Catalytic convertors

[Jamie Summers]

How do I know if my 89 Carrera 3.2 Sport (LHD German spec.) is fitted with a catalytic convertor ? Was it only the US spec cars that had convertors at this point in time.

Also does anyone have any strong views on the merits of 98 octane super unleaded vs ordinary 95 octane - Although the label on the filler cap clearly states you must use 98 octane minimum when I purchased my car I was told that the '89 model had been tweaked to run happily on 95 octane - and indeed mine has been doing so since July with no obvious problem. Would using 98 justify the extra expense or indeed require a mild tweak of the ECU to maximise performance.

While I'm about it, I was thinking of having the ECU re-mapped - AMD near Oxford do it for £250, giving an extra 10 bhp - they also offer a larger bore throttle body for £250. Is this money worth spending for a bit of extra poke or I'm I letting myself in for a host of unforseen problems ?

All views gratefully received !



Jamie


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[James Ball]

Hi Jamie

Re fuel. you should run 98 octane. There is nothing, electronic or otherwise, in your Carrera 3.2 that can detect knocking. You need to use Super Unleaded (98 octane)

Re. chips. General opinion also has it that unless your chip is programmed specifically for your car using a rolling road you are wasting your money. There are some great, unsubstantiated, claims out there for bhp. Take them with a pinch of salt.

The only real upgrade you can do to your car is
change the exhaust to SSIs (or a similar, equal-length exhaust) and no, you don't have a cat (I think!). I can double check that when I get home.


Cheers, James


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[Jamie Summers]

Thanks James,

I get no sign of knocking whatsover running 95 octance - car starts, idles and runs cleanly. Plently of letters etc in 911 & Porsche world have suggested that running 95 octane is absoulutely fine, but 98 better.

As for the re-chip. AMD use a proper rolling road and re-map according to the car's specific quirks and provide a full diagnosis and print out - seems to be a pretty pukka set-up.

Jamie


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[James Ball]

Cool. Sounds like you already know the answers.

Re 95 vs 98 - why have 98 on the fuel cap then? Also I gather than knocking tends to occur at high RPMs and is inaudible over engine noise. Having said all that, the discussions I have followed in the matter are always international and it gets damn confusing becuase different countries have different ways of measuring octane.

A remapped chip seems to be the only way to go for chips. For £250 it is worth a punt I guess. Does the chip require you to run 98 octance? I would imagine so.

The only problems I have heard of with chips is rough idling and poor fuel consumption. If yours has either of these after the upgrade I should imagine you would be in a good position to get a refund. I would also want a dyno readout before and after the mod (bearing in mind that dynos are a dark art that are affected by things like ambient air pressure!)

Cheers, James


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[Nathan]

Jamie,


I also have an '89 LHD catalysed 3.2, but mine came from Switzerland. If your car has a cat it's more than likely equipped with the "emissions friendly" engine which all the U.S. cars got. If this is the case you can happily run it on 95 unleaded - European fuel is generally much higher quality than the U.S stuff this engine was intended for. The downside to all this is that these cars have less HP (217) due to lower compression pistons.


The best way to tell which 3.2 engine you have is to check the engine type number. The type number is on the horizontal surface (behind oil temp/pressure senders) behind the engine serial number. If you have a Type
930/25
then you have the 217 Hp engine. If you have a Type 930/26, then you have the 231 HP engine.


I've been unhappy with the performance of mine so have ditched the cat for a straight through by-pass (around £90) which has the added benefit of a beautiful deep exhaust note (not noisy though) and have already contacted AMD about a chip. This still will allow me to run 95RON and gives approx 10hp. Speaking to other people who've had an AMD chip this is a realistic improvement figure.


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[Jamie Summers]

Thanks Nathan,

I'm reasonably sure that as a German model my car is a non-cat standard 231Bhp (but maybe I'm just kidding myself !). I think the Swiss model was a little different. The Swiss being essentially a nation of tree-huggers (despite every adult male being obliged by law to keep a rifle and do a month's military service every year) would, I'm sure, have gone with the more eco-friendly cat version of the 3.2 engine ! I take it from your post that even if mine is a non-cat 231Bhp engine it is still ok to run 95 RON ?

