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Old 06-03-2020, 09:00 AM   #151
pcampbell
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Default Vortech supercharger for ~500whp? Si Too big?

This really seems like it would work but , maybe just the wrong bolt spacing

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Old 06-03-2020, 01:26 PM   #152
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LOL something I should not forget is that ignition timing does apparently affect boost. So if I'm comparing runs , timing needs to be the same or else boost and maf flow may be lower and it is not an apples to apples comparison.

These Delta 1500 cams are so noisy, I get a lot of false knock.

Last edited by pcampbell; 06-03-2020 at 01:59 PM.
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Old 06-03-2020, 01:39 PM   #153
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Every supercharged car I've seen on the dyno or owned by friends that had belt slip, its always the tensioner in the end
Mine is the stock static tensioner, so basically you tighten it "a lot" and it will inevitably the belt will stretch a little bit. I am not sure if adding a spring tensioner would help, or not.

I know 928 motorsports says , solutions for belt slip:
2) if using a sprung belt tensioner, replace with static (solid) belt tensioner.

Last edited by pcampbell; 06-03-2020 at 01:52 PM.
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Old 06-03-2020, 02:01 PM   #154
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Quote:
Originally Posted by pcampbell View Post
Mine is the stock static tensioner, so basically you tighten it "a lot" and it will inevitably the belt will stretch a little bit. I am not sure if adding a spring tensioner would help, or not.

I know 928 motorsports says , solutions for belt slip:
2) if using a sprung belt tensioner, replace with static (solid) belt tensioner.
I personally have seen the best results from a strongly sprung tensioner. getting the correct amount of force on a static tensioner is a bit more tricky than letting a spring use a specific rate to apply pressure.

I say if it keeps slipping you add another pulley to the system, but just make sure its attached to another supercharger preferably a screw. LOL

Last edited by Scuby04STi; 06-03-2020 at 02:01 PM. Reason: Spelling sucks, lol.
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Old 06-04-2020, 01:14 PM   #155
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I found someone that'll make a bolt-in-front pulley for a Fluidampr for me. I need to figure some stuff out but it seems like it should be relatively easy.

Biggest pulleys that will fit both in diameter and ribs (8?), but build in room for at least 1 larger pulley on the SC side in case I need to gear down more, because 928 billet impeller will develop more boost at same impeller speed than stock impeller.

For example 8" crank and 3.6" SC is a little more aggressive than I have now. 3.7" is about the same and 3.8" is a little less aggressive. I have no idea if I can fit a 3.8" pulley on the SC side, or an 8" on the crank, yet.



The only thing I really see in the way is the pax fan shroud, seems like we should be able to go above or under it.

Here is my kids anthem for my car project


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Old 06-04-2020, 08:15 PM   #156
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3.7" SC pulley seems like it'll fit. If the hood doesn't close I can shave a little off the top! ha!



Here's my mock up 8 rib off the front:


It all fits ok, it's close around the fan shroud, but I think it'll fit. This guy I've been talking to about making the custom crank pulley has been great so far, very easy to deal with., he seems to know his stuff. He makes custom SC pulleys for Fluidampr on Audi's.

http://www.vdamper.com/30-V6-TSI-Supercharged_p_42.html

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Old 06-05-2020, 08:29 AM   #157
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Iím a little concerned with cantilevering the pulley on the SC input shaft. Itís going to stick out a bit more than itís supposed to, but that might just be an added wear that I take without having to redesign the SC mount.
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Old 06-05-2020, 07:29 PM   #158
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OK I have a custom SC crankshaft pulley coming in about a month or so. 8" diameter and 8 ribs, that will bolt onto a Fluidampr.

With a 3.7" SC pulley I'll be at stock impeller redline (55k) at 7100rpm . Hopefully it works. The question will be if I can make it line up right and then how much boost it will hold.

Last edited by pcampbell; 06-05-2020 at 08:57 PM.
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Old 06-06-2020, 09:26 PM   #159
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Just noticed this thread, are you running a ribbed or cogged belt? If you run cogged, the belt won't need to be tight as it tightens as rpms increase. It will also keep the same crank to SC speed ratio as it won't slip. There's a specific amount of slack, but that's what I've read in some supercharger threads on other forums.

