For your purpose of comparing a simplistic single value within the Europipe family of exhausts you have not missed anything. It *would* be nice to see a more sophisticated graph against rpm on x axis, overlaid on boost, etc. And of course, the bottom line, the dyno. What is your dyno's difference when you go from 4 psi to 2 psi, is there a diminishing return at some point? Is there loss of torque at earlier rpm?

As stated above, my question has not been about whether your measurement is accurate, but whether it is a valid number that could be interpreted across different cars and manufacturers. In other words, for example, could we use your measurement against the measurement of say Akrapovic? Is this variation why Akrapovic, FVD, Cargraphic, etc., make NO mentioning of this simple back pressure measurement? These are really questions and I am not being sarcastic at all.

BTW, followed is another person's opinion, I don't know who on earth "Tuner University" is , but I believe a similar point to what Tom wrote previously, and my question, is stated:
http://www.tuneruniversity.<wbr>com/blog/2012/08/how-to-<wbr>measure-exhaust-backpressure-<wbr>for-smarter-exhaust-upgrades/
Most exhaust systems are going to be in the upper 8-10psi range under full load. A decent aftermarket exhaust will peak out at around 4-5psi with some of the very large ones peaking around 1-2psi, though, once you get lower than 4 or 5psi, it’s kind of a diminishing returns kinda thing.It’s going to depend though on the car, the exhaust design, if there’s a turbo or not, and a number of other factors. The measurements are more comparative (ie, they are useful against themselves not necessarily against other people’s measurements) than anything.

 

If you have two different exhausts - using the same tune, under the same conditions, just plot the load vs rpm. You can do this with virtually any component to see if it makes difference.

 

I don't go from 4 psi to 2 psi. I go from 6.4 psi (stock exhaust) to 2.6 psi (stage 1) and to 1.75 psi (stage 2).
I gain hp and tq from down low to redline with both systems.


My answer is yes.



Yes you can.



That is an assumption. I don't know why they don't, please ask them.

I apologize to elite1 for ruining this thread.

 

Stef, not to worry, clearly I am the rude transgressor here, you are merely answering; and what's more interesting, 1 of 200,000 "which tuner is better" threads that's 2 pages from being locked , or back pressure and dyno? Kidding aside, elite1 pls pm as needed if this bothers you. And Stef you really don't have to answer if you don't like to; as obvious from my Bilstein thread, I am quite capable of carrying a monologue, by myself of course :-).

Re. back pressure, thanks for the clarification. Between stage 1 and and 2, the difference in back pressure is 0.85 psi at redline? I assume it's responsible for the hp gained between your EP stage 1 and 2?
Stage 1 exhaust
minimum + 18 hp
Stage 2 exhaust
minimum + 20 hp

Does the above mean you have run dyno's and notice a 2 hp difference from stage 1 to stage 2 on the dyno, without a re-tune?
It would be interesting to see the 2 dyno's of the 2 stages, where peak hp occurs on each, where difference occurs, etc. 2 hp is so insignificant and actually less than dyno variation? Sorry for all these questions or if I guess wrong, this is why I have been asking if you have the dyno's (at different back pressures as you mentioned) to share.

 

That is correct. 2.6 psi - 1.75 psi = 0.85 psi. Are you pulling my leg?

With our EP1 I see gains of up to 32 hp at around 6000 rpm over the stock exhaust with a stock ECU. The EP2 is slighly better at the top but the torque gains down low and at midrange are bigger. We use Bosch and Maha dynos, the Bosch is nice but with the Maha the torque comes in earlier. I don't share dyno sheets though, besides we don't claim big power gains on our website, I'm fine with underrated results.

The downside of all the dyno tests is that they're measured at wide open throttle while most of our driving is at part throttle.
So dyno resuts are just part of the equation.

Cheers

 

Thanks Stef for taking time to answer.

The 0.85 psi difference is measured at red line right? How about at lower rpm's - is there a rpm below which there is no difference in back pressure between Stage 1 and Stage 2?

In some videos of back pressure measurements, the exhaust flow pulses make the needle pulsate. Do you see same degree of pulsation in your measurement?

 

Weakness of a stock Porsche is the exhaust. The sound of my EP2 is worth a -20 HP in my opinion at 500HP. I like facts of a Dyno but, I would figure out how to properly demonstrate the correct sound of the EP2 on you tube. (If that’s even possible.) It’s much better sounding in person FOR SURE!

 

Anybody with EP in South Florida?

 

Between 6500 rpm and redline.


Yes at idle


That is a worthless test, you have to load the engine to measure the backpressure. That applies to NA engines as well.

If you're interested in more info about backpressure then please read my 2 year old thread: https://www.6speedonline.com/forums/...kpressure.html

Cheers

 

Nice to hear that you enjoy your new EP2.

 

Do you guys with 600+ HP kits track the cars? Or are they more the straight line stuff and getting a ridiculous rush driving around and remote runs? I really like tracking my car and wouldn't mind some more power but I want to make sure it's reliable. Are there kits more geared towards a track focus? Or should I just focus on handling upgrades? I have close to 500 hp on a dyno now.

 

I haven't tracked mine yet. I plan to. I probably have 100hp more than you at the wheels right now. I can see how it would be a handful on the track.

A good friend of mine has a bunch of exotics and tracks a lot of them. He told me that anything over 500hp (I'm assuming he meant at the crank) and the cars became a lot more difficult to drive. He also preferred N/A powerplants to turbos.