slim_boy_fat

Not 100% sure about this but i dont think the UK cars have either the RC or the IA plugs? I just didnt see anything like that when i was fitting the chip. Bear in mind at he same time i soldered the A/F into the DME harness so i was pulling and proding at it quite alot. This ither plug the IA is it much further up the loom?
BTW what is the Impedance adaptor for? (and dont say adapting the impedance!!)

Waterguy

The 951 (and the 944 from 1988 on) were tuned the same with and without catalytic converters. The impedance adaptor is used with ROW non-cat cars to let the DME know there is no oxygen sensor connected. I would guess that it forces the DME to run in open loop mode, but that is just my speculation.

The Coding plug is used to change to different maps within the DME.

Danno, as I said before the car is running great. Much less turbo lag, much better low-mid rpm drivability, no stumbling of any kind. Big improvement over the Autothority chips I had in there. I have the boost controller connected to the CV, and the car seems to be overboosting. I will install the aftermarket boost gauge and plumb the reliaboost straight to the wastegate, then comment on on-boost performance.

The biggest difference I have noticed so far is in 5th gear cruising. It never felt like there was any power in 5th below 2500 rpm (65 mph), so I seldom cruised in 5th below 70 mph. With the Guru chips it feels much smoother and stronger off boost, and will easily pull 5th at 2200 rpm, so the gear has become much more useful.

toddk911

Waterguy: Are those the 15 psi or 18 psi chips??

slim_boy_fat

All the 88-91 cars in the UK came with a CAT, hence why the IA plug is not required...Not sure how many other RoW countries didnt have the CAT fitted. I thought it was part of the marketing ploy for the 250bhp model that with or without the CAT it produced 250bhp. I think they raced them with the CAT fitted..

Waterguy

.The answer I received to that question is:
I will do a dyno day later this spring and try it at both 15 psi and 18 psi and post the results. No date set yet, though.

Danno

"I thought it was part of the marketing ploy for the 250bhp model that with or without the CAT it produced 250bhp."

Really? I always thought the cat was worth 3hp since the Euro cars had 250bhp and the US was 217bhp. I didn't realize the UK had them as well.

Ok, here's the locations of region-coding plug and impedance adaptor:


1. is the region-coding plug (about 5cm away from the box)
2. is impedance adaptor (10cm away from DME box)

These two plugs generates a 2-bit binary code in the DME. This creates 4 separate codes and selects from 3 distinct maps internally. Those codes correspond to the 4 regions of the World listed above. The USA map as selected from the above instructions picks Map1 with the standard GURU settings. Map2&3 have higher ignition advance for race-gas or a race-gas blend.

Since these maps require higher octane than available at the street pump, I recommend using the Map1 (USA) settings. The various combinations of these settings are detailed in the instructions I sent out. If you want further clarifications on these selections or don't quite understand my instructions, please email and I'll be happy to explain.

Gary

I think I may finally have worked out the answer to a question I've been asking in different ways here on and off for years

I have a Swiss '86 951 with no cat. In order to "tune" a little, I put an oxygen sensor in the exhaust (using the pre-drilled but blocked hole) and connected it to an ARM1 and a the DME (Danno and others explained how to do this years ago - thanks). However, I never got any of the dithering that people mentioned and the conclusion seemed to be that the DME was Euro specific and would not take into account any input from a sensor.

Apart from anything else, I figured that with the sensor in place, emissions would be better... (?)

I'll have to take a look but assuming I have the IA in place, should I remove it since I'm using US chips which assume the sensor is in place? I recently had the emmissions checked and it failed. I had to remove the 3bar FPR, install my old Adj. FPR and turn down the pressure to pass. Would running in closed loop solve this?

TIA and regards,

Gary.

Danno

"assuming I have the IA in place, should I remove it since I'm using US chips which assume the sensor is in place?"

Yes.

" I had to remove the 3bar FPR, install my old Adj. FPR and turn down the pressure to pass. Would running in closed loop solve this?"

Yes, the idle-maps on the GURU chips tend to be a little on the rich side. Especially combined with the 3bar FPR. While it does give you a smoother idle, it's borderline on the emissions. The O2-sensor does bring things back into stoichiometric/

slim_boy_fat

You taking the pi55?

I am talking about what you call turbo s cars the 250bhp version not the 220 bhp version.....

And yes all UK 250 cars had the CAT.

As i said i am sure the UK ones done have either of the plugs you have shown above. Prob not need to have an advanced timing setting in the UK as we dont have high octane fuel available, and the CAT is standard so no need for the IA plug either. I await to be corrected!!!!

Danno

Sorry, mis-typed. The TurboS cars in the US were rated at 247bhp, 3 less than their non-cat Euro versions just like the normal non-S cars. Which were 217bhp in the US and 220bhp in Europe. I guess the UK got a special higher-power catalytic version.

Ok, if you don't have either plug, it's no big deal. You just won't be able to select the higher-ignition maps for race gas that's all.

Duke

I thought the 3 bhp was just due to different measurements... like DIN HP and SAE HP etc.
Are you guys really sure it's 3 hp difference?

Waterguy

You are right Duke. Difference is due to measurement system. M44.52 was rated by Porsche at 247 net HP using SAE Method J 1349, 250 net HP using DIN method 80/1269/EC. US marketing and magazines quote SAE numbers, Euro quote DIN. No difference (at least acknowledged by Porshce) between cat and non-cat versions.

Danno

So there's really no power difference between the cat and non-cat versions of the car? wow... And I thought Ferrari was special for being able to do that with their federalized version of the F40. Although that model lost the ride-height adjustment in the process.

Duke

I suppose that on a completely stock car the KLR pushes the turbo a bit harder to make up for the added backpressure/flow loss genereated by the cat. Or what do you guys think?

Danno

Interesting idea. You should be getting your chips & headgasket in a couple days. Why don't you send me your KLR chip and I can compare to the stock US KLR chip.