Hi. I am new to this site. I am trying to figure out which Magnaflow cat (or other brand) I should buy for my TJ 3.5L magna sports. It has extractors with a std cat back exhaust section. Any suggestions really appreciated.

Cheers

A 200cpi cat is considered high flow. That is about the best you are going to get. 100cpi is also available but (at least in NSW) is illegal but much louder and is going to give you a better performance boost. I would not recommend using one though. It does shocking things to the air. A 200cpi cat may even be too loud for you. A member here has a 200cpi magnaflow and needs 2 resonators to shut it up.

The cat shouldn't change the sound much.... 200 is fine on a v6, i have a 100 and its really not needed.

Thanks. Should I round style 200cpi cat or an oval style one. Magnaflow do an oval style ceramic cat for about $180. What do you think?
The round style ones seem to be about 5 inches in diameter and the oval ones about 7 inches. Which one best for fuel economy?

Doesn't matter, get a metal cat.

Hayden, thinking of getting 200cpi for my tj sports manual as well (exhaust system completey standard at the moment) just courious but why do you recomend a metal cat? also want to keep sound level as close to standard as I can(dont mind a little extra sound though) so would you know if I can retain the standard rear sports/vrx box to achieve this? its on 105000kms so prob a good idea to change cat anyways I would of thought.

Cheers mate,

Ross.
Doesn't matter, get a metal cat.

Hayden, thinking of getting 200cpi for my tj sports manual as well (exhaust system completey standard at the moment) just courious but why do you recomend a metal cat? also want to keep sound level as close to standard as I can(dont mind a little extra sound though) so would you know if I can retain the standard rear sports/vrx box to achieve this? its on 105000kms so prob a good idea to change cat anyways I would of thought.

Cheers mate,

Ross.

If you still have a resonator and the VRX rear muffler you should find it's ok (only a little louder), however after only 105,000km I don't know if it's worth it unless you have a lot of other mods.
A standard cat should last over 150,000km.
On the other hand it won't cost too much I guess. Ballistic are highly recommended (available from Sureflow in Ingleburn and had a special run-out recently for $170 each)

If you have a stock rear muffler your exhaust won't be any louder with a hiflow, the rear muffler is just so big it can't make decent sound.

Thanks all. I have ordered the ballistic cat as recommended so will be welding it up when I get the item. All advice appreciated.

Next thing to do on your exhaust system is to get and fit a set of headers.
The combination of a sports rear muffler, high flow cat and headers makes a nice difference to how your car will drive.

Gerry

Next thing to do on your exhaust system is to get and fit a set of headers.
The combination of a sports rear muffler, high flow cat and headers makes a nice difference to how your car will drive.

Gerry

+1 on this. Headers make a massive difference

He said he has extractors in his first post.

Edit: deleted stuff that's just going to cause arguments

Just on a related note (no pun intended). What diameter cat is needed for KJ2's and will a round one fit or do I need to fit an oval one?

Reason I ask is that I have the HM Perry headers on mine with a 2 1/4 Y connector to the stock cat which feeds out to the stock pipe which I believe is a 2.5".

I've also just ordered a Magnaflow 14586 muffler ( 5" x 11" x 22") as im not keen on the smaller louder units.
Cheers.

Just on a related note (no pun intended). What diameter cat is needed for KJ2's and will a round one fit or do I need to fit an oval one?

Reason I ask is that I have the HM Perry headers on mine with a 2 1/4 Y connector to the stock cat which feeds out to the stock pipe which I believe is a 2.5".



I've also just ordered a Magnaflow 14586 muffler ( 5" x 11" x 22") as im not keen on the smaller louder units.
Cheers.

2.5 inch diameter will do nicely. Doesn't matter whether round or oval they both fit and do the same thing.

Cheers altera.

Got some thinking to do then before I do anything ai, cheers guys

He said he has extractors in his first post.

Edit: deleted stuff that's just going to cause arguments

My bad. Quick reply off my mobile without reading the op again

+1 on this. Headers make a massive difference

Not on my car it didn't ;) Headers are only good for 1-2 kw on the 3.5 magnas as the stock manifolds flow quite well. Fitting the headers gave me a nicer sportier sound with a tiny improvement in low end and midrange performance. The main performance gain is in the fitment of the straight through muffler ala VRX, Ralliart. Good for 5 -7kw alone according to Mitsubishi engineers.

Not on my car it didn't ;). Headers are only good for 1-2 kw as the stock headers flow quite well. Fitting the headers gave me a nicer sportier sound with a tiny improvement in low end performance.

Agreed. On an AWD they give more of an improvement due to the standard AWD having a slightly different setup, on a FWD magna the stock item is very good as far as factory stuff goes.

Hi Gerry. I have already fitted a set of wildcat extractors. Please correct me if I am wrong but isn't the standard (cat back) TJ sports exhaust system great as it is. I thought there was no need to replace with a cat back. Also I had to block off the egr intake on the intake manifold does anyone know how this will effect fuel economey? Cheers D

Hi Gerry. I have already fitted a set of wildcat extractors. Please correct me if I am wrong but isn't the standard (cat back) TJ sports exhaust system great as it is. I thought there was no need to replace with a cat back. Also I had to block off the egr intake on the intake manifold does anyone know how this will effect fuel economey? Cheers D

Tj sports and above system is good, Models below the sports have a restrictive rear muffler.