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NC Header: RoadsterSport MaxPower 1.8" replaced the 1.6"?

Posted: Mon Aug 23, 2021 3:22 pm
by EdwardC507
It looks like the 1.6" MaxPower will no longer be offered. Only the larger 1.8" primary header will be offered.

Has anyone installed the 1.8" MaxPower on their factory internal 2.0L? Are there dynos of the results; I'll take any info like A/F ratio readings and butt dynos too :)

I want to see if there are benefits from the 1.8" MaxPower if I only have access to a remote tune and not dyno tuning for such a large header. The other options are Racing Beat or Mazdaspeed/Kooks header for the 2.0L.

https://www.good-win-racing.com/Mazda-P ... -1979.html

Re: NC Header: RoadsterSport MaxPower 1.8" replaced the 1.6"

Posted: Mon Aug 23, 2021 6:01 pm
by Brian
Several customers did the dyno work on 2.0 motors with both sizes...and found 1.8 wins everywhere. That was not our assumption for a long time, but the results convinced us to go forward with focus on the bigger 1.8. Some searching in Miata.net NC power section will find those results.

BUT...then a reason to keep making 1.6 did jump up, which was that our customers in Australia need the 1.6 which clears steering rod on RHD cars. So, another batch of those in the works.

Re: NC Header: RoadsterSport MaxPower 1.8" replaced the 1.6"

Posted: Tue Aug 24, 2021 3:02 pm
by EdwardC507
Thanks Brian.

Good to hear that the 1.6" will be available, even if the need is more for the RHD cars.

I did find a few threads where it looks like the 1.8" does provide more power over the 1.6" on a 2.0L motor. I guess the old narrative of losing torque is still hanging around.

Re: NC Header: RoadsterSport MaxPower 1.8" replaced the 1.6"

Posted: Wed Aug 25, 2021 8:18 am
by Brian
EdwardC507 wrote:Thanks Brian.

Good to hear that the 1.6" will be available, even if the need is more for the RHD cars.

I did find a few threads where it looks like the 1.8" does provide more power over the 1.6" on a 2.0L motor. I guess the old narrative of losing torque is still hanging around.

The results showed there is torque shift, but not torque loss. So, peak torque at higher rpm with the bigger header, but the curve was still better everywhere. And more power everywhere wins. As a result we are working on next generation of the big 1.8 inch header. The current 1.8 was made to really fit the 2.5 motors, fit on the 2.0 is pretty tight to the engine mounts. New version of 1.8 header will have more clearance everywhere for both 2.0 and 2.0, that's likely a few months from being ready.

Re: NC Header: RoadsterSport MaxPower 1.8" replaced the 1.6"

Posted: Tue Sep 07, 2021 12:17 am
by EdwardC507
That's some awesome news!

Love hearing about the constant improvements. Has your R&D team looked into stepped primaries? Just wondering how it might fair; your header can be used by stock internal 2.0l and supercharged 2.5l customers (many variations).

Additional space if thoughtful and even perhaps selling some heat shields for the engine mount and alternator would be cool too.

Re: NC Header: RoadsterSport MaxPower 1.8" replaced the 1.6"

Posted: Tue Sep 07, 2021 8:35 am
by Brian
We experimented with stepped primaries years ago on this application and didn't find additional gains. Somewhere around here I still have the test headers that stepped from 1.6 to 1.75, 1.75 to 1.8, and 1.8 to 2.0.

Re: NC Header: RoadsterSport MaxPower 1.8" replaced the 1.6"

Posted: Thu Sep 09, 2021 3:47 pm
by EdwardC507
Thank you as always Brian. I went back and read through the build for Project Blue and the Header development. I guess the x2 cost to custom build a stepped header doesn't have that much ROI unless your setup is much more eXtreme.

Great info.
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