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.

Maf scaling needed if you change the entire intake or part of the intake that changes the position or the diameter of the tube the maf sensor or the patern of air flowing past the maf sensor.

just an intake tube or filter doesnt require maf rescale.

thanks for the help guys. And now, to complete the thread hijack - am I still current in thinking there really isn't much gain by doing anything else to the intake (or implementing a full aftermarket solution)?

See below for some of Grimmspeed's research:

http://www.grimmspeed.com/grimmspeed...-2013-brz-frs/

On an NA car best bang for buck is catless header, tune and add for E85 (with appropiate tune)if you have it available. and maybe drop in filter

just good catless header,tune,E85, drop in filter will give you around 85% or more of the possible gains from bolt on mods NA , gets you arround 30-35 wheel hp.

can be done for about $1000

doing the rest of the exhaust and intakes, power blocks spacers ect is expensive and gains are not that much more on an NA car

if you want more just go FI or sell the car :D

I have OFT and OFH... unfortunately e85 stations are [very] few and far between around these parts, so I stick with an 91oct tune.

I can see there's some gain to be had with the grimmspeed intake, but is that $350+ going to net me more than a couple horses over my current intake setup? I am guessing no.

Out of the remaining exhaust parts (over, front, mid, axle) am I correct in understanding replacing the overpipe is most critical for gains? And the rest is less critical?

I already have the urge for FI... waiting on oft350 and ft86sf info

overpipe probably only worth doiung if your going fi, each exhaust part after catess header only worth a couple of hp NA. maybe hi flow or catless front pipe but gains not much and can be niosy\raspy when secondary cat changed.

turbos tend to be good at cutting noise and rasp though.

some fi guys have been destroying secondary cat due heat, so probably worth changing that or at least going to metalised hi flow that more durable with fi.

if you change muffler with catless header and hi flow cat or catless midpipe get a quiet one

good to know, I wont bother dumping $300+ on an overpipe until it matters a lot more. thanks for the advice steve, as usual you are very helpful.

Hello all - Where does Perrin publish a MAF scale for their 2.75" intake? I looked on their site and I thought the whole thing with that intake was that it didn't require any changes to tuning, unlike their 3" bigMAF intake.

I'm considering this intake and have an OFT so if there's already a good MAF scale available for it I'd love to know.

Thanks!

end of this post has perrin scaling
http://www.ft86club.com/forums/showthread.php?t=64790

you might need to touch it up using proceedure in that post and vgi utility but will get you started.

.

Awesome - thank you Steve.

do you think running stage 2 91 uel tune while only replacing the header and nothing else behind it is safe? I am reading about exhaust back pressure causing the car to run rich, and I'm not sure how serious it can be.

Stage 2 is intended for catless headers. The other stuff doesn't matter.