My car was pretty stock, but I just change a turbo, & the supporting mod.

I was doing a lowly 273whp previously. With my new setup, I expect in the neighborhood of about 360-380whp.

I have stock exhuast manifold (Used to run aftermarket, but cracked so many times, I gave up & went back to stock). I have a tomei downpipe & a Apexi Muffler, but CAT is stock.

The technican that help me install my new setup was telling me that I should change to straight through (with a dummy CAT), as it will yield more torque/hp (which I agree) & so the inside of the stock CAT will not melt (or something a long the line).

He told me he can convert it to straight though (not too expensive too, at about $150) and it will pass inspection, or the cop, as you can't tell from outside.

As far as I am concern, I wanted to keep my car legal, & I do not mind the torque/hp lost, just for a peace of mind.

What I am concern is, will the CAT actually melt (or have some problem) with 380whp?

Can any one advice? Anyone running similar hp or higher that is still on stock CAT can verify.

Thanks a lot.

 

I cant see how a cat could actually melt since it works better the hotter it gets. As for keeping your car legal, I would just get a hfc. Lancershop carries a couple that will just bolt on. Your hp/tq numbers won't suffer that much.

 

^^ what he said...

<-- FL plates = no inspection = no cat

 

I agree that a HFC would help.


I am certain the CAT is a choke point on the exhaust system, but I was just "stunted" when the technician told me that the CAT may gets too hot & the internal component melts.

 

There's no such thing as a HFC guys, I think whoever dubbed it should have called it something else that's less disceiving. A more appropriate name for it should be a High Capacity Cat, because all a "HFC" really is is a cat that can hold more airflow capacity. If you take a stock cat and one of Milspec's "HFC" you will see that the honeycomb inside is all the same. A knowledgeable muffler mech. at a shop I go to spent an hour explaining all about it, and now I understand why he told me there's no such thing as one.

 

They both have honeycombs inside as all catalytic converters should have but they are NOT THE SAME. Stock cat is 300 cell while MilSpec cat is 100 cell. You can actually see through the MilSpec cat while you can't see through the stock cat.

 

^ True. HFC's are less restrictive than stock. Therefore, it flows more. High-flow cat. Lol ;P

I'm running a hfc now. Used to have a tp, but got tired of the exhaust fumes. I don't mind the little power difference.

 

I was told there was a chance a cat would increase exhaust temps and in turn would be more prone to knock. Take it with a grain of salt, Just something a buddy mentioned.

 

You could smell exhaust fumes with a tp?

Mikey

 

I just did a quick check on HFC,

This thing ain't cheap man.

http://www.amsperformance.com/cart/A...-Flow-Cat.html

No wonder a lot of people just use test pipe.

Since I am only going after only about 360-380 (on high boost), & maybe 320-330 on normal driving, I wonder if its neseccary for the extra cost, (or breaking th elaw with the test pipe) since I am fairly sure my new setup can well achieve the targets.

I am sure, with HFC or Test pipe, I can achieve higher Torque/HP, but since I ran stock internal, I am not taking any risk for over 400whp. Beside, I don't think at a fairly modest 380whp, its that hot for any CAT failure, & bearing in mind, I will be running mainly 330whp usually.

 

+1

 

Any others have any experience to share. I am still undecided to keep the cat or not.

 

ok why did you change turbos hopefully you got a cheap fp green because you can make that on stock turbo all day with the IX plus a cat can melt i did it in my 13:1 honda no big deal really it will flow better when it melts down and spits it out the exhaust

 

if you take out the CAT you should gain 40whp with ur going to make 380whp with stock cat.

and yes it is possable to make that much on stock CAT but just need alot more mods

 

I just asked, & realized a lot of my friends are running without CAT. In fact, my good friend told me to just do a straight though (clear out all the honeycomb inside). At least it looks legal (from the outside).

My main concern is reliability, not so much on hp gain, but having said this, 40whp is a lot!

Had no one mention that the stock CAT can possibly cause overheating, & melting of internal of CAT, resulting in damaging my turbo, I would not even consider this.