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Euro 931/932 vs US 931
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dwak  
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PostPosted: Sun May 05, 2002 9:48 am    Post subject: Reply with quote

Another nagging question!
What exactly gives the Euro spec 931 177HP and the US 931 a 150 HP? Does the Euro have a catalytic converter?
dwak
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Peter_in_AU  



Joined: 29 Jul 2001
Posts: 2740
Location: Sydney, Australia

PostPosted: Sun May 05, 2002 11:08 pm    Post subject: Reply with quote

the so-called Euro cars were not all built to the same spec as were the North American and Japanese cars.

For example, in Australia the use of unleaded fuel was not mandated until 1985 so all cars built for Oz didn't have a cat.

When North America and Japan rolled out unleaded fuel it was basically very low octane crap and the car manufacturers had to respond by reducing compression ratios and retarding ignition. When the rest of the world went unleaded the problems with the fuel had been ironed out.

Add to that the North America and Japanese emission laws which meant that manufacturers used cheap tricks like exhaust gas recirculation (basically pump some of the oxygen-depleted exhaust gas back into the inlet) which really killed power.

I suppose that the difference comes down to the "euro" cars being designed to run on good (leaded) fuel with virtually no emission gear and the North American cars being designed to run on the early attempts at unleaded and to comply with strict emissions laws without the help of an engine management computer
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dwak  
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PostPosted: Sun May 05, 2002 11:16 pm    Post subject: Reply with quote

Reason I'm asking is I'm in the process of dropping a Euro '82 931 engine into an '81
US 931 plus I'm rejuvinating an '80 US 931. It'll be interesing to compare and not so interesting what problems pop up.

dwak
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Peter_in_AU  



Joined: 29 Jul 2001
Posts: 2740
Location: Sydney, Australia

PostPosted: Sun May 05, 2002 11:29 pm    Post subject: Reply with quote

if you run the euro on "premium" fuel and have the ignition timing set to euro spec you should expect euro power levels and no loss of reliability.

Use cheap fuel and you'll probably kill it.
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gohim  
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PostPosted: Mon May 06, 2002 5:40 am    Post subject: Reply with quote

This is what I have found in the Porsche Spec. Book.

The 82 RoW 924T engine is 8.5CR and requires 98 RON Octane gas to produce 177hp DIN. I am not sure, but I believe that different electronics boxes, and no cat or O2 sensor.

The 82 US 924T engine is 8.0CR and requires 91 RON Octane gas to produce 156hp DIN on 91 RON Octane gas.

To get 177hp DIN from the 82 RoW engine, you would need to also need the Row exhaust, electronics (black boxes), Premium Gas, and Row Timing Specs.
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dwak  
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PostPosted: Mon May 06, 2002 11:09 am    Post subject: Reply with quote

ROW-is that rest of world?
The exhaust part is easy in my part of North America, timing easy, I might have to dig up a black box and does anyone know how North Amer. fuel compares to Euro fuel right now?
dwak
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John H  
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PostPosted: Mon May 06, 2002 12:05 pm    Post subject: Reply with quote

The 'black boxes' for the digital turbo's are all slightly different base donthe market they went to. Even ROW cars differ slightly. I'll see if I can remember to dig out the code numbers and you can use that to ensure that you at least have an good shot at getting Euro power.
ROW cars normally had not cats and no emission crap,slightly higher compression ratios and revised ignition curves as Peter mentioned to get the higher hp
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dwak  
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PostPosted: Mon May 06, 2002 2:10 pm    Post subject: Reply with quote

Thank's John. I'd appreciate the information if you find it.
dwak
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Rick MacLaren  
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PostPosted: Tue May 07, 2002 12:43 am    Post subject: Reply with quote

Dwak I got a lot of pleasure from dropping the cat from the car and just putting on a straight pipe and a nice ANSA exhaust. If you can do the computer changes (i.e., black box swap) you'll have a fast car there.
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924 turbo  
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PostPosted: Tue May 07, 2002 1:25 am    Post subject: Reply with quote

Remember that the BIGGEST reason the euro cars make more HP is because they run more boost. 0.70 bar for '79-'80 models (Euro), 0.65 bar for '81-'82 (Euro), and 0.43 for all North American models. Losing the cat will help, as will altering the ignition timing somewhat, but essentially, the difference is in the pistons and boost.
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kevrl  
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PostPosted: Tue May 07, 2002 4:46 am    Post subject: Reply with quote

Remember also that in Europe (well - in the UK at least)98 - 99 Octane (RON) unleaded fuel is still today readily available at the pumps, can you get that in North America ? - If I put 95 Octane fuel in my '82 Turbo it pings like crazy (i've tried it !) - even worse on a hot day. So as Peter says, the Euro-spec would only be reliable on good fuel.

Kevin

[ This Message was edited by: kevrl on 2002-05-07 03:49 ]
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friskynibbles  
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PostPosted: Tue May 07, 2002 10:16 am    Post subject: Reply with quote

mine's usa-spec and the highest octane i can get here is about 91-92. it won't blow up will it? hehehe

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924RACR  



Joined: 29 Jul 2001
Posts: 8114
Location: Royal Oak, MI, USA

PostPosted: Tue May 07, 2002 10:34 am    Post subject: Reply with quote

It's the difference between RON, which is the rating widely used in the EU, vs. the averaged value of RON and MON (R+M/2) used in the US - always lower. It's on the pumps.

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dwak  
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PostPosted: Tue May 07, 2002 12:14 pm    Post subject: Reply with quote

So Vaughan, what is the 'apples to apples' comparison of fuel types?
dwak
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Peter_in_AU  



Joined: 29 Jul 2001
Posts: 2740
Location: Sydney, Australia

PostPosted: Tue May 07, 2002 10:07 pm    Post subject: Reply with quote

my totally uninformed opinion is that North American fuel would be almost as good as it gets (as good as it gets is Japanese fuel where 100RON is the norm).

The problem 20+ years ago was that the US was pioneering unleaded and it took a long time to get right. The same thing happened in almost every country when they switched to unleaded - a couple of years of really bad fuel then things settled down.

That said, it's still a very bad idea to run a euro 924/931/932 on "regular" unleaded the octane rating is just too low. Modern engines can cope with it because they are designed to expect crap fuel so when the knock sensor tells the EMS that the fuel is bad the EMS just retards the ignition and everyone's happy except you've got less power but you get what you pay for.

Our babies don't have EMSs so you have to feed them what the good doctor specified. That means 98RON for Rest of World (what we all call euro) engines which normally equates to what they call "premium".

There's no magic in the ROW engines, they were just set up for better fuel and more relaxed (or no) emission laws - higher compression, more ignition advance and most of the emission gear either deleted or blocked off
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