LG Pro Owners, question
Drifting
Joined: Oct 2004
Posts: 1,384
Likes: 8
From: Southwest Virginia
LG originally recommended the X-pipe in front of the cats, and there is a slight performance gain to that setup. But if you are running rear O2 sensors you must have the cats up front. Either way seems to work well, may people have them both ways.
Moderator
Joined: Jun 2004
Posts: 22,663
Likes: 943
Cats will not get hot enough in the rear. I saw a dyno with and w/o cats on a 500 rwhp car. The cats cost about 6-7 hp if I remember right so the performance gain is negligible. LG recommended the X-pipe go after the headers unless you were running cats. If you are not running cats the proper placement is dependent upon where the exhaust starts to cool. The old way of doing it was to mark the pipes with a crayon or wax and where it stopped melting was where your collectors extensions ended and your X-pipe was installed. Mine are in front of the X-pipe.
Thread Starter
Safety Car
Joined: May 2004
Posts: 4,811
Likes: 2
From: Simpsonville SC
Im not running cats, so I should have my delete pipes after the x-pipe? I had already welded the x-pipe to the back 2 pipes. Looks like I need to do some cutting and re-welding. CRAP!!! I jumpd the gun big time. dont dog me too bad fellas. Thanks for the info!
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Moderator
Joined: Jun 2004
Posts: 22,663
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No lite off at all, you could probably handle them with bare hands in that position. And yes, with no cats I would have put the x-pipe right after the headers.
Drifting
Joined: Oct 2004
Posts: 1,384
Likes: 8
From: Southwest Virginia
Without cats it will make VERY VERY VERY little difference where you put the X-pipe, you are only talking 12", but I would put if up front if I was running without cats. But mine is in the back since I'm running cats.
Le Mans Master
Joined: Dec 2001
Posts: 7,788
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From: Winchester TN
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St. Jude Donor '03-'04-'05-'06-'07-'11
Hi happa -
When I had Sean and LG install my pros - he put them on with the X pipe and then the off-road pipes.
best regards -
mqqn
When I had Sean and LG install my pros - he put them on with the X pipe and then the off-road pipes.
best regards -
mqqn
Moderator
Joined: Jun 2004
Posts: 22,663
Likes: 943
Thats not true, the further back in the exhaust the cooler the exhaust is and the lower the velocity gets. The X-pipes design is to help with scavenging of the cylinders. This Works most effectively when you have velocity to help suck the exhaust out of the cylinders, thats what the x-pipe is for. Placing it further away from the heat source reduces the velocity of the exhaust thus reducing the effectiveness of the x-pipe. This is where the wax or crayon trick I mentioned earlier comes into play. The hotter the gases, the faster they will be moving thru the pipe. This speed is what pulls the exhaust gas out of the cylinder.
Le Mans Master
Joined: Jul 2004
Posts: 7,727
Likes: 7
From: Twilight zone
St. Jude Donor '05-'06
Let's put this issue into perspective
Maybe it does make a difference where it is located.But I am not so sure it is that much to even be concerned about.
How much difference could this possibly make?1-2-3-5-10-20 hp????
Pick a number here and we will then be able to decide whether or not,in each individuals perspective, it is of any REAL significance to each person.
This seems like a good place to start this discussion to me.
How much difference could this possibly make?1-2-3-5-10-20 hp????
Pick a number here and we will then be able to decide whether or not,in each individuals perspective, it is of any REAL significance to each person.
This seems like a good place to start this discussion to me.
Moderator
Joined: Jun 2004
Posts: 22,663
Likes: 943
Maybe it does make a difference where it is located.But I am not so sure it is that much to even be concerned about.
How much difference could this possibly make?1-2-3-5-10-20 hp????
Pick a number here and we will then be able to decide whether or not,in each individuals perspective, it is of any REAL significance to each person.
This seems like a good place to start this discussion to me.
How much difference could this possibly make?1-2-3-5-10-20 hp????
Pick a number here and we will then be able to decide whether or not,in each individuals perspective, it is of any REAL significance to each person.
This seems like a good place to start this discussion to me.
Drifting
Joined: Dec 2001
Posts: 1,808
Likes: 19
From: Little Rock, AR
My own personal experience for those that have to pass emissions. I put the x-pipe first then cats I failed emissions test. Moved the cats up front then x-pipe I passed. Cats don't light off in the rear position. If your not running cats then I would put the x-pipe first then the off road pipes.
Drifting
Joined: Feb 2006
Posts: 1,585
Likes: 15
From: New Hartford IA
Does anyone have any comments on how much the cats quiet the car down? I've had cats in since I've had the car and was curious how loud it would get without them. The slip fit makes it a pain to swap out the cats.