kattanh3

I was told by JUN-TW that their headers do not bring the CEL lights on

AznJason

iTrader: (5)

would these pass CA smog tests or whatever it is that CA's picky about?

Gernby

iTrader: (1)

The JUN headers should prevent the CEL since they do have primary cats. The Mazzuri headers would probably not pass CA's visual inspection, and definitely wouldn't pass their smog test unless you had some good cats installed in the mid pipe. If I were to buy the Mazurri headers, I would reinstall my secondary cats and relocate the secondary O2 sensors behind them. I think that would probably prevent the CEL, and would also reduce the amount of soot buildup on the back of the car that occurs when there aren't any cats at all. If my wife and I didn't just have a baby, I would be ordering the Mazzuri headers today.

mazzuri

To the mods on this forum, I am not trying to sell my product on here, I have more than enough PMs every day on IS300.net and am a Supporting Vedor there, I just want to point out a few things.

There was a CEL because the cats are gone, but there are 2 more down the line which get rid of any smell or black stuff at the back of the car. Correct me if I am wrong, but the JUN headers made more power with a full exhaust not just header?

Gernby

iTrader: (1)

I didn't see where JUN said what the power increase was. Didn't they just post the after results without the before results?

IAMJAVEDG

iTrader: (5)

dumb question but. where can I get a pair of Mazzuri's?

and is there a way to get around the CEL with the mazzuri's?

like a O2 sim. or something...

combfilter

iTrader: (3)

Wouldn't you have to trick the heat circuit on the o2 sensors also? From what I remember the primary cats also have to heat to a certain temperature in a certain amount of time or the o2 sensor gets mad. This has been the main problem in discussing headers on the is350 with some friends. If you relocate the secondary ones I am not sure how well that will work. The heat sensor might not like that.

newis350

wow...where do you get this detailed info?

If the Mazzuri headers do infact produce 30whp with the stock exhaust and the primary cats removed, IMHO the Mazzuri headers would be the best/easiest/cheapest way to add WHP to the IS350. I'm sure with the collective knowledge on CL it would be possible to figure out a way around the CEL issue without using a O2 sim, not that the O2 sim is a horrible alternative.

kattanh3

Hi mazzuri, dude i take off my hat to you... however JUN probably suites me best. When I contacted JUN-TW, they told me that their headers along with their full exhaust system did a 275hp on a 2Gen (Chinese) IS300 (stock 228hp). It has the cat which i want for 2 reasons:
1) if i remember correctly their full system was only 85db
2) i am considering aftermarket middle pipes without secondary cats

and the fact that the CEL will not be on is a plus for a daily driven car. I didn't see any dyno sheets though on the JUN so I can't be 100 sure

combfilter

iTrader: (3)

I am friends with a lexus 350 owner that also builds supra's up to 600+ hp. He knows his stuff. Also, from this board and others. Just reading and filtering out what is hype and what is not. People like Jeremy, and RoRo who are actually pushing the potential of their cars.

So yeah, basically the air on the stock ISx50 is cleaner coming out of the exhaust then most of the air coming in the intake. Our cars are ridiculously clean when it comes to complying with air standards. That being said we are definitely cool to run on just one set of cats. However, like I said previously the big problem is where to put the cats to make the o2 sensors happy (i am regurgitating this from my friend). You can't locate them too far down your exhaust because of the heat circuit issue. If you buy mazzuri's headers and have a borla offroad/joez offroad/custom/ or any exhaust with the cats removed you are screwed. You either need to find someone to build you a set with some high performance cats built into your exhaust or at the end of the headers, or find some o2 simulators that work on the IS. Mazzuri has a link to a site that is well respected when it comes to o2 sensors; however, I don't think even the ones with the heat circuit (trick) will work on our 350's. They are dirt cheap and would be worth a shot, but then if you are catless you are going to have one loud *** is350.

There are a couple of ways around the sound though if someone does find some o2 sensors that will work for us. I've seen on a lot of the vette/ls3/ss trailblazer forums where people are basically shotgunning a quad muffler sort of deal. The get the offroad racing magnaflow mufflers that look almost like a resonator, and put those right after the resonator, then that goes into your regular / magnaflow normal mufflers. It kind of looks like this , but not all the way. This was my friends ss trailblazer.
http://s85.photobucket.com/albums/k7...t=mufflers.jpg

Much props to mazzuri developing these though. Especially at a reasonable price. You are correct about the gains too. I'd much rather pay 650 for 30hp than 1200+ for 8-10hp from an exhaust.

Jeremy had also wrote a pretty good "bang for the buck" post about his NOS setup. for around 1200 bucks and super easy install you can have 50hp. Now that's a good deal.

p.s. I am glad he is developing headers for the 250 and 350 separate. The port sizes on the 250 are no where close to the 350 and there is no way headers designed for a 250 would work gainwise for a 350.

newis350

may be a stupid question but.....why can't we just add a bung hole for the O2sensor on the Mazzuri headers close to the original location on the stock manifold?

Also, do you have any info on the performance aftermarket cats that can be added?

combfilter

iTrader: (3)

because those cats are no longer there with the mazzuri.

about aftermarket cats, just google them. I am a big fan of magnaflow's products. They are price well, and have outstanding quality. You could maybe pm JoeZ and see what he is using for his exhaust. He said there are 100's to possibly 1000's of companies that make aftermarket high performance cats.

Joe Z

iTrader: (10)

Combfilter, I'm not sure whats gotten into you lately???

But, if your going to quote me, make sure you get it right....
Its kind of embarrassing.

mazzuri

The o2 bongs are on the header, they aren't in the pics, because they where taken before I added them. They are in the same place as stock, without them the car wouldn't run as those are use by the ecu for a/f.

Gernby

iTrader: (1)

I don't think there is any heat "sensor" in the exhaust at all. The secondary O2 sensors are just regular old narrow band sensors. The only thing I think might be a problem is if the ECU expects to see the secondary O2's go lean sooner than they can achieve with the secondaries acting as primaries. One thing that might help that situation would be to insulate everything (header wrap, heat shields, Jet Hot, etc.).