[QUOTE
I put on an AWE Tuning exhaust.[/QUOTE]

It's a neat design - I like how the tips look totally stock, but it sounds way better than stock.

 

Yea, I never understood this. You can start small and get bigger, but going the other way makes zero sense.

 

I’ll let her eat on the dyno and let everyone know the results next week. I’ll do some pills with and without tips and post results

The exhaust necking down at the last 1” of exhaust travel will not impact anything.

The car absolutely rips on a BBI tune and 91oct.

 

Over the top happy. I was looking for a used SOUL exhaust for this car since February. I knew it was only a matter of time. It sounds wildly different than the B&B and has 100% changed the car for the better. It’s loud enough with cats. Can’t imagine a Catless.

docwyte is a rockstar seller. I had it two days after I paid for it. All hardware, packaging and instruction from SOUL included like he stated. Was a great transaction. Not sure what he replaced it with.

 

I'd LOVE to see this. Can't imagine a 1" part of the exhaust necking down causes any loss of HP.

 

Necking down creates back pressure, which Rob's power.

Powdrhounds got some dyno plots where the ipd large plenum goes into the more restrictive turbo manifold and there most certainly some loses there.

The same applies to the back end, you want, for optimum performance, the same diameter piping thru and thru.

 

In theory. That's not how it works in practice though, which is why I want to see the dynos.

 

I can assure you I am not making this up. We dynoed this exact test, back to back dynos within an hour, without even removing the car from the dyno. I have no reason to make this up, as we sell both versions 3" with OEM tip outlets and 3" with full 3" tips. It was about 12 years ago...I will search later and see if I can find them. I absolutely know it to be true.

 

Here is the thread I was referring to - look at the plots, the dip is a known issue, due to the restrictions in the intake:

https://rennlist.com/forums/996-turb...t-results.html

They were, however, able to clean it up a but, but the restriction still is a restriction, and creates issues.

 

Another way to think about it is like this:

Put a straw in you mouth and blow - your lungs can clearly move more air, but the diameter of the straw restricts your lungs from exhaling fully and completely, in an efficient manner.

Now, with the same straw in your mouth, use a finger to cover half of the other end of the straw, your lungs are now further strained, as flow is restricted again.

As the motor (any motor) is effectively a pump (fuel, air go in, exhaust comes out, and power is made...), the easier your can make the pump rotate, the more efficiently it can make power. When you add restrictions to that pump, in this case forcing the exhaust to go from 3" down to 2.5", that restriction not only creates back pressure (not a friend to a turbo motor), but it takes energy to compress the exhaust gases in order to get them out of the exhaust - anyone more familiar with fluid dynamics than I am, can step in here.

What John (and other John with the dyno...) is saying is fundamentally correct, I have yet to put my turbo on the dyno, but have spent a fair bit of time on them with other toys and diesels. The big diesels would pick up some serious power and lower egts going from 3 - 4", and my big big diesel going from a 3' to 5" exhaust picked up close to 50hp, and more importantly, dropped egts down to 600f indicating that back pressure was almost non existent.

Makes a neat noise too.

 

Here you go, Doc, an actual dyno of the subject. You can clearly see the mid range benefit of a full 3" vs. a 3" with an OEM neck down. The OEM tips on a 3.0 system are quieter, as well. Some people use them to quiet a 3" system. Others prefer the full 3" sound level. I feel full 3" sounds better, but that's personal preference.

Red = a heat soaked run, we let the car cool, then: Blue = OEM 60mm tips on a 3" system - on a fresh cool run, Green = 25HP increase in the mid-range with a full 3' tips - about 15 minutes after the 60mm run, probably a medium temp run. You can see the full 3" tips clearly pull away from OEM diameter.

I think the blowing through the straw analogy simplifies it pretty well.

 

Frank at Exclusive Option.
Purveyors of incredible beautiful leather work.
I drank all their kool-aid!

http://shop.exclusiveoption.com/996-...a-99-04_c7.htm

A few bits from Exclusive Option-

 

New steering wheel for the Turbo finally arrived... Maybe I'll install it tomorrow.

 

That's really cool, who made that?

 

I used to be a Lambo!