Anyone do Downpipes yet?

[Rogues Gambit]

https://www.extremeterrain.com/afe-...teel-down-pipe-street-series-48-48025-hc.html

Figured I'd ask.

Notice a difference, hows it sound, worth it?

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[AnnDee4444]

Their power gain claims seem a little unrealistic, especially the 9.2% torque increase. I'm not sure that would be possible without a tune.

"Up to +14 Horsepower and +24 Pounds Per Feet of Torque Gains"​

 

[DesertFox]

Eliminating the cat will really free up the turbo, allowing more air through at the same boost level and a definite power increase. Other turbo vehicles see decent power gains. I can’t confirm the increase claimed above, but it would be much more than an intake or catback.

 

[AnnDee4444]

Eliminating the cat will really free up the turbo, allowing more air through at the same boost level and a definite power increase. Other turbo vehicles see decent power gains. I can’t confirm the increase claimed above, but it would be much more than an intake or catback.

This is the 3.6 section of the forum. No (factory) turbos here.

 

[AZDustMuncher]

This is the 3.6 section of the forum. No (factory) turbos here.

The use of the word downpipes probably threw him off. When I hear downpipe I automatically think turbo.

 

[Rogues Gambit]

The use of the word downpipes probably threw him off. When I hear downpipe I automatically think turbo.

Me too, except that's what they call them there, hence why I called them that was I forgot the name and just went with it

We'll see what it offers, just wondering how it sounds if someone installed it yet is all

 

[LateBraking]

Depends on how much "cat" is in that cat. I remember the old E92 BMW M3 picked up a ton of power for a naturally aspirated motor. That said, the car had not one, not two, but FOUR catalytic converters to make it emissions-compliant. That was 1,200 cell count worth of flow restriction in that exhaust system. Uncorking it entirely (no cats) saw a notable increase in power gains.

I'm not sure I believe +24 ft. lbs of tq. gain at the wheels going from two stock cats to two high flow cats, but if they are accounting for drivetrain losses, then the figures are believable. That, or if the stock cats on the JL are extremely restrictive.

More importantly, do they throw codes that can only be resolved with a tune? Most high flow cats nowadays do, due to the complexity of OEM exhaust monitoring systems.

Notice a difference, hows it sound, worth it?

For sound I'd just go with a properly designed intake. Properly designed meaning in a completely sealed box to preserve water fording capability and repel ambient heat from the engine getting sucked into the intake. K&N, aFe, and S&B all make one. My choice was S&B because it is a sealed airbox unit that takes in air where the OEM airbox takes in air, but unlike K&N it uses a dry filter meaning no fouling of the intake sensor due to oil build-up, and unlike both K&N and aFe it is CARB-certified with an E.O. and is therefore 50-states legal. You won't really make any "noticeable" power with an intake (probably 2 or 3 horses max, nothing you'd ever feel) but it makes a fun noise, and fun is why we have these cars.

 

[Andrew05LJR]

Depends on how much "cat" is in that cat. I remember the old E92 BMW M3 picked up a ton of power for a naturally aspirated motor. That said, the car had not one, not two, but FOUR catalytic converters to make it emissions-compliant. That was 1,200 cell count worth of flow restriction in that exhaust system. Uncorking it entirely (no cats) saw a notable increase in power gains.

I'm not sure I believe +24 ft. lbs of tq. gain at the wheels going from two stock cats to two high flow cats, but if they are accounting for drivetrain losses, then the figures are believable. That, or if the stock cats on the JL are extremely restrictive.

More importantly, do they throw codes that can only be resolved with a tune? Most high flow cats nowadays do, due to the complexity of OEM exhaust monitoring systems.



For sound I'd just go with a properly designed intake. Properly designed meaning in a completely sealed box to preserve water fording capability and repel ambient heat from the engine getting sucked into the intake. K&N, aFe, and S&B all make one. My choice was S&B because it is a sealed airbox unit that takes in air where the OEM airbox takes in air, but unlike K&N it uses a dry filter meaning no fouling of the intake sensor due to oil build-up, and unlike both K&N and aFe it is CARB-certified with an E.O. and is therefore 50-states legal. You won't really make any "noticeable" power with an intake (probably 2 or 3 horses max, nothing you'd ever feel) but it makes a fun noise, and fun is why we have these cars.

My E90 M3 woke the f up after primary cat delete and tune! But that’s a completely different animal than the 3.6. I’d like to think it’d gain a bunch but the tune is really where it made a difference in my E90

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