New Project - Tuning my 3.4L for POWER - Page 3 - 986 Forum - The Community for Porsche Boxster & Cayman Owners

insite · 05-27-2013, 06:46 AM

took baseline fuel map at WOT yesterday. getting ready to log some test points. the map below is how much fuel i will add/remove to average the prescribed AFR. i will do two baseline pulls at zero change & then run each of the nine test points back to back.

insite · 06-12-2013, 02:49 AM

ok, ran test points & did tuning. the logworks program is calculting power & torque using gear ratios & RPM. problem is, i still can't get the RPM channel to log with a frequency greater than .83s. it's choppy. the program has a smoothing function, but there is a great deal of sensitivity to how the data is chopped up.

i developed a method that is consistent; i used it across the board for these graphs. don't pay too much attention to the absolute numbers. just compare the output. the thick line is the baseline run. also of note; the percent AFR change on the fuel controller does NOT equate 1:1 with an actual change in AFR. i had to play with it a lot to get the test points i wanted. here are the first seven;

insite · 06-12-2013, 02:55 AM

here are a few more test points. when i collected the last data set, everything was a lot leaner than i had planned. i was missing some AFR's that i wanted to log. here they are:

insite · 06-12-2013, 05:09 AM

so you will note some things. first and foremost, nearly EVERY RPM range for EVERY AFR i tried was worse than the stock program. second, there ARE some opportunities.

i struggled with this. i really didn't think that running AFR's in the low 11's would be optimal. in some cases, it is.

insite · 06-12-2013, 05:13 AM

so i made the changes to achieve the top line HP/TQ values across the RPM range. the result is around 2.5% gain from 4500RPM on up. there is also a torque gain down low, the result of ADDING fuel below 2800 and pulling fuel above that.

i think the low end torque is noticable. the high end HP is harder to feel. i also have concerns running AFR above around 13.2 for temperature purposes. EGTs will start getting high above that. so will combustion temps, which will increase propensity to knock. i did check w/ the optimal program below; no knocking or pulled timing.

insite · 06-12-2013, 05:22 AM

even though i didn't make nearly the power i had hoped, i'm happy with the exercise. it helped me clear up my throttle issue & also showed me that the work i have done to the car has produced a well running machine.

at road atlanta the 1st and 2nd, the car was running really well. i also paid a lot of attention to WHERE the 996's & cayman s's could pull me. it's generally turn 7. turns out those cayman S's have a diff, and 996's have slick rear suspension. i think it comes down to grip & exit speed from turn 7. they get a jump on me going down the back straight & it feels like a power delta, but it's not.

j.fro · 06-12-2013, 05:24 AM

This is great info, but I am lost on one important bit...how are you getting the ECU to add/subtract fuel from the regular programming?

insite · 06-12-2013, 05:26 AM

Quote:

Originally Posted by j.fro

This is great info, but I am lost on one important bit...how are you getting the ECU to add/subtract fuel from the regular programming?

i use a piggyback fuel controller. it splices into the MAF signal. at full throttle, our cars use the MAF signal + a stored map to determine fuel. the fuel controller monkeys with the MAF reading at the ECU to trick it into adding / pulling fuel. the unit is an APEXi AFC Select. pretty slick.

insite · 06-12-2013, 05:27 AM

which leads me to another point: the AFC and the data logger are for sale. i smacked the wall at Road Atlanta in a torrential downpour. i am hocking some tidbits to fix the car & weld in a cage.

Topless · 06-12-2013, 06:28 AM

Quote:

Originally Posted by insite

which leads me to another point: the AFC and the data logger are for sale. i smacked the wall at Road Atlanta in a torrential downpour. i am hocking some tidbits to fix the car & weld in a cage.

Ouch! I hope you are ok Kevin.

As you know, once the car is turning much faster laps, bad things also happen much faster.

insite · 06-12-2013, 07:17 AM

Quote:

Originally Posted by Topless

Ouch! I hope you are ok Kevin.

As you know, once the car is turning much faster laps, bad things also happen much faster.

i'm good; thx. arm took a beating from the side airbag. i was going about 85 when i spun, but the hit to the wall was a glancing blow. still, the airbag went off and it hit me HARD. absolutely shocked and PISSED that these are in the car. i really think they do more harm than good in 99% of accidents.

car looks pretty good to me, but i haven't dug into it yet. snapped the subframe & a couple of control arms. only the driver's rear quarter panel shows damage. there COULD be a transmission issue; the left rear wheel hit the wall.

jaykay · 06-12-2013, 07:33 AM

Glad you are okay!

Yeah I wish that there was a way to disable the air bags for the track and then arm again ....or not

I wear an open face helmet with air bag in front so I don't get my head taken off...of course full face with no air bag is best

The Radium King · 06-12-2013, 08:20 AM

can't the pst2 or piwis disable airbags? turn them off for track, on for street.

stephen wilson · 06-12-2013, 08:25 AM

I'm having trouble seeing why airbags would be bad for the track, other than blocking your vision in a minor frontal hit. You don't think that side airbag might have saved you from more serious injury?

insite · 06-12-2013, 08:31 AM

Quote:

Originally Posted by stephen wilson

I'm having trouble seeing why airbags would be bad for the track, other than blocking your vision in a minor frontal hit. You don't think that side airbag might have saved you from more serious injury?

not a chance. my body wouldn't even have touched the door. racing seat w/ harnesses. i think that if i were a smaller guy (i'm 6' / 225lb with LARGE bones), this would have broken my arm BADLY. i was talking to some other guys & found out one of them had a compound fracture caused by a side airbag.

in my estimate, the ass of the car hit the wall at maybe a 15mph closing speed. i was probably going 70+ when i it, but again, the speed relative to the wall was much less. on a race track, there are comparatively few SQUARE hits to the door. this is because all traffic is generally going the same direction. you don't have the risk of someone running a red light & t-boning you. most side hits on a track are glancing blows.

j.fro · 06-12-2013, 09:13 AM

Thanks for the AFR info. Sorry to hear about the arm/crash. I'm not an airbag fan either. I've pulled my door airbags...and the idiot light in the dash for that exact reason ( and a little weight loss)
Somewhere I think I saw a bulletin from Porsche about disabling the door airbags when GT3 seats are installed..

stephen wilson · 06-12-2013, 10:25 AM

Interesting, I never knew they had enough force to break bones.

jaykay · 06-12-2013, 11:07 AM

You can compare it to shot gun shells going off around you

thstone · 06-12-2013, 11:31 AM

First, glad that you're ok and hope the damage to the car is repairable. The BSR car that I'm building won't have any air bags (no need with racing seat, harness, HANS, helmet, and window net).

The Radium King · 06-15-2013, 07:37 AM

When I was looking to use a BMW Maf housing in my 3.2 I noticed that the BMW unit, while close, was 1/16" to 1/8" smaller than oem. That's up to 14% less air than the Maf thinks its getting. That may be a reason for the rich condition you are getting at open loop.