ceeyahd1

I would like to do a mild tune, exhaust and 997/GT3 shifter on my stock 996TT. I understand that I will need to swap the exhaust to get the smog test done whenever it comes up since none of the aftermarket exhausts are CA legal. I have decided to go with the speedtech 2.5 X-cellerator with 100 cell cats since it does not seem too loud and gets good reviews from users on this forum. Not sure yet on the tune.

I want to know if I will run into any check engine light or will I have to change out any other parts if this is all I want to do regarding engine mods.? What is the least upgrade I can do on the suspension that will make the biggest difference without having to spend thousands of dollars on?

I do not plan on tracking the car and will probably drive a couple days a week.

Thanks for your help.

manimal

This couldn't go in your other thread?

Done properly, you won't see any CEL's.

Regarding suspension, check out the recent Bilstein B8 thread: https://rennlist.com/forums/996-turb...lstein-b8.html

I appreciate where you are coming from because I'm in a similar situation -- but doing mods, properly, without spending thousands, is probably a bad expectation for a 996TT.

"02996ttx50

(a) you shouldn't need to swap the exhaust for a smog test though in CA ( but i also go to the same smog guy every two years ) and i'd re-think that 100 cell cat choice and go safer with 200 cell..oem is something like double that. CARB is making everything more difficult these days, but there are workarounds. look into a kline 2.5 from sambo here. great sound, performance and its passes smog. no problems.

(b) a tune and exhaust won't cause any cels. only "issues" do.

(c) bilstein b8's with H&R reds ( per manimals suggestion ) is the best and least expensive upgrade option re suspension refresh.

add: just realized.. if your plan is to swap to the stocker every two years, then run whatever ya want. i used to run catless ( with decat pipes ) and i am still a free man. otherwise, ( as above ) i'd go with an exhaust that WILL pass. with 200 cell cats.

ceeyahd1

I had no idea the after market exhausts passed the sniffer test. I emailed John at speedtech and he told me the 2.5 X-cellerator with 100 cell cats will pass CA smog test with no problem so I will go with that setup. I will also order B8's with H&R springs for the suspension. I want to make sure I order everything needed for the shocks and springs install. I read something about top mounts that also need to be replaced. Does anyone have a link or part #'s I need. I want to make sure I have everything needed for the installer.

Anyone know a good mechanic in Ventura county CA?

Thanks for your help.

Third-Reef

You will most likely need rear toe links with the H&Rs to be able to get your rear toe and camber set properly. The H&Rs will be real low, mine went from 26.12" at the front wheel arch to 25.25" some people get as much as a 1.25" drop. I made spacers to get back to 25.38". Does not sound like much but you will get a whole new perspective on driveways, Looks great though. I gave wheel arch measurements because it is the easiest. There is a frame measurement that is the correct way to do it.

Below is my table i made. it is corrected for the different GT2 subframe.

"02996ttx50

here's your top mounts https://www.pelicanparts.com/catalog..._pg2.htm#item5. you'll need a L/R and get the shock bearing plates also. ( same pelican parts page ) i know a good shop in agoura.. not TOO far from ventura ( koncept moterwerks ) they aren't cheap and i only use them in an emergency as i DIY most everything not requiring a lift. i know an even BETTER race prep shop in NoHo but thats far from you.

+1 also on third reef's suggestion on needing aftermarekt toe links. i use torque solutions. ya need em on a lowered 96t or you'll kill rear wheel inner tread quickly. theyre about 450$ and worth it, long run.

ceeyahd1

Thanks for all the information. Can you give me an idea on what I should be looking at for labor if I were to get these done individually:

Speedtech exhaust
997/GT3 shifter
B8's and H & R springs

Trying to find a good local and reasonable shop nearby in Ventura county CA.

"02996ttx50

it takes 30 mins TOPS to swap an exhaust. it takes 30 min TOPS to swap a shifter. swapping suspension bits is a larger issue ( 2-3 hours min ) plus you need a new alignment. add that as "separate" labor, even if done by the same shop. ( it is ).

if a shop is doing this work? double the time you pay, for the actual time it takes. if you're *lucky*. welcome to the club.

John D II

I would figure 1-2 hrs. shop time for the exhaust. Although it can theoretically be done in 30 minutes, it takes time to get the car up on a lift, gather the proper tools, then clean up and put everything away when the job is complete. Shops charge for this time. And a good shop will take their time to treat the 02 sensors with care, as they can be damaged easily and then carefully align the tips at the end, so that they sit equally spaced and level (normally takes a few tries). I feel 1 hour is a very reasonable minimum, 1.5 hours is a common charge and 2 hours is a bit heavy, unless they run into severely rusted nuts, stripped/snapped studs, etc., in which case it will probably be more like 2 hours. If your turbo nuts are original, I would suggest that you request they clean the stud threads with a wire brush and penetrating oil, along with using new turbo nuts for the installation.

Shifter - I did mine in about 30-45 minutes taking my time. I would expect a shop to charge at least an hour.

Suspension - I don't recall exactly, I had it done, but it was about half a day, then immediate alignment.

ceeyahd1

Thanks.

ceeyahd1

Is there a noticeable exhaust smell between the 100 cell and 200 cell?

John D II

No difference

Kevin

With any exhaust build/purchase as a consumer I would request 200 cell 130/132mm HJS cats. This will prolong the life of your cats and offer years of service vs the dreaded CAT inefficiency CEL. Which will trigger your emission non readiness codes. Pay the extra monies to get at a minimum 130mm or 5 inch diameter HJS cats.

ceeyahd1

If the 100 cell cats. are better flowing than the 200 cell and the 100 cell passes the sniff test. Why wouldn't everyone want the 100 cell cats. over the 200 cell cats? Want to make sure I order the correct exhaust.

Kevin

Humor me.. How much HP is on your wish list? How much boost are you running with your engine package? How much air is metered thru your MAF (CFM)… For a STOCK engine (stock injectors, stock rods, stock heads and so forth) There is minimal HP gain from 200 cell to 100 cell. However NOT ALL CAT's are created equal. Manufacturing process, search cat matrix cell design. Look at the HJS website. The new 200 CELL HJS cats can flow better than most 100 CELL units due to the matrix core design. New school engineering vs old school.
Again my point is>>do you want to replace your cats due to a failure 11 months or 15 months down the road??? The failure is there is not enough surface area in the 100 cell cats to provide the catalyst function. You get CEL's tripping on your dashboard. You have cat inefficiency error codes. This is turning into a big deal in certain States.. MA, CA, CO, WA, and others.. Forget the HP gains, you are not at the performance level to "fell" the loss if any.