soon i am getting my turbo 2.4 finally tuned and the shop just sticks a sniffer at the end of the exhaust. what would a safe af ratio be with that method?

 

bump

 

i would see if you could look something up from your local dmv, they may have that info on their website, if you're doing it for emissions purposes. if you're doing that for actually tuning your a/f, i'm not sure if that's really the way to do it.

 

not for emissions, for tuning purposes only since i dont have a wideband, they stick a sensor in the exhuast after the cat. i just want to get an idea so i know what the tuner is doing.

 

wow.........

you put a turbo on and you don't have a wideband(shakes head) thats one of those horrible ideas that people tend to have....only this type can blow **** up.

your cat will totally **** your AFR's....make the car read richer by about a half point AFR

if you want to avoid having a wideband(horrible idea for a guy thats got a AM turbo kit) then remove the cat to use the sniffer....

but do yourself, and engine a favor and put a wide band in there....AND remove the cat.

or at least make sure to put the WB bung pre-cat

 

i want a wideband but cant afford that right now, this whole project has drained me and thrown me into bad debt

 

oof... esta no bueno... i would seriously consider not getting on your car if you don't have a wideband... i would have recommended you buy one BEFORE you put the turbo on...

i'm not sure about the a/f to answer your original question, let some of the guys that are more familiar chime in... but definitely don't push your car hard at all untill you can afford a wideband...

 

Ok, I have a lil bit of experience with this so I'll chime in.

Doug, the sniffer will be fine for tuning. Hopefully the guy knows what he's doing this time and takes care of your issue. The sniffer will read pretty close while on wide open throttle. All other conditions the car is in closed loop and will trim as necessary using your narrowband. I'm sure he'll scan for trims before hand and see which way the MAF calibration has to sway for closed loop conditions.

If you guys still have trouble getting commanded a/f to match up, if you can remember this...tell him to change airflow settings to allow the PCM to trust the MAF 100% of the time ("dynamic airflow properties" if using HPTuners, not sure what LS2edit calls it). I'm pretty sure thats what the tuner did wrong last time you were there. Any other problems, you have my number.

-Al

 

Allen,

the cat with throw the numbers off, toward the rice side by aprox .5afr

i had this experience myself....

 

Yeah, thats about right. Most wideband controllers I've used are off by about .2-.3 anyways so its not a huge deal imo.

Reading a different post by Doug I think he's using a Hahn solution for engine management so I'm not really sure whats going on with it now. Any updates?

 

you lost me smallz........on the 2nd part of your post that is.

 

In the Hahn 2.4 thread, Bill Hahn stated that celicacobalt was to be using an engine management system developed by them since his dyno shop was having trouble tuning his PCM. I'm guessing he picked up one of their PCMs and their boost-fueler. No idea really, just guessing.

Looking forward to an update from celicacobalt.

 

ohhhh ohhh ohhh.....wow i had a mind **** for a sec there.

from what it sounds like with this re-tune i would imagine he would have the hahn ecm, and the boost-fueler thing is more a novelty then anything to me....but i would assume that if he did score a ecm he prob has this as well....

+1 on the update.

 

yes, i have the hahn tuning setup coming and the boost fueler, the only tuning i can do will be on the boost fueler, i just want an idea of what im gonna be seeing on the screens while hes tuning the boost fueler.

 

well my only point of reference is the LSJ and most of us tune for higher 11:1's....i tune for 11.8-12.0 in the summer to make peek power while still staying in a safe range...

for you i would try to get the car 11.5-11.8 at first......

the ecotec is a vary efficient OE motor so we are able to pull of leaner air fules with out an issue.....tell the Subaru guys to tune for 11.8 and they'll **** them selves.

 

I tune for ~12.3 then a little richer up top. Never had an issue, I've been running it for over 20k miles.

 

Its not worth doing if not done right. Trust me if you can't afford to do it right then do not do it. Imagine how much debt you will be in when the motor fails. You need to make sure that you can always monitor your a/f and honestly it wouldn't hurt if you had hptuners to scan it regularily because things will change with weather.

I'm not trying to be an ass I'm trying to save you some money. Just save your money until you can get all the proper equipment.

 

well, if i shoot for 12's across the board, would that be safe and still good performance?

 

It should be safe, + or - .1
When I tune, I go lean until max torque then rich until max hp. I am not very familiar with turbo's so I am not sure how extra fuel will affect the turbo. I think it would be pretty much the same, but then again, I have no experience with turbo tuning. Although, without a wideband installed, I lean on being richer until you can monitor it all the time.

 

lol aqt least you have the correct approach....

tune for lean max TQ and add till rich max HP best way to have highest peak numbers.

the extra fuel shouldest have any effect on the turbo...not unless hes going stupid rich and the extra fuel is actually making it out to the exhaust housing...then its a totally new beast to tackle.

the largeist factor in a turbo tune is timeing tables...the higher the timeing the larger amount of expanding gas's for the turbo to use thus better spool rates.

 

yeah i mentioned running 12.0's to the tuner and he said thats fine on supercharged cars but turbo charged cars arnt the same approach.