L99 AFM -- It's REALLY a tough choice, for some. Step Inside.

[jmliptak]

There is a long thread about this in the engine section. What you say is theoretically true, but there is no torque converter to absorb the shock of the switch, and it would be seen as a problem with the engine by most folks. I am not aware of anybody with a manual AFM at this point, but I agree it would be cool. If you took the AFM and connected it with a mild hybrid that would shut off the engine at a stop, you could probably get some crazy mileage, but I think if it was easy it would have already been done by SOMEBODY, even at a ridiculous price, but I would be willing to give it a try if it wasn't outrageously expensive...What if the manual tranny was a dual clutch with an auto mode???????

[theholycow]

Originally Posted by CamaroSpike23

buuuuuuuuuuuuuuut, doesnt the AFM only activate during low load, idle, and cruising situations? (stick with me on this)

According to the documentation posted above, it doesn't activate during idle, only steady low load (cruising).

GM theoretcially should be able to do a manual L99 with AFM.....

The problem they claim is that it kicks a little when switching, and a torque converter absorbs that.

since the 6th gear is only really for fuel economy,

If 6th is really only for economy, it damn well better be good for 65mph at 1000rpm. Those of us trying for high MPG don't need blast-off acceleration in our top gear...my VW revs 3000 at 70mph and accelerates far more than necessary for general highway driving. I usually get into high gear under 30mph unless I'm in a hurry. I've never driven a GM manual transmission but I hope they use tall gears like they do with automatics.

add to that the AFM and you could yield 50+ mpg highway with the manual...

50+mpg is territory for a 2000 pound car with 85hp and very low aerodynamic drag (low coefficient of drag AND low frontal area). With the tall 6th as I request above, AFM, and DI, the Camaro could get 35mpg highway, depending on the size of the engine and its torque band...maybe even up to 40mpg with some aerodynamic improvements, but by then it would piss off everyone on this forum.

Making it GM mild hybrid or Prius-like hybrid could help with city mileage, and Volt-like hybrid could help with both city and highway.

Originally Posted by jmliptak

What if the manual tranny was a dual clutch with an auto mode???????

There's still no torque converter to absorb AFM's kick. It's not like the computer can feather the clutch under load to let AFM switch on and off...that'd be even worse than a little kick from the engine.

[CamaroSpike23]

ruin my fun...lol however....

Originally Posted by theholycow

According to the documentation posted above, it doesn't activate during idle, only steady low load (cruising).

ok... so dont activate it during idle, only when cruising

The problem they claim is that it kicks a little when switching, and a torque converter absorbs that
ok....so how bout a computer controlled servo on the clutch to temporarily disengage it while it switches. if it only takes 250milliseconds then it shouldnt be too noticeable


If 6th is really only for economy, it damn well better be good for 65mph at 1000rpm. Those of us trying for high MPG don't need blast-off acceleration in our top gear...my VW revs 3000 at 70mph and accelerates far more than necessary for general highway driving. I usually get into high gear under 30mph unless I'm in a hurry. I've never driven a GM manual transmission but I hope they use tall gears like they do with automatics.

check the spec sheet on the gearing, they are around .5X:1 or something like that for the 5th/6th (dont remember off the top of my head)

50+mpg is territory for a 2000 pound car with 85hp and very low aerodynamic drag (low coefficient of drag AND low frontal area). With the tall 6th as I request above, AFM, and DI, the Camaro could get 35mpg highway, depending on the size of the engine and its torque band...maybe even up to 40mpg with some aerodynamic improvements, but by then it would piss off everyone on this forum.
i know 50mpg isnt totally conceivable, but it could still get higher than the proposed mpg

Making it GM mild hybrid or Prius-like hybrid could help with city mileage, and Volt-like hybrid could help with both city and highway.

i dont see it going hybrid...ever...lol

There's still no torque converter to absorb AFM's kick. It's not like the computer can feather the clutch under load to let AFM switch on and off...that'd be even worse than a little kick from the engine.

not necessarily, the computer can control the clutch in some applications *though the price of such as system i dont even want to fathom* but it wouldnt be that big of a kick, like i said before 250milliseconds is not very long, a quick pulse in the clutch via hydraulic actuatedservo from the cpu hits it just slightly enough to let it slip till the motor switches over

[theholycow]

I agree that a 250ms pulse isn't that long, but a clutch pulse large enough to encompass the whole AFM switch (especially turning AFM off during load) would have to be felt even more than just leaving the clutch engaged and feeling AFM, whose kick can't last the whole 250ms that is quoted for complete AFM cycling.

Personally I would enjoy feeling a little kick from AFM. I like that kind of stuff. I want quiet, smooth (no vibrations), free of road noise, road bumps absorbed...and some nice shift shock or other occasional kick from the engine/transmission to let me know the car is running.

[Supermans]

Thanks for the info I'm always a little worried about technology like this.. Does it give the engine more of an opportunity to go bad sooner down the road??? And can something like this go wrong during the process that may cause a problem???

[TFord]

Originally Posted by theholycow

If 6th is really only for economy, it damn well better be good for 65mph at 1000rpm. Those of us trying for high MPG don't need blast-off acceleration in our top gear...my VW revs 3000 at 70mph and accelerates far more than necessary for general highway driving. I usually get into high gear under 30mph unless I'm in a hurry. I've never driven a GM manual transmission but I hope they use tall gears like they do with automatics.

