Holden V8 AFM reviews show its nothing flash!

[FPV8U]

AFM = Fail..

My 03 Manual XR8 Does that.. Mid 9L/100km @ 110km/h, No tune either.

A mate of mines VY SS with Bolt on's + Tune did 8L/100km @ 110km/h, Maybe the Holden techs should just drop the new cars off at tune shops to improve economy and performance, instead of one or the other...

[phillyc]

Ford already has AFM on the Falcon range...

Turbochargers are the best form of variable displacement and with the XR6T & F6 we already have a working version!

During the FG launch tests they were talking about G6ET's getting 7s & 8s on the highway at 110+kmh.

ie Heavy foot equals high boost or increased effective capacity, light foot is minimal boost.

This is why Ford is working on direct injection turbo charged engines such as the eco-boost series of engines.

[xbgs351]

Originally Posted by EDManual

90% of the trip from Melbourne to Sydney is NOT road works
(I drive it all the time, there would be less than 80km where you have to do less than 100). and is 110zone al least 80% of it where 90% of drivers sit on 120. The roadworks is slower and would HELP fuel consumption when you have to do 60 or 80 for a few km here and there.

Plus they admitted that their speedo was out and you bet thats what they were driving at.

Why dont they sit on 50km/h and try for a low 8l/100?

And Wheels claim its good?!!

I wouldn't bet on it. Between Albury and just north of Gundagai there are a lot of roadworks and during the day they can be very low.

All speedos are out, including Ford ones.

[Jondalar]

Originally Posted by phillyc

Ford already has AFM on the Falcon range...

Turbochargers are the best form of variable displacement and with the XR6T & F6 we already have a working version!

During the FG launch tests they were talking about G6ET's getting 7s & 8s on the highway at 110+kmh.
.

I have to agree, my G6ET gets those numbers all the time. I've seen high 7's average on two trips Gold Coast to Brisbane (all hwy) and got 8.8 average for a long drive to Ballina and back including much sight seeing last Saturday. So Ford's variable displacement works very well already. Plus it would whip an AFM Dunnydore easilly.

[nugget378]

Doesnt appear that good, I get mid 9's highway driving at 120kph on cruise, and under 9 at 100kph, inner city driving is a real killer though, mid 17's for that, but loaded up with tools..

[vztrt]

Wheels did this (with a commo V8) about the time the VE came out. Same test where they tried getting as much out of the tank as possible.

[nugget378]

Ford did it with the AU, and they got 1000km out of a tank..

[AUXRVIII]

I'm not defending the car or the article, but it is a step forward as far as the industry goes, a lot of the technology required for this to be in todays vehicles come from outside suppliers and will become availiable to Ford etc in the future. I don't remember a 6l petrol engined anything going from Syd to Melb on one tank of fuel so for Holden to have a car which could, good on them.
What does it matter how they achieved it, fact is they did it without any hocus pocus, yes they sat below the speed limit, but it was a speed close to the limit on most Vic country roads rather than the Hume so really not that far from real world conditions.
If it were a Ford we all would be happy with the article.

[naddis01]

My question is why the decrease in power in the first place? Different tune maybe (to lower consumption)? Since AFM is only active during light loads and reverts back to full 8cyl the rest of the time. So why the decrease in power??? There shouldnt be a difference in peak power.

[AUXRVIII]

Originally Posted by naddis01

My question is why the decrease in power in the first place? Different tune maybe (to lower consumption)? Since AFM is only active during light loads and reverts back to full 8cyl the rest of the time. So why the decrease in power??? There shouldnt be a difference in peak power.

Possibly required a different camshaft specification.

[DougM]

Originally Posted by AUXRVIII

Possibly required a different camshaft specification.

Makes sense to me.........The cam may need to be a compromise in order for the engine to run smoothly on 4 cylinders........

[XR Martin]

So apart from peoples short length consumption figures they have posted up, has anyone ever made it from Sydney to Melbourne on a tank of fuel in a late model XR8 or XR6T? Also havnt seen anyone post up a similar or greater maximum distance achieved with a tank of fuel.

