Catless dp no tune

[A90Sean]

Does anyone here run a catless downpipe with no tune on their 2020 Supra? Would it make the car run lean because it thinks it’s running rich due to the extra fumes? Would it run okay?

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[noogie]

Changing exhaust flow efficiency requires a review of the data log and potentially a new tune . Are there people running without a tune? I’m sure there is.

 

[razorlab]

Does anyone here run a catless downpipe with no tune on their 2020 Supra? Would it make the car run lean because it thinks it’s running rich due to the extra fumes? Would it run okay?

That’s not how it works as the AFR sensor is pre cat, plus the 2020’s run lean at WOT stock anyway. 14.6-14.3 is normal operating for a 2020 at WOT.

 

[ChrisMK5]

3k miles on my Armytrix, no cel ??

 

[Sub-MkV]

I have a Armytrix catless dp plus a piggyback at +2 psi and I was looking at my afr during WOT and I saw 13.7 at the top end which is around the range of stock afr on these motors. I also run 93 oct blend to create, e28 (25% e85 - 75% 93oct)

 

[Bigjsn250]

2020, same as above, Armytrix catless DP, no CEL and no issues. Quiet as a mouse with valves closed, great sound in sport mode. Obviously a bit more hp, I’m guess 20-30. My DME is headed to A90 shop for unlock and then my BM3 tune will be added and Bm3 flex fuel, but right now no issues and the car runs/sounds great.

 

[RyanA90]

Me

 

[FLtrackdays]

Changing exhaust flow efficiency requires a review of the data log and potentially a new tune . Are there people running without a tune? I’m sure there is.

Catless dp and AWE track exhaust. I turn my JB4 off when tracking. Absolutely no problems. I only have the JB4 because it was a trade for my old downpipe. The JB4 is fun as ? in town!

 

[cbrummell]

i run an A90 shop catless downpipe with a modified 3.5 inch bottom section to match the AWE resonated touring exhaust!

the car definitely picked up power even with no tune and i havent had any huge issues so far. the only thing that has come up since i added it the catless downpipe was my transmission short shifts under WOT pull in automatic mode if i launch the car... i've posted about the short shifting problem on the forum before and people didn't believe me but it consistently short shifts 2nd 3rd 4th if i launch the car.

outside of that isolated issue, i've never had a problem running catless with no tune.

 

[ColonelAdama]

I run catless with just a JB+ piggyback (at +3.5 psi). It runs fine! Not a huge difference but likely in the 10-15 whp range for gains over stock dp.

 

[Joseph Kwon]

I have seen a lot of people run a catlass dp without a tune, and they seem to be just fine as the ECU makes adjustments. However, I am not sure about long term use. if its a 2020, I would get it tuned since the ECU is not locked anyway and you will gain more power and efficiency.

 

[Mason]

I ran without a tune. I wouldn’t say it makes it any faster. But it won’t do any damage if you’re just wanting the exhaust note

 

[m240]

People do way worse things than run a downpipe with no tune and get away with it... like using a JB4 to crank the boost with no tune.

 

[ColonelAdama]

People do way worse things than run a downpipe with no tune and get away with it... like using a JB4 to crank the boost with no tune.

What are you talking about? The JB4 is supposed to be used with no tune. Show/link me a B58 that was killed by a JB4.

 

[Bread1267]

Catless dp and AWE track exhaust. I turn my JB4 off when tracking. Absolutely no problems. I only have the JB4 because it was a trade for my old downpipe. The JB4 is fun as ? in town!

Holy shit track exhaust and catless thing must be so loud! Is Jb4 worth it?

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