Dual Pulley Setup?

[Danny2323]

Who's running a smaller supercharger pulley and a crank overdrive pulley? I'm considering options, and it seems like a good option for torque. My concern, of course, is twofold: 1) I don't want to over spin the supercharger, and 2) can a stage 2 tune prevent the additional boost from bleeding off.

Given the info in the Pulley RPM Thread, most smaller supercharger pulleys are about a 10% increase in speed. Therefore, a stage 2 supercharger is seeing about 20,200rpms at 7,200rpm. Given the fact that the crank pulley would increase it by another 9.5%, that's spin the supercharger 22,119rpms at 7,200rpm. That's pretty uncomfortable to me.

However, if my main goal is good, streetable torque (ya know - area under the curve), what are your thoughts on a dual pulley with no TCU tune (I'm DSG). This would drop the shift points back to 6,400rpm, or 19,661rpms for the supercharger.

Doesn't this mean that a dual pulley setup, with the greatest ability for early boost low in the powerband, would spin the supercharger even less than a typical Stage 2 + TCU setup (19,661rpm for the dual vs 20,200rpm for the Stage 2 + TCU)?

This seems like a great option for a fun, streetable, torque monster, IF a typical stage 2 tune can keep the additional boost from bleeding off.

Thoughts? Am I off in my thinking?

[GRUMPY-S4]

Subbed...

[14S4GWM]

Heres another similar thread
http://www.audizine.com/forum/showth...charger-Pulley

[Danny2323]

Heres another similar thread
http://www.audizine.com/forum/showth...charger-Pulley

That thread only discusses using a crank pulley instead of a supercharger pulley. I searched like crazy, but there's very little info on running a dual pulley setup.

[doug97gxe]

That thread only discusses using a crank pulley instead of a supercharger pulley. I searched like crazy, but there's very little info on running a dual pulley setup.

very little info because those that have done it have kept it quiet .. not much info on here.. but this is an excellent thread with a great write up.. lots of things you mention i never thought of but i'm anxious to hear the answers .. the only person i can think of who might have some idea on that is @Tony@EPL

[14S4GWM]

That thread only discusses using a crank pulley instead of a supercharger pulley. I searched like crazy, but there's very little info on running a dual pulley setup.

I figured info might be shared between the two threads

[DGVR6]

I'll prolly go for it.. Used chargers go for 900. Why not blow one up?

[Dudemans4]

I will be installing my overdrive pulley this Saturday I'm a already stage 2 but my crank pulley failed. so I figure why not the fastest stage2 car is running dual pulleys. ill be the first on the epl tune though.

[doug97gxe]

I will be installing my overdrive pulley this Saturday I'm a already stage 2 but my crank pulley failed. so I figure why not the fastest stage2 car is running dual pulleys. ill be the first on the epl tune though.

did you talk to Tony about it? i'm curious to his thoughts

[GRUMPY-S4]

I will be installing my overdrive pulley this Saturday I'm a already stage 2 but my crank pulley failed. so I figure why not the fastest stage2 car is running dual pulleys. ill be the first on the epl tune though.

AndThen will be first as he's doing it Thursday

[colby7]

Who's running a smaller supercharger pulley and a crank overdrive pulley? I'm considering options, and it seems like a good option for torque. My concern, of course, is twofold: 1) I don't want to over spin the supercharger, and 2) can a stage 2 tune prevent the additional boost from bleeding off.

Given the info in the Pulley RPM Thread, most smaller supercharger pulleys are about a 10% increase in speed. Therefore, a stage 2 supercharger is seeing about 20,200rpms at 7,200rpm. Given the fact that the crank pulley would increase it by another 9.5%, that's spin the supercharger 22,119rpms at 7,200rpm. That's pretty uncomfortable to me.

However, if my main goal is good, streetable torque (ya know - area under the curve), what are your thoughts on a dual pulley with no TCU tune (I'm DSG). This would drop the shift points back to 6,400rpm, or 19,661rpms for the supercharger.

Doesn't this mean that a dual pulley setup, with the greatest ability for early boost low in the powerband, would spin the supercharger even less than a typical Stage 2 + TCU setup (19,661rpm for the dual vs 20,200rpm for the Stage 2 + TCU)?

This seems like a great option for a fun, streetable, torque monster, IF a typical stage 2 tune can keep the additional boost from bleeding off.

Thoughts? Am I off in my thinking?

This will work great for the Q5 and SQ5 with their respective 6200 and 6500 redlines in auto mode. Q5 will redline the supercharger at a conservative 19100rpm, and the SQ5 at an rpm still below that of a TCU tuned Stage 2 S4 (20000 for the SQ5 vs 20200 for the S4).

