Extremely thirsty supermodel - eco attempt!

[serialk11r]

Originally Posted by jakobnev

They have 0w-50 now, but maybe that's too expensive for your eco-project.

And you can swap that Infinity for a proper slow car like an old Prius now, just add a bumper sticker that says: "My other car is an Aston Martin"

I got the Infiniti because it was the cheapest Japanese, somewhat modern manual trans car I could find, with the intention of getting rid of it in a year (I only have a temporary need to drive a lot right now, I would normally drive well under 1000 miles a year). I almost bought an old BMW, but got scared off by stories about replacing water pumps every other year.

I'm not buying a Nissan product ever again...maybe I have a bad example, but all the plastic bits are crumbling apart (it's a 2004, not that old...), there are tons of things that seem to be intentionally designed to rattle from the factory, and apparently all the weird unhealthy noises from the drivetrain are completely normal.

At some point in the future, I plan to add an ultra-light sports car again for a more carefree and raw/fun driving experience. I took the Vantage on a twisty hill today, and the width of the car made me very uneasy on narrower roads.

AFAIK, 0w-50 only exists as racing oil, which is a no-no. Mobil1 0W-50 racing has very similar specs to Redline 0W-40, but Redline oil is crazy expensive. Mixing 0w-40 and 5w-50 would get something close for 40% the cost. Mobil1 5w-40 or 10w-40 would be similar but not quite as good, meeting ACEA A3/B3 with HTHS of 3.9 cSt.

[cRiPpLe_rOoStEr]

Originally Posted by serialk11r

maybe I have a bad example, but all the plastic bits are crumbling apart (it's a 2004, not that old...)

Most of the Nissans of that same vintage I usually see are Frontiers and XTerras, and they're often in a good condition.

[serialk11r]

Road trip today! A lot of findings from watching the mpg gauge...mostly bad. It appears I went through approximately 16 gallons in 285 miles, though the first 4 I burned while trying to diagnose rattles and driving around town for fun, so today I got more like 20-21 mpg.

6th gear cruise control flat ground: 26mpg @ 50mph, 24mpg @ 60mph, 22mpg @70mph, a little under 20mpg @80mph. Wow, this is more awful than I expected.

Pulse and glide got me to 26mpg averaging about 75mph. The one good thing about the short 6th gear is it climbs hills pretty efficiently, I managed to get 19mpg climbing the Sierra Nevadas @ 75mph (going slower doesn't help all that much, you just end up idling more and losing efficiency on the pulses). 3600lbs and reasonably low drag makes the glides very long.

I was wondering why the fuel level gauge was dropping so rapidly when I hit some slower traffic...I noticed later on that THERE IS NO DFCO in gears 1-4 (it does DFCO in 6th gear, but I didn't check 5th). That's also why shifting seems so sluggish, it loses revs slowly since it's still injecting fuel.

So basically, I really need to get this ECU tune sorted out.

[Cd]

My neighbor had one of these.
I would just stand there staring each time he had the garage door open and I could see the car.
( My apartment rents garages )
He had the DB-9, a late 90's 911, and a 1984 Mercedes.
Oddly enough, his favorite was the Benz, because he grew up in it.
His dad was wealthly, and this guy lived in my aparments.
Didn't really work either.
Just tinkered with his cars.
TOTALLY out of place.
It was amusing when I would see him drive up in the Aston with some lady.
I could just imagine what the women must have thought.
" Wait - you live HERE ?? " " C-YA ! "

I remember him saying how annoyed he was when he would have people call the car an Austin Martin ( I live in Austin, Texas lol. )

BTW, I'd love to see more pictures of your car !

[cRiPpLe_rOoStEr]

Originally Posted by Cd

His dad was wealthly, and this guy lived in my aparments.
Didn't really work either.
Just tinkered with his cars.
TOTALLY out of place.

As long as a place is not criminality-ridden, I wouldn't be uncomfortable to live in a similar way if I had the money. But I'm sure I would prefer a house or a country estate over an apartment, as it would be supposed to not cause much trouble with neighbors complaining over noise or smell of gasoline and oil leaks at a shared parking lot.

[serialk11r]

Working more on the ECU, still not finding much info at all on this ECU, but I believe I found the VVT table and it seems like there is WAY too much valve overlap at low load, which may be why the gas mileage is so atrocious at low speed.

For some reason, all these years I've been a car enthusiast I never bought a legit OBD2 scanner that is fast enough to actually datalog, so I just ordered one off Amazon (Veepeak, still a relatively cheap one at 32 bucks, I watched some Youtube videos and it seems to log more datapoints than I can count in 1 second, which is good enough). I'll look at the logs and try to estimate how much internal EGR is going on so I can reduce the cam overlap if needed.

