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Discussion Starter #1
For those who are interested, I've been using my TS for the work run down the highway. I bought it for the transaxle to transfer into my 3lt but the car was in too good condition to scrap out so put my 3lt TA into it.
I've been keeping my receipts for fuel and checking my L/100km each week.

Learning to drive the TS with a tall diff has been odd. Going form the 3lt with almost everything modified it felt like a completely different car in every aspect. But I'm learning, still, how to drive it, how to use the revs and throttle position to gain speed efficiently but still accelerating to keep up with other road users.

According to Google maps, my run from home to work is 38km, so I'll call 350km a week would be highway km's. The rest would be town/city km's.

Here's the receipts I have kept for the last 6 weeks.



Coming from the 3lt which averaged 20lt/100km for the few weeks I drove it with the 4.1 TA [Honestly, I drove it hard and never with economy in mind], down to mid 7l/100km is pretty awesome on my wallet! Believe it or not, it's also better than my partners 2012 Holden/Chev Cruze 1.4lt. That averages around 8L/100km.

The car still needs a real service. I have only changed the oils and oil filter. The car is as I bought it otherwise. If the oil colour was guide to its last service, I'd say its been a very long time...


Craig's Place, Fuel Quality Plug (S30)
I just fill it up with regular fuel, 91 octane.
The weeks before the receipts we're all around the 9.5L/100km mark, running with no fuel quality plug.
After fiddling with that plug, I've settled on the 'yellow' setting. Blue gave the car a cold miss when accelerating - dangerously bad. Yellow is perfect. No different with fuel econ' and better response too.

So has anyone else got numbers to compare with?
 

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Those are some really good numbers.
It'd be really interesting to put a wide band AFR meter on it and see what AFRs she cruises with.
If it could be set up to cruise leaner than 14.7, you'd probably get into the sixes.
I can't say I know much about the workings of the Motronic, but I know that the earlier Nissan ECU, which from what Festy posted about the Motronic stuff, look very similar to the Motronic ECUs, used a settable 'flag' to tell the ECU which cells in the fuel map to actually pay attention to the 02 sensor.
Now if the TS ECU functions the same way, then a dual map (2 complete maps of everything on the chip) EPROM could be set up. 1 that is the typical ECU mapping and 1 where, assuming that the 4.1 system uses O2 sensor 'flags', the O2 sensor flags are all turned off and those rev/load points that correspond to highway cruising are set to a leaner AFR. Lean enough that car is still drivable and fairly well behaved and not so lean that exhaust gasses get too hot, but lean enough to achieve genuine fuel savings.
It'd be a bit of a crude system, tho. Just a simple switch to change between cruising fuel economy and properly drivable and safe to thrash standard/near standard maps.

Something else worth considering: AutoSpeed - Modifying Under-Car Airflow, Part 2
 

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Discussion Starter #3 (Edited)
Cut-copy from a facebook chat with Marcus [I believe you know him too].

"I did some data logging with the TS! hooked up my wideband for some testing. I have it running narrowband into the ECU too"

"left shows 91 map, with wot 11.95AFR, right shows 97 map with wot at 10.2

idle stability is really good during 91 closed loop... you can see it jump around during open 97. The 97RON tune is way lean, even with normal driving - averages like 15-16AFR"



Edit: Probably getting too far into it with tunes. I don't want to spend money or too much time on this car, but 6's sounds good! Haha.
I have pondered the idea of some under body aero work... But I still have my rear tyres mounted backwards [rotational], I've been a bit flat out lately and haven't even remember to switch those!
 

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When I used it for work 90 miles per day mine used to get 38Mpg and if I drove like Miss Daisy I could get 40. So long as traffic was ok.

Got a Fiat for work now (that does 55 Mpg) so I don't check the Alfas figures, probably a good thing as it just does the "fun" stuff now (good morning Officer).
 

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Discussion Starter #5
Fill-to-fill MPG or is that trip computer MPG? I only just found out yesterday that there is UK and US MPG's...
I also get my numbers NOT trying to drive like Miss Daisy, just driving around effortlessly. The TS isn't any fun at all to drive, I get most excited at the bowser on my phone calculating L/100km so it's pretty easy not to try and make things fun while driving.
 

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"left shows 91 map, with wot 11.95AFR, right shows 97 map with wot at 10.2
Purely from a performance perspective, 10.2:1 is way too rich for best performance, even for a force fed engine. Even 11.95:1 is at least 0.5 richer than the richest you'd deliberately tune for.