I may be wrong but I thought most european engines we're "higher reving" (producing HP in the higher RPM bands) my 4th gen A4 cruses at 65 mph at about 1500rpm

[Mr. Wyndham]

Originally Posted by TFord

See I understand your logic put the problem I see is this...

with a roots style blower your boosted no matter what. The amount of boost is directly porportional to the engine RPM's hince the term "blower" lets say I gun it untill I hit 70 mph and then cruse, once Im crusing afm kicks in and 4 cylinders close Im still forcing in a volume of air porportional to my RPM's thats designed to be split between 8 cylinders, but now I have 4 so I just doubled the volume of air being sent to these 4 cylinders. Isnt there is the potential to do this to your block

My "experience" is with Magnuson (Eaton) blowers. All the new ones have a vacuum actuated bypass valve, that essencially "turns off the boost" when you're cruising. As long as your not on the throttle, then there's no boost.

It's sort of the same with turbos, and wannabe turbos(centrifugal supercharger). At low rpms, they are producing very low, if any boost.

[Captain Awesome]

Originally Posted by theholycow

According to the documentation posted above, it doesn't activate during idle, only steady low load (cruising).



The problem they claim is that it kicks a little when switching, and a torque converter absorbs that.



If 6th is really only for economy, it damn well better be good for 65mph at 1000rpm. Those of us trying for high MPG don't need blast-off acceleration in our top gear...my VW revs 3000 at 70mph and accelerates far more than necessary for general highway driving. I usually get into high gear under 30mph unless I'm in a hurry. I've never driven a GM manual transmission but I hope they use tall gears like they do with automatics.



50+mpg is territory for a 2000 pound car with 85hp and very low aerodynamic drag (low coefficient of drag AND low frontal area). With the tall 6th as I request above, AFM, and DI, the Camaro could get 35mpg highway, depending on the size of the engine and its torque band...maybe even up to 40mpg with some aerodynamic improvements, but by then it would piss off everyone on this forum.

Making it GM mild hybrid or Prius-like hybrid could help with city mileage, and Volt-like hybrid could help with both city and highway.



There's still no torque converter to absorb AFM's kick. It's not like the computer can feather the clutch under load to let AFM switch on and off...that'd be even worse than a little kick from the engine.

Here's an idea.... since it's a MANUAL then why not make the M6 version of AFM a MANUALLY CONTROLLED OPTION. Make it like "Seventh Gear" or something. The driver pushes in the clutch and hits a button and lets the clutch back out. PRESTO! No shock to absorb.

Who would be willing to operate it manually?

[TFord]

Originally Posted by Dragoneye

My "experience" is with Magnuson (Eaton) blowers. All the new ones have a vacuum actuated bypass valve, that essencially "turns off the boost" when you're cruising. As long as your not on the throttle, then there's no boost.

It's sort of the same with turbos, and wannabe turbos(centrifugal supercharger). At low rpms, they are producing very low, if any boost.

where the he!! was I? Im one of the biggest eaton/magnacharger fanboys around and Ive been wondering when they come up with a bypass valve? I hope it dosent go PSSSST like the Turbo's do

[Mr. Wyndham]

Originally Posted by TFord

where the he!! was I? Im one of the biggest eaton/magnacharger fanboys around and Ive been wondering when they come up with a bypass valve? I hope it dosent go PSSSST like the Turbo's do

I dunno...it's been around for a few years, now.
They claim that the system uses 1/3 a horsepower to spin the blower when cruising.

I don't know about the sound...Camarospike can elaborate on that I'm certain!

[GTAHVIT]

On the supercharger the valve is open at low rpm/load you don't hear it. When you increase the vacuum the valve closes to route the compressed air into the intake manifold.

Unlike the Turbo which releases unused air when backing off the throttle.

[theholycow]

Originally Posted by TFord

I may be wrong but I thought most european engines we're "higher reving" (producing HP in the higher RPM bands) my 4th gen A4 cruses at 65 mph at about 1500rpm

I haven't heard that about European engines...definitely true of Japanese, though, especially Honda. There's no reason my VW needs to buzz along at 3000 rpm, it's got more than enough torque for half that RPM. As I said, I usually am in high gear before 30mph.

Originally Posted by Captain Awesome

why not make the M6 version of AFM a MANUALLY CONTROLLED OPTION. [...] Who would be willing to operate it manually?

I love it.

[Muscle Master]

Originally Posted by CamaroSpike23

hey.... i just got to thinking about something after reading a post from DGthe3 in another thread...



people are complaining about the manual SS not being paired up with the L99.... buuuuuuuuuuuuuuut, doesnt the AFM only activate during low load, idle, and cruising situations? (stick with me on this)

GM theoretcially should be able to do a manual L99 with AFM..... but they would have to program it so that it only activates when at idle in N or with the clutch fully depressed at a stop (with a microswitch/sensor on the clutch linkage so that when you release the clutch it goes back to V8) and have it programmed to be active when cruising in 6th gear (highway) and deactivate when you push the clutch in when cruising. and since the 6th gear is only really for fuel economy, add to that the AFM and you could yield 50+ mpg highway with the manual...

now this is all theoretical, but i dont see why it wouldnt work....

Believe me its way harder than it sounds to program a complex and delicate program like that

[CamaroSpike23]

Originally Posted by Muscle Master

Believe me its way harder than it sounds to program a complex and delicate program like that

well, they've already managed to program the L99 to deactivate the injectors, lifters and whatnot at speed, in addition to controlling everything else going on. put a gun to their head and tell'm to get to work.