Ed Hughes

IMHO, mapping and newer ECU does not have to be dependent on one another. Porsche put more aggressive maps on chips in the latter 80's, resulting in higher HP. The DME pin numbers changed too. The newer DME's, in of themselves, did not make the engine perform any better.

Falcondrivr

My '95 keeps up with the LWF just fine. (It also keeps up with '96-98s just fine.) However, i'm glad I have the '95 because after a few trips to the track, I now know that it's capabilities are well beyond my own. I can't imagine how far behind it I would be in one of them '96s....

Mark in Baltimore

You're saying that a faster processor attributes to a real world performance difference? I just have a really hard time believing that it will make any difference other than having a bunch of engineers speckle the charts after they whack off to the numbers.

JM993

It's a good question and not one I can answer with complete certainty. However, I do have a theory based on my own experience. My car has a standard mid year US 95 ECU with an ROW 96-98 chip to operate the VRAM. I also have a LWF. I do not have a stalling problem. It's my theory that the capacity to accomodate a LWF is in the chip, not the ECU itself. Note that mid year to late 95 ECUs can be "updated" to 96-98 ROW specs just by substituting a 96-98 ROW chip (see link in my sig for more details). I'm betting that when Porsche created the LWF for the RS they anticpated that these may be installed in non-RS cars and updated the chip for this along with the capability to operate the VRAM.

Cheers,
Joe

ljugete

Ditto! MY 1995 Rules baby!

TheOtherEric

This little bit of advice stems entirely from one guy who acknowledged here that he never even checked if the geometry was any different. Porsche certainly never said that. It's just one American who says he heard it from somebody who supposedly knows.

I've always thought it's BS and it's good to see people trying to dispel the myth.

It's a good question, but it's based upon the assumption that there is indeed HP differences between 95 and 96+ (yes, we're all agreed on TQ but not HP). Many of us don't believe Porsche's 272 vs. 285 HP numbers. A few years back somebody posted all the dyno data from several 993's dyno'd at a shop on the same day. '95 and '96+ all averaged the same peak HP. Interesting, eh? But it's mostly trivial since there's definitely a TQ improvement for '96+, but conventional wisdom says that's due to V-ram.

CalvinC4S

It is my understanding that the air/fuel/timing map is more advanced, higher definition of parameters resulting in a smoother map. The later ECU also plays a role in tuning the Varioram intake.

I do not give the Varioram 100% credit for the increased HP/TQ in the 96-98 cars. With that said the ECU gets a pat on the back as well as the varioram wouldn’t work with out the ECU telling it when to open/close

The later ECU measures from both banks taking 3 cylinders per side rather then all 6. If this attributes to precision or just emissions, I do not honestly know; leaving the 2 behind the cat out of it.

Faster, being how the ECU/motor reacts between WOT and cut to idle.

Eric, why is Porsche still stocking 95 specific control arms?

CalvinC4S

How do we get more TQ and no change to HP with an induction modification?

Wilder

The factory does.

Talk to Steve W., Colin or any of the other experts on the board. Why do RSRs use an upgraded intake? Why does a properly polished and ported VRam add 5-10HP/TQ? It certainly is, if not the sole, certainly the primary reason VRam cars make more power.

However, I have to agree with Mark that all this is a hair-splitting exercise. There are benefits and drawbacks to the 95 and in the end, I think most would agree they are awash. While it's nice to have more mid range power on the street, it makes little difference at the track. Carrying 20 extra lbs at the top rear of a 911 is not the best way to increase its performance and that alone brings into question the purpose of the VRam, SAI issues not withstanding.

The best part about the non-VRam cars is that they command lower values due to generalizations and misconceptions by the not-so-well-informed, making them great value IMO.

Bill Verburg

You certainly have a lot of misunderstandings

2.10.1 and 5.2.0 both include exactly the the same selective and adaptive individual cylinder control for knock sensing and have the same engine operating inputs. All other engine control is also the same. 5.2 added only extra OBD2 monitoring and freeze frame memory of 1 fault

By the way i am nit making any of this up. It all come directly from Porsche Tech and Training manual 'P21 Fuel and Ignition Systems'

the extra hp in '96 comes from larger valves and vram intake that can vary it's geometry to better optimize low and high rpm operation. non vram intake is optimized more for upper rpm use and is far less variable.

the lwf issue is 100% related to the chip, my '97 stalls when ac is used my '95 does not. If I go back to an older chip the '97 won't stall but I don't use ac much and I like the rest of the chips parameters so that's the one I use.

Bill Verburg

You do know that RSRs don't use vram at all

CalvinC4S

The factory gives 100% credit to the varioram?

I agree primary, but not sole.

No question about it that the intake manifold is a great place to find HP.

CalvinC4S

You certainly have a lot of misunderstandings,yes

Knock sensing, yes.

same engine operating inputs, no

All other engine control is also the same, no

vram intake that can vary it's geometry to better optimize low and high rpm operation. non vram intake is optimized more for upper rpm use and is far less variable., yes

the lwf issue is 100% related to the chip, yes .. part of the ECU

Did you take P21 or have the book?

Anything in P90?

Bill Verburg

Oh really, please enlighten us.

Wilder

Yes, that's why I said "intake" and not VRam. Actually, it was you that enlightened me to that fact a few years ago.