US vs Euro engine specifications

Hi

I have a US spec 1973 246 GT. At some point most of the smog gear has been removed, otherwise the car is very original.

Is removal of the smog gear common and do you need to make any other changes when that gear is removed?

Were the Carb's and Cams in US and Euro spec Dino's the same in 1973. Were the Fuels the same? Where did that extra HP come from for the Euro Spec?

Thanks


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I had been told many years ago by a shop that Federalized European spec cars that the camshaft timing is different and the distributor timing is different. The carburetor jets may be different. Possibly the US spec carbs run a little leaner, but my specifications are still packed in boxes after my move from California to Nevada.

 

Thanks,
Any idea if the cam lobe profiles might be different?


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The information from that conversion shop was only partially correct, I believe. The camshafts and camshaft timings were identical between US and Euro spec cars. In fact, all the internal engine parts were identical between the two versions.

The distributors were indeed different, with the US version having a different advance curve. Surprisingly, the US distributor offered slightly more ultimate advance, but the progression through the rpm range was slightly different.

Equally surprising, the carburetor jettings were identical between the two versions.

 

Many thanks for the advise - we are pulling the engine apart at the moment and plan to profile the existing cams so we can compare. So far, we are fairly sure the engine has never been apart before but we're still looking into everything we can before disassembly.


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Removal of the smog gear was very common. No, you don't have to make any other changes.

Yes, as mentioned, the carbs and cams were the same.

The answer to your question about where the extra HP for the Euro version came from, is this: They didn't! The 175 HP figure sometimes mentioned for the US version was a myth, based on an estimate published in a Road & Track magazine test. In reality, the US version produced almost identical power. The US version was sold and marketed by Ferrari as a 195 HP car, identical to the Euro version. Although doubted by everybody at the time, it was probably very close to the correct figure.
It did have drivability problems, though, mainly off idle in the lower rpm range. That may have been the reason many owners had the smog gear removed.
At higher rpms, the air pump in the Dino is disconnected and exerts no drag on the engine at all.

 

Many thanks for the help. We figured the usual Ferrari HP myth would apply. I'm in New Zealand with a US car missing about 1/2 the smog gear so as long as removing the other 1/2 had no issues it would seem to be a better long term plan for the car to run without it. Thanks again.


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I never could figure out why so many think that the U.S. spec Dinos were down 20hp, when in fact they weren't. However, they did weigh a little more because of the extra weight of the air pump and associated equipment.

I do note though that some sources claim that the U.S. spec Dino 308 GT4 was down up to 40hp versus the Euro spec Dino 308 GT4. I always wondered whether that was true or not too.

 

Extra weight is much more than the emission equipment. For all those US crash requirements the frame is almost around the car totally different. Not only the double fixation of the bumpers, metal beam for side impact inside the doors and also much more massive frame towards front and end. I one restored a US- GTS after I finished my Euro GT and was surprised about all these differences.

 

The idle jets on the USA cars were 0.55mm against the euro at 0.50mm

 

Thanks for the advise. We have started to notice a few differences but have a long way to go so appreciate all comments.


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Thanks - will watch for those. Carbs came off yesterday but not taken apart yet


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http://www.ferrarichat.com/forum/206-246/449868-dino-rolling-road.html

may be worth reading this article, modern fuels need to be taken into account now. When my car was on the dyno, at mid range she was very lean and had to change the air correction jets.

 

To make things more interesting, the Stratos is rated at 190hp vs 195hp for the Euro Dino. Engines are identical except for the carbs and intake manifold. My "seat of the pants" comparison is my Dino with the Stratos induction is more power and torque than with my stock induction without any other changes.

Freeman

 

If so, I stand corrected. Where did you see that specification? The parts manual or the owners manuals? I compared the specs a few years ago and saw no difference in the jet sizes. I believe I looked them up in the US supplement to the owners manual for my own US Dino. I may of course have missed it, but it is also possible that the owners manual had not been updated.

In any case, there certainly was no power loss from the jettings.

 

Lars - The Weber manual and Ferrari manual, the DCNF19 was jetted the same spec as the euro dino except the idle jet. I cannot post as I don't have any spare uploads left.

There shouldn't be any loss of power as the main circuit jets were the same. The quality of fuel will be a factor though. When I had my car on a dyno it was running at about 175bhp, for a 40 year old engine (rebuilt) wasn't that bad imo. The guy on the dyno reckoned with proper AC jetting to offset the poor fuels we get today would possibly see that increase to about 190.

Tony

 

Hi Tony,
Can you send me that link again - the current one sends me to the wrong place unless I have my settings here wrong. But in any case I totally agree. We will need to re-jet for modern fuel. At mid range do you mean about 3500rpm was running lean?


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The link works for me, try the advanced search with that title.

4-5k was very lean, with smaller air correction jets it is much better.

http://www.ferrarichat.com/forum/206-246/449868-dino-rolling-road.html

 

May I ask if you know the weights of the US 246 GT and GTS?

 

@Dino Club Germany hasn't logged in since last year. Does anyone know the weight of the US Dinos? @GermanDino perhaps?

 

In the day I don't remember anyone keeping their smog equipment on very long. Mine was removed & discarded within the first 2 mo. of ownership. Yes we did think removing improved drivability & made servicing slightly less cumbersome plus made the engine compartment more attractive.

 

2850 lbs / 1293 kg
but Ferrari doesn`t make a difference for GT or GTS US-models
so for sure not the real weight

 

Thank you. So this is what Ferrari quote? I'd guess it's much higher than that as IIRC you said that the European 246 GT is 1250 KG with the European 246 GTS being 40 KG heavier.

 

yes....

 

Perhaps @DWR46, who has weighed many Ferraris, will know the weights of the smog equipment and body strengthened (bumper mounts and doors) US Dinos.