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7 minute(s) of a 144 minute read
5-28-2013
Its already been a week and I only have two more before I actually get the car back. Finished. I'll get to drive it all summer long! A new experience.
Nothing to report, but I'm trying to get a video to display differently. I had posted links to Logan's first drive in the car, but wanted to post a version that displayed the video picture to appear here. I love the sound and can't wait to hear it with the cutout operating the second exhaust pipe.
G
Love the sound. Listening to it helps waiting. 
8-23-2013
Okay... Test run at Mid-Ohio on initial street tune. Motor has a few days heat cycling. Rpm was held to 6500 with one or 2 times hitting 7500 for a few seconds. Actuator for secondary exhaust pipe not working, so some exhaust restriction at higher rpms.
Gordon
8-24-2013
Agree that "crisp" is a good description. For what its worth, this is what I had in my head as what it should sound like years ago when I started. For me, it doesn't get any better. And, windows up, its pretty quiet even at full throttle inside. Very quiet at cruise as you can tell when it comes back in the pits at the end. I can also tell from the in-cabin video sound difference to outside that my sound deadening really works well.
Finally, Logan said that when the car breaks away, all 4 wheels break away at the same time. So, my weight distribution of about 48F/52R and my tires resulted in very neutral handling. The addition of the exhaust in the bumper and the huge subwoofer enclosure (70 pounds) adds weight to the rear. The lighter weight of the basic NA 3 rotor versus OEM stock, having deleted the power steering, and having the lighter billet aluminum Atomic Rex rack, lowers the front end weight from stock. So, pretty good shift of balance toward the rear.
Gordon
8-27-2013
Here are a couple of pictures of the car when I got it back.
Gordon
8-29-2013
I love the exhaust. We haven't had a heat issue with the muffler box inside the bumper, which is fully enclosed in Incolnel, but there was some deforming of the plastic bumper skin where the stainless trim tubes got heat transferred from the tips, because there's less than a quarter inch between the two cylinders in some places. So, we've had to use a 4 inch diameter opening instead of the 3.5 around the tips and I may lengthen the tips themselves an inch or so.
The functional dual pipe exhaust (from collector to bumper) is working exactly as planned. Up to 3500 rpm the exhaust coming out of the collector goes through a 2.5 inch diameter pipe with a muffler in it and at 3500 rpm a butterfly valve opens the second pipe which has no muffler other than the exhaust muffler box in the bumper. When you go below 3500, the second pipe closes.
Thanks, again, for the comment, David. This basically worked out as I'd hoped. (You know, one out of a hundred. 
)
8-30-2013
Jacob... I am rethinking whether the tips should extend a bit. Was trying to downplay them a bit, but might have them stick out an inch. The exhaust setup copies the 360 Modena's exhaust. (I copied the butterflies in the secondary intake ports from my LT5 motor.)
I noted a few things in my thread about the video we did of the car at Mid Ohio that I haven't noted here and just want to add them. The main thing is certainly what a dual purpose motor this is. It is absolutely factory-like in its low speed, idle, and cruising characteristics. When you get on it, the motor is still factory-like, but the secondary butterflies open and you have a different engine note and more power by half. The sounds are very precise, so you sort of hear how well its running.
Its now been heat cycled, broken in on a track, and been driven on public roads for a few hundred miles. No leaks, drips, or drops. Oil temps have run 180-185. Didn't overheat at all in bad Philly traffic. Has started every time on the first crank.
9-4-2013
A few more random pictures. Still 2 weeks from finally getting it back. Sometimes it seems like everything that can go wrong does. We were supposed to dyno the car last Saturday and the dyno owner has a motorcycle accident Friday night... Can't get on any dyno till next Tuesday. 
Gordon
7-24-2014
I'm enjoying the car. Kyle from Speed1 was over today and took a couple of short videos. Its a bit loud now, but it was too quiet before. Seems I have a Goldilocks dilemma.
Gordon
(I never do the videos right, but this should work clicking on the video.)
http://s234.photobucket.com/user/gmonsen/media/Mazda%20Rx7/Rx7%2007-20-14/MVI_2107_zpsc95872ed.mp4.html
And here's the other one.
http://s234.photobucket.com/user/gmonsen/media/Mazda%20Rx7/Rx7%2007-20-14/MVI_2108_zpse765cc09.mp4.html
7-28-2014
The engine bay looks the same, minus the 3 plugs cosmetically. I put some filters over the ITB's.
Gordon
David... Not sure who he got them from, but those Brit-style intake runners reposition the third ITB further away than it is with my more traditional manifold. Because my back two ITBs are so close, I can't fit those kinds of air cleaners. Also, I would love to hear from Simon how the runners work. I had thought they were pretty much for turbo cars.
Fritz... Yippee.
t-von... Thanks.
And so, here's a few more pictures of my dual exhaust setup.
Gordon
Nice job!
Posted by Diggymart on 3/13/19 @ 9:54:43 PM