Unfortunately, the Jaguar VVT actuator seems to have a very limited range of 37 degrees (could be more, but eyeballing a picture of the physical mechanism agrees), and messing with the VVT position too much could throw off the spark timing since I don't know if there is VVT based spark timing compensation. Of course, if the spark timing logs show pretty sensible numbers, then I would be in the clear, so hopefully that's what ends up happening.

However, if the logs do suggest extremely poor combustion efficiency from big cams and lots of valve overlap, then I won't be trying to utilize much more external EGR and thus don't need to worry about spark compensation for EGR.

Figuring out DFCO is probably the next priority, but the lack of DFCO can be mitigated by braking in neutral with a lower idle speed (not great, but better than guzzling fuel in gear with foot completely off the pedal :/).

I'm still optimistic I can get a 26mpg cruise, high 20s pulse and glide, and something like 16+mpg "city".

[skyking]

What is it?

[serialk11r]

2006 AM V8 Vantage

Gonna continue using this thread to keep notes on my tuning efforts. Unfortunately, I still have not been able to figure out the DFCO parameters, which is costing me some fuel.

Idle: I think it'll idle okay at 680 instead of 750, dropping my hot idle gph from 0.42 ish to 0.37 ish. I haven't been able to find the idle speed control table though.

VVT: I made some really rough estimates, assuming around 30% iEGR dilution at idle based on observing that a small change in vacuum produced a big change in load, comparing hot vs. cold idle. I think I can bring down the iEGR amount in the low load, low speed cells to improve combustion stability for mpg, and then feed more EGR in at higher speed with later intake valve closure to reduce overall vacuum by around 0.5-1psi, by targeting ~20% total EGR (compared to 100% undiluted cold air, this has around 60% oxygen concentration, a good improvement!).

I think I can push that retarded cam position to medium load as well AND feed more external EGR in, giving me higher pulse efficiency for P&G.

0.5psi at cruising speed is a respectable ~600 watts, 1psi is around ~1200 watts (compare to the ~15-22 kW it takes to go down the freeway), and improved combustion stability hopefully has a noticeable effect. If I can get 50mph cruise from 26 to 29mpg, the numbers would start to look a little more like a normal car, and if I can crack 30mpg at 45mph, that would be amazing. Otherwise, I'll continue to P&G diligently.

[serialk11r]

I just came to a realization that oil might make a much bigger difference than I thought...

FMEP of a piston engine at 2000-3000rpm is something like 0.5-1 bar depending on load (0.5 is probably an underestimate). For this V8 at 2500rpm, 0.5 bar is a whopping 1250/60*0.5*4.3 = 4.5kW = 6hp!!!

Using the Ecomodder calculator, my car needs around 20hp to do 65mph. Well, the problem is pretty obvious now right?

It's even worse at 40mph, where we only need around 8hp, but friction is consuming 4hp.

If I can cut 10% of friction, I'm already up 3% in fuel economy. It seems switching away from 10W-60 should easily accomplish that. Any 0W-40 will meet ACEA A3/B3 (3.5cP HTHS is one of the main criteria), but given the factory only okayed 5W-50, let's take a look at some HTHS values:
Mobil1 0W-40: 3.6 cP
Mobil1 0W-50 Racing: 3.8 cP
Mobil1 5W-40: 3.9 cP
Mobil1 High Mileage 10W-40: 3.9 cP
Redline 0W-40: 4.0 cP
Castrol Edge 5W-50: 4.1 cP
Redline 5W-40: 4.4 cP
Mobil1 5W-50: 4.4 cP
Mobil1 15W-50: 4.5 cP
Redline 5W-50: 5.0 cP
Castrol 10W-60 (OE fill): 5.2 cP

I wasn't expecting the bottom shelf pricing Mobil1 10w-40 to have such a high HTHS! It's full synthetic, has high TBN, ACEA A3/B3 certification, API SP, and the 10W part isn't a problem since I'm not driving at -20. It's basically a slightly thin 50. If I spend double the money, I can get Redline 0W-40 which is a little bit better, but since this car won't be driven much, it would be a waste to just dump that Redline oil after 1000-2000 miles, so I got 10 quarts of the Mobil1 for 50 bucks total from Walmart, and one extra quart of Mobil1 5W-50 as a top off oil.

Word has it Shell Rotella T6 is actually "better", but the slightly higher phosphorus content isn't good for cats so I decided to pass on that. Unfortunately, the air oil separator on this car doesn't have a good reputation.

Given the oil viscosity is going to be reduced by 40%, I expect BIG mpg gains

[Ecky]

If you're feeling adventurous, you can always go even thinner, and send a sample off to Blackstone for analysis (metal content). I determined 0w20 has very marginally higher wear than 0w30 in my car - which I don't feel is worth it, since the 0w30 is *nearly* as thin when cold, and most of my fuel economy losses happen at low temperature.