NC DYNO: INTAKE, EXHAUST, MIDPIPE, HEADER, SUPERCHARGER!

GT Veloce · Post by **GT Veloce** » Sat Dec 02, 2006 3:13 pm

Brian, are you planning to develop a header for the NC? If not, what's out there that would be an acceptable substitute for the stock header / cat assembly? Are you running the DC header?

Post by **Brian** » Sat Dec 02, 2006 5:14 pm

Yes, as noted above, we have been working on the header for months. Likely early Spring before we have it for sale...

Post by **Brian** » Wed Mar 21, 2007 4:18 pm

Header is done. Should be on sale in another few weeks. In doing the final dyno work we discovered something VERY interesting. First, the good news is that we hit a new high of 163 hp at the wheels. That means we are up 30+ hp from stock as measured at the wheels.

Here is the surprise, that high mark was with the glass packed baffles INSTALLED. Yep, those baffles actually help make MORE power. We had assumed that they would restrict flow and cost us some power once we had the header and midpipe and exhaust installed. I told some folks that once the header was done we would test the packed baffles. The gain of having the baffles installed was 2 horsepower and an equal amount of torque and that gain was from way low in the rpms to very high in the rpms. It just goes to show, you can't assume anything!

Looking closer at this, it turns out we have great flow through our RoadsterSport header and through our RoadsterSport midpipe and into the core of the duals but our tube size connecting the RoadsterSport muffler to the dual tips was actually bigger than optimal and that was causing some loss of velocity and turbulence in that section and having the baffles installed improved that. In future production runs of the muffler we are going to cut the size of that connection to the tips from 2.25 inches to 2 inches to help maintain velocity for those not using the baffles. This will actually quiet the muffler slightly too because the connection continues in through the muffler core and that will leave slightly more space for sound packing in the core. Have already tested the new version and it will be in production soon.

cmos9 · Post by **cmos9** » Wed Mar 21, 2007 10:45 pm

Any update on the overall "loudness" of the complete system as compared to say completly stock and stock header w/ your midpipe and muffler?
Peter

Post by **Brian** » Thu Mar 22, 2007 7:41 am

If the muffler is 20% more sound than stock, and the midpipe adds another 5%, then I would say the header is a 35% jump in sound. The header won't be for everyone because of the amount of sound it adds. Big gains in horsepower with the header but it comes with the big gain in sound.

cmos9 · Post by **cmos9** » Thu Mar 22, 2007 9:21 am

then the next natural question might be, any plans to offer a quieter muffler and/or midpipe option for use with the header?
Peter

Post by **Brian** » Thu Mar 22, 2007 9:57 am

Funny you should ask. We can't do more than we have with our midpipe, no room for more than the 18 inch resonator we currently use. But we are considering a larger muffler and I have tested some prototypes...nothing I am happy with yet.

senda · Post by **senda** » Thu Mar 22, 2007 1:39 pm

We are waiting to bay this header. when will it happen?

Post by **Brian** » Thu Mar 22, 2007 2:06 pm

In a few weeks...

The Captain · Post by **The Captain** » Fri Mar 23, 2007 8:49 am

Brian wrote:If the muffler is 20% more sound than stock, and the midpipe adds another 5%, then I would say the header is a 35% jump in sound. The header won't be for everyone because of the amount of sound it adds. Big gains in horsepower with the header but it comes with the big gain in sound.

Are you saying that it is 35% louder overall with all 3 pieces?
muffler 20
midpipe 5
header 10
TOTAL 35