Stephen Porter

Hi,

I'm in the market for a nice 951 and often I run across possible candidates that have been modified to one degree or another. I don't really have any experience in doing modifications myself, nor have I ever owned a car that wasn't pretty much stock.

I'd like some guidelines, if there are any, from fellow-Californians who know what it takes to get these cars to pass California smog requirements at registration. I don't think I would buy a really heavily modified car, but as an example, there is a nice-looking '89 on Rennlist right now, for sale in Michigan with these mods:

Vitesse Stg II Turbo, MAF & Piggyback.
GReddy Spec II Profec B EBC
Pauer Tuning fuel line & Bosch HV fuel pump
Lindsey racing DP Waste gate
Adjustable FPR
and more.....

I think that he mentioned that he has the original catalytic converter, or that it may still be on the car....

Looking forward to learning some more, and TIA for any pointers.

ilko

The PO of my car was in CA. The car was registered there for 14 years, much of that time he had Autothority Stage II chips installed and it passed.

Brantley

It may pass the smog check as far as emission's go, though, if that is the original cat, it might need to be replaced, though, you will really only know this by seeing results from a smog check. The following is a good link that describes possible problems based upon test results,

http://www.interro.com/techgas.html#anchortwelve

Also any cone type air filter such as the MAF will not pass the visual inspection unless you take it to a smog station that will turn their cheek to it... though, I have never found one that will...

Tom M'Guinn

California has several zones: in remote areas smog testing is only needed when you tranfer title. In less remote areas, bi-annual smog tests are done with the car in neutral. And in populated areas, bi-annual smog tests are done on a rolling dyno-like contraption. In all cases, most visual changes to the intake or exhaust (to the back of the cat) are a problem, regardless how clean the car's emissions. Factory replacement parts are ok (and I'd include fuel lines in that category personally), but things like MAF's, headers, big turbos, test pipes, adjustable fuel pressure regulators, big injectors, etc. will all cause the car to flunk the "visual" portion of the test -- even if pure oxygen is coming out the tail-pipe. The only exception is for parts with CARB approval, which are far and few between for the 951. This is why "stealth" mods are popular here, and there are a few people who have done a remarkable job creating lots of HP with stock-looking engine bays....

Stephen Porter

Hi Tom,

Well, I'm in L.A. and I guess that qualifies as "populated" ;-). Rolling-road dyno tests on all cars I've ever registered here. I've never tried to register something that was visually out of line... That sounds like a deal-breaker I guess, unless I were willing to turn it back to stock and then back again....which doesn't sound very feasible to me. Any California high-horsepower guys want to chime in?

Tom M'Guinn

Well, I can go from an off-road only 355 rear wheel horsepwer to street-trim smog-passable in one long saturday...

Stephen Porter

I amend my comment to "feasible FOR me" then.... ;-)

ibkevin

Don't worry about turbo mods, most inspectors are clueless and rpm's are low enough to keep the turbo from spooling.

A new Tial sticks out like a sore thumb, my inspector almost caught mine. Next time she gets a coat of black paint. My stainless fuel lines didn't raise any eyebrows.

I pulled my MAF/chipboard and reinstalled the APE II chips/stock AFM. It's an easy reversal that shouldn't keep you from the joys of 951 motoring.

Ran the car at ~65 for 40 min after putting a can of Guaranteed To Pass octane booster in a quarter tank of premium. Left the car running while the mech did the paper work.

My numbers came out better than the last test two years ago.

RK951

Hey Steve,
I don't think anyone is going to post on an public forum how to circumvent the CA smog requirements but there are options for getting it passed from a center that will turn their cheek. I am certain there are 951 and thousands of non-P cars driving around the state with MAFs and a big cone filter. Where there is a will there is a way

ibkevin

By the rules, a cone filter is acceptable, proving it to the mech takes more time than reinstalling the AFM.

mtnman82

I would say that as long as you can pass a visual inspection (which can vary from person to person and shop to shop, obviously) and it burns clean enough (within the limits) then you're fine. The shop I go to doesn't say anything about the manual boost **** sitting right next to the aftermarket boost guage in the dash. I KNOW that wouldn't fly in some shops, and would only lead to closer inspection. I'm in a 'less-remote' area, so I doubt they even look under the car. I've got a larger turbo, 46mm Tial, MBC, baby blue Lindsey vacuum line running everywhere under the hood, and Guru chips. Passed like a champ in March, as it did a year prior when I bought it. I will without a doubt be trying to pass with the Vitesse chip/board and most likely stock AFM next time (unless I can figure out a stealth install for the Vitesse MAF). BTW, I had John load two programs in my chip board, one for the stock AFM (just for the all mighty smog check) and the other for his MAF setup. It's not that involved or time consuming to switch out to the stock airbox/AFM every couple years for a smog check.

pflyers

I live in LA and haven't had any problems. You have two options.

1. make sure if the car is modified that you get the stock airbox and afm as well as stock chips to go with the car. It takes all of 15 minutes to swap one back on.

2. just try different shops, tell them you want to run it first before sending the data to sacramento to see if it's going to pass. or just find a porshce mechanic near you and ask him who they use. I always have them run it first off the record no matter what car it is.

MPD47

The stuff you have listed is easily concealable. You may be down a few (less than 10) horsepower from those with the same mods, as I do not know how restrictive the stock airbox is. But you can definitely get away with hiding them.

PuttingThePoorBackInPorsche

Pretty much what Tom McGuinn said. If it ain't stock or CARB-approved, you run the risk of a visual failure. That said, most shops don't know what the hell they're looking at in a 951. Technically they have all kinds of pictures and books and other resources available to them to cross-check, but unless there's some compelling reason for them to, most want you in, out, collect their 60 bucks and free up the garage bay as quickly as possible. It ain't worth it to them to dicker around with stuff if there's no obvious reason to.

Get an exhaust with one of those "plug in" catylitic thingys and you should be fine. Stock chips/fuel maps/FPR and AFM sensor (not MAF or MAP) should be enough to pass, YMMV.

Only 10 more years until we no longer have to deal with this crap.

fast951

The VR kits with the latest chip/board run much cleaner than the older setup with the generic chip. Of course they are both for off-road use only!

Can you see the MAF?