Quote:
Originally Posted by cjd
The slopes do start at a common 0,~700 and are different off idle, and in the transition into deceleration, both places I'd expect lower rotational mass to show up in such a log. Beyond that I have to agree, the rate of change is too similar for analysis by eye on a web optimized graph.  The net idle to redline to... Approaching idle still gains time, so this will benefit people that like to rev their favourite tune, too!
All kidding aside, if you are chasing every last bit of potential rotational energy, this should help.
Sampling rate over the 12Hz offered by the OFT may be needed. (I think that's the right rate...) |
Exactly, the largest changes are measurable are off idle, and the transition to deceleration, as you would expect. Just getting down to basics: Tau = I*alpha, and nearly everywhere else you would expect the rate of change of the graph to be similar because the overpowering figure by a long shot is the torque. The point where the torque figure is smallest will be immediately off idle or off the pedal at any point, which is why the change is felt most in transition. We are definitely not saying it is as big of a change as a lightweight flywheel, and we certainly are not dynoing it and saying it made 13whp if you can remember anyone ever doing that :P Lots of people sell lightweight flywheels, but I've never seen anyone show any data to backup ANY claims. We did some testing, observed data that matches our hypothesis using that simple law that everyone knows (basically the angular version of F=MA), and thought it would be cool to show it.
I know you're kidding too, but I would kill to have a substantially greater sampling rate for logging.
Quote:
Originally Posted by mike the snake
What are your thoughts on the warnings and reports of failures from lightening both ends of the engine? I've gathered it seems OK to lighten one, or the other, but not both, something to do with harmonics and pounding bearings.
I ask because most people looking to lose weight are likely to get both lightened flywheel And lightened pulleys, and I' won'der if they might be setting themselves up for possible premature wear/failures.
I don't know how much actual proof there is to these claims, but I know a lightened flywheel makes a MUCH bigger difference in rotational mass, throttle response, so much so that the lightened pulley improvements are negligable in comparison.
|
Quote:
Originally Posted by Travisty75
In the Subaru world we've been dealing with people throwing LWCP (lightweight crank pulley) and lightened flywheels on the EJ engines for a while. With those motors and both of those components lighter than factory, we've always introduced false knock.
It's a community-accepted fact that one or the other is okay, but not both. Most people opt to throw on a LWCP since it's so much easier to get to, but also because driving with a lightened flywheel is more tricky on the street, where 90% of people spend 100% of their time.
|
Could not have said it better myself. In fact, that false knock is the main reason you don't see extremely light crank pulleys, because there is only so far you can go before you have that problem. On the FA20, that isn't an issue, and you can make the pulley quite light. Some of these other LWCPs end up being under a pound even.
At the end of the day I will always listen to the engine builders who have experience. If they're saying that a LWFW and LWCP are causing bearing wear issues I have no reason to believe they're lying, because what do they have to gain from that? Less engine rebuilds? :P Do I have the same first hand experience as these engine builders who have tore apart tons of motors and seen these exact issues? Nope, so I will listen to one who I trust.
And like I said, Travisty75's last paragraph sums it up perfectly. Good on ya
Quote:
Originally Posted by weederr33
Are you guys going to come out with a 5 piece pulley set like Raceseng's S2 kit?
|
Currently we have no plans to do that, but you never know. We might add a few more bits to our lineups as time goes on, but right now we're working on some bigger projects
Chase
Engineering