A ribbed pulley will require a good bit of tension to resist slipping and I could see it wearing and needing to be readjusted constantly, and possibly causing tuning issues if the SC and engine rpm are not staying consistent. I'm not sure of how much torque the ribbed belts can handle before slipping, considering superchargers do require a good bit of torque to cram air into the engine.
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Old 06-07-2020, 09:52 AM   #160
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Iíve been running the stock 5 rib on very small pullies (5.22 and 2.4). The plan was to switch to 8 rib and very large diameter pullies (8 and 3.7).

I didnít think that a cogged setup was very friendly for the street , and very hard on the supercharger so I was avoiding that. Going from 5 rib to 8 with the larger pullies will increase belt contact by at least double.

I do think a 35mm cog would fit space wise though.
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Old 06-17-2020, 07:32 AM   #161
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I finally found some more details on the 500whp brz. Running the same supercharger as me, not the smaller h67b. I think I can calculate what they spun it to based on their build. Pretty surprised they fit a v3 si under the hood.


https://www.lasleeve.com/tech/laslee...z-files-videos

According to the article they're spinning 8k on a Fluidampr (5 7/8) and a 2.62 pulley which puts them at 65000 rpm . That seems a bit off for a V3 Si - i mean a little overspeed sure but 65k is 10-13k overspeed.

they also said 26psi... which I would expect the V3Si to put out more pressure at 65k rpm.
So I've asked for clarification.

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Old 06-17-2020, 01:12 PM   #162
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Does anyone know if anyone makes a direct fit low profile Fan?
Seems like it would be nice if the passenger side were less deep for wider belt.

EDIT: Word is this fits 05-09 Legacy/Outback.

https://www.rallysportdirect.com/par...iABEgJdrfD_BwE

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Old 06-17-2020, 02:09 PM   #163
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Doubtful but should be easy enough to mount a good Spal fan on.

Or if you're using two fans....remove one ( old classics with the horizontal flow rads this was easy )
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Old 06-17-2020, 05:52 PM   #164
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Talked to someone today who said the Mishimoto setup fits, not sure why but that was the report. I am asking Mishimoto for clarification.

I'll definitely take the one out that is in the way for fitment. I don't honestly think these fans go on unless I turn on the A/C, maybe if coolant temp gets out of control I am not sure, essentially not a concern for everyday driving here in Vermont.

I actually wonder if off the shelf Sti or other model fans are less deep than an Outback fan, because they do not have as much room. Either way I'm sure there is something that fits, that is skinner. The stock one is super deep.

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Old 06-17-2020, 07:35 PM   #165
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Originally Posted by pcampbell View Post
Talked to someone today who said the Mishimoto setup fits, not sure why but that was the report. I am asking Mishimoto for clarification.

I'll definitely take the one out that is in the way for fitment. I don't honestly think these fans go on unless I turn on the A/C, maybe if coolant temp gets out of control I am not sure, essentially not a concern for everyday driving here in Vermont.

I actually wonder if off the shelf Sti or other model fans are less deep than an Outback fan, because they do not have as much room. Either way I'm sure there is something that fits, that is skinner. The stock one is super deep.
Mishimoto is junk, don't buy it. Find a fan that actually works, oem is a massive upgrade over a mishimoto...
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Old 06-17-2020, 09:33 PM   #166
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Whatever you do, be sure the fan shrouds are separated so when only one fan is running, it won't just be sucking air from the other fan shroud. Most of those aftermarket shrouds are garbage and unless both fans are running, most of the air doesn't even get sucked through the radiator. Oems are done correctly with the shrouds sealed fairly well to the radiator and separated where they meet in the middle, with walls that extend to the radiator surface down the middle.

If you do get something aftermarket, the shroud design will be critical, as oem fans flow a lot.
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Old 06-18-2020, 05:17 AM   #167
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OEM fans are hard to beat.

But yes, if there are 2 fans, one will always be for coolant, the other may also be for coolant as well as a/c

I think some other models with a single fan use the same fan for both.