[Dudemans4]

did you talk to Tony about it? i'm curious to his thoughts

Nope I sure haven't im running test pipes also I'm still waiting for a test pipe file

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AndThen will be first as he's doing it Thursday

Sweet

[Lockon_B7]

I'll prolly go for it.. Used chargers go for 900. Why not blow one up?

Boost, for purely scientific reasons of course.

[B8 S4]

+1 exactly what I was thinking. Also is the crank on the same belt than the supercharger? If so is there a different size belt that will be needed to accomidate but the overdrive crank pulley and the underdrive supercharger pylley?

[ntsantos]

This will work great for the Q5 and SQ5 with their respective 6200 and 6500 redlines in auto mode. Q5 will redline the supercharger at a conservative 19100rpm, and the SQ5 at an rpm still below that of a TCU tuned Stage 2 S4 (20000 for the SQ5 vs 20200 for the S4).

This...my A7 has a 6500 redline so I'm not to worried about overspinning the SC. I'm pulling the trigger on dual pulleys soon.

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[Danny2323]

The crank pulley is sandwiched with the acc drive pulley, but they're on different belts. I'm not certain, but I think the dual pulley setup will work with the belt that comes with the crank pulley. There would just be a little more slack that the tensioner would need to take up (I think)

Regarding boost bypass... From what I can understand from searching, the GAIC tune requests high enough boost that it wouldn't be possible for bleed off, but APR's tune specifies a lower amount which might cause some boost to bleed off (I think it was 2600 hPa vs 2300 hPa). Does this mean GAIC is the only option? Are there other ways to prevent boost bleed off in a dual setup?

I believe the guys who are running dual pulleys are all TCU flashed cars or 6MT. Does anybody know if the TCU flash enhances power handling (i.e. does it increase clamping forces)? If it doesn't, the idea to skip a TCU tune, and run a dual setup to shift at the OEM specified points to stay at essentially the same supercharger max rpm of a Stage 2+TCU sounds good to me. If TCU does increase clamping forces, maybe a TCU flash with a lower redline is wise. Can a customer request a lower redline for TCU flashes?

[rtl5009]

It would work great on a GIAC car, as they request 18-20 lbs, which will never bleed off.

Only thing you are doing is over spinning the super charger. Might get away with it might not. Who knows. There are several guys running this set up currently. I would get the GMG dampened on over the JHM one for your motors sake.

[wwhan]

Primetime has the dual pulley setup on a 2010 DSG car & APR stg 2 tune. http://www.audizine.com/forum/showth...1#post11121589 ¼ mile ET for stage II – 11.5047 @ 123.13mph

He also had a 1/4 mile - 11.4500 sec, 119.56mph run posted on AR (cannot link from this website), but his time is posted here on AZ

After these results were posted, I think he is now toying with experimental ECU tunes, but his 2010 DSG has a few hickups with shifting (always has).

[GRUMPY-S4]

It would work great on a GIAC car, as they request 18-20 lbs, which will never bleed off.

Only thing you are doing is over spinning the super charger. Might get away with it might not. Who knows. There are several guys running this set up currently. I would get the GMG dampened on over the JHM one for your motors sake.

Why for Motors sake? Is undampened bad for motor? How bad is vibration inside car?

[Danny2323]

Only thing you are doing is over spinning the super charger. Might get away with it might not. Who knows.

I might be wrong, but I don't think the supercharger would be spinning any faster than a typical Stage 2 with a TCU tune. There are a ton of St2+TCU cars running to a 7,200 redline. A dual setup shifting at OEM redline (6,400) would spin it slightly slower at the shift point, right? 20,200rpm vs. 19,661rpm

They're both spinning the supercharger to the same rpm, just the St2+TCU tune does it on the big end (via an extended redline), but a dual pulley shifting early at OEM spins it up early, but would cut it off short, for those that want area under the graph.

[rtl5009]

Why for Motors sake? Is undampened bad for motor? How bad is vibration inside car?

http://www.hotrod.com/how-to/engine/...kshaft-damper/

There you go ;)

[Dudemans4]

Primetime has the dual pulley setup on a 2010 DSG car & APR stg 2 tune. http://www.audizine.com/forum/showth...1#post11121589 ¼ mile ET for stage II – 11.5047 @ 123.13mph

He also had a 1/4 mile - 11.4500 sec, 119.56mph run posted on AR (cannot link from this website), but his time is posted here on AZ

After these results were posted, I think he is now toying with experimental ECU tunes, but his 2010 DSG has a few hickups with shifting (always has).

