Pulleys
 

Where are you guys sourcing your pulleys?

The 9lb pulley on Z1's website is ~$155, ConceptZ ~$220, I couldn't find a 7-rib pulley on Vortech...

I saw some discussion about picking up a smaller 8-rib pulley for the SC side...

I know there was some talk on Topgunz A2A thread about the pulley ratios and such but in an effort to break down the monster thread into more manageable pieces, maybe we could talk about pulley setups here :tup:.

Thanks!

I second the pulley info...I almost ready to go A2A but I am only on page 79 of 115ish of the thread...and am having trouble keeping things straight with pulleys, sizes, belts.

/Z/

The slip comes mostly from the serpentine side around the stillen pulley. The 8psi pulley is 3.2" and shotpeened for grip (not sure how effective it is) and obviously has a larger diameter than the 9psi (2.8") pulley, hence will have more traction. There is minimal wrap around that pulley. This is the reason Tbatt sells his extra pulley mod that places a pulley in front of the stillen one to create twice the amount of wrap on it.

Now on the supercharger side we have a 3.2" driving a 3.2" or 1:1 ratio. Here we do not see slip but can change these out to accomplish more boost instead of swapping serp side pulleys. The problem is that the idler pulley on that side has little room to keep tension on the belt when the pulley size drops. Pending you drop the pulley that comes directly off the shaft of the SC. The jackshaft pulley could go bigger but then you cant get the belt on. So, to remedy that you can buy a smaller SC pulley, directly off the SC, and then buy a larger idler pulley (3") so you still get the throw distance you need to keep tension on the belt. j

Another method is to get a smaller supercharger pulley but a larger jackshaft pulley so you keep the same amount of tension on the belt without needing a larger idler. This is what I did. 3.4 jackshaft and a 3.0 supercharger. This keeps the belt tension the exact same but will spin the supercharger about 10K faster than the 1:1.

Those pulleys from vortech are $99 each. So the cheaper method is the get the smaller supercharger pulley in a 3.0 or 2.8, depending how fast you want to spin, and the idler pulley that is $30. This method saves about $70 overall.

At least this is what I recall from everything I did almost 2 years ago. Is everyone confused yet?

Tbatt can you confirm this?

You are dead on!

Just to be sure I am understanding the names of the different pulleys, attached is my guess at them. Can someone confirm I understand correctly?

Thanks
/Z/

That is correct!

Except I would remove the 8psi from the SC and move it to the serp jackshaft pulley as that is the pulley that is swapped out from stillens definition of 8psi pulley or 9psi pulley. The SC pulley that comes off the shaft really doesnt have a "psi" denoted to it.

Ok, thanks for the clarification. So up 4 posts you did a great explanation, however I just want to be sure of something...you mentioned "This is what I did. 3.4 jackshaft and a 3.0 supercharger"...so that means in my picture with the way I happened to label it, you changed the jackshaft on SC side pulley and the jackshaft on serp side pulley, correct?. Aka...both pulleys on opposite sides of the mounting bracket.

I think my previous post has the wrong understanding...i think you replaced the pulley off the shaft of the SC and the jackshaft pulley...so you changed the two pulleys that are both on the SC side. Am I correct here?

Close but not quite there. The only drive pulley that changes is the one on the SC. When you go to a smaller diameter SC pulley you need a larger SC idler pulley to take up the slack.

I changed the Jackshaft on the supercharger side and the supercharger pulley. Those come stock at 3.2 and 3.2. By going to a 3.4 and 3.0 it is the exact same tension on the belt as stock. It also spins it the same ratio as going from the stillen 8psi pulley (3.2") to the stillen 9psi pulley (2.8")

Here play with this. Our crank diameter is 5.75 and redline is 7500.

https://vortechsuperchargers.com/pag...eed-calculator

Even with your kit? Could you install the old sc pulley as the idler pulley or is it not compatible and/or big enough?

Not compatible, you have to use a larger idler pulley if you go to a smaller SC pulley.

There are several ways to get to a 9psi drive system. You can either spin the jackshaft faster and leave the SC drive belt system as is (this is how Stillen does it) or you can keep the serpentine drive belt side stock and go to a smaller SC diameter pulley. Either way you spin the SC faster which increases boost.

When you spin the SC faster, it takes more power to do so which leads to belt slip on the serpentine drive belt at the jackshaft pulley. My kit gives the belt more wrap (contact area) on the jackshaft pulley and eliminates the belt slip.

When you increase boost, you increase the amount of power that is needed to drive the SC. At 9psi it takes around 60hp to drive the SC. That is a lot of power running through the serpentine belt. That is why my kit includes the HD belt. It can handle the load and the additional pulley insures that the jackshaft is getting all of the power to the SC. With a SC, it takes power to make power where a turbo is kind of "free" power.

I like the linear power curve of the SC. I can look at my tach and tell you how much power the engine is making. It is purely a function of throttle position and RPM. I love it!

