backdating exhaust....

[vash]

in january 2004, my car will be smog exempt here in california. i am curious about backdating my exhaust. i guess it involves different heat exchangers/muffler, getting rid of the cats...and the blower motor gets removed? so only the engine fan moves the air through the exchangers? maybe i need to see a picture.. also, can i simply remove the air pump, and all attached plumbing? i love when you guys post pictures of really clean engines compartments. mine has Cr@p everywhere.

cliff

[banjomike]

I would talk with your mechanic or someone who does emissions tests. The law is not a clearcut as everyone seems to think. Anyone able to shed more light on the California emissions exemption rule?

Having said that...
'backdating' the exhaust only involves removing the headers and everything downstream. Get the SSIs, not a used header from an older car (the old stock headers were not stainless and the airboxes tended to rust). Then you will need a muffler with two inlets. Bang you're done. Removing the air pump can be done, but other than for esthetic reasons why bother. It consumes only a tiny fraction of 1hp, and makes your exhaust cleaner (the air pumped into the exhaust helps the remaining gas in the exhaust burn). I think the air pump is a good thing.

The other thing you are talking about is backdating the heater. This will also clean up your engine bay, but the heater won't work as well (I couldn't get along with any less of a heater than I have). When I get in the car with a wet jacket the windshield fogs up like I was parked on lover's land. The defogger is barely able to deal with this right now, I couldn't drive in the rain with backdated heating.

It must be said that an engine w/out the air pump and the extra heater blower is a fine thing to look at so I can understand if you do it all.

[Superman]

Most of you knew I would be willing to satisfy this request. I'm not particularly ashamed of this engine.

[ubiquity0]

What- no engine stickers?

[Joe Bob]

The 75s are the first of the Porsche model years that have down stream smog equipment as well as air pumps in some cases.

The rule says exempt from inspection, not exempt from smog requirements. Removal is at your own risk......

[Joe Bob]

NOW for the real world.....NO ONE looks for this. Take a look at all the hot rod Model Ts and such out there with modern V8s that don't have a spec of smog control.....

[dd74]

Originally posted by Superman

Question 1: have you pics of the rest of the car?

Question 2: is the engine always that clean?

[vash]

mikez, that is an interesting point. but once i get my car registered, no one will ever look at the smog stuff again right? i dont know about makeing the heater less effective, my gfriend is alway cold! so backdating the exhaust gets rid of the air blower? looking at supes pics it doesnt look like it. i can get an exhaust that gets rid of the cats, and keep the blower? banjomike, is prob dead on about the air pump being a good thing, but that thing really gets in the way. i havent messed with my timing yet, but i bet i need to remove the belt to safely mess with the distr. with the car running. thanks guys, sorry for the long response. superman knows, i can get confused quickly.

yes supe, get more photos up ASAP. and isnt there dirt and oil up there?

[vash]

sorry, i rambled. all i really want is to get rid of the cats. getting the compartment cleaned up would really be a bonus.
so i looked, there seems to be an SSI that lets me keep the blower, gfriend will be happy. thank you banjo for the heater info.

cliff

[arcsine]

With a set of SSI's and a backdated heater system (heater blower removed) at anything above idle, you should have more than enough heat if the flappers are working. I could only take full heat for a couple of minutes tops before I was roasting.

[Chuck Moreland]

Unfixed, if you'd like to see a car so modified you can look at mine. I'm in San Jose.

FYI, the heater blower motor has nothing to do with emissions. You can make all those changes and leave the blower. But it never gets cold in California and the engine is nice and clean without the blower.

[SC-targa]

A 75 911 doesn't have cats. In CA they did have thermal reactors in 74, which are real engine killers. You would also have EGR and an air pump.

[RoninLB]

SSI will provide better heat than '75 stock HE..
the engine blower and hoses are 99.99% unnecessary, IMO.......Ron

[vash]

miner is a 75 from one of the other 49 states. so i have the air pump, cats and thank god no thermal reactors.

and chuck, i will take you up on the offer. i hang in the south bay alot during the weekends. thanks. i will PM you in advance. looking forward to seeing your project. i also need to see the routing of the external cooling lines, in respect to my AC line in the same vicinity. i bet you got that covered too?

[Joe Bob]

Some 75 Porsche's DID have cats.....49 state cars had them instead of the infernal reactors and the 914s had cats on the 2.0s along with air injection.

And don't tell me a 914 is not a real Porsche.....

[JTO]

My 75 911S was delivered to Medford, OR in the fall of 1974 as a 1975 model. The car came with the air pump but no thermal reactors/cats.

Just my $0.02.

Troy

[Loual]

When I bought my '75 in '83 the P.O. had already had already had the engine rebuilt in '80 at 69k miles due to heat related valve guide wear resulting in a broken valve. When it was reassembled, he left out the offending smog controls. Despite lack of the smog controls, with an otherwise stock engine, it consistently passed emissions testing in New Jersey until 1999, when it became smog testing exemt in NJ (since I registered it with Historics plates).
Go for it!

[CARRERIC]

Here is my 75, originally from Cali. I removed the smog and thermos. Also backdated the exhaust to SSI's and dansk muffler. Got rid of the heater blower motor and extra piping (backdated to 74 style as well).

[vash]

carreric, i wish you wouldnt post too many pictures of you car, it tends to give me an ego problem. not to mention heart tremors! damn your car is hot! well it comfirms it, engines look better with the stuff removed. i like lou's, so maybe keep the blower motor so my gfriend doesnt freeze.

[CARRERIC]

Unfixed, my mechanic removed the heater blower when he did my rebuild. I was concerned it would make a big difference. The heat works just as good with the 1974 set up and half the hoses. Much more room in the engine bay. Not so messy.