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:
SVXBot

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

Reply
 
Thread Tools Display Modes
  #16  
Old 11-05-2005, 12:42 AM
SilverSpear's Avatar
SilverSpear SilverSpear is offline
Still 1.7K to go...
Subaru Silver Contributor
 
Join Date: Oct 2004
Location: Lebanon, Middle East
Posts: 7,587
Send a message via AIM to SilverSpear Send a message via MSN to SilverSpear Send a message via Skype™ to SilverSpear
Registered SVX
Quote:
Originally Posted by mbtoloczko
I was thinking about that last night. Those gray plastic joints are made of a thermoplastic material, so I can heat one up and reshape it. I'll give it a try on Saturday morning.
If they do, just get heat isolating material and cover them with it. Also the Heat isolating duct tape will work, same as I did with my copper intake... BTW i will post new pics about it very soon.
__________________
Danny

1994 Silver SVX in hybernation, awaiting for the monsterous awakening (Lebanon)
1967 Mercedes-Benz 250SL Euro Specs, Hard/Softtop, White/Red. Under Complete Restoration
2013 Mercedes-Benz SL350 Euro Specs, White/Red. Mint... Another step into SL Collection.
Reply With Quote
  #17  
Old 11-05-2005, 04:56 AM
Myxalplyx's Avatar
Myxalplyx Myxalplyx is offline
XT6 is SVX's Daddy
 
Join Date: Apr 2002
Location: New Castle, DE
Posts: 1,113
Send a message via ICQ to Myxalplyx Send a message via AIM to Myxalplyx Send a message via Yahoo to Myxalplyx
Nice

Very nice thread and great info Mychailo. You do realize that this info can spread like a disease to other forums for other models of Subarus right? The later modelled turbo'd Subarus of the late 80's has problems with fuel cut due to the Maf voltage reaching a certain point. If this mod could prove successful in application on these turbo'd subarus, the bypass can keep the airflow at bay by not letting too much air through the maf sensor during WOT thus preventing a fuel cut. Of course a valve can be put in line to regulate how much air can bypass. Also, you could have more than one bypass or use bigger diametered tubing, just in case not enough air bypasses.

Interesting! I posted a thread a USMB today.
http://www.ultimatesubaru.net/forum/...547#post365547

Thanks for the info.
__________________
Kevin Thomas
1997 2.2ltr Subaru Impreza Outback Sport Wagon (AWD/Auto) 13.03@100mph
1989 2.7ltr Subaru XT6 (AWD/Auto) 15.912@85.93mph
1996 3.3ltr SVX (AWD/Auto) 15.070@91.38mph
***R.I.P***
2010 RAV4 AWD Sport (13.717 @ 99.19mph )
2015 Honda Fit LX CVT (15.2 @ 90mph)
Reply With Quote
  #18  
Old 11-05-2005, 07:38 AM
SVXRide's Avatar
SVXRide SVXRide is offline
Official AutoX Part Breaker
Subaru Gold Contributor
 
Join Date: Aug 2002
Location: Dunkirk, Maryland, zip code=20754
Posts: 8,144
Registered SVX
One word of caution on the bypass mod -- everyone should notice that Mychailo took a very scientific/engineering approach to the process and used a wide band to measure exactly what the the bypass was doing to the AFR. As a result, we (the SVX community) have a baseline system that we can copy and not have to worry about burning up our engines due to overly lean AFR. The last thing you want to do in this area is adopt a "larger tube is better" approach
-Bill
__________________
NASA future mission development - MAVEN (now orbiting Mars and making amazing discoveries) and OSIRIS-REx (asteroid sample return, launched in September 2016, returning with samples in September 2023)
Center Network Member #989
'92 Black LSL aka Shooting Star -- FP class in the works with multiple interesting one-of-a-kind "improvements"
'92 Pearlie LSL aka Mach 5 -- STX class now being pushed to the rule book limits
Official sponsor of OT's RaceCar - now with sticky Hoosier 295 A6s on Cobra rims!
My Locker
Reply With Quote
  #19  
Old 11-05-2005, 09:27 AM
Myxalplyx's Avatar
Myxalplyx Myxalplyx is offline
XT6 is SVX's Daddy
 
Join Date: Apr 2002
Location: New Castle, DE
Posts: 1,113
Send a message via ICQ to Myxalplyx Send a message via AIM to Myxalplyx Send a message via Yahoo to Myxalplyx
Quote:
Originally Posted by SVXRide
One word of caution on the bypass mod -- everyone should notice that Mychailo took a very scientific/engineering approach to the process and used a wide band to measure exactly what the the bypass was doing to the AFR. As a result, we (the SVX community) have a baseline system that we can copy and not have to worry about burning up our engines due to overly lean AFR. The last thing you want to do in this area is adopt a "larger tube is better" approach
-Bill

