Pullied S4?
10-03-2009, 08:26 AM
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Pullied S4?
I have been out of the Audi scene for a while but my Audi driving experience has always kept me interested in Audis. Anyway, I love the idea of the Supercharged V6 but I see that platform as an option to build some serious HP. (similar to my 2003 Cobra) Besides the MTM tuning are there any rumors on pulley upgrades or ECU modifications to get the numbers up. 400 whp on a daily driver is kind of my thing... 
10-03-2009, 10:43 AM
#2
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Runor is that the pully is not a easy swap out, you will have to do some mods on the mount as well, seems most are currently focusing on chip alone for the moment, I think once that is well mapped out they will work on the pulley - modding take time and care, and you will want to explore one variable fully before changing more than one thing at a time or risk serious harm to the engine.
10-03-2009, 01:30 PM
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Too bad - i did a pulley mod on my Mini Cooper S - cheap and easy (although they had to lift the engine off the mounts to reach the pulley) - was about $500 good for about 10 - 15% more power as i recall
10-03-2009, 07:52 PM
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Same here... I pullied and tuned my Cobra and got about 80 horsepower if not more. Didnt dyno it since i am not done wiht the mods. Porting the blower over the winter and then Dyno time. Hoping for about 540 rwhp.
I am not sure what tuning alone will do to the S4, it seems like there has to be a mechanical limitation to the boost since it can only spin so fast but I am no expert... I am just excited to start seeing the numbers these things put down after some time and some brains get to work on them.
I am not sure what tuning alone will do to the S4, it seems like there has to be a mechanical limitation to the boost since it can only spin so fast but I am no expert... I am just excited to start seeing the numbers these things put down after some time and some brains get to work on them.
10-03-2009, 08:22 PM
#5
the car can produce 21psi off the blower allready, but it is ecu limited to 15. The extra is diverted/bypased. Changing the ecu signals can get you 100hp more just by keeping the boost directed to the intake manifold.
As it stands, a pulley would only make even more of the available boost bypass, and create more heat, reduce efficiency, lose power.
To get big power, a larger charger of the same type may be the big mod. Then again more than 21 psi in a motor with over 10 to 1 compression...just seems wrong.
A reliable 450hp will be found a year from now. (without a charger, or pulley mod) Software,intake,exhaust, should do it.
As it stands, a pulley would only make even more of the available boost bypass, and create more heat, reduce efficiency, lose power.
To get big power, a larger charger of the same type may be the big mod. Then again more than 21 psi in a motor with over 10 to 1 compression...just seems wrong.
A reliable 450hp will be found a year from now. (without a charger, or pulley mod) Software,intake,exhaust, should do it.
10-04-2009, 11:01 AM
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Thats good info, thanks! I didnt realize that there was a diverter valve on this supercharger setup or any supercharger setup to be honest... Theoretically this ECU tuning would do the same thing they do on the A4s and S4s of the past with the K03s.
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10-05-2009, 11:59 AM
#9
the car can produce 21psi off the blower allready, but it is ecu limited to 15. The extra is diverted/bypased. Changing the ecu signals can get you 100hp more just by keeping the boost directed to the intake manifold.
As it stands, a pulley would only make even more of the available boost bypass, and create more heat, reduce efficiency, lose power.
To get big power, a larger charger of the same type may be the big mod. Then again more than 21 psi in a motor with over 10 to 1 compression...just seems wrong.
A reliable 450hp will be found a year from now. (without a charger, or pulley mod) Software,intake,exhaust, should do it.
As it stands, a pulley would only make even more of the available boost bypass, and create more heat, reduce efficiency, lose power.
To get big power, a larger charger of the same type may be the big mod. Then again more than 21 psi in a motor with over 10 to 1 compression...just seems wrong.
A reliable 450hp will be found a year from now. (without a charger, or pulley mod) Software,intake,exhaust, should do it.
Can you please provide a link to support the above? I don't believe w/o a pulley the blower can make 21psi....
10-05-2009, 12:24 PM
#10
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The final engine compression is 10.3:1 stock, so 11.6 seems in line with this. 21psi seems a might high though.
http://en.wikipedia.org/wiki/File:Ro...ciency_map.jpg
This chart shows efficiencies of Roots style supers like on the S4 (which is a modified version by Eaton called TVS - Twin Vortices Series, so they might be more efficient and have higher boosts).
Not sure of the exact boost, but 21 a bit high, since the Eaton site boasts a 2.4 pressure ratio, and the above chart tops out around 2.25, and this chart shows ~2.1 is 15psi, so scaling in a linear manner, every 1 pressure ratio should equal ~7.1429 PSI.
This puts 2.4 pressure ratio at ~17.14psi max, and operating at about 70% efficiency also according to Eaton. The beefiest TVS style chargers I could find max out around 20psi, so I would think with the proper pulley and ECU, you can achieve 21, but that may be pushing the threashold of the capabilities of this device.
http://www.eaton.com/EatonCom/Produc.../TVS/index.htm
As for a bypass, all have them, since even at idle speeds, air is being compressed and needs a place to go. Very nice little video on this page from Eaton,which shows a nice graphical of how Superchargers and intercooling works in motion as well as the bypass valve.
http://www.eaton.com/EatonCom/Produc...tion/index.htm
http://en.wikipedia.org/wiki/File:Ro...ciency_map.jpg
This chart shows efficiencies of Roots style supers like on the S4 (which is a modified version by Eaton called TVS - Twin Vortices Series, so they might be more efficient and have higher boosts).
Not sure of the exact boost, but 21 a bit high, since the Eaton site boasts a 2.4 pressure ratio, and the above chart tops out around 2.25, and this chart shows ~2.1 is 15psi, so scaling in a linear manner, every 1 pressure ratio should equal ~7.1429 PSI.
This puts 2.4 pressure ratio at ~17.14psi max, and operating at about 70% efficiency also according to Eaton. The beefiest TVS style chargers I could find max out around 20psi, so I would think with the proper pulley and ECU, you can achieve 21, but that may be pushing the threashold of the capabilities of this device.
http://www.eaton.com/EatonCom/Produc.../TVS/index.htm
As for a bypass, all have them, since even at idle speeds, air is being compressed and needs a place to go. Very nice little video on this page from Eaton,which shows a nice graphical of how Superchargers and intercooling works in motion as well as the bypass valve.
http://www.eaton.com/EatonCom/Produc...tion/index.htm