downpipes

[AlBel1214]

What exactly are the benefits of downpipes?

[Riss Racing]

Originally Posted by AlBel1214

What exactly are the benefits of downpipes?

Catless downpipes will remove the primary cats directly off your turbo outless increasing flow benefiting in about a 30whp gain.

The OEM downpipes have a smashed head and a "pipe in a pipe" design that basically goes from a 3 inch turbo outlet to a 2 inch crush bent pipe & a very restrictive CAT.

Catted downpipes also do the same as catless however have a High Flow Cat. That will increase flow and is much less restrictive than the OEM CAT/DP. You won't get as high of power gains as catless. However there are still very nice gains.

Basically in the end downpipes elminate back pressure which is a must for any turbo car. (if your looking for power gains)

Hope this helps!

[F0Bman]

They have increased flow to spool your turbos faster. WIth faster turbo spool that means you can develop boot much faster.

[raolc]

Originally Posted by anthony@rissracing

Catless downpipes will remove the primary cats directly off your turbo outless increasing flow benefiting in about a 30whp gain.

The OEM downpipes have a smashed head and a "pipe in a pipe" design that basically goes from a 3 inch turbo outlet to a 2 inch crush bent pipe & a very restrictive CAT.

Catted downpipes also do the same as catless however have a High Flow Cat. That will increase flow and is much less restrictive than the OEM CAT/DP. You won't get as high of power gains as catless. However there are still very nice gains.

Basically in the end downpipes elminate back pressure which is a must for any turbo car. (if your looking for power gains)

Hope this helps!

Oh and you defintely can't forget, it also sounds amazing!!

(the first part of this video is the riss racing exhaust, so you see what the exhaust does, then the second part shows you the difference it makes with downpipes)

[scrapiron7]

Originally Posted by anthony@rissracing

Catted downpipes also do the same as catless however have a High Flow Cat. That will increase flow and is much less restrictive than the OEM CAT/DP. You won't get as high of power gains as catless. However there are still very nice gains.

What's the power difference between a high flow cat DP and catless DP? Typically on other cars it's about 2-3 WHP.

[My135]

Is this legal to run the catless down pipe on the street or just for racing only?

[skddmorse]

I just installed my downpipes on Saturday and i can tell dramatic differences. The sounds is amazing and I can finally hear my turbo's spooling....

[gargoyal]

Originally Posted by My135

Is this legal to run the catless down pipe on the street or just for racing only?

That is a state by state question. in general it is not legal.

[scrapiron7]

Originally Posted by gargoyal

That is a state by state question. in general it is not legal.

You can not legally remove the converter from a vehicle. It is a federal law not state law. Federal regulations state that no emission devices can be removed or tampered with. (i.e. gutting the converter.) What ever devices came with the vehicle must remain intact. Todays vehicles are designed to operate efficiently with the cat.

[gargoyal]

Originally Posted by scrapiron7

You can not legally remove the converter from a vehicle. It is a federal law not state law. Federal regulations state that no emission devices can be removed or tampered with. (i.e. gutting the converter.) What ever devices came with the vehicle must remain intact. Todays vehicles are designed to operate efficiently with the cat.

Federal law? what agency enforces it? The EPA set the emissions standards and the states choose how to implement the emission standards. It is called a state implemented plan (SIP).

In some states they choose to just go by exhaust emissions only. Most of the time if you remove 1 cat in a 2 cat system the car will still pass the exhaust emissions test. In most state there is a visual inspection also, where the removal of the cat will cause a failure of the visual inspection.

In general it is illegally . but that is a state thing not a federal issue

[jeremyc74]

Originally Posted by gargoyal

Federal law? what agency enforces it? The EPA set the emissions standards and the states choose how to implement the emission standards. It is called a state implemented plan (SIP).

In some states they choose to just go by exhaust emissions only. Most of the time if you remove 1 cat in a 2 cat system the car will still pass the exhaust emissions test. In most state there is a visual inspection also, where the removal of the cat will cause a failure of the visual inspection.

In general it is illegally . but that is a state thing not a federal issue

It's part of the Code of Federal Regulations, and the EPA could enforce it, but that doesn't really happen. More common is that the states make the EPA standards their law, and then some enforce it that way.

