Welcome to the North American Subaru Impreza Owners Club Thursday March 4, 2021
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Built Motor Discussion

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.







* As an Amazon Associate I earn from qualifying purchases. 
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 05-25-2019, 02:44 PM   #26
stevieturbo
Scooby Newbie
 
Member#: 20366
Join Date: Jun 2002
Chapter/Region: International
Location: Norn Iron
Default

Ahhh...more potential issues. I see you're using the normal accessory belt, I thought you'd slapped another pulley on out front.

Pros and cons.....Pros are handy and it's closer in to the engine so less leverage on the nose.
Cons would be...the pulley is a rubber damped pulley...so all the drive loads are via that rubber middle, so more chance of it failing. I know over here in the UK, some EJ25 front pulleys just failed even on normal turbo cars.

But if it's ok for now....let's not worry about it.

Additional wrap around the crank would be good though. And any spring tensioner will need to go on the slack side of the belt...ie in your case down low on the left side ( looking at front of engine ).

Most tensioners apply tension to the smooth side of the belt...maybe in place of a fixed idler.

For a visual, I really like what ECS did on their Gen5 Camaro setup, where their tensioner uses a fixed idler near the blower, but the tensioner then pulls up on the belt instead. It means wrap always stays consistent and the two sections of belt are never getting pushed toward one another, which will happen as it stretches.

ie



Compared to this which pushes on the belt....I had this style myself, and it worked...but the other setup is much better IMO ( cant preview the pic link )

https://tse4.mm.bing.net/th?id=OIP.e...=0&w=300&h=300
* Registered users of the site do not see these ads.
stevieturbo is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 05-29-2019, 02:42 PM   #27
pcampbell
Scooby Specialist
 
Member#: 437670
Join Date: Jan 2016
Location: VT
Vehicle:
2005 2.5 SC OB

Default Vortech supercharger for ~500whp? Si Too big?

I think as long as the spring tensioner can apply up force rather than down force itíll work in that spot if i need to use one.

As for crank pulley, the one I have to go in is brand new oem so Iím not that worried but a single piece billet pulley is an option , although I have heard some concerns with those, which I why I picked the oem one.
pcampbell is offline   Reply With Quote
Old 05-29-2019, 06:22 PM   #28
stevieturbo
Scooby Newbie
 
Member#: 20366
Join Date: Jun 2002
Chapter/Region: International
Location: Norn Iron
Default

The spring tensioner must be on the slack side.

And I'd agree the OEM crank pulley is a very good piece.
stevieturbo is offline   Reply With Quote
Old 05-30-2019, 07:44 AM   #29
pcampbell
Scooby Specialist
 
Member#: 437670
Join Date: Jan 2016
Location: VT
Vehicle:
2005 2.5 SC OB

Default Vortech supercharger for ~500whp? Si Too big?

One thing I am seeing now is the tensioner May hold the pulley too far off of the plate if I surface mount the tensioner to the plate. The belt runs like 1/4Ē off the plate at most, probably more like 3/16Ē. I bet there are certain models that are near flush mount though? For example


https://www.google.com/shopping/prod...:1,prmr:1,cs:1
pcampbell is offline   Reply With Quote
Old 05-30-2019, 03:04 PM   #30
stevieturbo
Scooby Newbie
 
Member#: 20366
Join Date: Jun 2002
Chapter/Region: International
Location: Norn Iron
Default

When I did my own setup for my LS, I used a tensioner like this. Although I was pushing on the back of the belt...but all you'd need is a pulley change to a ribbed to drive against the ribbed side ( might work with smooth too though )

https://www.ebay.com/itm/Gates-38285...4AAOSwk1haJZuX

There's no reason this type couldnt allow the belt to run barely a few mm away from your fixing plate, as it did with mine as space was very tight.

it is also quite strong with a good range of motion ( that one is a width for a 10 rib I think although I changed pulleys for a 12 rib )
stevieturbo is offline   Reply With Quote
Old 06-01-2019, 08:23 AM   #31
pcampbell
Scooby Specialist
 
Member#: 437670
Join Date: Jan 2016
Location: VT
Vehicle:
2005 2.5 SC OB

Default Vortech supercharger for ~500whp? Si Too big?

Hereís a few more pics with more belt wrap around the crank. Now with 2.62Ē pulley. Not sure yet if itís slipping. Only around 12 psi. I really thought the bigger blower would push a lot more. I probably should have gone with the smaller Vortech h68b compressor which would have been slightly more efficient at this power level:boost ratio.

