did not realize "pulley swap" changes diameter
03-18-2012, 08:39 PM
#22
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LOL Voltron
Don't feel bad westwest - I just discovered Facetube, have no idea what a twitter is, and my brain's been permanently scarred by just pondering the existence of cloud-computing.
Don't feel bad westwest - I just discovered Facetube, have no idea what a twitter is, and my brain's been permanently scarred by just pondering the existence of cloud-computing.
03-18-2012, 10:43 PM
#23
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West - not trying to be a douche or anything, but none of this is news. You seem to follow the forums pretty regularly, so I'm just surprised that you haven't heard of any of this. Pulley and Stage II software came out close to a year ago.
Also, Stasis' "offering" is simply a re-branded version of APR's 91 tune.
Also, Stasis' "offering" is simply a re-branded version of APR's 91 tune.
People change ridiculous items on their cars and I don't pay attention to a lot of it. On my e90 3 series people would change the pulleys, even though there was zero reason to do so because they were replacing with the same size. I'm new to the forced induction game. People used to also change the throttle body to be 7% bigger, which was also ridiculous and not needed.
It would have popped a bit more if the marketers specified "60mm pulley" or something that indicated size.
It would have popped a bit more if the marketers specified "60mm pulley" or something that indicated size.
you're getting confused.
Naturally aspirated cars benefit from a lightweight crank pulley as it reduces the rotating mass that the crank is turning. And it does so...at the crank. Most effective. The supercharged cars benefit from a reduced size pulley that drives the blower...as explained above. Different types of pulleys. Crank pulleys are quite a bit bigger and heavier.
The B7 S4 I used to own had a 7.0 lb crank pulley...and JHM made a balanced lightweight version that weighed 1.5 pounds. Removing this 1.5 lbs at the crank, as well as another 13lbs with a lightweight JHM flywheel (which you guys will get in 2012) you're looking at 18.5 lbs of rotating mass at the crank taken out of the car. That's pretty serious. I think people say this is the equivalent of losing about 50 lbs of unsprung weight, or about 150-200 lbs of sprung weight...or has the dynamic effect of gaining 20hp. Just from reducing weight. Sneaky little mods that don't really show up on the dyno, but do on the street. It's not an accident that the two fastest B8 S4s have addressed their heavy stock wheels/tire combos (55+ lbs per corner stock) with LW wheels/tires that shave rotating mass.
Last edited by sakimano; 03-18-2012 at 10:52 PM.
03-19-2012, 09:28 PM
#24
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also, I heard the B5 S4 responds to tuning really well.
you're getting confused.
Naturally aspirated cars benefit from a lightweight crank pulley as it reduces the rotating mass that the crank is turning. And it does so...at the crank. Most effective. The supercharged cars benefit from a reduced size pulley that drives the blower...as explained above. Different types of pulleys. Crank pulleys are quite a bit bigger and heavier.
The B7 S4 I used to own had a 7.0 lb crank pulley...and JHM made a balanced lightweight version that weighed 1.5 pounds. Removing this 1.5 lbs at the crank, as well as another 13lbs with a lightweight JHM flywheel (which you guys will get in 2012) you're looking at 18.5 lbs of rotating mass at the crank taken out of the car. That's pretty serious. I think people say this is the equivalent of losing about 50 lbs of unsprung weight, or about 150-200 lbs of sprung weight...or has the dynamic effect of gaining 20hp. Just from reducing weight. Sneaky little mods that don't really show up on the dyno, but do on the street. It's not an accident that the two fastest B8 S4s have addressed their heavy stock wheels/tire combos (55+ lbs per corner stock) with LW wheels/tires that shave rotating mass.
you're getting confused.
Naturally aspirated cars benefit from a lightweight crank pulley as it reduces the rotating mass that the crank is turning. And it does so...at the crank. Most effective. The supercharged cars benefit from a reduced size pulley that drives the blower...as explained above. Different types of pulleys. Crank pulleys are quite a bit bigger and heavier.
The B7 S4 I used to own had a 7.0 lb crank pulley...and JHM made a balanced lightweight version that weighed 1.5 pounds. Removing this 1.5 lbs at the crank, as well as another 13lbs with a lightweight JHM flywheel (which you guys will get in 2012) you're looking at 18.5 lbs of rotating mass at the crank taken out of the car. That's pretty serious. I think people say this is the equivalent of losing about 50 lbs of unsprung weight, or about 150-200 lbs of sprung weight...or has the dynamic effect of gaining 20hp. Just from reducing weight. Sneaky little mods that don't really show up on the dyno, but do on the street. It's not an accident that the two fastest B8 S4s have addressed their heavy stock wheels/tire combos (55+ lbs per corner stock) with LW wheels/tires that shave rotating mass.
On track I run the car hard for 25-30 minutes. It stays hot all day.
Cooling first to preserve the cold power. Then add more heat when you've got a cooling surplus.
03-20-2012, 10:36 AM
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I'm going to go against conventional wisdom and say the best mod is cooling. The APR performance cooling kit it $1999 and about 4-5 hours to install. All these other mods only make your car fast for the first 6 pulls. Then the engine soaks with heat, the ECU realizes it, and the supercharger bypass valve stays open. At this point you aren't making 400hp - you're making less than cold stock, 300 if you're lucky.
On track I run the car hard for 25-30 minutes. It stays hot all day.
Cooling first to preserve the cold power. Then add more heat when you've got a cooling surplus.
On track I run the car hard for 25-30 minutes. It stays hot all day.
Cooling first to preserve the cold power. Then add more heat when you've got a cooling surplus.
well...I was just trying to help you understand the pulley confusion you were having but if you want to change the subject to the 'best mod' and nominate cooling, that's fine.
03-25-2012, 07:42 AM
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I'm having difficulty swallowing this whole mess. Looking at 5 grand for the requisite cooling, software, pulley, and labor. I'm worried about the cooling system hoses getting loose and needing to be tightened all of the time. I have vivid memories of the Subaru WRX guys in the paddock after every run tightening clamps and worrying their cooling tubes were going to come loose. The worst possible thing that can happen on track is your cooling spills all over it. It's dangerous for the other cars and it disables your car immediately. You can also end up with a bill, in some cases, for cleaning up the track.
03-25-2012, 10:11 AM
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I'm having difficulty swallowing this whole mess. Looking at 5 grand for the requisite cooling, software, pulley, and labor. I'm worried about the cooling system hoses getting loose and needing to be tightened all of the time. I have vivid memories of the Subaru WRX guys in the paddock after every run tightening clamps and worrying their cooling tubes were going to come loose. The worst possible thing that can happen on track is your cooling spills all over it. It's dangerous for the other cars and it disables your car immediately. You can also end up with a bill, in some cases, for cleaning up the track.
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