I understand fully. I mentioned that it would probably be advisable to use a wideband, EGT guage or a dyno when doing this mod. My thinking is flawed though. On a boosted car, the boost pressure would push outward from the bypass instead of sucking the air in from the bypass. That is for another thread/another forum. Thanks anyways! Carry on!
__________________
Kevin Thomas
1997 2.2ltr Subaru Impreza Outback Sport Wagon (AWD/Auto) 13.03@100mph
1989 2.7ltr Subaru XT6 (AWD/Auto) 15.912@85.93mph
1996 3.3ltr SVX (AWD/Auto) 15.070@91.38mph
***R.I.P***
2010 RAV4 AWD Sport (13.717 @ 99.19mph )
2015 Honda Fit LX CVT (15.2 @ 90mph)
Reply With Quote
  #20  
Old 11-06-2005, 09:01 PM
mbtoloczko's Avatar
mbtoloczko mbtoloczko is offline
sans SVX
 
Join Date: Sep 2002
Location: Richland, WA
Posts: 4,250
Send a message via AIM to mbtoloczko
new bypass tube...

Went looking for better tubing and found what looks to be ideal. Its the tubing that is actually meant to be used with the fittings. :-) The tubing is flexible yet kink resistant. All the parts are by Carlson Electric. Its 3/4" dia hose and fittings. I found that if I heated the tubing at around 150F in the oven for a few minutes, its much more flexible and easier to install.

Drove the car this evening, and its running great. The idle was a little loppy when I first started the car but after a bit of driving, it steadied out. Seems that initially, the ECU was running the afr a little lean at idle, and when it would swing way lean, the idle speed would take a dip. Under agressive driving, the afr is right around 13.2:1 from 3000-5000 rpm. I'll post a log tomorrow.

__________________
Mychailo
:: 2006 Silver Mitsubishi Evolution 9, E85, 34 psi peak, 425wtq/505whp DJ ::
1995 Laguna Blue SVX L AWD 5MT (sold)

Visit my locker

SVX Mods: ND iridium spark plugs, Impreza RS fpr, afr tuned to 13.2:1 using a custom MAF bypass, custom exhaust, WRX 5MT w/ STi RA 1st-4th gear & stock WRX 5th gear, Exedy 13 lb flywheel & Sport Clutch, STi Group N tranny & engine mounts, urethane spacers in rear subframe, rear diff mounts, and pitch stopper, SVX Sport Strut Springs (185f/150r), custom 19 mm rear swaybar, urethane swaybar mounts, Rota Torque 17x8", 225/45-17 Proxes 4 tires, Axxis Deluxe Plus organic brake pads.
Reply With Quote
  #21  
Old 11-06-2005, 10:47 PM
drivemusicnow's Avatar
drivemusicnow drivemusicnow is offline
Poor College Racer
 
Join Date: Sep 2002
Location: IL/MI
Posts: 1,522
Send a message via AIM to drivemusicnow
Quote:
Originally Posted by Myxalplyx
I understand fully. I mentioned that it would probably be advisable to use a wideband, EGT guage or a dyno when doing this mod. My thinking is flawed though. On a boosted car, the boost pressure would push outward from the bypass instead of sucking the air in from the bypass. That is for another thread/another forum. Thanks anyways! Carry on!
You're over thinking it... All you have to do is bypass the MAF... even if you let the air enter 3 inches after it, you're effectively letting unmetered air in, and therefore causeing the car to go leaner. This would then be before a turbo, and it wouldn't cause any problems.

I still think the valve idea would be the best way to do it. It would effectively be an AFC and would allow you to run at whatever A/F ratio you wanted (fitting the stock maps and not knocking)

I think someone looking into a turbo setup could use this pretty effectively. maybe even use a throttlebody from the junkyard, attach it after the MAF to the intake tube. (before the turbo if its a turbo car, have a similar, or more restrictive filter) and voila! insta air fuel control. you could even get all fancy and have an electronically controlled actuator to control the TB valve. I would however suggest making sure your knock sensors are in perfect working order before you tried this. (Maybe that J&S safeguard or whatever its called)
__________________
Greg

97 Red SVX LSi clean
96 Black SVX LSi beater
90 Red Eclipse GSX track ho
99 Ford F250 work horse
My Locker
Reply With Quote
  #22  
Old 11-06-2005, 11:26 PM
SilverSpear's Avatar
SilverSpear SilverSpear is offline
Still 1.7K to go...
Subaru Silver Contributor
 
Join Date: Oct 2004
Location: Lebanon, Middle East
Posts: 7,587
Send a message via AIM to SilverSpear Send a message via MSN to SilverSpear Send a message via Skype™ to SilverSpear
Registered SVX
I wonder if the H-6 cover still fits without touching the tube
__________________
Danny

1994 Silver SVX in hybernation, awaiting for the monsterous awakening (Lebanon)
1967 Mercedes-Benz 250SL Euro Specs, Hard/Softtop, White/Red. Under Complete Restoration
2013 Mercedes-Benz SL350 Euro Specs, White/Red. Mint... Another step into SL Collection.
Reply With Quote
  #23  
Old 11-07-2005, 01:22 PM
Earthworm's Avatar
Earthworm Earthworm is offline
Meow!
 