Not sure how much my AWIC is hurting things, with 2.5Ē pipes where as the SC is 2.75Ē out and the TB is 2.7Ē I think.

Delta blower cams is also an option. Estimate power around 250-275whp. Kind of weak but then itís not a ton of boost.

pcampbell is offline   Reply With Quote
Old 06-01-2019, 08:38 AM   #32
stevieturbo
Scooby Newbie
 
Member#: 20366
Join Date: Jun 2002
Chapter/Region: International
Location: Norn Iron
Default

You could easily make 700hp with 2.5" pipes, so not a concern there.

If you had an aftermarket ecu you could rig up something to log blower speed..but it probably isnt necessary.

If boost climbs at a steady rate vs rpm with no blips or drops then it is almost certainly not slipping
stevieturbo is offline   Reply With Quote
Old 06-02-2019, 08:29 AM   #33
pcampbell
Scooby Specialist
 
Member#: 437670
Join Date: Jan 2016
Location: VT
Vehicle:
2005 2.5 SC OB

Default

Thanks for all of your help. I think itís slipping a bit now with the 2.62Ē. Iím wondering if I should also be trying a continental elite belt (formerly gatorback). Itís the ones with all the slots in the belt. Not expensive so perhaps worth a try among the other things.
pcampbell is offline   Reply With Quote
Old 06-02-2019, 01:50 PM   #34
stevieturbo
Scooby Newbie
 
Member#: 20366
Join Date: Jun 2002
Chapter/Region: International
Location: Norn Iron
Default

Plot boost vs rpm on a pull. If it is a straight line, then it is almost certain there is no slip.
stevieturbo is offline   Reply With Quote
Old 06-02-2019, 04:04 PM   #35
NSFW
Scooby Guru
 
Member#: 140444
Join Date: Feb 2007
Chapter/Region: NWIC
Location: Near Seattle, WA
Vehicle:
05 Stage Free LGT
ATP 3076, 6MT, AVO FMIC

Default

Quote:
Originally Posted by pcampbell View Post
Hereís a few more pics with more belt wrap around the crank. Now with 2.62Ē pulley. Not sure yet if itís slipping. Only around 12 psi. I really thought the bigger blower would push a lot more. I probably should have gone with the smaller Vortech h68b compressor which would have been slightly more efficient at this power level:boost ratio.

Not sure how much my AWIC is hurting things, with 2.5Ē pipes where as the SC is 2.75Ē out and the TB is 2.7Ē I think.

Delta blower cams is also an option. Estimate power around 250-275whp. Kind of weak but then itís not a ton of boost.
Do you still have the option of using that smaller compressor?

The Si blower is pretty popular with the Corvette crowd, so I'm guessing it was intended for 5.7-to-7 liter engines. The compressor map suggests that at 12psi it wants to be flowing around 60 lb/min, and your whp right now probably works out to around 30-35 lb/min.

If you can swap the blower for something that's a bigger fit your displacement, I think that'll be a win.

That said, you've already got basically "stage 2" power with zero lag, which is pretty cool.
NSFW is offline   Reply With Quote
Old 06-03-2019, 12:14 AM   #36
pcampbell
Scooby Specialist
 
Member#: 437670
Join Date: Jan 2016
Location: VT
Vehicle:
2005 2.5 SC OB

Default

Yeah the smaller Vortech will bolt right up to my bracket, but I donít know if I want to deal with selling it at a loss for a smaller one. I will probably look into getting some delta 1500 cams to allow the motor the breathe a little more. I initially got the big Vortech thinking I could get it to throw a lot more air (itís rated to 22 psi but as it turns out belt slip will be an issue way before that).
If I can get the belt to grip well there is a company that sells a slightly smaller pulley for maybe 14 psi. It is pretty fun though.
pcampbell is offline   Reply With Quote
Old 06-03-2019, 05:03 PM   #37
stevieturbo
Scooby Newbie
 
Member#: 20366
Join Date: Jun 2002
Chapter/Region: International
Location: Norn Iron
Default

boost is only a measure of restriction.

Again....plot boost vs rpm and you will see if there is any slip worth worrying about. Belt dust is another sign of lots of slippage.
stevieturbo is offline   Reply With Quote
Old 06-03-2019, 11:22 PM   #38
NSFW
Scooby Guru
 
Member#: 140444
Join Date: Feb 2007
Chapter/Region: NWIC
Location: Near Seattle, WA
Vehicle:
05 Stage Free LGT
ATP 3076, 6MT, AVO FMIC

Default

Quote:
Originally Posted by stevieturbo View Post
boost is only a measure of restriction.
That cliche is kind of goofy, because boost is also what pushes air into the cylinders, and that's really quite a useful property. It's also the "density" in speed-density fueling, and that's a critical bit of math for ECUs that use it.

