The Subaru SVX World Network   SVX Network Forums
Live Chat!
SVX or Subaru Links
Old Lockers
Photo Post
How-To Documents
Message Archive
SVX Shop Search
IRC users:

Go Back   The Subaru SVX World Network > SVX Main Forums > MOD Mania > Proven Engine Enhancements

Reply
 
Thread Tools Display Modes
  #1  
Old 09-19-2007, 02:17 PM
2.5InchTrueDual's Avatar
2.5InchTrueDual 2.5InchTrueDual is offline
Will
 
Join Date: Nov 2006
Location: New London IA
Posts: 62
Questions on an underdrive pulley

Hey, has anyone used the Motorsports Underdrive pulley set-up? I'm replacing my timing belt on my 94 LS and i thought now would be a great time to order the step up from something stock, plus it comes with belts, i think. Any inputy to the stuation would help.
Reply With Quote
  #2  
Old 09-19-2007, 02:23 PM
It's Just Eric's Avatar
It's Just Eric It's Just Eric is offline
Missing in action
 
Join Date: Oct 2005
Location: Tuckerton, NJ, USA
Posts: 3,027
Send a message via AIM to It's Just Eric
Registered SVX
Works great. I have the underdrive on ne car and the standard size one peice on the other. Doesnt seem to have any effect on performance, though Id imagine if you combined it with other lightweight stuff, in theroy, it could make a slightly noticable diffrence to performance. More or less, it's shiney, and wont seperate like the factory ones sometimes do..plus it makes your mod list 1 longer

If it doesnt come with belts, make sure to get some. The stock size will be too big, I think you need something like 1 or 2 inches smaller
__________________
R.I.P Cool Signature.
You're gone but not forgotten. I mean, sure, I kindof don't remember some of the finer details..but I remember you were funny, and at one point you said spaghetti in Dutch....but definantly not forgotten

Reply With Quote
  #3  
Old 09-19-2007, 04:44 PM
Trevor's Avatar
Trevor Trevor is offline
Registered User
 
Join Date: Feb 2002
Location: Auckland, New Zealand
Posts: 5,223
Registered SVX
Yes it will work and may look pretty and you may not have any problems.

However, your engine will no longer incorporate any means of torsional vibration dampening and this will impose unwanted stresses on the crankshaft. Accessories will run at a slower speed including the alternator, which could be important if you are running extra electrically powered gear.
__________________
Trevor, New Zealand.

As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit!
Reply With Quote
  #4  
Old 09-19-2007, 05:00 PM
TomsSVX's Avatar
TomsSVX TomsSVX is offline
Maniac modifier
 
Join Date: Dec 2003
Location: Branchburg, New Jersey
Posts: 15,489
Registered SVX Classic SVX
Quote:
Originally Posted by Trevor View Post
Yes it will work and may look pretty and you may not have any problems.

However, your engine will no longer incorporate any means of torsional vibration dampening and this will impose unwanted stresses on the crankshaft. Accessories will run at a slower speed including the alternator, which could be important if you are running extra electrically powered gear.
To be honest trevor, I don't see the stocker really doing much along the lines of dampening vibrations. I have been running an undersized pulley for my S/C for quite some time now with the only alternator issue being that sometimes it likes to get torn off the car Either way... the only upside to an underdrive pulley would be that it is a one piece... Other than that any real performance gains cannot be obtain through such simple means

Tom
Reply With Quote
  #5  
Old 09-19-2007, 05:48 PM
Trevor's Avatar
Trevor Trevor is offline
Registered User
 
Join Date: Feb 2002
Location: Auckland, New Zealand
Posts: 5,223
Registered SVX
Quote:
Originally Posted by TomsSVX View Post
To be honest trevor, I don't see the stocker really doing much along the lines of dampening vibrations. I have been running an undersized pulley for my S/C for quite some time now with the only alternator issue being that sometimes it likes to get torn off the car Either way... the only upside to an underdrive pulley would be that it is a one piece... Other than that any real performance gains cannot be obtain through such simple means

Tom
Tom, this argument has been well and truly thrashed.

