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 > Regional SVX Forum & Clubs > European Forum

Reply
 
Thread Tools Rate Thread Display Modes
  #1  
Old 10-15-2011, 12:32 PM
stevek stevek is offline
Registered User
Subaru Bronze Contributor
 
Join Date: Aug 2008
Location: uk
Posts: 129
4500rpm

Tell me, why is there such a marked increase in performance after 4500rpm? What changes at this point - can't imagine it's cam profile/timing or gas flow as it seems too well defined.
Oh, and by the way I read elsewhere on the site that there are no more windscreens available. Is that right?
Reply With Quote
  #2  
Old 10-15-2011, 02:30 PM
Huskymaniac's Avatar
Huskymaniac Huskymaniac is offline
Uses the ignore feature
 
Join Date: Jul 2010
Location: Corning, NY
Posts: 1,872
Registered SVX
Re: 4500rpm

Quote:
Originally Posted by stevek View Post
Tell me, why is there such a marked increase in performance after 4500rpm? What changes at this point - can't imagine it's cam profile/timing or gas flow as it seems too well defined.
Oh, and by the way I read elsewhere on the site that there are no more windscreens available. Is that right?
That's where the peak of the torque curve is.
__________________
Tony

1996 Polo Green Subaru SVX LSi, 168,XXX miles, Redline D4 ATF, Redline 75W90 gear oil, K&N HP-4001 Oil Filter, Mobil 1 5W50 FS (3qt) and 5W30 High Mileage (4qt) Oil Blend, Motul RBF600 Brake Fluid, AC Delco A975C Air Filter, NGK BKR6EIX-11 plugs, Centric Rotors, Power Stop Evolution Carbon Fiber Ceramic Brake Pads
2005 Gray Acura RL, 165,XXX miles, Redline D4 ATF with Lubegard Platinum Protectant, Mobil 1 5W20 High Mileage Extended Performance Oil
2009 Red Toyota Venza, 123,XXX, Mobil 1 5W30 High Mileage Oil
1992 Red Ferrari 348 ts, 82,XXX, Redline everything
Reply With Quote
  #3  
Old 10-15-2011, 03:33 PM
bwb3's Avatar
bwb3 bwb3 is offline
Cruisin' in Gator Country
Alcyone Gold Contributor
 
Join Date: Jun 2005
Location: Gainesville, Florida
Posts: 1,894
Registered SVX Classic SVX
Re: 4500rpm

It has been reported that only bronze glass is still available in the USA. However, Subaruparts.com still offers bronze, blue and green. Glass from Japan may still be in supply.
Gene
__________________
Gene and Ben
1992 SVX LS AWD 110K - Liquid Silver
1994 SVX LSi AWD 128K - White Pearl (daily driver)
1994 SVX LSi AWD 95K - Emerald Pearl (sold)
1992 SVX LS-L AWD 115K - Dark Teal 4.44 swap (sold)
Reply With Quote
  #4  
Old 10-15-2011, 03:49 PM
immortal_suby's Avatar
immortal_suby immortal_suby is offline
Thread Killah
Alcyone Gold Contributor
 
Join Date: Feb 2001
Location: Greenville, SC
Posts: 5,835
Registered SVX
Re: 4500rpm

Search for threads on the IRIS valve or read about it in the road and track guide - this will explain the power increase around 4500rpm

This one is a good read - http://www.subaru-svx.net/forum/show...highlight=IRIS
__________________
Matt
Locker Link
2015 BRZ Limited 6MT
92 Ebony LS-L ECUtune Stage2av1, Z32 MAF, 370cc injectors, TomsSVX intake, BontragerWorks 22mm RSB #003, HID Hi and Lo beams, OT endlink and bushing mods, PWR Aluminum radiator, Harvey's QC shift kit, 2.5" flowmaster 80 exhaust, 17" Michelin Pilot Sport A/S, Poly sway bar bushings, Slotted Bradi rotors, AFBeefcake powdercoated calipers, 97 grill, and a huge set of air horns. 300,000 miles and counting
92 Ebony LS-L. ecutune stage1v4, motorsport 1pc pulley. Garage Queen - sold to Dad in upstate NY 155,000 miles
19 Subaru Ascent Premium - -Hers !.
89 DL 4x4 little red wagon - a.k.a. The immortal suby. 275k R.I.P.

Last edited by immortal_suby; 10-15-2011 at 04:16 PM.
Reply With Quote
  #5  
Old 10-17-2011, 05:20 PM
stevek stevek is offline
Registered User
Subaru Bronze Contributor
 
Join Date: Aug 2008
Location: uk
Posts: 129
Re: 4500rpm

Firstly, thank you for the screen info. Much appreciated. This IRIS valve seems to me to be a way of increasing gas speed and fuel/air mixing at lower revs, then allowing high flow at higher revs? Works like an intake version of a Yamaha exhaust EXUP valve. I wonder if anyone has tried combining the two? Or is VVT a more cost effective solution?
Does IRIS stand for intake resonance induction system? Or the name of the marketing managers girlfriend.....?
Reply With Quote
  #6  
Old 10-17-2011, 07:47 PM
icingdeath88's Avatar
icingdeath88 icingdeath88 is offline
some sort of nerd. some sort.
Subaru Silver Contributor
 