Good to hear that the AMD chip seems to be worthwhile - despite emailing them several weeks ago I've yet to get a response form them. I was beginning to think that if they couldn't be bothered to reply to my queries then maybe I couldn't be bothered to give them my business ! Please let me know how it goes if you have the work done.

Jamie


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[Nathan]

Jamie,

I'm not too sure if the 231 engine is OK on 95 only. You really need to check which engine you've got by looking for the engine type as described above. It's a little difficult to see at first, but can be seen without moving anything out of the way. You'll probably need a torch to see it.

I've heard that many German cars had the US/Swiss engine, so it's worthwhile checking.

It took a long time for me to initially get a reply from AMD. I guess they're very busy.



Nathan


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[Jamie Summers]

Nathan,

I had a good trawl through the car's paperwork last night to see if I could shed any light on the situation and came away none the wiser ! I didn't much fancy scrabbling under the bonnet in the dark, cold and rain to look for the serial number - I think that's going to be a weekend job !

Presumably the cat by-pass and AMD chip will boost the bhp of a 217 engine to roughly the same as a standard 231 ? (but with better throttle response and the ability to run on 95RON) I think that sounds worthwhile if the cost is around £350 (providing my maths is correct !)

Jamie


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[Jamie Summers]

As promised I had a good rummage around for the engine type code, but am embarassed to say I failed to find it - perhaps the aircon pump is in the way. Almost every component has a 930 ........ ....... code on it, but nothing that showed a 25 or 26 engine type. The log book and owners manual proved equally unhelpful.

I'm now reasonably convinced that my car does have a catalytic convertor, so Nathan, I'd be interested to hear about the straight through by-pass, and indeed where the hell to find the engine number !

thanks,

Jamie


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[James Ball]

Jamie


The serial
number
is located on a boss towards the lower right side of the fan...


It is in the upper left of this photo, on the right column of the fan.

You might need a torch and mirror to see it.

Cheers, James


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[Nathan]

Jamie, have you found the engine serial number (not type number)? It should be to the right of the fan, and type number is stamped on the horizontal surface behind the serial number and oil temp sender. It may be difficult to see if the surface is dirty as it's only stamped in small letters.

I would recommend dumping the cat. Mine felt much more willing to rev without it and now sounds like a 911 should! It's no louder during "normal" driving but open the throttle and give it some revs and it sounds beautiful!! I went for the straight link pipe - you can use the UK models normal presilencer but it's about twice the price and has baffles in it, which I figured can't help performance.

Geoff at AMD told me the combination of cat by-pass and chip should give approx 15 hp extra. I'm not too happy about the fact I'm having to pay to get power which I thought was already there (I didn't realise my car was US spec when I bought it), but it's my first Porsche and I'll know in future!




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[Jamie Summers]

James,

Sadly the photo doesn't appear on my computer - anyway I think I know where you mean, and I know that's where the number should be, only problem is that it is totally inaccessible due to the position of the aircon pump.

Jamie


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[James Ball]

jamie

Sounds like you know where the number is but I have updated the link to the photo anyway.

James


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[Jamie Summers]

Thanks Nathan - I re-read an old 911 and Porsche World article last night about changing the mild steel exhaust system for a stainless one. The mild steel one in question had a cat and as far as I can see mine looks identical (12 inch torpedo shaped bulge just ahead of the main exhaust box) - needless to say the replacement stainless system had no cat !

Out of interest do you know if AMD would do the cat bypass too ?

Jamie


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[Nathan]

Just be sure you have got a cat first. The normal Euro spec pre-silencer looks very much like a cat. I stand to be corrected on this, but I don't think the normal presilencer has the CO2 sensor which the cat has. Check to see if your "cat" has a sensor bolted into it with wires connected. It would be on top of the cat. Also, mine had a heat shield between the NSR wheel and the cat. Again, I don't think the non-cat cars have this.

AMD will also fit/supply the bypass for you, if you need it.

By the way, I couldn't justify buying the stainless one - the mild steel one is very thick gauge anyway and as it's a pipe, as opposed to a silencer, I don't think it will ever rot.


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