OFT datalog with Perrin intake
 

Hi, so I recently purchased the OFT and wow, what a great tool! I've read the various posts about MAF scaling, and was hoping to get some feedback on my recent datalog. The car has the Perrin intake (2.75" version, not the large 3" one) and muffler delete pipe. The map is the OFT v2.06 stage 1 91 oct. I followed the instructions to keep the car in closed loop mode, and logged the STFT and LTFT.

Any comments/feedback would be appreciated, thank you!

http://www.datazap.me/u/acj47/19nov2...0&data=1-10-11

Your LTFT indicates your MAF scale is off by 4-8%. Updating your tune to use Perrin's scale would fix that right up. There's not much need to do your own scaling, Perrin's is quite accurate.

Also log command afr to get a better idea of how far you're off. (or at least it helps me) Looks like you're running rich due to MAF scale having too high of numbers on the "mass flow g/s" part of the scale.

I don't even log closed loop. lol I went straight to open loop 2k-7.6k pulls.

Update: used the MAF scaling values for the 2.75" Perrin intake and reflashed. Will log again in a few days. Thanks for your help phrosty and BuBlake!

Any update?

I just installed a 2.75" as well and I'm sitting at -12.50 lt trim on idle/cruising in neutral. I believe the trims look good when driving around, didn't get the chance to do long pulls. Anyone know what the problem may be?

http://www.datazap.me/u/donkeyrage/p...3578-5494-4774

did you put the perrin maf scale values in your tune ?

if you did and ltft still that far off check for intake leaks and gasket at maf sensor

check for exhaust leaks near or before o2 sensors

if still no good you will need to manually scale maf and insert values into tune

see links below on maf scalling, perrin intake scales at end of maf scaling post

Yup I used the 2.75 scale.
My trims were < 6% on the stock air box so I don't think I have an exhaust leak but I'll have to check.
I'll take a look at the intake connections again and tighten down the sensor.
I'm just confused as to why the trims look good when I'm on throttle (any amount) but as soon as I let off the lt trim goes rich.

Thanks Steve

Update: I drove around for a bit with the Perrin MAF values, and the trims were much closer to zero. I was too eager to install the E85 map, so I didn't get any logs before switching to the E...

you probably should transfer the perrin maf values to the e85 tune if they were ok on petrol

Yup, that's exactly what I did. Ran the 91 octane map with Perrin MAF values, made sure the trims were ok, then edited the E85 map for Perrin MAF and filled up on the E & loaded the map.

I am looking at doing the 3" system, yet I just read in a previous post that @steve99 , you said not to scale the MAF while running OFT e85 maps. Does that still true? or should I scale them when I get it?

The problem with maf scaling on e85 is the ethanol content varies. this throws off your trims.

shiv,s E85 tune like others likely has the maf scaling done on the average E85 content.

he likely also used the maf scaling to make it run on the rich side for safety.

the varing ethanol content is another variable to need to consider , as is making sure your new maf scaling does not make your tune run too rich or too lean as ethanol content varies. between about E60 and E90.

luckly in OZ we have a pump E85 that is guaranteed 85% ethanol so it makes life easier.

The maf reading are also an input into the engine load calculation which is used to set timing and fueling to engine , Shifting the maf scale can shift you to diferent load cells in the timing and fueling tables. so log your new tune carefully checking for knock, afr and fuel trims.

This is a new topic for me.

I have been running oft stg1 91oct v2.06 tune as well... I have a K/N drop in panel filter, perrin inlet hose, and otherwise unmodified box and snorkel. Should I be paying attention to my MAF scaling? Car seems to be operating normally.

I don't believe you need to with just the filter.