A bit off topic, but most people tend not to realize that a decent tune in a computer controlled engine revolve around removing excess safety (No factory car ever runs lean unless there is a fault of some kind.) fuel from the high load and transient (acceleration) driving conditions and then tweaking the ignition timing to get the highest achievable torque at any given rev/load combination. Typically this will help with fuel economy too.
 

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The TS isn't any fun at all to drive, I get most excited at the bowser on my phone calculating L/100km so it's pretty easy not to try and make things fun while driving.



Joking aside, my 75 doesn't have a computer so that's brim to brim with proper British gallons.

The Fiat does have a computer but that 55 is brim to brim, the computer makes it 57.
 

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Discussion Starter #8
Haha, meme responses give me giggles. I'm serious, it's not much fun at all! Coming from a modified 3lt for comparison though; it has a massive turn circle [Both left and right, no idea why], the handling is terrible with loads of initial understeer and no steering feel [probably need a wheel alignment], the brakes are crap [cheap hard pads I presume because everything feels normal] and it's so ****ed far to change the gears! Oh, slow too, so slow that a friends Hyundai Excel, stock, is faster through the pines... My 3lt trumps it, but I've put effort into making it what it is.

It's cheap to run though. I was gonna be happy with any figure around 10L/100km [Proper metric haha]
 

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Sounds like there's a lot wrong with it! The joy of the Twinspark isn't the straight lines, it's the way it handles and steers. Put one on a twisty road or track and it should wipe the floor with a V6, they really are that much better.

There's a good reason why Ron Simons used Twinsparks as rentals for his Nurburgring Experience for years.
 

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Completely agree with Mound!! Whether it is stock or modified, twin spark are definitely better balanced than the nose heavy 3 litres and more fun to drive.

By the way: with the stock 10/41 pinion ring set, I run with my twin spark 883 km from Florence (Italy) to Ivrea (north east of Turin, Italy) and back to Florence, to collect a beautiful Alfetta interor (the other Alfa I have). Running at constant speed and doing my best to decrease the fuel consumption I could achieve a very good 15 km/litre (I needed a bit less than 60 litres of petrol), which I consider very good for a 197000km car with stock engine.

This is not only the opinion of a few people (and maybe even Ron Simon's one)... I just came across this page, in German, where a stock twin spark, a stock 3 litres and a tuned 3 litres are compared:

http://www.alfaforum.de/download.php?id=7767

Words like "Der Twin Spark vermittelte den meisten Fahrspass" (the Twin Spark gave the biggest fun to drive) can only mean one thing. If you speak German and read the rest of the article, you'll find even more compliments to the small 2 litres equipped car.
If I was in your shoes, I'd put the 10/41 back in the twin spark.... I believe that you swapped the clutches too and the 2 shafts that go from the differential to the wheels., but there is one bearing inside the gearbox close to the pinion's head that is different if you consider the 4 cylinders Alfa 75 and the v6 or turbos. The safe way to get a 10/41 for a 3 litre is buying it from a Milano Platinum, not from a Twin Spark
 

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I do not want to jinx it, but I think this might be useful for many Alfisti in the forum...
I was in the previous post talking about the bearing located near the pinion's head and here is what I found:

  • 60522435 is the code corresponding to the bearing for 4 cylinders alfas (excluding Turbo)
  • 60518381 is the code corresponding to 6 cylinders, turbo and 2.4 litre turbodiesel
It looks like this reflects on the gearbox rear casing (the part where the differential is located. The bearing close to the pinion's head is assembled here). I believe, since the codes are different, that the bearings have different dimensons in fact:

  • 60741597 is the gearbox rear casing for 4 cylinders, excluding turbo
  • 60531990 is the gearbox rear casing for the v6, turbos and 2.4 litre turbodiesels
As I mentioned earlier, to get a shorter pinion ring set, I'd rather look for a Platinum, definitely not for a twin spark. In Australia, you might look for a 75 2.5 v6 or for an Alfa 90 2.5 litre Super, but then you'll need a specialist to put a limited slip differential in (in this case it is necessary to re-shim the differential to get the proper differential bearings pre-load and the proper pinion/ring clearances).
Another option, but problematic in Australia, is to get a turbo gearbox, with the 11/43 ratio. I believe this would be the best solution for normal use, Alfa Romeo chose this ratio for the v6 3 litre S.Z. and R.Z.
 
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