It can nor be denied that the OEM pulley incorporates a means of, and is a torsional dampening device. The expense of incorporating same will have been taken into account by Subaru.

I agree that the effects or affect can not be seen, are from obvious and lack of same may not directly cause a problem. But is dispensing with a known advantage warranted? A will disclose some very interesting facts and detail regarding the technology involved.

All accessories driven via a flexible belt comprise an excellent means of absorbing torsional vibration and a supercharger will add to the affect. I would not suggest such a load should be imposed on the OEM pulley and you have no alternative option.

As a matter of interest I ran up against the lengths designers go to in respect of torsional vibration when I built my first car for competition, over fifty years ago. The Fiat engine had the generator flexibly coupled directly to the front of the crankshaft. The fan was fitted directly to the overhead crankshaft, chain driven at the rear end, via cone clutch sort of slipping hub. This set up was beautifully neat and tidy, but belt drives are superior.

Sincerely, I would love to have the opportunity to talk engine design, etc., etc., Tom/Tom/Trevor, over e beer or two.

Cheers, Trevor.
__________________
Trevor, New Zealand.

As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit!
Reply With Quote
  #6  
Old 09-19-2007, 06:13 PM
TomsSVX's Avatar
TomsSVX TomsSVX is offline
Maniac modifier
 
Join Date: Dec 2003
Location: Branchburg, New Jersey
Posts: 15,489
Registered SVX Classic SVX
tehn come to the states and we can do this

Tom
Reply With Quote
  #7  
Old 09-19-2007, 06:22 PM
Trevor's Avatar
Trevor Trevor is offline
Registered User
 
Join Date: Feb 2002
Location: Auckland, New Zealand
Posts: 5,223
Registered SVX
Quote:
Originally Posted by TomsSVX View Post
tehn come to the states and we can do this

Tom
Thanks Tom.

Invitation much appreciated, noted, recorded and put on hold pending a windfall.
__________________
Trevor, New Zealand.

As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit!
Reply With Quote
  #8  
Old 09-19-2007, 06:30 PM
redlightningsvx's Avatar
redlightningsvx redlightningsvx is offline
Collision Refinishing Tech
 
Join Date: Aug 2007
Location: Huntingdon, PA
Posts: 2,279
Registered SVX
I have emailed dayle about his pullys and he told the the best one to get for your money and proformance would be the stock size pully that is lightened if that helps anyone?
__________________
Seth
94' Barcelona Red w/ Tricoat black 2-tone AWD Ls -Sold
Mods:AWD conversion/4.44 swap by Budfreak, Custom red interior lights, Custom Satin black dash, Power mode switch, Cold air intake, Permecool tranny filter,Sony xplode 10" sub, Sony xplode 1000w amp, Blitz in-line driver, DDM Tuning 6000k HID's, New paint job/body work by me, 97' Grill, QC shift kit, 17'' MB Motoring rims, 15&20 min mod, front & rear urethane swaybar bushings, Custom fiberglass sub box, Custom red led a/c control unit, perrin lightweight crank pulley, Black wrinkle finish powdercoated intake manifold w/ clear hoses , 02' outback heated/power black leather seats
Soon to come:Fiberglass hood, upholster ALL suede to black leather
Past subies:

92' Pearl White/black top LS-L-SOLD
96' Legacy Outback-TOTALED
99' Legacy Outback Limited 30th anniversary edition-TOTALED
98' Forester L -Totaled
Other toys:
99' Forester S -WRX brake upgrade, soon an 04 wrx motor swap
06' B9 Tribeca-Stock
1982' Yamaha xj650 Maxim
Mods:
work in progress
Reply With Quote
  #9  
Old 09-19-2007, 06:32 PM
TomsSVX's Avatar
TomsSVX TomsSVX is offline
Maniac modifier
 
Join Date: Dec 2003
Location: Branchburg, New Jersey
Posts: 15,489
Registered SVX Classic SVX
i agree... the stock sized pulley is your best bet for aftermarket pulleys. You can also find them on ebay as they are the same as other subies for the most part. But they are of lesser quality than dayle's