I purchased a 9lb jackshaft pulley and I also purchased a (if I'm not making the power that I want) 2.87 suoercharger pulley. Of course I have your kit. Supercharger is being installed this week and goes to Seb on Tuesday for tune.

So, what you're saying is that I can install the 9lb jackshaft pulley without changing the idler pulley but if I want to use the 2.87 pulley then I'll need to install a larger idler pulley? You're tensioner kit wouldn't take up the slack of using the stock idler pulley?

I'm hoping to not have to use either of the pulleys as I'm installing an si supercharger and Seb thinks he can hit my numbers with the stock pulleys but I just wanted to have back up pulleys just in case.

Sorry but you are confused by the two drive belts.

My kit goes on the serpentine belt that is driven by the crankshaft pulley. That is why I include a longer belt. The other belt that connects to the SC also has an idler that is used to adjust the belt tension. If you switch to a smaller than stock SC pulley you won't have enough adjustment with the stock idler so you need to go to a 64mm idler pulley to take up the slack (Gates #36225).

You're right, I was (but not now, I hope) confused :o So, on the supercharger side you have a jackshaft pulley, an idler pulley and the supercharger pulley. Correct? Thanks for the Gates info.

Yes, you got it. I considered doing what Topgunz did and change the SC a little smaller and then up the idler pulley in size but I stuck my hand down in there and there is only the width of my pinky finger between the current idler and something else...I am a little nervous of the larger idler rubbing against something. I need to take a closer liike.

Since I already have the 2.87 supercharger pulley I went ahead and ordered the larger idler pulley that tbatt showed. Since my sc isn't installed yet I don't know if I'll have the same clearance problem you have. I'll know in the next couple of days. Hopefully I'll make the power numbers I want with the a2a kit and e85 where I won't need to upgrade the pulleys. I'll find out on Tuesday when it goes in for tune.

Hey, I'm sorry to bring this back and for missing this info earlier, but if I drop down to the smaller 9lb serp-side pulley, do I need get a larger idler pulley than the one that came with your kit? I'm having boost issues and everything trends correctly until top end, where I think I'm getting belt slip, but I can't hear it. I had no belt slip and expected boost with the 8lb pulley, but I'm now losing boost top end after switching to the 9lb pulley. I didn't change anything else other than replacing the serp-side pulley with the smaller one. Is this where I messed up? Thanks!

9lb pulley on stock system .. belt slip?
 

I have a stillen sc with stock 8lb pulley no other upgrades. I want to upgrade to a2a and add 9lb pulley . Can I just take up the slack with the tensioner as stated on z1 and concept Z website or will it have slip?

Has anyone done this and have some input of this ? Thanks.

Who installed it? Very first thing you should do is go make sure the key is in there. I can totally see it having enough friction to grab until a certain point then without a key it lets go and free spins the pulley.

With the T batt mod there should be zero slip. I have sold many SC kits that does not include that mod and they do not have slip. They use my personal anti-slip pulley mod but it is no where near as aggressive as the one you have.

Most of the slack will be taken up from the auto tensioner. You may experience a little slip but not much. If you upgrade to the Si trim impeller you will have a higher chance of slip due to the fact that it creates more drag on the supercharger which ties all the way back to the serp belt.

I can get you my kit with my anti-slip pulley I send with my full supercharger kits as pictured below.

http://www.the370z.com/members/topgu...6-grip-mod.png

Thanks Topz ,
Not planning to do the Si upgrade. But I do like that anti slip setup , not sure why stillen didn't have that in the first place lol.

I know this is an old thread being revived but I’m in the market for some pulley upgrades. I also am confused on the pulley sides. Maybe someone can point me in the right direction. Currently running the V-3 SCi with TopGunz A2A Kit.

I plan on doing the 928 SuperVortech upgrade. Right now only have the Stillen 9lb pulley that only gives me 8.76psi at 7300rpm. I replaced it as advised by Stillen back when I was on Stillen Kit before TopGunz made his kit available. (Refer to attached pic). Apparently the pulley that was there before was color Blue and I was told by Stillen at the time that the Blue pulley was their 8pb pulley that came with the kit (which only gave me 6/7psi). Reading this thread got me
confused as to whether this was the right pulley i replaced as recommended by Stillen back in 2015

What pulleys would any of u gents recommend with the 928 SuperVortech upgrade and what kind of boost increase would each or any of the pulleys u all recommend actually deliver. 928 is advertising their upgrade to be capable of 72k RPMs and running at 60k + RPMs all day.

My car with the 928 super vortech, 9lb pulley, 3.47 jackshaft pulley sc side and 3.00 sc pulley made 16.4 psi.

With the 928 impeller and the 9lb pulley I bet you see closer to 11 psi. Also, if I remember correctly, the 9lb pulley is a 2.87. You can measure your's to verify what you have.

Maybe should mention what else you modded to fit the 3.47" and 3.0" pulley on the SC belt side. IIRC you needed pulley spacers of a certain size and needed to change the idler pulley on the SC side as well? To make this combination work or no?

