Modded 308

The stacks are there to set the rpm that the intake works best...I've never really noticed that they change sound though?

The intake noise is heard mostly where ever the air intake happens, which should be the side vent. If you remove or change the air filter that sound will change. Remove the cold air intake setup and the sound will change....but changing stacks not really.

 

Open stacks with no filters is a most excellent way of ruining your engine.....it usually doesn't take very long, a few thousand miles maybe before you start to see leakdown numbers increasing. I saw an article years ago that talked about a roadrace engine with vs without for the season and it was basically 0 piston wear vs 0.006" on the non-filter engine....just running 10-12 weekends on a clean tracks.

 

F1 engine run airfilters and have for many years.
https://www.racecar-engineering.com/articles/f1/technology-explained-f1-airboxes-filters/

Open stacks looks really cool, no question about that but its not a very good option for anything other than display. I was playing with an idea to move the filter near the vents and make the top of the airbox clear (hard to keep clean) or perhaps attach it to the decklid so when the decklid is up you see open stacks on the engine but have had more pressing issues to deal with...someday maybe.

 

If that's not quite what you're after I talked to my production guy and custom 3pcs is an option. He said its a long lead so I'm trying to find out what part of it is a long lead exactly. I could design 308 and/or GTO looking centers and have them made then 7, 8, 9, 10, 12 or whatever wide is just a question of what rim halves they are assembled with.

I assume we're talking about 16" like the GTO wheels? Because of the way the center needs to be shrunk to make a place for the bolts a 16" three pc has a more 14 or 15" 1 pc look as far as the center and the openness of the spokes goes...just something to keep in mind.

I personally don't much care for the center caps on the GTO wheel that are a function of the single center bolt setup I guess and would prefer a more exposed bolt 308 looking design...but I could make either design that bolt to a 308 or 328 if someone wants to be a guinea pig

 

This works for me and I think you would get an increase in sucking noise Image Unavailable, Please Login

 

Can you take a photo of the whole diffuser and the rear of the car

 

Never seen anything like it, that muffler shroud.....

The problem with the K&N filter set up is you are now drawing much warmer air that's rising off the headers, vs the side scoop intake system.
Great thread......