GruppeM dyno

I can't make any statement about GruppeM, but doesn't the presence of test pipes on the airbx'd car somewhat erode the validity of this particular dyno sheet?


...or, maybe I misread your post. By Challenge exhaust, do you mean straight pipe and no muffler?

 

Hi Bob...thanks for posting this info. There is so little actual posted data for the 355 engine/dyno runs I welcome anything, even if it is less than perfect.
Looking at these runs I have questions:
1. Barometic pressure at each run
2. Ambient intake air temperature
3. Are both cars 2.7 or is one 5.2
4. Is fuel the same

Lastly there is no standardization.....CH cars did vary in exhaust setups....some ran air filters..some didn't....if they did what kind and were they treated(e.g. K&N uses oil..etc.) on CH car dynoed?
Most importantly is, were both engines exactly the same in set-up(cam timing,plugs...and on and on)....
The proper way to qualify the difference in effectiveness between oem Street vs CH vs street with GruppeM is to take the same engine...mount CH parts and do atleast 2 runs......remove CH parts and install street parts again 2 runs.......lastly remove street air box..install GruppeM..and again, 2 runs.....this is how you arrive at the true value of each set-up.
From the data that you have posted I can make one statement(not absolute)......there is a trick for overcoming the so called beneficial exhaust backpressure for low end torque gains theory....and that is to flow more air into the intake...and that is exactly what the GruppeM air box did and the torque numbers show the benefit. I only wish these runs had been standardized because the data would have been extremely valuable for those people wanting to know their "bang for the buck" ratio of this expensive upgrade.

 

The other way around, 1kw=1.341022 hp

 

While ANY dyno data for 355s is great, this does look a little apples to oranges....

 

I would like to add this: 355 owners that have spent $$$ on the nice Hyper-Flow cats and X-ost, Capristo(especially level 3), Tubi(especially their race exh) exhausts..etc.........go to a clean country road and remove your air filters....you will hear and feel a difference....and that is only a little taste of the difference a PROPERLY designed air box and filtering system can have on your engines performance and sound....

 

So true.... Even humble K&Ns sound better....

 

Can't ask for better than that.

I think it's good information and you are so right about the shape of the curves being important. On a street car, a nice wide flat torque curve makes all the difference. It would show on lap time unless the driver is making mistakes, but on the street where you just can't be in the perfect gear at all times, you will definately notice the wider torque curve.

 

Again I would like to thank you for the post Bob......your views are not subjective because the data supports your experience....I am glad the numbers are not just numbers but are in reality translated into something you can feel...that is what makes your driving experience pleasurable i.e.when you look at the bill$$$ and can smile...lol

 

people often mistake more noise for more power.....the extra noise makes it seem faster. I've seem a couple TV ads claiming "you can hear the power" or something....they don't claim to give you any power, just make it sound like you have power. Best to stick to a dyno to answer the "does it help" question.