I know people in VA who have been fined for removing cats (typically on trucks where it's very obvious).

[gargoyal]

Originally Posted by jeremyc74

It's part of the Code of Federal Regulations, and the EPA could enforce it, but that doesn't really happen. More common is that the states make the EPA standards their law, and then some enforce it that way.

I know people in VA who have been fined for removing cats (typically on trucks where it's very obvious).

The EPA enforces it on the states by withholding federal funds if the state is not compliment to the emission standards, not on motorist. Here is the EPA web site. There is nothing about not removing cats or visual inspection(that’s not federal law) . It is a state thing. The clean air act (CAA) is implemented by each state in a SIP. Look it up. That’s how it works.

http://www.epa.gov/otaq/hwy.htm

[jeremyc74]

Originally Posted by gargoyal

The EPA enforces it on the states by withholding federal funds if the state is not compliment to the emission standards, not on motorist. Here is the EPA web site. There is nothing about not removing cats or visual inspection(that’s not federal law) . It is a state thing. The clean air act (CAA) is implemented by each state in a SIP. Look it up. That’s how it works.

http://www.epa.gov/compliance/resour...hsysrepair.pdf

Originally Posted by EPA

To whom may it concern:
As you know, the Clean Air Act was amended on November 15,

1990. Several of the changes in the Amendments affect the
automotive repairfservice industry directly. These changes include
the expansion of the tampering prohibition to include private
individuals and the prohibition against the manufacture,
installation, sale or offering for sale of any part or component
used on any motor vehicle or motor vehicle engine where a principal
effect is to bypass, defeat, or render inoperative any emission
control device or element of design of any emission control system.
The enclosed Fact Sheet: Exhaust Svstem ReDair Guidelines
has been revised to Conform to the new provisions of the Clean Air
Act and represents a change in our enforcement policy with regard
to exhaust repair.
Essentially, the changes in these guidelines reflect EPA'S
position that any pipe used to replace the section of exhaust where
the catalytic converter should be, would be considered illegal
under the revised Clean Air Act. Therefore, any work in this area
of the exhaust system must include proper converter replacement.

answer 1.
Under federal law, catalytic converters may not be removed
and replaced with "converter replacement pipes' by any person.
The 1990 Clean Air Act Amendments even prohibit private
individuals from installing "converter replacement pipes" on their
own vehicles. Anyone who installs such pipes would violate section

203(a)(3)(A) and (B) of the Clean Air Act (Act).

I have looked it up and there it is in writing. Now lets put this to bed. It's against federal law. Period.

[gargoyal]

I stand corrected, but I do not know if that is still in affect. read furter and according to that 1990 document you can't sell a catless down pipe or install one for off road use either. (questions 2 and 4)

your material is dated or Riss may be getting a call from the FBI

[jeremyc74]

Originally Posted by gargoyal

I stand corrected, but I do not know if that is still in affect. read furter and according to that 1990 document you can't sell a catless down pipe or install one for off road use either. (questions 2 and 4)

your material is dated or Riss may be getting a call from the FBI

I'd say it's a pretty safe bet that the regulations haven't relaxed any in recent years.

I think the EPA has bigger fish to fry than to go after automotive enthusiasts that make up a fraction of a % of the total number of drivers on the road.

(FWIW...I'm running catless downpipes, but I'm doing so with full knowledge that there is a slight chance I'll get fined for doing so)

[gargoyal]

Did some quick research, the feds don’t enforce section 203 and several other sections of the CCA . they allows state to enforce through the SIP. Technically , manufacturing, selling and installing a catless DP is illegal federally, but it is not enforced. You can only get a ticket from a state right now (the feds are not enforcing) . As I stated earlier check your state laws. According to the docs I read there are 5 states that do not have specific laws against modifying emission controls( it didn’t name them)

[scrapiron7]

I never said the Feds enforced it, just stated it's a federal law. The odds of getting pulled over and tickets by Feds is slim, but local cops are likely to be more of a pain.

[BerkTechnology]

Downpipes are illegal for public road use in all 50 states. However, not all states enforce these laws. Driving a BMW though, your chances are slim that the cops would look under your car, but caveat emptor.

There are very good gains to be had with catless downpipes. However, there are minimal gains to be had with aftermarket catted downpipes.