Rpeck

I am going to spring for a wide band, so I was reading up on some things .. what i read said 12.7:1 is optimal power. but full rich on my narrow band (I always hear everyone say it should go full rich under boost) is about 12.0:1. Is 12:7:1 what i am trying to attain while tuning under full boost? or should I shoot for richer than that?


Thx.

Scott 89t2

richer. 11.7

Rpeck

Richer to avoid detonation? or richer to add more power? whats optimal for 'safe' max power?

Had to toss this in; I just got done reading "Maximum Boost" by Corky Bell. Great book on Turbo's and Turbo systems ... but I was disapointed in the whole book he only has 1 picture of a Rx7 motor & no info at all pertaining to rotary turbo configuration I was kinda bitter. But the Pic was a 87 TII with a water cooled intercooler setup, it was Badass!@ I would like to know who makes it.

Cheers!

richer to avoid detonation.
11.7 is good.. if i was tuning my safc i would shoot for 11.7 to 12.1

NZConvertible

What are you using to get that number? It sounds like of those turbo timers with an A/F meter built in. You cannot trust this to give you A/F ratios that are accurate!

The problem is not the meter (which is just a simple digital voltmeter), it's the stock O2 sensor. They are only accurate right on stoichiometric, and the readings they give vary dramatically with temperature. It will give you a general idea of the mixture, but you can't use it to say "it's 12.7:1" or any other number, because it's probably not.

Until you get to a dyno with a real wide-band A/F meter (not a DIY kit), err on the side of caution, and keep it nice and rich!

Rpeck

I'm sure your right. This is the AF guage I have;



But I know I am WAY rich right now .. but it does not show full rich under any boost (right now low boost ~6 PSI) It is showing in what would be the 12.7 ish range on this picture. BTW: I know its no better than stock, but I did put in a brand new NTK single wire sensor when I installed this A/F meter.

RETed

Don't trust the AF30 - it still uses a narrow-band O2 sensor.
You need a REAL wide-band UEGO to run accurate numbers like you're talking about.

~12.5:1 is best power for NA engines.
~11.5:1 is best, safe power for turbo'd engines.
Numbers will vary due to position of the probe.


-Ted

Rpeck

Ted, they said they want to drill a hole in my Dp for me .. to add there Bung.. so should I shoot for 11.5:1 with the bung right at the Turbo exit? or in the tail pipe? please clarify.

SaabGuy

Drill a hole????? No way. Use a sniffer style out the exhaust pipe. Either that or just temp replace the stock o2 sensor.

RETed

And I said don't bother trying to get accurate readings off this meter and your stock O2 sensor...


-Ted

Rpeck

ya i thought that was odd also .. but I was told it is the MOST accurate with a new hole drilled in the propper place they want there Bung. and they said they cap it off perfect once its done. They said its way to inacurate out of the tail pipe .. and even worse with a dual exhaust. They said they can't use the stock O2 sensor location cause they want it to be in effect doing it's thing while tuning also .. for best results .. plus they want to charge me $60 to drill that hole .. and plug it up when finished. This place has a very good repputation .. infact thats why they are book up till late decemberon the dyno right now.

Rpeck

I meant can you clrify if I am looking for 11.5:1 at the tail pipe, or at the Turbo outlet/DP

fastrotaries

drill a hole????? that sounds serious. but is it really worth it, and can it be done without doing this.

Rpeck

They said it 'can' be done at the tail pipe. But they will not gaurantee results that way, they say they want to do it the "right" way. and the "right" way acording to them is with a new hole in the DP. The machine is a dynapack or somthing like that .. soposed to be the best, no tire drag, or wheel spin issues. Etc. They take your tires off the car... it looks really cool. And I KNOW its more accurate than a standard Dyno.

I even called the dynapack company to get info on there setup & asked them if drilling a hole in a DP is normal practice .. they told me the same thing, for the best results .. yes. Then I asked how much one of thse costs I want one in my garage they said 56K dollars for a base 2 wheel drive setup .... haha I think I wil get a wide band first

RETed

Closest to the engine is better, so turbo outlet/DP is best.
Like I said before, the stock O2 sensor cannot do this kinda accuracy.
If we're talking about THEM putting in a wide-band for the numbers, then get it as close to the engine as possible.
If it's "standard thread", remove your stock O2 sensor and put the wide-band in the existing hole - you don't need the stock O2 sensor for idle and WOT.
It sounds like you're talking to Motorsports Dynamics up in Sac.


-Ted

Rpeck

Yup, thats them. You have any other recomendations .. i here they are very good. But waiting till late december is not going to cut it. I talked to Paul at K2RD .. he told me motorsports dynamics also. (he's a good guy) but I am thinking if I have to wait untill december I will just buy a wide band. I tried another place with a dynopack in the Bay area.. they said sorry "porches only" .. I guess my 7 is not good enough for there dyno... wait till they are eating my rotary fumes