Dark Lightning

Just thought I'd toss this out there for comment. I plan on tuning between a 12.0:1 and 12.5:1 AFR. For a modification list (it's almost stock) check out my site.

93 octane, 3rd gear, Guru v8 chips @ 18psi falling to ~13psi by 6500 with no modification to the airflow signal:



Same everything, 2nd & 3rd gear, after some mild tuning:

Mike B

Torque, horsepower?

Dark Lightning

No dyno within 300 miles. I'm working on it.

hally

looks like you have a nice tuning setup there Dark. How have you routed your o2 sensor cable with the LM? After frying my first tech edge cable, i need to work out a better / cooler way into the cabin than heading back into the engine bay.
Also i notice that your max AFM voltage is about 4.3v which is similiar to that which i got when dialing in my chips for 15psi for a k26/8. I know there was some discussion in the past about what conditions the AFM gets maxed out.

MildMax951

Looks promising Dark, I am in the process of doing the same for my Vitesse k26/6 AFM chips but don't have a wideband O2 sensor so the process is a little slower. My initial dyno run on the vitesse chips showed the same trend as your Guru's ie goes very rich at 4000 rpm and stays there. I have Tial and accuboost but I do live at 5000 ft altitude and boost drops to 12 psi absolute by 6000 rpm. As soon as I have dyno results (hopefully today) I will post. Burning your own chips is, how shall I put it , satisfying.

Dark Lightning

I actually zip-tied mine to the fuel lines coming up the middle/passenger side of the firewall. It's warm but not lethal. 10,000 more miles and we'll know for sure.
Now, I need to do some reading but if memory serves the AFM goes up to 5 volts. The DME simply doesn't pay attention after 4.6. That correct?

Dark Lightning

4th gear


I got rid of the 6000 rpm burp.

hosrom_951

Lean out some fuel past 4000rpms to redline.

macnewma

DL, how significantly is this tuning affecting the proverbial butt-dyno?

hally

how about that lean bump at 3200, probably should plane that one down to 13?
I think that the fact that i got the same max AFM voltage at 15psi as you at 18psi suggests that the AFM is maxed out around there in operation, potentially the age / strength of the spring would cause some variation, my AFM is only 12 months old. Maybe if you stick a finger in there and push the door open manually you could get it up closer to 5v, havn't tried it though.
Will have a look at following the fuel lines with sensor cable, thanks for suggestion.

mark944turbo

the max output holding the door open should be 4.6 volts according to the porsche factory manuals. .25 volts closed door.

Dark Lightning

I was pleasantly surprised at the gains; it felt like I went up a pound or two of boost. Now that I'm fine-tuning I don't feel much difference with small changes but I know it'd show if I was on a dyno.

I'm working on that as well. I try +/- a few percent every time I head into town or back home; there just aren't a whole lot of spots to wind out 4th gear, ya know?

MildMax951

DL, when I still had a shimmed stock wastegate (only 3mm) and LBE I was getting max boost (18 psi) and max torque at about 3200 rpm measured in 4th gear on a load based chassis dyno (not a Dynojet).
any time you get near any kind of incline in 4th or 5th on the actual road this is achievable. I think you are a bit lean in the peak torque area of a k26/6, the car will go like sh*t but I don't know how safe it is. A lot of 951 tuning myths have been disproven over time, so this may be one of them and you could run for years. Interesting stuff, keep going

Edit:' By will go like sh*t' I mean it will be really quick! (That's a South Africanism and I'm not sure how it translates eleswhere)

porshhhh951

my 26/6 go's like ****. So I understand what you mean about disproving old 951 miths. As more and more people push the envelope and get better at tuning and understanding the car I think products and support will continue to just get better and better

special tool

I couldn't agree more!