[MAD]

Measuring distance versus "a tank of fuel" means nothing. I could just hook up a boot full of jerry cans and increase my "tank".
That's why average fuel consumption exists.

[Lukeyson]

yeah the test was dumb, in my Boss 302 GT i get mid 9's, no worse than 10L/100km on a trip, and i never take it easy

[EDManual]

I actually like the new govt consumption rules where they state the hwy and city use. Its much more practical.

Did you know a smart for2 uses over 8 litres per hundred at 100! and yet around town it can use 3 or 4?!!

So make sure you laugh at one if you see one on the highway!!

And yet a new FG can use less on the hwy. Then more in town obviously...

Now if you were only doing country driving which would you choose?

Most small cars use around 7 or 8 on the hwy. No better than a falcon.

I drive a new Hyundai Elantra that does this. I have driven new corollas that do too.
And yet a falcon does just as well.

It all depends on the driving you do.

City cars for city people, if you do longer commutes like geelong to melbourne, a small car is of no help.

[Smoke Pursuit]

Originally Posted by EDManual

I actually like the new govt consumption rules where they state the hwy and city use. Its much more practical.

Did you know a smart for2 uses over 8 litres per hundred at 100! and yet around town it can use 3 or 4?!!

So make sure you laugh at one if you see one on the highway!!

And yet a new FG can use less on the hwy. Then more in town obviously...

Now if you were only doing country driving which would you choose?

Most small cars use around 7 or 8 on the hwy. No better than a falcon.

I drive a new Hyundai Elantra that does this. I have driven new corollas that do too.
And yet a falcon does just as well.

It all depends on the driving you do.

City cars for city people, if you do longer commutes like geelong to melbourne, a small car is of no help.

Yes alot of companies are starting to work this out, they put their reps in smaller cars like Corrolla wagons etc and got worse fuel then having them in falcons... Running costs were also higher with fwd tyres wearing out etc.

[vztrt]

Originally Posted by EDManual

I actually like the new govt consumption rules where they state the hwy and city use. Its much more practical.

Did you know a smart for2 uses over 8 litres per hundred at 100! and yet around town it can use 3 or 4?!!

So make sure you laugh at one if you see one on the highway!!

And yet a new FG can use less on the hwy. Then more in town obviously...

Now if you were only doing country driving which would you choose?

Most small cars use around 7 or 8 on the hwy. No better than a falcon.

I drive a new Hyundai Elantra that does this. I have driven new corollas that do too.
And yet a falcon does just as well.

It all depends on the driving you do.

City cars for city people, if you do longer commutes like geelong to melbourne, a small car is of no help.

This would be due to their gearing. The Falcons/Commos do well until they hit peak hour traffic.

[Buzz Box]

Well heres a humorous one for all you consumption people lol

We live in Ballarat and I work in Melb CBD so it Freeway the whole way except a few 80km zones and its only 300m off the freeway to park and because we are over the great dividing range so theres some decent hill sections as well.

Focus - 8.2l (98RON)
Fairmont - 8.9l (91RON)

Average speeds are always above 80-90k's and cruise control.

Now guess which one sounds like a lawnmower too when your driving at 110 lol

[colossus]

Originally Posted by XR6 Martin

So apart from peoples short length consumption figures they have posted up, has anyone ever made it from Sydney to Melbourne on a tank of fuel in a late model XR8 or XR6T? Also havnt seen anyone post up a similar or greater maximum distance achieved with a tank of fuel.

But this just depends on tank size - i.e. I could have a 100 litre tank and claim I can drive from Sydney to melbourne. Dosn't mean much though which is why consumption figures are quoted.

I am sure many mid size or small cars could do it in one tank if they had a tank the size of a V8 Commodore. The argument about one tank is fairly redundant as you'd have to stop for food/rest regardless of wether you needed fuel.

I think someone alreaady made the point - just about ANY car can achieve under 10L/100km in the highway cycle. It is thus the city cycle where it counts and here the AFM has been shown to be completley useless. Its a nice idea but really its a marketing gimmick - as said turbocharging smaller engines is much more efficient.

