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Removing primary CAT converter

8K views 65 replies 9 participants last post by  toymr2trd 
#1 ·
Ok. Now I’m being punished. I’m doing primary delete on lp640. I’ve done this successfully on two murcies prior.
Passenger side cat came out without a hitch. Drivers side is giving me huge issues. first time to see the clamp nuts facing up- Not down. So I cannot break nuts from bottom. With it facing up there’s no access - The clearance between exhaust header and primary cat is very narrow. Even my 1/4 socket won’t fit between the space.

Has anyone encountered this beforeAny suggestions on how to get drivers side cat out? I don’t think lifting engine will help since my issue is not between cat and heat shield.

thanks
 

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#2 ·
Definitely unusual to have the clamp facing up. Maybe the engine was out previously and they put the clamp on the other way around while the engine was out.

Looks like you are going to need remove the O2 sensor first, and then use an usually angled wrench, or crows foot, to get at least that one nut off. Then if you shoot the clamp with penetrating fluid, you can whack it around to spin it 180 degrees to get the other nut off from below.

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#4 ·
Hi Stimpy. I woke up first thing and gave it another go. I first removed the O2 sensor to get more room (thank you for that suggestion). I couldn't access the nut in the photo but i was able to access the nut on opposite end. i got that off with my slim socket. i ran out of time (had to get to work) but i should be able to rotate the bracket to get access to the second nut. I see light at end of tunnel. Whew. Thanks to all that supported. I'll take video and share how primary delete with LOC for LP640 sounds.
 
#7 ·
Ok. Here’s the setup

1. Fabspeed primary delete
2. Secondary delete
3. LOC exhaust
4. Factory tips

Missing - plug for the LP640 tip. I need to cap off the bypass Tubes. Caps installed soon.
Without the caps I have exhaust blowing out the exhaust tips and also in the engine room. Very smelly. But you can hear the tone in the video. I expect the volume will be louder once I cap the extra exhaust pipes off the tip

let me know what you think. Click on link below:

 
#9 ·
Thanks Stimpy. My eyes are still watering. Not only because I love the sound “but” because the gas vapor are
So strong. I don’t have plates yet as you can see. I’ll need to take her out for a spin around the block to see how she sounds on load. If Fumes done improve, I may need to find another solution - the fumes stick on clothes - several hours later. My office still smells like a gas station.
 
#10 ·
Yes, that is a big problem, especially with lady passengers that don't want to smell like rotten eggs all evening.

At least with the LOC, you can easily add back the OEM secondary cats, or aftermarket high-flow secondary cats, without having to wrestle the primaries again.
 
#12 ·
Change your spark plugs and inspect your coils. When the ignition system isn't 100% is when the fuel smell becomes prominent on the catless cars.

Just realized your tip is not capped off. It's going to make the smell much worse since it's sending fumes forward into the car vs. out the back of the tip.
 
#17 ·
update - I took her out for a spin last night. Driving in the upper RPMs the lp640 sounds amazing.

dislike - what I don’t like is the sound of the murci at low speed. The Low RPM (under 2500) drone is terrible. Worse than pre-lp. I didn’t have this drone with primary cat.

next step - I’m going to swap out the LOC muffler with the Fabspeed. This means fabspeed primary and fabspeed muffler (fabspeed doesn’t use secondary). I hope this is better.
 
#18 ·
update - I took her out for a spin last night. Driving in the upper RPMs the lp640 sounds amazing.

dislike - what I don’t like is the sound of the murci at low speed. The Low RPM (under 2500) drone is terrible. Worse than pre-lp. I didn’t have this drone with primary cat.

next step - I’m going to swap out the LOC muffler with the Fabspeed. This means fabspeed primary and fabspeed muffler (fabspeed doesn’t use secondary). I hope this is better.
You’re headed down the same path I went. Although I always thought it was easier to keep the drone away on the LP.

I ended up after many iterations with the Fabspeed primary cats with valves (and valves permanently closed now), with stock secondary, Larini muffler, and Larini tips (converted to non-valve tips).

My combos included stock primary cats/Fabspeed high flow cats, stock secondaries/stock bypass, stock muffler/LOC/Larini, stock tips/Larini tips.

Current setup is no drone, with much more sound than stock, but very mild compared to the screaming exhausts.

A valved exhaust seems the way to go, but I never got to the point that the sound with the valves open was good quality and also loud.

What I wanted to do as the final test was to have a custom X pipe exhaust tip made that would connect to the valved primaries to keep the exhaust that is dumping out of the valves separate from the exhaust going into the muffler area, but still have an X intersection to improve sound quality of that raw exhaust.

Kinda lost interest after all the swapping and droning exercises. I wore myself out removing and installing the stock muffler by myself a bunch of times.
 
#25 ·
Don’t get me wrong. Fabspeed makes great quality parts- No doubt. I’m not pushing any parts here. The Fabspeed extenders are overpriced in my opinion. You will not see any noticeable performance improvements. And the extenders are hidden so nothing to show off. The goal is to keep CEL off. I did have Fabspeed extenders but ended up selling because the angled design makes it hard to remove. Ebay sells similar designed extenders (see photos) if you feel better about having “mini-cat” style inside the extender. Good luck. With money saved, get a set of new plugs and filters.
Cheers!!

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#26 ·
I think the fact that there is no flowing gases in the bung makes the mini-cat ineffective. Also, if the O2 sensor does not reach operating temp fast enough it will trigger a P600 code. I am going to try the Vibrant extenders that come with three orifices to adjust the amount of gas reaching the sensor.
 
#27 ·
you’re on the right track. I’ve done it the hard way by experimenting with different styles and lengths. Good luck Jason. Focus more attention on the grin on your face when you delete the primary cat. Sound is night and day better. Like others recommend - if you get lots of fuel vapors then make sure to check coils and plugs. I did that and now the exhaust smell and vapors are not bad at all.
 
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