Never heard of Helix. Can you tell me about the company and it's products.

Thanks!

 

CARB does hand out exemption orders for catalysts. This is from their website:

http://www.arb.ca.gov/msprog/aftermkt/replace.htm

It is not legal to replace your Evo's factory catalyst with an aftermarket unit in ANY state (except California, if the cat has a CARB EO) until the car has 80K miles or is 8 years old.
Federal Clean Air Act

However, if you live in California, a CARB approved catalyst might qualify as a "factory or equivalent" catalyst in this state, which would make it legal for you to replace it prior to reaching 8-years/80,000-miles. The Federal Clean Air Act's ban on "aftermarket" catalysts only applies to catalysts which are not certified as "factory or equivalent". Unfortunately MOST catalysts, except the stock one of course, are NOT certified as factory or equivalent, even if they are a legal replacement after the 80K/8year mark. In order for any cat to be certified, it must be tested on that make/model of car and approved. Then it will get a CARB EO, just as any other modified part, and will be legal on ALL cars of that make/model.

It is also not true to say that ALL modified parts are illegal. There are legal modifications, such as intercoolers on a factory turbocharged car as well as water (no alky) injection. CARB's website has some insight as to things which are, and which are not, legal, as well as the forms to apply for exemption here: http://www.arb.ca.gov/msprog/aftermkt/topforms.htm

-Adrian

 

"Yes, officer, but my factory cat and exhaust were completely destroyed when I ran over this debris on the expressway, so I had no choice but to put on this aftermarket cat and this aftermarket exhaust."

 

While it _is_ possible to remove it that way (after about 5 hours), you could also cut along one side, open it up like a clam and take the whole lump out. A lot of work and you need a bit of skills not to absolutely destroy the thing. Unless you have a complicated looking cat pipe like the Sti, get a piece of pipe, make a couple of flanges and weld them on. 5 million times easier but doesn't look stock.

Sorry to go ot... nice metal substrate cat and very nice price!!!

 

I have to ask but considering these things are worth 10hp over factory converters I doubt the difference can be more than that from ceramic high flows to metal high flows...but if you can feel less then 10hp you are the human dyno..thats for sure.

 

Okay, here's some quantifiable data for you guys. It's not a true before/after, so take it for what it's worth. All dyno runs were done at Gruppe-S on 91 octane.

Dyno Day 1
Mods: WORKS P2, WORKS air filter, Helix IC pipes, HKS downpipe, WORKS HFC, HKS cat-back, DIY ground kit, JDM MR DV
1) 234.3whp @ 7250rpm, 241.4wtq @ 4000rpm
2) 234.7whp @ 5250rpm, 240.2wtq @ 4000rpm
3) 240.6whp @ 6000rpm, 235.1wtq @ 5000rpm
4) 237.9whp @ 6250rpm, 232.3wtq @ 4000rpm

Dyno Day 2
Mods added: 10.5 hotside, Helix HFC
1) 253.7whp @ 6750rpm, 241.6wtq @ 4000rpm
2) 254.8whp @ 6500rpm, 244.9wtq @ 4000rpm
3) 251.4whp @ 6500rpm, 241.1wtq @ 4000rpm

Dyno Day 3
Mods added: +1 degrees of timing at 7 and 7.5k
1) 265.4whp @ 6250rpm, 258.0wtq @ 4000rpm
2) 263.3whp @ 6250rpm, 253.8wtq @ 5000rpm
3) 260.2whp @ 6250rpm, 255.0wtq @ 4000rpm

I am pretty sure my boost went up slightly between dyno day 2 and 3 due to cooler weather. Dyno day 3 also took place 2 tanks of gas after I had a track day, where I mixed in a few gallons of 100 octane. So perhaps the ECU was on a more aggressive timing map.

 

does anyone know if this Helix HFC will bolt on to the AMS catback exhaust? Im only talking about the catback not the down pipe section. My Perrin testpipe seems to mat up to the AMS exhaust fine so I would like to think that the Helix would fit fine but not sure. Would appreciate any info. thanks

 

The Helix HFC is made to be a direct replacement for the stock cat. So if a stock cat can bolt to your current exhaust, the Helix should be able to as well.

 

AMS uses 3 bolt flanges, so you would have to modify your exhaust or Helix cat to make it work. Any good exhaust shop (that welds stainless steel) can do this for you.

 

Does the Helix hi-flow have an O2 bung at the mouth?

 

I live in NY so it really depends on what state, but my car was rear-ended twice over a period of two years, the second time it damaged my cat, and I replaced it with an aftermarket one (through my repair shop that did the body work) and they supplied me with some sort of paperwork that the catalytic converter was replaced due to accident damage and is an OE equivalent part (Its a Catco cat, and not really a true OE equivalent replacement, but nobody noticed) so there is a procedure to replace a missing or damaged catalytic converter where you would get paperwork that would satisfy a judge if you ever had a problem.

 

Here in CA, I had to replace the cat on our VW after about 100,000 (the car is 7 years old) miles and I was told by the dealer that cars built after 1994 had to replace their cat with another OEM cat. I then looked up aftermarket cats (not hi-flow mind you) on various parts websites and saw similar statements to what my local VW dealer said. Unfortunately the VW dealer sourced part was ridiculously expensive (no suprise there! ). I don't know how this gels with what was posted earlier by Saabtuner. I hope I didn't get screwed, but them's the breaks....

As for ceramic vs. metallic, I'd personally go with ceramic here in CA. A little less power is worth a little less potential hassle. Just my opinion.