts?

Fluid dynamics states that best results (however minimal) will be seen when the size of the channel (in this case, the pipe) is consistent throughout and as strait as possible. Most axle-backs are 2.5", while some are 3" and the greddy unit is 2.75" OD. I forget the stock mid-pipe OD, but it's somewhere around 2.15 or something, which is tiny and when mated to a 2.5"+ axle-back, results in turbulent air flow. With that said, the exact gains from having consistent sized piping will depend on things such as the way the pipe is routed (number of bends, etc..) and the shape and construction of the muffler. With that said, unless your build is purely aesthetic, then you should strive for piping diameter that is consistent as possible.

The only cat-back I have direct experience with is the FT86SpeedFactory V2 single-exit cat-back. It's 2.5" (which has the most aftermarket support) and has the straitest mid-pipe I have seen for our cars. Being single exit means less turbulence and, theoretically, should result in better flow, thus better gains. I have no dyno sheets or anything else to go by other than pure speculation since I do not know how the muffler was constructed, but my gut told me it was the best choice for a functional cat-back. Again, if aesthetics are of a higher priority, then you probably don't want the single exit design.

To summarize, the answer to your question depends entirely on your goals and personal taste.

This is kind of how I felt, thanks for the extensive input.

If I had to guess I'd guess that replacing the ~2.12" mid-pipe with a 2.5" pipe should add 2whp. More with supporting mods like FI.

here is a comparison of a stock midpipe vs. a modified midpipe

http://i1053.photobucket.com/albums/...DBA11E9EA5.jpg

http://i1053.photobucket.com/albums/...DBCFEA481F.jpg

my test car showed 5-6 hp gains with the modified mid pipe


click here for more info ---> http://www.ft86club.com/forums/showthread.php?t=24472

and here to order ---> http://www.86-zn6.com/WORKS-EXhale-M...aust_p_50.html

I was wondering samething as OP. hmmm i still can't decide if i should go with full-catback or axleback

I'm going nameless axelback with that works midpipe.

for what it's worth, Nameless said.....that the original mid pipe is lighter and has the same performance as the midpipe Nameless built and tested.

Nameless recommends using the original mid pipe which is what I did.

Nameless axle back + nameless header back front pipe with high flow cat.

dyno numbers coming soon.

please let me know the numbers, I will probably be going nameless headerback>stock mid>greddy sp elite. I imagine your numbers will be slightly higher

let me know when your ready to get the midpipe. ill hook you up with a good deal :thumbsup:

Even so.....I'd feel more comfortable having a full 2.5" system haha. Can't hurt?

correct, just knowing it's there is part of the fun.

In terms of performance the stock midpipe is ok, unless you go turbo with high boost (300+hp).
The real bottlenecks are the cats on the headers and front pipe.

I feel you bro. I'm gonna contact nameless and see if they will fab me up a mid pipe when I order. If not... Well Works it is.