O2 sensor spacers (mini-cats)
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Joined: Jan 2014
Posts: 699
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From: Virginia
I understand that point of view and completely respect it. With that said, after taking my car for a relatively short test drive after installing the fvd M&M GT4 race exhaust system, all I can say is it has transformed the car. Gone is the midrange torque dip - the power delivery is much more linear. The car no longer feels like it has turbo lag when accelerate from around 3500 rpm's. You do not feel the car come on cam and you do not feel you have to run at hight rpm's to get instant throttle response. I plan to add a Softronic tune which should make the transformation even more extreme. In speaking with Scott at Softronic regarding his GT4 tune, he said he had originally done it on a GT4 with this exact exhaust system. Based on the dyno runs at the time, peak HP increased by 25 - 30 HP, but more importantly, midrange HP increased by about 50 HP. I plan on doing some dyno pulls on my car to see what results I actually see but even with just changing the exhaust, I'm extremely happy and can't wait to see (feel) the complete package. BTW the mini cats are only a sort term fix as the Softronic tune will remove the CEL.
Last edited by Last_935; Mar 2, 2021 at 03:27 PM.
AutoX
Joined: Dec 2020
Posts: 13
Likes: 0
From: Chicago,IL
Hi John,
yes they are, but I didn’t purchase them direct I bought them from a person second hand. I’d certainly appreciate your input though. Thanks
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Joined: Jan 2014
Posts: 699
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From: Virginia
Anyone have experience with these mini cats from Prosport Performance?
Mini Cat O2 Sensor CEL FIX (45°)
Mini Cat O2 Sensor CEL FIX (45°)
Pro
Joined: Nov 2015
Posts: 637
Likes: 56
From: Ohio
I am running race headers (no cats), first year was fine with no issues, last year, started getting CEL on long drives. I bought these and plan on putting them on this year to hopefully fix the issues. I got the mini cats from fabspeed. Will update later in the summer.
Thread Starter
Burning Brakes
Joined: Sep 2016
Posts: 1,006
Likes: 194
From: where it gets hot in summer
+1 on what @RobC4sX51 said. I felt like I was running an R&D project when I was trying to get the mini-cats to work. Was watching O2 sensor data while the engine was running and it was a mess. Could not really make heads or tails of what was happening. The left side was a good bit different than the right side. I was guessing it might have been because the mini-cats were installed at different angles. As a mechanical engineer, I'm not afraid to get into the tech part of things and learn about it, but man I felt like I was going to have to quit my job for a year and spend full time on this to sort it out! 
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Joined: Aug 2014
Posts: 759
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From: Honolulu Hi
+1 on what @RobC4sX51 said. I felt like I was running an R&D project when I was trying to get the mini-cats to work. Was watching O2 sensor data while the engine was running and it was a mess. Could not really make heads or tails of what was happening. The left side was a good bit different than the right side. I was guessing it might have been because the mini-cats were installed at different angles. As a mechanical engineer, I'm not afraid to get into the tech part of things and learn about it, but man I felt like I was going to have to quit my job for a year and spend full time on this to sort it out!
Thread Starter
Burning Brakes
Joined: Sep 2016
Posts: 1,006
Likes: 194
From: where it gets hot in summer
No, not using them. All this took place several years ago...I had to get the car inspected and had the CEL light. Thus, I opted to stop fighting it and put OEM headers on. CEL light went off. Passed inspection. Put Fabspeed headers back on after washing out the inside with soap and water, and ceramic coating the outside - all has been good since.
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Joined: Mar 2017
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From: Philadelphia, Pennsylvania
No, not using them. All this took place several years ago...I had to get the car inspected and had the CEL light. Thus, I opted to stop fighting it and put OEM headers on. CEL light went off. Passed inspection. Put Fabspeed headers back on after washing out the inside with soap and water, and ceramic coating the outside - all has been good since.
You should have reached out! We would've been happy to work with you on some solutions.
Regardless, Thank you for your kind words. We are glad you are enjoying them and everything is going swimmingly.