Join Date: Mar 2002
Location: Winnipeg, Manitoba
Posts: 11,961
Send a message via ICQ to Earthworm Send a message via AIM to Earthworm Send a message via MSN to Earthworm Send a message via Yahoo to Earthworm Send a message via Skype™ to Earthworm
Quote:
Originally Posted by SilverSpear
I wonder if the H-6 cover still fits without touching the tube
It's all how you decide to build it. All you need is enough hose to get around the MAF. You don't have to run all the way to the throttlebody.
Reply With Quote
  #24  
Old 11-07-2005, 01:37 PM
Hocrest's Avatar
Hocrest Hocrest is offline
Freezepop's are Awesome!!!!
Subaru Silver Contributor
 
Join Date: Oct 2003
Location: Pittston, PA
Posts: 5,333
Send a message via AIM to Hocrest
What would the ~60 psi FPR out of an XT6 contribute to this??? I'll ship one out if anybody with the proper meters wants to play
__________________
Dave
- 03 Baja - 92 SVX - 86 Brat - 01 OB 3.0
Reply With Quote
  #25  
Old 11-07-2005, 05:48 PM
mbtoloczko's Avatar
mbtoloczko mbtoloczko is offline
sans SVX
 
Join Date: Sep 2002
Location: Richland, WA
Posts: 4,250
Send a message via AIM to mbtoloczko
Quote:
Originally Posted by Hocrest
What would the ~60 psi FPR out of an XT6 contribute to this??? I'll ship one out if anybody with the proper meters wants to play
A 60 psi fpr will push about 30% more fuel into the motor. To get 30% of the air to go around the MAF, the bypass tube would have to be roughly 1.5" in diameter. I think that there would be some major issues with idle and timing advance with that much air going around the MAF.
__________________
Mychailo
:: 2006 Silver Mitsubishi Evolution 9, E85, 34 psi peak, 425wtq/505whp DJ ::
1995 Laguna Blue SVX L AWD 5MT (sold)

Visit my locker

SVX Mods: ND iridium spark plugs, Impreza RS fpr, afr tuned to 13.2:1 using a custom MAF bypass, custom exhaust, WRX 5MT w/ STi RA 1st-4th gear & stock WRX 5th gear, Exedy 13 lb flywheel & Sport Clutch, STi Group N tranny & engine mounts, urethane spacers in rear subframe, rear diff mounts, and pitch stopper, SVX Sport Strut Springs (185f/150r), custom 19 mm rear swaybar, urethane swaybar mounts, Rota Torque 17x8", 225/45-17 Proxes 4 tires, Axxis Deluxe Plus organic brake pads.
Reply With Quote
  #26  
Old 11-08-2005, 12:41 PM
Hocrest's Avatar
Hocrest Hocrest is offline
Freezepop's are Awesome!!!!
Subaru Silver Contributor
 
Join Date: Oct 2003
Location: Pittston, PA
Posts: 5,333
Send a message via AIM to Hocrest
Quote:
Originally Posted by Hocrest
What would the ~60 psi FPR out of an XT6 contribute to this??? I'll ship one out if anybody with the proper meters wants to play
I was corrected, according to the FSM's the XT6 fpr is 43.5 psi.
__________________
Dave
- 03 Baja - 92 SVX - 86 Brat - 01 OB 3.0
Reply With Quote
  #27  
Old 11-09-2005, 01:07 PM
Chiketkd's Avatar
Chiketkd Chiketkd is offline
Row faster...I hear banjos!!!!
 
Join Date: Mar 2004
Location: Charlottesville, VA
Posts: 10,335
Quote:
Originally Posted by mbtoloczko
Went looking for better tubing and found what looks to be ideal. Its the tubing that is actually meant to be used with the fittings. :-) The tubing is flexible yet kink resistant. All the parts are by Carlson Electric. Its 3/4" dia hose and fittings. I found that if I heated the tubing at around 150F in the oven for a few minutes, its much more flexible and easier to install.

Drove the car this evening, and its running great. The idle was a little loppy when I first started the car but after a bit of driving, it steadied out. Seems that initially, the ECU was running the afr a little lean at idle, and when it would swing way lean, the idle speed would take a dip. Under agressive driving, the afr is right around 13.2:1 from 3000-5000 rpm. I'll post a log tomorrow.

Mychailo,

This new version looks terrific. Did you get a chance to do that log?

