joseywhales

Just added a Tail 38mm WG and was wondering if I needed to have any tweaking done, such as A/F mixture check. It's my first turbo and not sure what "cause and effect" has as I make upgrades. Just added SFR exhaust w/ WG and boy it did make a difference, but I noticed a smoke from the rear as the turbo kicked in, Anything special needed to check and correct A/F mixture, any advice would be appreciated. Thanks!

Scott

Mike B

Improving your wastegate and exhaust will have no effect on your air/fuel ratios.

Are you using a manual or electronic boost contoller or the stock system?What colour is the "smoke" under acceleration?

adrial

Wastegate will most definetely have an effect on your air/fuel ratios. Your new wastegate is probably letting you hold boost to redline better, thus making your car need more fuel that it did before.

Which stage 2 chips does your car have? Autothority? If so, they are designed for a dropping boost curve which your car no longer has and you WILL run lean at higher rpm.

Which part of the SFR exhaust did you get?

joseywhales

Thanks for replies, It's the Authority chip w/ stock boost controller and I installed the complete SFR system w/ cat (needed to pass emissions). The smoke was hard to tell, it was at night and I had a boxter on my rear and I wanted him off, and when the turbo kick in a big cloud appeared in his lights. I guess I need to have someone drive behind me to determine if it's black or white smoke unless their is a way to determine in garage. Thanks!
Scott

tazman

Do you have an after market boost gauge? The stock one is inaccurate! I have my dyno sheet to show you what adrial is talking about with the Autothority chips. Depending on what your plans are with your car a new set of chips might be what you will need. You should definately find out what your A/F curve looks like.

SamGrant951

I have a testpipe, sfr exhaust, tial wg, mbc, ape chips. I have it set to 13psi just because I dont trust the upper rev range. The chips are mapped to "roll off" boost with a factory wastegate, that no longer applies with a tial, mine will hold 15+ easy...so like Adrial said, the A/F ratios are most likely wrong...tread lightly.

joseywhales

If I understand ya'll correctly I need to have the a/f mixture tested and lower boost, or change to a differant chip (something other than auth.2 chip) And I difinently know what tread lightly means. Is this something a shop like Zim's Auto teknic should do (local). if chips are required is one set up better than another for my situation. Not a racer but a weekender. Thanks all!
Scott

adrial

From a performance standpoint, I would just toss the autothority chips and get something else.

Guru seems popular, but personally I dont trust any chips anymore. I will only raise the boost on my car (after a toasted HG) when I can monitor air/fuel ratio's at all times (wideband O2) and have a means of adding/substracting fuel throughout the rev-range.

joseywhales

Is there a good aftermarket a/f gauge out there?
Scott

SamGrant951

well, there is if you pony up about 300-500 dollars. PLX, Techedge, Lindsey sells a wideband that will tell you alot and most say they are within >.1 of a actual wideband dyno. A narrowband A/F gauge is more for a quick look, not tuning.