Does a light weight pulley actually help increase hp?
#21
Flywheel is sweet, but it makes a 5spd harder to drive for a beginner no? I have the 07 sw tc 5spd, and its my first 5spd ever. Pulleys make the revving quicker, which can be an advantage to a good driver. Had one on my auto.
I'd recommend 5-speed newbies (no mockery intended) to keep modifications to audio/visual until fully comfortable with the car's power as it is stock, and fully confident in your ability to handle shifting in all situations, be it rain, snow, steep friggin hills, etc.
Hell, I've been driving stick since I was a sophomore in high school and I haven't modded the Evo yet because I'm still getting used to the increased power over the tC. :p
#22
Originally Posted by WhitetC21
Flywheel is sweet, but it makes a 5spd harder to drive for a beginner no? I have the 07 sw tc 5spd, and its my first 5spd ever.
Pulleys make the revving quicker, which can be an advantage to a good driver. Had one on my auto.
Pulleys make the revving quicker, which can be an advantage to a good driver. Had one on my auto.
The flywheel will make launching a bit harder since the engine carries less momentum (this feeds back to why you are not "freeing up horsepower") as you decrease rotating mass. So you will need to launch higher and harder to get the same result. This is why if all I cared about was 1/4 mile racing, I wouldnt bother with a lighter flywheel as quickly. The improved launch with the heavier unit can be an advantage off the line.
So I wouldnt say more difficult, but it will change the way you drive the car. Depending on what you have driven before and how used to the tC you are, it could make it harder or easier.
#23
Senior Member
SL Member
Team ScioNRG
Thread Starter
Join Date: Jun 2006
Location: Portland, ME
Posts: 347
I think I will save my money and use it for bolt ons that are not intergrated into the engine or things like that. So now, I hope to sell my Tsudo N1 system for a tanabe concept g and a injen cai. Thanks people for your input, but I think its safe to say that Im not a racer, and if its only a little hp if any its not worth the risk or money to put it on myself or get it done. So Thanks,
#24
Originally Posted by engifineer
A lightweight flywheel has the same performance effect as a lightweight pulley, only its effects are much more noticeable because you are removing mass from a larger diameter. The other difference is that you are not removing the damper, so you do not decrease engine life (removing the damper WILL decrease engine life to some degree.. that degree depends on engine, use, driver, etc).
#25
Senior Member
SL Member
Scion Evolution
Originally Posted by kurt26
Originally Posted by engifineer
A lightweight flywheel has the same performance effect as a lightweight pulley, only its effects are much more noticeable because you are removing mass from a larger diameter. The other difference is that you are not removing the damper, so you do not decrease engine life (removing the damper WILL decrease engine life to some degree.. that degree depends on engine, use, driver, etc).
#26
ATI makes a dampened pulley; only, it weighs more than stock to deal with the excess power in Leslie Durst's tC. No dice there.
A lot of people were interested at YStC but there aren't enough people there to get them to make a lightened pulley. I wonder how many people here would want one from ATI or Fluiddampr? Somehow, I imagine most people here would want the NST or ZPI pulley.
A lot of people were interested at YStC but there aren't enough people there to get them to make a lightened pulley. I wonder how many people here would want one from ATI or Fluiddampr? Somehow, I imagine most people here would want the NST or ZPI pulley.
#28
Originally Posted by kurt26
So why doesn't any aftermarket company make a pulley with a damper?
1. The cost of building such a pulley would push the retail price over $300 and people do not like paying such prices. How long would it take them to sell 100 pulleys of such design? People cry and complain that "we want this and we want that, but when the time comes to open their wallets they run and hide!"
2. According to their experience with pulleys over the years, they have seen enough first hand pulley use to conclude that such a piece is not absolutely necessary.
How many people do we have on SL using solid pulleys of various types who have had engine failure? How many people do we have using solid pulleys who have strong running engines? I think we have a thread covering those stats somewhere
#33
Originally Posted by WhitetC21
So.....the flywheel and pulley do free up horsepower, especially with other bolt ons header, exhaust, etc?
Start with 100 horsepower and you will see a little bit of gain, start with 300 horsepower and you will see a little bit more gain in response and performance. This is why turbo charged cars usually see better performance gains with basic bolt ons.
#34
Well, if you want to find something you can take for fact regarding whether reducing rotational mass increases the amount of HP the system outputs, then you can find yourself a book on basic mechanical phyics. Read all you can on the laws of motion first. Then read about rotational motion and how the principles relate between the two types of motion and you will have some good fact regarding why you havent freed up any power.
If you reduce it enough, will you have noticeable effects on accelleration? It depends on the load on the system. Revving in neutral will be more effected than revving in gear while pulling the car, and both effects depend on the amount of mass removed and the diameter it is removed from.
So you have affected rotational acceleration, but not power output.
Then, look here:
http://www.germanmotorcars.com/Dyno_...0inertia_1.htm
to see why inertial dyno numbers can be inaccurately affected by rotational mass changes. That article will put the rest of the info above into perspective and will serve as some good reading nonetheless.
If you reduce it enough, will you have noticeable effects on accelleration? It depends on the load on the system. Revving in neutral will be more effected than revving in gear while pulling the car, and both effects depend on the amount of mass removed and the diameter it is removed from.
So you have affected rotational acceleration, but not power output.
Then, look here:
http://www.germanmotorcars.com/Dyno_...0inertia_1.htm
to see why inertial dyno numbers can be inaccurately affected by rotational mass changes. That article will put the rest of the info above into perspective and will serve as some good reading nonetheless.
#37
For those of you beating on the "a pulley does not make power", "nor does it free up power", what is your educated explanation for such dyno graph pictured below.
Before pulley 134.4whp 145wtq
After ZPI vr.2 Crank Pulley 146whp 163wtq
That's a gain of 11.6whp and 18wtq. Is this considered "GHOST" hp and tq?
Before pulley 134.4whp 145wtq
After ZPI vr.2 Crank Pulley 146whp 163wtq
That's a gain of 11.6whp and 18wtq. Is this considered "GHOST" hp and tq?
#38
#40
Originally Posted by zer0
http://clubstlscion.com/forum/forum_posts.asp?TID=2835&PN=1&TPN=3
If someone can come out and dispell the laws of motion that we use everyday to calculate everything from automotive physics to the motions of the planets, then I will be all ears. And if one person can take a good number of 1/4 mile runs with a stock pulley, swap to a lighter one and take a good number more and show me a significantly (respectively) lower time, I may look closer. Will reducing mass help? Sure, since you are making acceleration of the engine easier, but I can bet that you will find that the real performance increase you measure on the track (especially with such a small change in rotational mass on a small diameter object) will not add up to a 15whp or so gain.
Anyway, as usual we are all beating this to death, and the people that believe anything a shop with a dyno and a part to sell will believe that, the people that want to believe one way or the other will believe the same and those of us that are a little more skeptical after seeing mod after mod produce little or none of what is promised (not suprisingly when the physics says it wont) will believe what we do. So I guess we can at least agree on that point and go to bed now.... :D