This is exactly why I bought it. He's running the pulley so why not.

[ntsantos]

http://www.hotrod.com/how-to/engine/...kshaft-damper/

There you go ;)

Well...good point. Now torn between JHM and GMG. The GMG may be a no brainer but it's double the cost of the JHM...although it may be worth the extra 500 for the peace of mind.

[GRUMPY-S4]

You guys are Gutsy. If I ever do this I would get the dampened.

[GRUMPY-S4]

Well...good point. Now torn between JHM and GMG. The GMG may be a no brainer but it's double the cost of the JHM...although it may be worth the extra 500 for the peace of mind.

I would go GMG if I ever do this. But isn't their lead time like 6months?

[ntsantos]

I would go GMG if I ever do this. But isn't their lead time like 6months?

I contacted them today and said they're in stock. I just pulled the trigger.

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[GRUMPY-S4]

I contacted them today and said they're in stock. I just pulled the trigger.

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Thats awesome!

Im gonna wait for an EPL Tune on E85 for it and see some people run it for a while to see. Some of the higher mileage guys should see SC failures rather quickly if indeed the over spinning causes issues... Right?

[rtl5009]

I contacted them today and said they're in stock. I just pulled the trigger.

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What tune do you have? In for some real data! Please log before and after.

[14S4GWM]

edit

[rtl5009]

My car will build 17 psi at redline on really cold mornings.

GIAC stage 2 with cold front and Ecs intake.

[Dudemans4]

Thats awesome!

Im gonna wait for an EPL Tune on E85 for it and see some people run it for a while to see. Some of the higher mileage guys should see SC failures rather quickly if indeed the over spinning causes issues... Right?

I'm at 80 k so I guess we will see.

[GRUMPY-S4]

AndThen is also in the 70K range... I honestly dont think it will be any issues.

How much more power are you guys expecting with the extra boost? Will internals hold?

[ntsantos]

Thats awesome!

Im gonna wait for an EPL Tune on E85 for it and see some people run it for a while to see. Some of the higher mileage guys should see SC failures rather quickly if indeed the over spinning causes issues... Right?

I think some guys get a lot of track time with their rigs which, even without mods may cause increased wear sooner. But they also seem to be hard core wrenchers so it may be less of an issue for them to fix anything.

I personally don't plan on tracking a whole lot, just a few weekend runs to see what she does. I just think of how much I love the stage 2, it just falls a little short due to the limits that the SC pulley could be modified. I believe (or hope), the overdrive pulley will pick up where APR, GIAC, etc left off. And maybe all the players will start making tunes to support this setup.

..or maybe it all blows up and i have to get a new car.

[ntsantos]

What tune do you have? In for some real data! Please log before and after.

Giac stage 2, Injen intake and stock exhaust for now. I've been running 50/50 e85/91oct on the race file and it's been running smoothly.

I'll definitely do some before and after logs.

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[Dudemans4]

AndThen is also in the 70K range... I honestly dont think it will be any issues.

How much more power are you guys expecting with the extra boost? Will internals hold?

who knows it may not even make a difference. I imagine boost will come on a lot quicker that may be it . i am a fan of aftermarket risk taking and it just so happened my pulley failed.

[Danny2323]

Giac stage 2, Injen intake and stock exhaust for now. I've been running 50/50 e85/91oct on the race file and it's been running smoothly.

I'll definitely do some before and after logs.

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This is very exciting! I'd really like to see the logs. I'm very interested to see what requested boost is versus actual, and where it starts bleeding off (if at all).

[PerimeterJones]

How does a crank pulley fail?

I will be installing my overdrive pulley this Saturday I'm a already stage 2 but my crank pulley failed.
so I figure why not the fastest stage2 car is running dual pulleys. ill be the first on the epl tune though.

[GRUMPY-S4]

who knows it may not even make a difference. I imagine boost will come on a lot quicker that may be it . i am a fan of aftermarket risk taking and it just so happened my pulley failed.

Did the failure cause any other damage?

[Dudemans4]

How does a crank pulley fail?

See my thread 85k and....

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Did the failure cause any other damage?

Fortunately no just my bank account after tow bill and parts

[GRUMPY-S4]

See my thread 85k and....

- - - Updated - - -



Fortunately no just my bank account after tow bill and parts

Thats awesome... You know what I mean! Ive read that the pulley failure can get scary with other damages. So I am happy you made out with just a tow bill... The parts is a wash as you were probably going to upgrade anyway!