Vervish

iTrader: (4)

I am very happy with the tune and cat-back exhaust combo..there is a notable improvement in mid and high end power. I am gutting the primary cats next weekend, should I expect a dramatic bump in power?

blackisF08

iTrader: (2)

5-10hp but not more than that for sure

nicklausw

YES. From other results that have been posted you should yield about 5hp less than headers.

Vervish

iTrader: (4)

RR got about 400 whp with gutted cats, exhaust and tune - not sure where I am right now with cats in place. Hopefully it is a significant change - power is addictive!

idoke1

iTrader: (5)

There is a MAJOR power difference with gutted primary cats. I posted it on here a few months back. My car made 409whp with tune, gutted cats and custom 2.5 inch exhaust. The only downside is the strong smell of gasoline...being catless ofcourse.

Here is the link:
https://www.clublexus.com/forums/is-...e-results.html

Vervish

iTrader: (4)

Can't wait..

I ran catless on my suby, smell was not terrible IMO.

LUKE6028

Would removing only the primary cats and leaving the rest of the exhaust system stock provide much HP gains? Also thinking of applying tune after removing primary cats if anyone thinks that would add HP. Thanks

flowrider

iTrader: (9)

^^^^The Primary cats are an integral part of the exhaust manifolds (stock headers). And there are measurements taken before and after the manifolds. If the primaries are removed, without an o2 conditioner installed you will throw a CEL. Removing the secondary cats from the stock exhaust system would make more sense. No measurements are taken with the secondary cats.

Lou

hamooduae

THANKS RR..

i was just wondering if there is any solution for the smell when gutting the header cats.iv got pair of oem headers .

nicklausw

There is a fix for the smell. Cats.... More smell = more power. High flow cats will make more power, but will invariably yield lower peak hp/tq numbers.

Lets Drive

iTrader: (3)

Throw some higher flowing cats on there, and it will cut the smell. The difference in power is negligible and it adds to quality of life.

idoke1

iTrader: (5)

From what I read and understand, gesi cats will eliminate the smell of gasoline with no loss of power. I believe gesi cats are rated up to 600 hp.

Vervish

iTrader: (4)

Just gutted the primaries - exhaust note got a little louder and I felt a very slight loss in low-midrange power. The upper range feels very strong now, I am bumping in to the rev limiter regularly as I get accustomed to how quickly the revs rise.

Worthwhile mod if you have the tune - feels like a got a big bump in power up high.

Evil Teo

iTrader: (13)

just curious about how your going to pass inspection? or do you go to a guy? lol i have no cats by the way. nice to see you like the mod.

Vervish

iTrader: (4)

Inspection is a big reason I went the gut route (instead of headers) - it should pass the visual inspection, and the tune clears the associated CEL. I should pass without a problem.