-Chike
__________________
"Wise men talk because they have something to say; fools, because they have to say something." - Plato

2013 Cosmic Blue 5spd Evo X GSR
2006 Galaxy Gray 6MT RX-8 (sold)
2006 Steel Gray WRX TR (sold)
1996 Brilliant Red SVX L (sold)
Reply With Quote
  #28  
Old 11-09-2005, 03:12 PM
mbtoloczko's Avatar
mbtoloczko mbtoloczko is offline
sans SVX
 
Join Date: Sep 2002
Location: Richland, WA
Posts: 4,250
Send a message via AIM to mbtoloczko
Quote:
Originally Posted by Chiketkd
Mychailo,

This new version looks terrific. Did you get a chance to do that log?

-Chike
Haven't had a chance to do the log yet, but I can say that the car is much more peppy compared to no bypass tube, and my real-time observations of the afr readout on the LM-1 put the afr at around 13.2:1 in the 3000-5000 rpm range. As a bonus, it seems that the engine stalling issue I've had since installing my 5MT has been somewhat reduced since I installed the bypass. The only negative that I can see so far is that idle is loppy when the motor is cold. The loppy idle is caused by fairly large swings in the afr. I can watch it swing from 13.5:1 to 15.5:1 during cold idle. It doesn't stall though. Just loppy. On a side note, this leads me to conclude that the MAF does play a role in controlling idle, and going to a larger tube may result in a very uneven idle even when the engine is warm.

Anyhow, I'll try to get a log tonight.
__________________
Mychailo
:: 2006 Silver Mitsubishi Evolution 9, E85, 34 psi peak, 425wtq/505whp DJ ::
1995 Laguna Blue SVX L AWD 5MT (sold)

Visit my locker

SVX Mods: ND iridium spark plugs, Impreza RS fpr, afr tuned to 13.2:1 using a custom MAF bypass, custom exhaust, WRX 5MT w/ STi RA 1st-4th gear & stock WRX 5th gear, Exedy 13 lb flywheel & Sport Clutch, STi Group N tranny & engine mounts, urethane spacers in rear subframe, rear diff mounts, and pitch stopper, SVX Sport Strut Springs (185f/150r), custom 19 mm rear swaybar, urethane swaybar mounts, Rota Torque 17x8", 225/45-17 Proxes 4 tires, Axxis Deluxe Plus organic brake pads.
Reply With Quote
  #29  
Old 11-11-2005, 08:47 AM
mbtoloczko's Avatar
mbtoloczko mbtoloczko is offline
sans SVX
 
Join Date: Sep 2002
Location: Richland, WA
Posts: 4,250
Send a message via AIM to mbtoloczko
After a few more days of driving with the MAF bypass, I have found that when the engine is not up to full temperature, there is some tendency for the engine to stall, at least with my 5MT. No stalling problems when the engine is stone cold, and no problems when the temperature needle is in the full warm spot, but about halfway between stone cold and full warm, there is some tendency. Putting a slight restriction in the bypass line should fix it.
__________________
Mychailo
:: 2006 Silver Mitsubishi Evolution 9, E85, 34 psi peak, 425wtq/505whp DJ ::
1995 Laguna Blue SVX L AWD 5MT (sold)

Visit my locker

SVX Mods: ND iridium spark plugs, Impreza RS fpr, afr tuned to 13.2:1 using a custom MAF bypass, custom exhaust, WRX 5MT w/ STi RA 1st-4th gear & stock WRX 5th gear, Exedy 13 lb flywheel & Sport Clutch, STi Group N tranny & engine mounts, urethane spacers in rear subframe, rear diff mounts, and pitch stopper, SVX Sport Strut Springs (185f/150r), custom 19 mm rear swaybar, urethane swaybar mounts, Rota Torque 17x8", 225/45-17 Proxes 4 tires, Axxis Deluxe Plus organic brake pads.
Reply With Quote
  #30  
Old 11-11-2005, 09:58 AM
Phast SVX's Avatar
Phast SVX Phast SVX is offline
BOOOOOOOOOOOOOOOOOST
 
Join Date: Feb 2001
Location: Madison, WI
Posts: 2,800
Send a message via AIM to Phast SVX
Quote:
Originally Posted by mbtoloczko
After a few more days of driving with the MAF bypass, I have found that when the engine is not up to full temperature, there is some tendency for the engine to stall, at least with my 5MT. No stalling problems when the engine is stone cold, and no problems when the temperature needle is in the full warm spot, but about halfway between stone cold and full warm, there is some tendency. Putting a slight restriction in the bypass line should fix it.
the nature of bypassing the meter will most likely bring a condition like this at some point in the range of function.
phil
__________________
~Phil
Teal 1992 Subaru SVX Turbo - Sold in May 2011 to peace-frog.
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 12:11 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
2001-2015 SVX World Network
(208)-906-1122