And that you have a turbo guard instead of the K&N air filter to be able to make the 16.4 psi, since I'm not sure if everyone is running with a turbo guard or not.

The spacers you can get from 928 for less than $30.00. Those have nothing to do with boost levels as he was asking about.

My car made over 10 psi with the Si sc, 9lb pulley and stock filter. That's why I believe he will make over that with the 928 upgrade.

But yes, when I went to the 3.47/3.00 combo I went to the turbo guard.

My car also made 12.86 psi with the stock Si sc, 9lb pulley, stock 3.2 jackshaft pulley, upgraded 2.85 sc pulley and stock filter.

For 62k+, you will be dealing with belt tension and slip when putting the K$N filter on. :D

Go to the Vortech website and buy their "high traction" pulleys. I did that for my two SC-side pulleys. I went 3.15-3.00" with the larger tensioner pulley

What’s recommended if you already have a Stillen high boost pulley?

It all depends on how much boost you want to make and what you have to support it.

If you intend to spin the SC faster than you do with the 9lb pulley, you should definitely look at getting the 928 impeller.

Things that you can do with pulleys:
Get an even smaller pulley to place where the Stillen "high boost" pulley is.
Get a larger SC-side jackshaft pulley
Get a smaller SC-side SC pulley
Any combination of the above

Keep in mind that changing the SC-side pulleys may require you to get a larger idler pulley.

Actually, if you plan to spin the V3 faster than it's max rpm of 52000 then you should get the 928 ceramic bearings. The Si impeller is just fine. Mine actually started making boost sooner than the 928. I ran both on the dyno.

I am deciding if I want to switch from my 8 lb pulley to the 9 lb pulley I have . Just not sure I want to go thru all pain in the *** of more remote tuning again. I really hate that.

Great feedback from everyone...TY Gents... I also forgot to mention that I have TBatts idler pulley/belt upgrade. Hoping that helps keep things down. I am also like Redondoaveb and using the turbo guard with no filter.

Are the spacers needed for the upgrade @redondoaveb for the jackshaft/SC pulley upgrades? Its been a minute since I’ve been on the forums but I also recall ur set up having the fabricated wastegate to the charge pipe. I recalled u referring me to Alex with L-Spec up in Hawthorne. I also reached out to Seb since he’s the one that has tuned my Z and was working/tuning ur Z at the time and he mentioned they (Specialty Z) were considering fabricating the piping and wastegate set up for open sell to others like myself....but not sure if that ever materialized or not. I also emailed Alex but last I heard they were working on a putting a pricing group together but received no other update since that time which was about almost a year ago. LOL

If the wastegate upgrade isn’t available then I won’t be going for boost anywhere in ur range... @redondoaveb. Don’t think it would be feasible for me without that and a boost controller as I am on a stock block with stock internals ...I’m using the CJM S1-SE set up what the 485 Walbro pump/CJM Top hat 1000cc Bosch Injectors for plumbing but unfortunately my fuel options are limited. The weather out here in the West Pacific doesn’t work well with E-85 or any flex type fuel due to our humidity. 91 at the pump is the highest we get with the exception of course of VP MS109 from our local race shop that ships that good stuff in. But at $120 for a five gallon can...we save that strictly for track days/money race events...Lol. We do have great sunny weather year round and nice white sandy beaches though LOL!!!!! Give and take I guess... Oh well...:tup:

Since a little more has been shared on my set up any great advise from those of u with the experience here would be greatly appreciated. Thank you for laying down the groundwork for improving this kit. If it wasn’t for TopGunz and guys like you on this forum we would all be stuck with the basic Stillen Kit.

If 91 is the only fuel you're going to run then the wastegate wouldn't be needed. You can run around 13 psi on 91 before knock. If you plan on boosting above that level by using a higher octane fuel then you would need the wastgate in order to dump excess boost when you're running 91. I bet if you contacted Seb, he would be able to build you a custom set up like he did with me.

Sounds like a great idea....I’ll reach out to him before we send the charger out to 928. Thanks again Pat. If the waste gate doesn’t happen what pulleys would I need to change out to get up to 13psi? I’m currently at about 8 to 8.3psi with the 9lb SC pulley that Stillen sent me which is on the Jack-Serp side. This low boost has tk die wit my location, weather and sea level factors

I used the 9lb and a 2.85 supercharger pulley to get to 13 psi (12.86 to be exact). You'll have to go to a 3.00 idler on the supercharger side if you go with the 2.85.

Awesome... Will these pulley changes require the spacers mentioned by Cupcakez? I know it was mentioned earlier On the thread I believe by by imazman that it was a pretty tight fit on the idler pulley (SC Side).

Remember that your SC will not come with a warranty if you send it to 928. If you send it to Vortech and get the Si impeller then it does come with a warranty.

As long as you do not change the jackshaft pulley on the supercharger side, you won't need the spacers. You may need the RPM belt instead if your goal is 13psi and you put the filter on, depending on the belt tension and impeller.