It's possible to be lead astray by thinking of boost as a goal rather than as a means to an end, but is there some reason to think that's what's happening here?
NSFW is offline   Reply With Quote
Old 06-04-2019, 03:20 AM   #39
stevieturbo
Scooby Newbie
 
Member#: 20366
Join Date: Jun 2002
Chapter/Region: International
Location: Norn Iron
Default

Yes....but just because Vortech say the blower is rated to 22psi...doesnt mean it will always produce 22psi.
stevieturbo is offline   Reply With Quote
Old 06-04-2019, 10:58 AM   #40
pcampbell
Scooby Specialist
 
Member#: 437670
Join Date: Jan 2016
Location: VT
Vehicle:
2005 2.5 SC OB

Default Vortech supercharger for ~500whp? Si Too big?

Nah, I just wanted to go for as big as was possible. I thought Iíd land outside of the range of the smaller h67b.

Last edited by pcampbell; 06-04-2019 at 11:16 AM.
pcampbell is offline   Reply With Quote
Old 06-04-2019, 01:59 PM   #41
stevieturbo
Scooby Newbie
 
Member#: 20366
Join Date: Jun 2002
Chapter/Region: International
Location: Norn Iron
Default

Go big...it'll cover future upgrades and work.
stevieturbo is offline   Reply With Quote
Old 06-10-2019, 05:36 PM   #42
pcampbell
Scooby Specialist
 
Member#: 437670
Join Date: Jan 2016
Location: VT
Vehicle:
2005 2.5 SC OB

Default Vortech supercharger for ~500whp? Si Too big?

I graphed out a wot pull. Each data point is between .14 and .44 (psi) higher than the previous. There is a little belt dust but I donít think itís enough to worry about. Now I can probably consider a grip treated 2.4Ē pulley.

I switched out to the larger 375ml snow nozzle and I am working on timing now. I had a full 4 degree pulled from my last best rom from 1.4 load at 3600 to redline so it feels pretty good but I think there is a bit more room to grow without knocking.

Last edited by pcampbell; 06-10-2019 at 05:49 PM.
pcampbell is offline   Reply With Quote
Old 06-11-2019, 09:40 AM   #43
pcampbell
Scooby Specialist
 
Member#: 437670
Join Date: Jan 2016
Location: VT
Vehicle:
2005 2.5 SC OB

Default Vortech supercharger for ~500whp? Si Too big?

I thought this was interesting. If I had gone with a Procharger Cs-1, they have a huge step up ratio, probably specifically for small crank pulleys like Subaru. They also use billet impellers with 80k rpm redline. To get 80k rpm with a Subaru you would use a 3.5Ē SC pulley. I believe that is a more ideal SC for a Subaru. For the next person trying this!!! It is also significantly smaller in size.
pcampbell is offline   Reply With Quote
Old 06-20-2019, 02:16 PM   #44
pcampbell
Scooby Specialist
 
Member#: 437670
Join Date: Jan 2016
Location: VT
Vehicle:
2005 2.5 SC OB

Default

So I think we could get to 400whp from here.

Delta cams
Forged rods with ARP bolts
Forged pistons, preferably somewhere in the 9's static CR
2.4" pulley + Rev to ~6800rpm
Bigger injectors, parallel fuel
Supertech springs
Optional: billet impeller

I just ordered the 2.4" pulley, we'll see how that goes. The full build is just an idea right now. I am out of $$$$$ anyway.
pcampbell is offline   Reply With Quote
Old 06-20-2019, 11:45 PM   #45
NSFW
Scooby Guru
 
Member#: 140444
Join Date: Feb 2007
Chapter/Region: NWIC
Location: Near Seattle, WA
Vehicle:
05 Stage Free LGT
ATP 3076, 6MT, AVO FMIC

Default

There are some guys in the Corvette community (not many...) who select pulleys so that the blower hits its max RPM at the same time that the engine hits its max RPM. Then use a wastegate/BOV (acts like a wastegate, but installed where you'd put a BOV) to vent any pressure that's above whatever they want their boost to be. Plus it helps build more boost at lower RPM, as compared to limiting boost by slowing down the blower.

