That is slightly different as it is reduced unsprung weight rather than rotating engine mass, good news for handling and ride
Either way a good thing
The 4.7 also responds well to both mass reductions

 

Wheels/tires, brake rotors, etc. are all also rotating mass (flywheels) that must be accelerated by the engine. People tend to focus on the "unsprung weight" aspect of these items to the extent that their rotational mass is sometimes forgotten. The mass of anything that rotates anywhere in the drive train will have an effect on vehicle acceleration, but it seemed that the OP may have been mainly concerned with throttle response (rapidity of change in engine revs). This would narrow things down to anything in/on the engine that rotates with the engine...

 

A point to ponder here: what's the point of having a CF prop shaft upstream of any gear reduction yet still have an extra 4.5lbs rotating mass?
My big question: can one R&R the pulley without removing the steering rack and oil tank?

 

Okay, there are a lot of good points in this thread and definitely some very educated answers. Keeping in mind that someone can be very educated and still very wrong, I think it is best to keep an open mind to new idea. A lightweight dampener is not a new idea. Neither are lightweight or power-adding pulleys (size changes). All of these options have well know, documented pros/cons. I think a lot of good information has been spelled out here (and some not so good information that is relatively easy to identify). At the end of the day, reducing rotating mass is a good thing for power but not always for drivability.

Reducing the drive-shaft weight is a no-brainer, cost is the only reason not to use carbon. Same with the brakes, even tho some argue that carbon brakes need more heat to work at comfortable potential. The clutch/flywheel is probably the item where a person can garner the most power-adding effects. 'New' carbon/carbon clutch technology can allow you to remove 30+ lbs of rotating mass. That's some serious weight reduction, even at 2000rpm. The danger is removing the momentum that the engine uses to run smoothly at a slow rotation. As far as I know, there is no way to calculate the affect, the mod must be installed and then documented.

The OP mentioned that this was a Vantage S and I have only seen the Vantage S with AMT style transmissions. I have a 2012 V8-S and I would love to hear about any mods alongs these lines. I have discussed clutch options with Stuart and so far as I know, there is nothing aftermarket that is confirmed to work on Aston's AMT setup. My local dealer said they installed an aftermarket clutch for a customer on a V8-S but the computer would throw back errors after the first drive.

I not trying to de-rail this thread, actually hoping it would get back to the OP's original project objectives.

 

Talked to Ford's engine design manager. In summary he said removing the added iron from the V8's crank pulley should have little or no effect on the durability of the engine or the complete powertrain for that matter. The engine's harmonic balancer will still be in place and untouched i.e. the harmonic balance is unchanged.

His activity did not engineer the Vantage V8, it had been the joint responsibility of Jag and AM. Ford was responsible for the AM V12, however, and he was aware of the V8,s development.

He opined that the weight added to the FEAD (front end accessory drive) crank pulley was to negate gear rattle during gear changes on the ASM (automatically shifted manual) transmission. (SS in Aston speak) His activity had recently engineered the new Fiesta engines who also have ASM transmissions. Weight had been added to the flywheel to negate gear noise on those systems.
Why did they use the front pulley on the Aston?, I asked. Probably because it was more easily accessed, to add or delete alternative weights and they had the package space available for the addition on the front end.

Back to the V8

He said, try it. Get another pulley and machine off the weight. R&R the OE part. If an objectionable annoyance occurs (classically called NVH, for noise, vibration and harshness) that you can not tolerate, reinstall the OE part. No objectionable annoyance, you have a 4.5# cantilevered, rotating weight save in hand.
Post Script
He said ASMs are built with slightly more gear lash (the source of the noise), than conventionally shifted transmissions. The goal is to improve the accuracy and completion of their electronically controlled gear changes.

 

Hey guys,

Due to everyone's excitement and interest in this project I have acquired another pulley and will get the pulley machined again and do before and after dynos. After I found out how much work is involved in the headers I have decided to do this mod before I do the headers (after the high flow cats and stage 2 tune). Will have updates in the coming weeks.

Yes the harmonic damper was retained when I did this and there would be no negative effects for doing this as mentioned. I think the only real reason they did this after the fact with the crank pulley is this was done more as an after thought to fine tune smoothness (power / throttle response be damned). The only real negative I can see from this is probably the car may be slightly easier to stall. But 9.x lbs crank pulley is still extremely heavy by modern standards. Most OEM stock pulleys these days are in the 6.x lbs range so even machined this is still one heavy damper unit.

Thanks,
007

 

The headers aren't hard to install....
...
..
.....................................there a PAIN IN THE ***!!!
...
..........but the sound and power is worth the knuckle bleeding!!

 

I did a dyno before and after with the pulley 007 Vantage and there is no difference!

 

I agree, I think the extra mass is overkill because you already have the 10lb torque tube as well. There Is a bunch of room to work on the front of the engine, thanks to its mid engine design. You should be able to install it easily just by releasing the belt tensioner and a long breaker bar and tightening it with high torque wrench.

 

Looks to me like the the pulley will hit the steering rack before it's free of the crank, but I've not tried it. I sincerely hope your experience proves differently.

 

It does hit..You can move the rack to get the extra room. I've never had to do just a crank pulley..wonder if you gut the front hoses+oil tank+rack if it gives enough room for the pulley removal tool and a ratcheting breaker bar..when I take them off it's only for a timing cover seal, which I have the subframe off the car anyways so I have lots of room

 

All,

I have decided to this mod next before the cats or headers. I already have an extra stock pulley unit and plan on getting it machined.

I have done some more research and I think I will be able to machine another 1-2 lbs out of the OEM core, if I can get 6+ lbs out of the OEM unit it will make the impact much more. Machining costs will be a little bit more but worth it in my opinion.

6+ lbs will be no joke as far and engine response and hopefully more low end to midrange torque. I will balance the pulley to 8000+ Rpm at a custom performance machining shop to see just how close to perfect I can get the OEM pulley balance to become.

More updates to come...

 

Great info! Much appreciated!

 

I did a dyno before and after with the pulley 007 Vantage and there is no difference!


Why are you ignoring this statement? Do you doubt the measurements?
It looks like it has been tried and failed before, so why should the outcome be any different?
(i'm not trying to be smart, I just don't get it..)


Regards. Ben
Holland

 

The fact that a brand new poster with only 3 posts magically appears out of no where appears incredibly fishy, haha


Lightweight crank pulley will always show gains, done it many times before and produced results on many different cars. The gains only show up on a loading dyno because there has to be a real load. Dynojets are not real dynos, hence why they don't show gains, however, the actual elapsed time of the dyno will change (hence showing the improvement via time instead of power due to the increased acceleration of the 5000lb inertia drum). That's how all inertia dynos are. Any REAL loading dyno will show the gains from crank pulleys and lightweight flywheels.

This is modding 101, if you do not understand that then you clearly do not understand the forces at work.