SVX Network Forums Live Chat! SVX or Subaru Links Old Lockers Photo Post How-To Documents Message Archive SVX Shop Search |
IRC users: |
#1
|
|||
|
|||
Quick Change Shift Kit Question
Am thinking about ordering a quick change shift kit, but am curious if there is any negative effect on the already weak transmission. The last thing I want to do is make it weaker. Anyone know? I've read some posts on it but nothing seemed to really address this question. Thanks.
|
#2
|
||||
|
||||
Re: Quick Change Shift Kit Question
The quick change helps prolong the life of the transmission actually. Long smooth gear changes actually wear components out faster.
|
#3
|
||||
|
||||
Re: Quick Change Shift Kit Question
Can anybody explain how disabling the engine torque reduction signal is good for the transmission? Because I would expect the exact opposite.
Presumably, the clutches slip during a gear shift, and the more torque you apply to them when they are slipping, the quicker they will wear out.
__________________
Subaru ECU and TCU Website 1992 Alcyone SVX Version L 1992 Alcyone SVX Version L 1994 Alcyone SVX S40-II 2004 Subaru Legacy 2.5 SE Sports Tourer 1996 Subaru Legacy 2.2 GX Wagon 1988 Subaru Justy J12 SL-II |
#4
|
||||
|
||||
Re: Quick Change Shift Kit Question
Duck and cover!
__________________
1994 SVX L - FWD Barcelona Red 190K miles ~ SOLD 1994 SVX LS - 5spd AWD Emerald Green 202k miles PWR Radiator, HID 5000k, New paint job with issues, 17" STI BBS wheels, converted to 5spd AWD from FWD. Purchased from SVXyGirl 2/20/09 -- Undergoing complete rebuild 1993 Justy 4wd 5door- Teal of sorts , beater. 2008 OBXT Newport Pearl 65k miles |
#5
|
||||
|
||||
Re: Quick Change Shift Kit Question
Here we go....
__________________
Mike 1992 SVX LS-L Pearl White 102,000 miles (Gone) 2005 Evolution 8 SSL Tarmac Black (new daily) 1995 Eclipse GSX Durango Copper Pearl (teh beast) 276awhp/280awtq @ 18psi (560's inj) 260awhp/260awtq @ 17psi (stock inj) |
#6
|
||||
|
||||
Re: Quick Change Shift Kit Question
Have not had a problem with mine. I love it. Had it in since June 2008. I imagine if you abused the transmission by regularly hammering out full throttle shifts with no torque reduction you might break something.
Harvey specifically states not to put one on a failing tranny or without a good resistor in the quick change thread on the svxwf. Quote:
__________________
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. |
#7
|
||||
|
||||
Re: Quick Change Shift Kit Question
Quote:
A quite drastic change is made in respect of the original design parameters. Were Subaru engineers stupid?
__________________
Trevor, New Zealand. As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit! |
#8
|
||||
|
||||
Re: Quick Change Shift Kit Question
How does a WRX or forester XT 4EAT deal with this shock load without using torque reduction?
__________________
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. |
#9
|
|||
|
|||
Re: Quick Change Shift Kit Question
Quote:
Not trying to argue for or against the quick change, just giving response to your question. |
#10
|
|||
|
|||
Re: Quick Change Shift Kit Question
Quote:
Quote:
Quote:
When this transmission was used in the Sporty WRX and RS Turbo, the change was fast and solid, just what you would expect of a Sporty car. When the SVX was designed it was aimed at the higher end of the Luxury Grand Touring market. The same fast solid change did not suit this market, so they programmed the TCU to lower the line pressure during the change, to remove the solid engagement. Because the reduced pressure would allow the clutch and band to do a lot of slipping to smooth the change, they turned the Engine torque down to prevent excessive wear. The result was that silky smooth gear change that suited the Luxury profile that they wanted, but at the expense of clutch and band wear. As the Quick Change prevents the line pressure from being lowered during the change, there is no need to reduce the engine torque. So it converts the gear change to the same fast solid shift, as we had with the Sporty models. Any fears of the transmission having shock loadings, is only in the minds of those that have not driven a car that is fitted with a Quick Change. 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. |
#11
|
||||
|
||||
Re: Quick Change Shift Kit Question
Quote:
__________________
Trevor, New Zealand. As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit! |
#12
|
||||
|
||||
Re: Quick Change Shift Kit Question
Quote:
I'll have to dig up my road and track guide to the svx to verify, but IIRC there was a section devoted to the pursuit of a seamless gear change on the svx to promote the luxury car ideal. Of course that is not fact as it is journalism, but the fact that concurrent subaru models of similar weight and torque did not use torque reduction while the svx did is evidence to validate the article.
__________________
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. |
#13
|
||||
|
||||
Re: Quick Change Shift Kit Question
Quote:
Quote:
__________________
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; 03-23-2010 at 07:17 PM. |
#14
|
||||
|
||||
Re: Quick Change Shift Kit Question
Quote:
But the less torque you apply to the clutches, the less they will slip and the longer they will last. It seems to me that reducing the torque during a shift must a good thing for gearbox longevity. Conversely, disabling the torque-cut signal must surely subject the clutches to more torque, more slip and more wear than leaving it alone. I accept that the primary goal of the QS device is performance, rather than gearbox longevity. But it's stretching things a bit far to claim that it will definitely make the transmission last longer. Maybe in a few years time, when people have done 80000+ miles with a QC, we'll be able to look at the failure stats and say whether it is better or worse. But right now it's just speculation either way.
__________________
Subaru ECU and TCU Website 1992 Alcyone SVX Version L 1992 Alcyone SVX Version L 1994 Alcyone SVX S40-II 2004 Subaru Legacy 2.5 SE Sports Tourer 1996 Subaru Legacy 2.2 GX Wagon 1988 Subaru Justy J12 SL-II |
#15
|
|||
|
|||
Re: Quick Change Shift Kit Question
Quote:
MY OPINION, as a person who has extensive experience with this transmission (but again, absolutely zero with the QC product) is that the torque control signal was put in place to make the thing hold together AND to make it shift better, though I find it odd that it does not occur on the 1-2 shift which is where I think it is needed the most as far as feel goes. Further, I believe that a modification of the valve body to increase base line, apply pressure to the band, high clutch, drain from those areas to compensate for the added flow, and flow thru the cooler circuit could help with the longevity of the transmission, and that such modifications make the QC essentially unnecessary by achieving the same results. I believe a member here has made a product, which, like any modification, lacks the testing that an OEM part would, but that is a product to add to our lineup of impressive feats that we as a community have achieved together in these past 10 years that we have been together on the network. This is to be appreciated, and to be purchased and used by those who choose to use it. From what I have heard, the product does what it is supposed to. Why, Nifty, did they not do this from the factory, you may ask, stating an excellent opinion that the pump in this trans is too weak, and I would answer "because it killed my fuel economy by an indeterminable amount that is somewhere between .2-.9 MPG.
__________________
2007 GS 450h-Active Stabilizer/Radar cruise 1994 L Blue 3.70 VTD ASE Master Automobile ASE Advanced Level Specialist Toyota Master Diagnostic Technician (former life) |
|
|