[da_ilks]

I don't see the big fuss about AFM to be honest.

By my (simple) logic, cutting cylinders means cutting power for a given rev range, which means more fuel is required to keep the power going and the speed consistant, negating any benefits from running less cylinders? Isn't the point of a big V8/turbo 6 is to sit on a lazy 1500rpm at 100km/h and revel in the torque? My XR6T will happily average 9.5l/100km's at 110km/h with aircon on, and it's been much the same with even my old 5L Commodore V8's.

As mentioned above, 4cylinder cars are normally no better then family sedans at highway speeds, it's inner city/heavy traffic a small car dominates with economy.

Am I off with my thinking here? Is this just a marketing tool, not a real world one?

[xbgs351]

Yes your logic is simple and also incorrect.

[MAD]

Not entirely incorrect.

Let's say we need 12kW to cruise at 100kmh.
Using 8 cyls each cyl is required to produce 1.5kW.
Using 4 cyls each cyl is required to produce 2.0kW.

Now whether or not that extra production of power actually requires MORE fuel in the real world is unknown. It could be offset by the butterfly being open a touch more therefore removing the tiniest bit or air restriction and wasted energy allowing the remaining cylinders to run slightly more efficiently.

But the tests on AFM so far would suggest there is no advantage.

Its a very simplistic way to look at it, but often its the best way to make sense of it.

[Jondalar]

You got your math wrong, on 4cyl it's 3.0kW / cyl not 2.0...

Even if they are opening both valves on the deactivated cylinders there is still the friction of pushing the piston up and down, which is why these systems rarely produce anything more than a marketing benefit.

Originally Posted by MAD

Not entirely incorrect.

Let's say we need 12kW to cruise at 100kmh.
Using 8 cyls each cyl is required to produce 1.5kW.
Using 4 cyls each cyl is required to produce 2.0kW.

Now whether or not that extra production of power actually requires MORE fuel in the real world is unknown. It could be offset by the butterfly being open a touch more therefore removing the tiniest bit or air restriction and wasted energy allowing the remaining cylinders to run slightly more efficiently.

But the tests on AFM so far would suggest there is no advantage.

Its a very simplistic way to look at it, but often its the best way to make sense of it.

[MAD]

Originally Posted by Jondalar

You got your math wrong, on 4cyl it's 3.0kW / cyl not 2.0...

Even if they are opening both valves on the deactivated cylinders there is still the friction of pushing the piston up and down, which is why these systems rarely produce anything more than a marketing benefit.

Oh yeah so I did, for some reason I had 6cyl in my head. Never the less, it still shows the point that each cyl has to make more power.

[da_ilks]

Originally Posted by da_ilks

I don't see the big fuss about AFM to be honest.

By my (simple) logic, cutting cylinders means cutting power for a given rev range, which means more fuel is required to keep the power going and the speed consistant, negating any benefits from running less cylinders? Isn't the point of a big V8/turbo 6 is to sit on a lazy 1500rpm at 100km/h and revel in the torque? My XR6T will happily average 9.5l/100km's at 110km/h with aircon on, and it's been much the same with even my old 5L Commodore V8's.

As mentioned above, 4cylinder cars are normally no better then family sedans at highway speeds, it's inner city/heavy traffic a small car dominates with economy.

Am I off with my thinking here? Is this just a marketing tool, not a real world one?

Was doing some more thinking about this.

As we all know, 4 cylinder cars will never match a big engine car for torque. If you combine a 6sp auto's gearing (low to keep revs low on the highway) with an engine which will be working harder to produce the same power/torque for the same rev range, and put that in a big, heavy 2tonne family sedan, I still don't see the benefits of cutting the cylinders on the highway?

[Buzz Box]

Well as much as I love the theoretical maths above in the real world da_ilks is 100% correct.

The focus/corolla etc are city cars and are GREAT in the city but once you start going over 80k's is where the 6/8's come into their own.

Now we've restricted the focus to city driving its driving better, sounding better and better drive ability but anytime we go anywhere we take the Fairmont and on the freeway etc the fairmont kills the focus economy and drivewise on the freeway but in town its obviously the other way around.