Stillen exhaust piping diameter ?
 

Are most exhaust applications for our cars using 2.5 or 2.25 ?

Also whats the diameter of the piping on the Stillen CBE...I already know the tips are 4.5

Thanks

2.5 - nevermind :)

i think i read somewhere that it varied from 2.25 to 2.5 since it had different pieces
and that it would have produced more power if they stayed 2.5 all around

Written by someone who has no experience building an exhaust for a 370Z. The piping size does vary, by design, tuned for maximum power.

:)

LOL - GG Josh...

but seriously i think its 2.5 into 3ish in the center back out to 2.5..

lol not my opinion i just read it
and i found the thread for it :D
http://www.the370z.com/engine-drivet...html#post71932

I think an ex Nissan engineer, me, has a bit of experiance with designing exhausts and tuning Nissans.

So you work at technosquare now?

Good to have an ex-nissan engineer on the board then... what area were you assigned to ? how long did you work there ? nissan corporate or the sales / marketing division ? new vehicle design, aftermarket parts (nismo), dealer support, or something else ? lots of engineers around here... i'm sure most will tell you they keep their expert opinion focused on what they know... so, were you working on thermal management and emissions?

Awesome.. So I'm sure in your tenure with Nissan and being an Nissan enthusiast you would be familiar with Steve Millen, his enormous success with Nissan with the IMSA Sports Car Series, and STILLEN's longstanding devotion to creating quality products, especially for the Z cars, where countless hours of R&D have been allocated to create, dyno test and tune (both for horsepower and sound) products such as exhaust systems designed to provide maximum power at a competitive price.

We always appreciate editorial on our products, and are always open to discuss our process (within reason, some things must remain in R&D to not hand the keys to the castle away.. ), a simple phone call could have assisted in some background information on the exhaust design.

Making assumptions on the design elements and their reason for function, without doing extensive development testing to back the statements up, borderline as irresponsible as the general consumer can interpret that statement as fact, such as what you've seen happen in this very post, due to the story you've written and the liberties you've taken.

That's also fueled by the inconsistency in every other dyno being run by numerous forum members, including the results from the owner of the other 370Z tested at that same facility, on the same dyno.

So in regards to the specific caption from your article.. "The Stillen 370Z exhaust goes from 2.5 inches in diameter to 2.25 inches and back again in several places along the flow path. If it were 2.5 inches all the way through, it would make more power" is incorrect and irresponsible, the exhaust was designed as is for a reason, and a good one, horsepower and tone.

My statements are based on making an assumption in saying you have not designed a specific exhaust system for the 370Z and have not tested the effects of tubing sizes and their effect on power and sound.. if I'm incorrect on that point I apologize.

That's why I have a Stillen exhaust and intake! Race breed parts!

No I help run 370z.com and am working on several other webzines that will launch over the next few months.

I worked at Nissan North America as an engineer for 18 years and at TRD for 4 years before that, two of those years were as an engineer. I was also engineering editor for Turbo magazine and a contributing editor for SCC magazine for many years. At Nissan I worked with the accesory group and was one of the orginal Nismo team members bringing Nismo parts to the US. I was activly involved with the development of US specific Nismo parts and adapting JDM Nismo parts to the American market.

I have been tuning and racing Nissans for most of my adult life.

I have been a friend and supporter of Stillen for many years and have used high quality Stillen parts in many evaluations I have written for many magazines over the years. Stillen has always helped me in providing support for my editorial and racing endevors.

However, I call them as I see them. I always have, otherwise an article would seem like a catalog discription for Stillen and not a neutral observation. Although the Stillen exhaust is a good high quality piece which I stated in my editorial, in my opinion it can be improved upon. All designs including every single thing I have designed can be improved upon. Stating all of somethings attributes, good and not as good gives more crediabitly to a part than if it was an all sunny review heaping praises like a piece of ad copy.

As for reasons in dyno testing inconsistancy. Technosqaures superflow dyno has a correction programmed into it where it trys to mimic the output of a more liberal dynojet which is useful when trying to compare the output to what others are getting with the more common dynojet. Killerbees report uses these corrected numbers.

However I prefer to state and publish the actual much lower output of the superflow. I want to be conservative as my reputation is on the line as a reporter. When looking at a more stingy dyno, you have to look at the delta from part to part, same car, same dyno, not the numbers compared to different cars and different dynos.

I can appreciate that, and your review stated both things you liked and things you would have preferred to see, and many of those things we've had the same discussions internally before releasing.

But making a statement so determinate, you can see how others reading the stated caption would take that to mean fact, given your resume in the aftermarket world, when it really hasn't been tested on your end?

Well, I did heap praise upon your fine intake ;)

lol.. true

You should at least maybe preface the dyno significance before you publish numbers unstandard from every other dyno used in today's world.. or maybe post the "mathematical" relation to the dynojet.. haha

The whole first part of the article explanes the dyno numbers and the differences between them and power output.

Regardless of what the actual number turnouts were the article is packed with a ton of good information on exhaust design and those 3 bolt on mods which many of us will be running. If anyone is considering doing these bolt on mods I would suggest taking a look at the site. There is tons of good info there!