Tom
Reply With Quote
  #10  
Old 09-19-2007, 09:52 PM
94SubieSVX's Avatar
94SubieSVX 94SubieSVX is offline
OOC for a while
 
Join Date: Jun 2007
Location: Hamilton, NJ
Posts: 1,552
Send a message via AIM to 94SubieSVX
I have Dayle's lightweight stock pulley and I noticed that the engine cranks over a little easier. Other than that it's pretty much the same.
__________________
bLAh
Reply With Quote
  #11  
Old 09-20-2007, 03:26 PM
AlcyoneDaze's Avatar
AlcyoneDaze AlcyoneDaze is offline
<-- custom hood ornament
 
Join Date: Nov 2006
Location: NJ
Posts: 689
Send a message via AIM to AlcyoneDaze Send a message via Yahoo to AlcyoneDaze
wouldn't torsional vibration dampening be less important on a H6 than on some other cars like an I4 design, as its already a fairly well-balanced design?
__________________
1992 Pearl White/Black Onyx Subaru Alcyone SVX LS-L
Donating Forum Member In Good Standing
JDM 4.11 Geared Transmission
JDM 'ALCYONE' Rear Panel
JDM 'BOXER' Eingngine Cover
JDM 'SVX' Hood Badge
L-Edition Suede Rear Seats
Reply With Quote
  #12  
Old 09-20-2007, 05:33 PM
2.5InchTrueDual's Avatar
2.5InchTrueDual 2.5InchTrueDual is offline
Will
 
Join Date: Nov 2006
Location: New London IA
Posts: 62
Thanks for the advice

I'm not really expecting any more hp from the underdrive pulley, i just thought it would help with lowering the total recipricating mass by alittle. But you all pose so many good points its still hard to decide what to do. I have another question for you all. I've been told that not having enough back-pressure in your exhaust can make you lose power. Now i have always thought the other way, less back-pressure, more power. I know for a fact that i have 0 back-pressure as you can see in the pic i'm posting, but is there a certain amount i should have? there not in the pic, but i have a pair of Thrush glass-paks about 2/3's the way down the straight pipes.
Anywho thanks again.
P.S. if my pic fails to show, check out my cardomain page. www.cardomain.com/ride/2488463
Reply With Quote
  #13  
Old 09-20-2007, 07:36 PM
YourConfused YourConfused is offline
Registered User
 
Join Date: Jan 2007
Location: Austin, TX
Posts: 1,276
ooooooooops
__________________
"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." Benjamin Franklin


blk 92' LSL w/ average mods

pics here http://s306.photobucket.com/albums/nn277/yourconfused/


Cash68: "Hmm, I wouldn't brag about beating Escorts. That's like saying you tricked a retarded person."
Reply With Quote
  #14  
Old 09-20-2007, 07:36 PM
YourConfused YourConfused is offline
Registered User
 
Join Date: Jan 2007
Location: Austin, TX
Posts: 1,276
2.5InchTrueDual

My puter didn't like your link.
__________________
"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." Benjamin Franklin


blk 92' LSL w/ average mods

pics here http://s306.photobucket.com/albums/nn277/yourconfused/


Cash68: "Hmm, I wouldn't brag about beating Escorts. That's like saying you tricked a retarded person."
Reply With Quote
  #15  
Old 09-20-2007, 07:43 PM
YourConfused YourConfused is offline
Registered User
 
Join Date: Jan 2007
Location: Austin, TX
Posts: 1,276
TomSVX

"i agree... the stock sized pulley is your best bet for aftermarket pulleys. You can also find them on ebay as they are the same as other subies for the most part. But they are of lesser quality than dayle's

Tom"


How is Dayle's of better quality? What is it made of? 7075, 6061, 6063? Is it hard anodized? Or does it come with a sticker?
Seriously though, I am curious. What is it that make it better?
__________________
"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." Benjamin Franklin


blk 92' LSL w/ average mods

pics here http://s306.photobucket.com/albums/nn277/yourconfused/


Cash68: "Hmm, I wouldn't brag about beating Escorts. That's like saying you tricked a retarded person."
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 -6. The time now is 07:10 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
© 2001-2015 SVX World Network
(208)-906-1122