Join Date: Aug 2009
Location: Tampa, FL
Posts: 3,560
Registered SVX
Re: 4500rpm

Quote:
Originally Posted by stevek View Post
Firstly, thank you for the screen info. Much appreciated. This IRIS valve seems to me to be a way of increasing gas speed and fuel/air mixing at lower revs, then allowing high flow at higher revs? Works like an intake version of a Yamaha exhaust EXUP valve. I wonder if anyone has tried combining the two? Or is VVT a more cost effective solution?
Does IRIS stand for intake resonance induction system? Or the name of the marketing managers girlfriend.....?
Inertia resonance induction (or maybe intake?) system
__________________
'94 Laguna Blue LSi ~159k.......JDM ultra short-geared 3.900 STi Version 7 6-speed w/ Cobb shortshifter, ECUtune 244,8.1mm/256,9.1mm i/e cams, group N motor mounts, '97 grille, JDM clear corners, Momo JDM Legacy GT steering wheel, apkarian's LED tails, silver STi BBS wheels, PWR radiator, redstuff pads f/r, drilled/slotted rotors, bontragerworks rsb #18, Koni/GC 450f/375r coilovers, Megan Racing adjustable lateral links, KMac c/c plates, Stebro exhaust, ECUtune 1v5, Optima battery in the trunk where it belongs. Turbo project

'97 Ebony LSi ~137k #036.......Power mode mod, JDM clear corners, BBS wheels. AUX/pocket mod

Now a mod "over there" ............Photo album
Reply With Quote
  #7  
Old 10-18-2011, 02:51 PM
stevek stevek is offline
Registered User
Subaru Bronze Contributor
 
Join Date: Aug 2008
Location: uk
Posts: 129
Re: 4500rpm

Thanks for the acronym definition - my horizons now broadened. Anyone know what's amiss when the fault codes tell me both speed sensors are kippered (32&33)? Is that likely - I've checked the connectors and wiring, all seems fine. If I take the transducer bit off SS2 and can twist the shaft freely presumably that points to a broken plastic gear? Haven't tried it yet btw.
All I did was leave it stood a while, and the only clue is that it 'only just' started (has an alarm fitted which kills the battery over time). There were some odd electrical malfunctions for a few miles but everything but the speedo is normal now. I didn't 'jump' or 'boost' it.
Drives fine but after about 5 miles the check engine light comes on. And no speedo at all.
Help...
Reply With Quote
  #8  
Old 10-18-2011, 08:14 PM
oab_au oab_au is offline
Registered User
Subaru Gold Contributor
 
Join Date: Mar 2001
Location: Coffs Harb, Australia.
Posts: 5,032
Significant Technical Input Registered SVX
Re: 4500rpm

Quote:
Originally Posted by stevek View Post
Firstly, thank you for the screen info. Much appreciated. This IRIS valve seems to me to be a way of increasing gas speed and fuel/air mixing at lower revs, then allowing high flow at higher revs? Works like an intake version of a Yamaha exhaust EXUP valve. I wonder if anyone has tried combining the two? Or is VVT a more cost effective solution?
Does IRIS stand for intake resonance induction system? Or the name of the marketing managers girlfriend.....?
Giday Steve, when the Inertia system is on at low engine speeds it increases the inlet tract air pressure; they are using the low 7mm lift to increase the velocity at that time.

The Yamaha exhaust EXUP valve, and the Inertia system are both based on the Helmholtz chamber principle, of bouncing a air pressure back and forth, producing high and low pressure pulses. The EXUP uses the chamber formed by the 4 engine pipes and the junction, to form the pressure chamber, when the valve is closed at low engine speeds.
Here, it is powered by the exhaust pulses, and uses the low-pressure pulse, to drop the pressure in the cylinder, at valve overlap.

The Inertia system uses the, ‘sucking’ of the three inductions to power the Helmholtz chamber, formed by the inlet manifold, to use the high-pressure pulse, to push the air into the cylinder.

Same principle, just using the different pressure pulse, to suit their purpose.

Quote:
wonder if anyone has tried combining the two? Or is VVT a more cost effective solution?
The bikes use this exhaust trick because they don’t have the space to use the long pipes to utilise the inertia of the gas flow to produce a low pressure, and pipes long enough to form the resonate length, that the lower torque speeds of the car needs, there are no space problems with the car.

The Variable Valve Timing has more to do with being able to use longer cam duration, but still be able to shorten it back for low speed running, and of course Emissions.

Always enjoy talking to bike blokes.
Harvey.
__________________
One Arm Bloke.
Tell it like it is!

95 Lsi. Bordeaux Pearl, Aust. RHD.149,000Kls Subaru BBS wheels.
97 Liberty GX Auto sedan. 320,000Kls.
04 Liberty 30R Auto Premium. 92.000kls.
Reply With Quote
  #9  
Old 10-19-2011, 12:14 PM
stevek stevek is offline
Registered User
Subaru Bronze Contributor
 
Join Date: Aug 2008
Location: uk
Posts: 129
Re: 4500rpm

Harvey - thanks for the info. If you haven't already ridden one have a go on the latest R1 with it's 'long bang' motor. Not only does it ride well it sounds, at differing rpm, like a twin,triple,four then a 'don't know what', top end!
Now come on all you IT wizards, log in to my SVX with Bluetooth, diagnose and fix my speedo. And while you're at it, hack into the DVLA computer, remove my licence points and tax the car for 12 months.
Thanks in advance,
Steve
Reply With Quote
  #10  
Old 11-12-2011, 03:05 PM
stevek stevek is offline
Registered User
Subaru Bronze Contributor
 
Join Date: Aug 2008
Location: uk
Posts: 129
Re: 4500rpm

Just to let you all know that speed sensor 2 was at the root of my problems, very kindly sorted by the Irish and International SVX Guru - Joe. No signal generated apparently. And it doesn't come apart without destroying the bugger so not fixable. WTF would something that has no mechanism as such, no touching parts, therefore no reason to croak stop working? 'Kin electricity...

On a lighter note I managed to get a pair of glass headlamps off fleabay so may be able to see the road as well as my speedo now. Have 2 sets of RHD plastic lensed ones if anyone is desperate.
Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

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 03:14 PM.


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