It's the approach I wanted to take with mine before horror stories about blowers and track days scared me off. Apparently it's hard to keep them reliable, keep heat down, keep belts on, etc.

Anyway, that approach might work especially well for your setup since it's going to be hard to get a 4-cyl to move as much air as this blower was designed for. Venting some air will move you to the right on the compressor map, which should help avoid surge.

Having done nothing like this myself that's largely speculation, but it seems good on paper...
NSFW is offline   Reply With Quote
Old 06-21-2019, 03:17 AM   #46
stevieturbo
Scooby Newbie
 
Member#: 20366
Join Date: Jun 2002
Chapter/Region: International
Location: Norn Iron
Default

I did that with my YSi. It is a bad approach, and really it made little difference to how it made boost early on.

And when it was venting, the car just felt horrible.

Many also say it places unnecessary loads on the compressor itself by dumping a lot of air.
stevieturbo is offline   Reply With Quote
Old 06-21-2019, 08:31 AM   #47
pcampbell
Scooby Specialist
 
Member#: 437670
Join Date: Jan 2016
Location: VT
Vehicle:
2005 2.5 SC OB

Default Vortech supercharger for ~500whp? Si Too big?

Unfortunately Iím already into semi custom size (small) pulleys to make it spin faster. I think Iíll be close to but still under the impeller ďredlineĒ. Iíll get up to about 50k rpm with the 2.4Ē and they say 53k max, however with a billet impeller they say 60k. Iím guessing 2.4 and 6400 this will be about 2 more psi, maybe 14 psi at redline. But I think 2.4Ē is about as small as Iíd go (I donít actually think smaller exist ) for not wanting to deal with belt slip.

So Iím kind of banging my head over that procharger cs1 that would have a nice fat belt gripping 3.5Ē pulley send the impeller to redline at my engine redline. That is a smaller compressor though.... no compressor map available ,but perhaps more suited. to the Subaru 2.5. I am going to see if anyone has run the Slingshot CS-1 kit all the way to redline and see what kind of power it makes. They run that on a 2.4 Ecotec GM motor.

For example, Letís say a 3.5Ē pulley does 16 psi @6400 on a Cs1 which is what I expect out of the Vortech with a 2.3Ē pulley. But a 2.3Ē pulley a) doesnít exist and b) would lilely slip. I believe this would make around 360whp before talking about cams.

Last edited by pcampbell; 06-22-2019 at 05:58 AM.
pcampbell is offline   Reply With Quote
Old 06-25-2019, 12:57 PM   #48
pcampbell
Scooby Specialist
 
Member#: 437670
Join Date: Jan 2016
Location: VT
Vehicle:
2005 2.5 SC OB

Default

How does this look for a build? It is based off of my spare motor so I can get it all ready in advance and then swap it in in one day. I'd really like to be able to rev it to 6800 even 7k if I want, so I put in some HD springs.

SHORT BLOCK
Machine shop(????) line bore? 500
Manley pistons and rings 550
Eagle or Manley rods? 400
Bearings (king?) 150



HEADS
Machine shop 350
Timing kit 220
Head and gasket set 200
Install stuff (sealant, new water jacket washers) 50
ARP studs (260-4702) 225
Supertech springs 435
Oil pan (SPECTRA PREMIUM SUP02A {#11109AA092, 11109AA093} 50
Delta 1500 cams 250

Clutch 500

Total is under $4k
pcampbell is offline   Reply With Quote
Old 06-27-2019, 07:47 AM   #49
pcampbell
Scooby Specialist
 
Member#: 437670
Join Date: Jan 2016
Location: VT
Vehicle:
2005 2.5 SC OB

Default

Ok Iím going to just hit the dyno after I get the 13ish psi pulley on there to try to figure out potential. No point in speculating. I know my maf readings but donít know how much the SC robs. My hope is 1 g/s is still roughly 1whp. Weíve got a power robber on there but it is a 10:1 motor so maybe it sort of evens out.
pcampbell is offline   Reply With Quote
Old 07-02-2019, 09:32 AM   #50
pcampbell
Scooby Specialist
 
Member#: 437670
Join Date: Jan 2016
Location: VT
Vehicle:
2005 2.5 SC OB

Default Vortech supercharger for ~500whp? Si Too big?

How much compression do I want to run if I end up around 18-20psi with a big fat water meth injection I want to stay at high as possible to have good timing and power. Iím thinking 9.5 ish.
pcampbell is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -4. The time now is 12:43 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2021 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.