Just watch the fans to see what one comes on first, or if you have a/c turn it on and see what fan operates. Then remove the one you dont need.
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Old 06-18-2020, 06:36 AM   #168
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Thanks for clarifying. pretty sure the one in my way is for A/C but I will confirm.
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Old 06-18-2020, 01:13 PM   #169
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Playing around width (see what I did there LOL) whether a 10 rib would fit. I think it could.

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Old 06-18-2020, 02:26 PM   #170
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With that pulley there....you could do about a 30 rib lol.

But with the very small engagement a Subaru pulley has in its crankshaft, I wouldnt go nuts extending things too far forward.
Although on the flip side, a wider belt will mean a lot less tension needed.
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Old 06-21-2020, 09:41 AM   #171
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Default Vortech supercharger for ~500whp? Si Too big?

Trying to decide between 10 rib and smaller pulleys vs 8 and bigger pulleys.

3.6Ē and 8Ē 8 rib
3.12Ē and 7Ē 10 rib

Napkin math suggests 10 rib has just slightly more belt contact if theyíre all at 50% wrap but could get more wrap on the bigger pulleys maybe.

Not going to get too concerned I can always try 10, if I start with 8.

What happened is I found an off the shelf 10 rib crank pulley that will bolt to a Subaru Fluidampr after I custom ordered my 8 rib! Too late to cancel the custom 8. The Mopar bolt pattern is the same as Subaru Fluidampr supposedly. So a vortech generic 10 rib crank pulley will probably bolt up to a Subaru Fluidampr.
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Old 06-21-2020, 12:24 PM   #172
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Happens Lots of wasted money trying to figure things out when sometimes the solution is right there. Then later people will chime in with "yeah, I could have told you that" or whatever. It's just money though, right?
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Old 06-21-2020, 01:15 PM   #173
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I would not be hanging a drive pulley off the front off a Subaru pulley unless you had some sort of proper bracing for the nose.

A Subaru crank is not a SBC, BBC or LS crank !

It is mega flimsy in comparison, especially wit the small nose, and thin webs due to the nature of the flat 4. I wouldnt want to be side loading very much at all
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Old 06-22-2020, 08:36 AM   #174
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Quote:
Originally Posted by junebugfareast View Post
Are you saying a roots blower discharging into an open pipe will be at positive pressure?
well, it will be positive pressure at discharge and then of course you are releasing it to atmosphere

Quote:
Originally Posted by stevieturbo View Post
Which is impossible....because there is no restriction.

Regardless of how anyone describes each compressor....unless it is discharged into some sort of restriction, you arent going to see any positive pressure or boost.
Wrong.
It's impossible unless you have a physical compressor, which a turbo is not but a PD roots type is. Nobody is pretending you can maintain pressure in an open pipe, obviously that is ridiculous, but it would discharge at pressure no different than a piston compressor pushing up into it's chamber and then the valve opens and blows out physically compressed air.
A turbo will never do that, it is just a fan, it only moves air, it doesn't compress it.

Quote:
Originally Posted by Scuby04STi View Post
What they are saying is that the twin-screw superchargers are different from a roots or centrical in that it doesn't simply move air until it hits a restriction to create boost. It actually has sealing between the screws that create its own restriction as the air moves from one end to the other until you touch the throttle and release the boosted charge into the motor.

Basically if you wanted to tap into the housing on all three options just before the discharge and you let it discharge into an open pipe only one will have an internal boost reading.

There is a reason a twin-screw is by far the most efficient supercharger style, also why it is basically regulated out of a lot of drag racing classes.
^this guy gets it.
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Old 06-22-2020, 09:38 AM   #175
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Default Vortech supercharger for ~500whp? Si Too big?

Quote:
Originally Posted by stevieturbo View Post
I would not be hanging a drive pulley off the front off a Subaru pulley unless you had some sort of proper bracing for the nose.

A Subaru crank is not a SBC, BBC or LS crank !

It is mega flimsy in comparison, especially wit the small nose, and thin webs due to the nature of the flat 4. I wouldnt want to be side loading very much at all


This is a good point. Iím hoping pulleys with less tension off the front will not be as hard as closer in pulley with significantly higher tension.

Last edited by pcampbell; 06-22-2020 at 04:18 PM.
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