The Scrapcento

[maczo]

Originally Posted by AndrzejM

2600 is pretty high, but I've seen worst. Anyway Punto with your engine has 5.3 l/100km average, by the factory, so your Scrapcento shouldn't be worst. Have you tried to P&G?

Yes, the sporting gearbox is definitely shorter. And yes, I've tried moderate P&G, traffic permitting. Mostly pulsing from traffic lights and coasting to the next ones, to sharp turns, speed bumps etc. Nothing extreme, really. But I think it helped a lot to get 6.5 l/100km in mixed driving. When compared to the same 6.5 achieved mostly on the expressway it seems quite nice.


Anyway, I was on my way today to the "Festival of Science", where I wanted to attend a lecture on aerodynamics of fast cars, then suddenly:



Quiz for the observant: What is wrong with this picture?
Hint: I didn't make it to the lecture and my wallet is lighter by $80 just for getting the car to the mechanic.

[AndrzejM]

Does your driveshaft came out the gearbox?

[maczo]

Originally Posted by AndrzejM

Does your driveshaft came out the gearbox?

Correct!

The left engine mounting broke and the engine and the gearbox rotated down and right on the other mounts, making the left drive shaft loose and fall out. And all this after I ran over some minor irregularities of the road... Looks like the mounting had a hard time at Rally Wyszków and was on its last legs.

[Piwoslaw]

Originally Posted by maczo

And all this after I ran over some minor irregularities of the road...

Only minor? Where in Warsaw did you find a road in such good shape?

[euromodder]

Originally Posted by maczo

Nothing extreme, really. But I think it helped a lot to get 6.5 l/100km in mixed driving. When compared to the same 6.5 achieved mostly on the expressway it seems quite nice.

Still, 6.5 L/100km seems like a lot for a small engine / small car.

Do you coast - either with the engine off or on ?
If not, give it a try.

[AndrzejM]

Originally Posted by euromodder

Still, 6.5 L/100km seems like a lot for a small engine / small car.

I agree completely! I'm thinking maybe that's because of that camshaft which is set up for top end power that maczo mentioned before. Maybe it should be adjusted for low end power and torque then Scrapchento should be more fuel efficient. Maybe ignition timing should be slightly advanced too.

[maczo]

Originally Posted by euromodder

Still, 6.5 L/100km seems like a lot for a small engine / small car.

Do you coast - either with the engine off or on ?
If not, give it a try.

Yes, as mentioned above, I try to coast whenever practical (engine-on). If I'm on a one lane street with traffic behind me I just maintain constant 50-60km/h. If I see a red light far ahead, I coast. If there's a 2nd gear turn in a few hundred meters and no one right behind me, I coast. Whenever seriously slowing down (not coasting) I do engine braking, keeping the revs relatively high. It's not like the 6.5 came with a snap of the fingers

Originally Posted by AndrzejM

I agree completely! I'm thinking maybe that's because of that camshaft which is set up for top end power that maczo mentioned before. Maybe it should be adjusted for low end power and torque then Scrapchento should be more fuel efficient. Maybe ignition timing should be slightly advanced too.

Well, I agree completely too But engine and car size are really not the only parts of the equation and I think the mentioned valve timing, "loose" exhaust, short gearing - they all may contribute to high baseline fuel consumption. And then there's the most important argument that other 1.2s burn even more fuel (and I mean 'centos, not the Punto)

Of course I cannot rule out a mechanical problem (and I know the brakes are notorious for stuck calipers). I will ask the mechanic to check the lambda since the car is already at his workshop. Maybe the injectors are worn out and pour fuel instead of spraying? What other problems might there be?

Bottom line is - maybe there's something to fix mechanically and I'd love to figure out what that might be. But then again if there's nothing to fix I wouldn't be very surprised.

Originally Posted by Piwoslaw

Only minor? Where in Warsaw did you find a road in such good shape?

I know what you mean This was the last place that I'd expect to cause such damage. Relatively new asphalt with just one big patch that started to cave in irregularly. Nothing special when compared to some surprises that you can encounter here

[maczo]

Aaaaand the car is back from the mechanic.

What is not faulty:
- lambda
- brakes (not stuck)

What is not faulty, but causes bad FE. This time not my opinions, but the mechanic's. I didn't give him hints on what to check, apart from the lambda and injectors. Here it goes:
- re-programmed computer with altered ignition timing and fuel dosage. This is a small surprise, because I cannot recall that detail from the swapping process. But the ECU was indeed bought used from someone with a 1.2 'cento, so it kind of fits.
- exhaust too loose (and I don't mean the mounts )
- intake (current is semi-CAI, cone filter)

So now I feel partially excused for getting mediocre FE

The big question is: what now? Kill-switch + aero to coast longer? WAI? (I could probably isolate the filter from sources of fresh air).

Any and all suggestions welcome

[AndrzejM]

WAI, aero mods, as much as you can, LRR tyres inflated to max sidewall, DRLs to reduce alternator load, fixed ECU...

You've mentioned that you have camshaft adjusted for top end power, you should set it back to factory. You may think of longer (custom made maybe) intake mainfold to lower max torque revs.

And the most important thing, get some FE instrumentation! Vacuum gauge, MPGuino, ScanGauge or UltraGauge. I can help you with MPGuino - I have some practice.

[maczo]

OK, my bad. Not all mods welcome, I will restate that I don't want to compromise performance.

WAI could be de-installed quickly for events.

How much of a gain would DRLs give me?

I'm thinking more and more about the vacuum gauge. Am I right that the rule to follow is:
a) when accelerating, aim for the least possible vacuum (small negative numbers)
b) when maintaining speed (i.e. on highway), aim for most vacuum (large negative numbers) in top gear
Right?