Does anyone have a dyno shart with the a/f plot from the dreaded APE Stage II chips? I'm looking for a regular 951 with just the chips and maybe a boost controller.

TIA
-Kevin

 

someone has one im sure, but for now you could check danno's racerx website, it had one iirc

 

Do you want APE-II chips in the configuration as shipped and designed by the manufacturer? Or you do want it in the mutated and modified form that many people do? Once you stray away from the configuration anticipated by APE, all bets are off...

 

Huh?

 

I think what Danno is saying is that you want the a/f ratio graph of a stock car with JUST the chips installed or a plot showing the APE chips being changed due to MAF/MAP, higher boost etc (the one where many people usually do)....right Dan?

 

Oh... if thats the case, I tried to make that clear in the first post. I'm looking for a plot from an otherwise stock 951. If someone has one with just the chips and a boost controller of some sort (jet, LBE, AccuBoost, etc.) that's cool too.

 

The APE chips came with a jetted banjo bolt. It's when people add boost controllers or LBEs that the boost profile changes, which changes the A/F ratio.

 

That's true... either way, I'm just looking for a simple plot! lol, I know somebody has one... I'm not looking for "Kevin, don't do this/that" or general APE knowledge info stuff. I know I'm sounding groggy, but it's been a long day. Guys... I know APE runs pig rich in the mid range and lean higher up. I know they aren't the best. I'm curious... you all don't need to worry about informing me of chipping consequences; I work at a Porsche specialist shop and witness it first hand

 

Just remembered, Jeremy Himself may have the dyno runs of the APE chips with him, since he tested out the 'chip manufactures' out there and even has results on them on fully stock cars (if i remember) try contacting him........or hopefully he would jump in on this thread

 

Awesome, thanks

 

Ok, I found two charts for you from customers that submitted dyno-plots for custom chips:

K27/6 @ 15.5psi, MBC, stock AFM, APE-II chips, higher 3.5-bar on adjustable FPR


K27/8 @ 15psi, MBC, stock AFM, APE-II chips, 3-bar FPR


Shows the typical mid-range richness with high-end lean tendency. The combination of larger k27 turbo and MBC causes a greater V-shape than you'd typically see. That's because the turbo/MBC combo can hold a flatter boost-curve than stock (15psi all the way to redline), which results in the high-end lean. The super-rich mid-range also causes extra turbo & boost-lag, as can be seen in the 2nd chart.

On a K26/6 turbo with APE-II chips and banjo-bolt restrictor only, you'd see a boost-curve that goes from 15psi max in the mid-range down to 10psi by redline. Since the chips are mapped for that kind of a boost curve, the air-fuel ratio plot never gets leaner than 11.0:1 (mid-range 10.0:1 richness still there though...)

 

Danno, that curve never seems to get up past 13.5, am I correct? THat isn't so bad in that respect (though it's a completely different turbo and FPR than mine)... that thing is out of control rich though. Ouch! OWNED!!

I have an MBC that will keep boost until redline (only drops off 1-2 psi), so I'm curious as to how much I might be getting lean. Well... I'm parking her until next summer after next week (minus the weekly drive, however) so it can wait until then. I think next summer will bring a little dyno time and tuning for whhat small mods I have now! Dyno tune and track time will be nice... here's hoping I get the time to do it!

 

"that curve never seems to get up past 13.5, am I correct? "

yeah, but you don't ever want to run leaner than 12.0:1 in the upper-RPMs. Non-boost applications, like a 944NA may see maximum power at 13.0:1, but even 13.5:1 on an NA is too lean. If anything, you want an air-fuel ratio that gets richer and richer with increasing RPM for safety. Not much power difference between 12.0:1 or 11.0:1, so you're better off too rich rather than lean.

 

I understand that 13.5 is a little past comfort level, but do you have any proof that 12.5-13 aren't a good balance between temperature and safety vs. power making? Of course it's better to be rich than lean... but I'm still trying to find people who have shown that these levels are detrimental to engine life.