924Board.org

[coconutcowboy]

I am thinking of adding a 3 way 3" freeflow cat to my 924 na motor. It has a smog pump fitting on it so I am thinking of using a gm or ford diverter and backfire valve system between the cat and the porsche smog pump.

also feeding air into the cat directly doesn't affect the 02 sensor since the air will be injected downstream.

Also will use the 1980 model ignition distributer with less advance for detonation / emissions reasons.

And last but not least I will refit the egr valve and associated plumbing back onto the engine using a ported manifold welded up to mount an Audi 5000 tb. This EGR refit will lower the NOX emissions if I understand my car manuals correctly.

exhaust will be a bursch header adapted to the cat sized pipe and stock 944 s4 turbo exhaust from there.


engine will have a mild economy/performance grind cam and the engine will be running 9.3 cr pistons and 931 head ghasket.

I am wondering if this combo will suceed as there are ultra low emissions laws coming to georgia where I live.

Sean Ross A@P

[gohim]

The modifications that you have made, and are planning to make to your car will most probably violate the very laws that you are planing on trying to me. Here in CA, to me emissions regulations, not only do you have to meet the emissions specs, you have to meet a visual inspection as well. Cars must have all of the emissions equipment that they were original equipped with by the manufacturer, and it must be functional if tested by the Test Station. If you change the engine, then the car must meet the emissions specs for the newer of the engine, or the car. You are not allowed to install or modify any system on the car that would affect the emissions quality of the car or engine.

9.3cr pistons would be a tecnical violation, that could not be detected, so you could get away with them, if the car met the emissions standard. Carbs, 3-way cat, headers, altered timing specs, and the cam that you are running would be technical violations. Again, here in CA, if you replace engine parts like a cam, you are required to display the manufacturer's state approved exemption number for each modified part, and when you change the engine, you must have the car inspected and approved at a state test station, with a special exemption number issued, and displayed on the car.

Your Frankstein emissions system, may, or may not bring the emissions down to the state spec. but if there is a visual inspection, you will failed.

[kaffine krazed]

It depends on what the laws are in your state. Where I live if it orignaly had it it must be there and hooked up and they only egr, air, cat, gas cap, and restrictor plate(no functionality tests) older cars pre 80 or 81 can't remeber they only check the gas cap and restrictor plate.


Egr valves will help reduce NOX so will a 3 way cat. If I was doing it I would leave the emmision system alone to begin with then if it fails start modifing the emission system depending on how it failed.

Do you know what the new emission standards are going to be and if they are going to make it retroactive or just require any car built after that date to meet the new standards?

[coconutcowboy]

The cars systems were rotted out, that is what wasn't butchered. Here in Ga alot of 924's were rigged to death and the smog stuff removed as soon as it falled into a uninformed (or unenlightened)gearheads hands.



_________________
porsche924 in georgia

[ This Message was edited by: coconutcowboy on 2002-06-06 00:16 ]

[gohim]

If the stuff is all gone, then just wait till the new emissions specs are official.

Then you will know exactly what it will take to pass, and you will not have spent time and money to assemble something that is not legal.

[coconutcowboy]

talked to a friend and he said if I updated my engine to a 1980 spec engine using a VC code head that I could get by by intalling the lambda system then I could get by without the egr.

He is however going to check with the state boys if this can be added to since it will be an early engine rebuilt using vc spec parts and early egr, smog manifolds, piping and valves and pumps. only concesion being to bursch header and 3 way cat.

He said I must use the stock 924 smog pump system if I plan to use it. However I could move the injection point to suite the rquiremnts of the new cat.

you gotta understand most early and mid 924's had cobbled up emisions system when new
and most were added after being brought to the states. Porsche standardized the system later.

this info came from a bit of research my friend did.
Sean Ross

_________________
porsche924 in georgia

[ This Message was edited by: coconutcowboy on 2002-06-07 13:43 ]

[Cbass]

The car I am saving my pennies(thousands) for has no smog stuff at all. It was all removed, as we don't get testing on the island. They do in the lower mainland, so when I move there, I will need to get some, or at least get my engine running smooth. In Vancouver, they don't care what sort of gear you run, just as long as you pass the standards.

[jamez]

I just removed the smog pump from my car, my car used to pop out the exhaust on downshifting, it doesn't at all anymore, so I guess my emissions control must have been a little screwed up...

[kaffine krazed]

You had a bad diverter valve. On decel there is excesive raw fuel in the exaust and air to it will cause it to burn in the exaust manifold causing a poping noise. The diverter valve shuts the air flow to the exaust manifold off to prevent that.