996 Turbo / GT2 Turbo discussion on previous model 2000-2005 Porsche 911 Twin Turbo and 911 GT2.

Blow off/diverter valve questions 996tt

Thread Tools
 
Search this Thread
 
Rate Thread
 
  #1  
Old 03-17-2006, 03:14 PM
SR996's Avatar
Registered User
Thread Starter
Join Date: Nov 2005
Location: miami
Age: 40
Posts: 221
Rep Power: 0
SR996 is an unknown quantity at this point
Blow off/diverter valve questions 996tt

Since no one is responding in the tunning threads maybe this will help. (hope this is ok)

https://www.6speedonline.com/forums/...ad.php?t=44619
 
  #2  
Old 03-17-2006, 03:27 PM
Ruiner's Avatar
Registered User
Join Date: Dec 2005
Location: Atlanta, GA
Posts: 1,321
Rep Power: 71
Ruiner is on a distinguished road
Originally Posted by SR996
Since no one is responding in the tunning threads maybe this will help. (hope this is ok)

https://www.6speedonline.com/forums/...ad.php?t=44619
Well, there is a difference between the two:

A "diverter valve" vents back into the intake, so you won't hear the "woosh" that you typically hear with an "open atmosphere" blow-off valve. They are the same thing, essentialy; one just vents into (diverts) into the intake while the other vents into (blows off) the atmosphere.

B. Because we run a MAF setup, the air volume is metered as it enters into the system behind the intake. The problem with running a blow-off valve is that some of the metered air is lost. The ECU, however, does not know this. You would have to program for this loss else you will run rich during shifts (when the throttle bottle closes and the BOV does its thing). Fuel is applied based on what the ECU "thinks" should be in the system. The amount of air that it thinks is there is not there, so it still adds the fuel causing a rich condition.

With that said, Sharky (Alex) has a BOV on his car that is drilled into the y-pipe. I believe that it is an HKS, but it might be a Blitz. You will want to ask him about his setup. Personally, I would stay with a diverter valve type setup...
 
  #3  
Old 03-17-2006, 04:02 PM
SR996's Avatar
Registered User
Thread Starter
Join Date: Nov 2005
Location: miami
Age: 40
Posts: 221
Rep Power: 0
SR996 is an unknown quantity at this point
Originally Posted by Ruiner
Well, there is a difference between the two:

A "diverter valve" vents back into the intake, so you won't hear the "woosh" that you typically hear with an "open atmosphere" blow-off valve. They are the same thing, essentialy; one just vents into (diverts) into the intake while the other vents into (blows off) the atmosphere.

B. Because we run a MAF setup, the air volume is metered as it enters into the system behind the intake. The problem with running a blow-off valve is that some of the metered air is lost. The ECU, however, does not know this. You would have to program for this loss else you will run rich during shifts (when the throttle bottle closes and the BOV does its thing). Fuel is applied based on what the ECU "thinks" should be in the system. The amount of air that it thinks is there is not there, so it still adds the fuel causing a rich condition.

With that said, Sharky (Alex) has a BOV on his car that is drilled into the y-pipe. I believe that it is an HKS, but it might be a Blitz. You will want to ask him about his setup. Personally, I would stay with a diverter valve type setup...

Wowsers!! I didnt think it would be that complicated. The thing is that Ive had a couple turbo cars in the past and I miss the BOV sound I appreciate your response and information thank you. I guess I ll let the famous sharky take it from here


(sound clips would be greatly appreciated) thnks in advance

-Sam
 
  #4  
Old 03-17-2006, 07:19 PM
tom kerr's Avatar
Registered User
Join Date: Oct 2005
Location: tampa florida
Posts: 3,577
Rep Power: 209
tom kerr Is a GOD !tom kerr Is a GOD !tom kerr Is a GOD !tom kerr Is a GOD !tom kerr Is a GOD !tom kerr Is a GOD !tom kerr Is a GOD !tom kerr Is a GOD !tom kerr Is a GOD !tom kerr Is a GOD !tom kerr Is a GOD !
Ruiner nice explaination sent ya some kudos!!
 
  #5  
Old 03-17-2006, 07:22 PM
sharkster's Avatar
Registered User
Join Date: Jul 2003
Age: 49
Posts: 23,889
Rep Power: 1515
sharkster Is a GOD !sharkster Is a GOD !sharkster Is a GOD !sharkster Is a GOD !sharkster Is a GOD !sharkster Is a GOD !sharkster Is a GOD !sharkster Is a GOD !sharkster Is a GOD !sharkster Is a GOD !sharkster Is a GOD !
Ruiner is THE man. Oh and he has a black 996TT of course

Oh and just to re-iterate. I did play around with that set up and I ended up getting it to work from car to car but only with an adjustable GFB unit. I too would stick with a DV instead of a VTA...
 
  #6  
Old 03-17-2006, 09:16 PM
carendt242's Avatar
Registered User
Join Date: Oct 2004
Location: SF, CA
Age: 49
Posts: 2,558
Rep Power: 125
carendt242 is a jewel in the roughcarendt242 is a jewel in the roughcarendt242 is a jewel in the roughcarendt242 is a jewel in the rough
my car has an HKS bov routed back into the intake. Sharky doesn't like it but it works for me

supposedly, the previous owner vented it to the atmosphere w/o any trouble; but what Ruiner explains is definitely true in most cases. to expand a touch, when the ECU dumps in the extra fuel, your car is likely to stall in near-idle situations (coming to a stop, etc.)

i'll probably try this soon - the car would love another noise

- chuck
 
  #7  
Old 03-17-2006, 09:22 PM
sharkster's Avatar
Registered User
Join Date: Jul 2003
Age: 49
Posts: 23,889
Rep Power: 1515
sharkster Is a GOD !sharkster Is a GOD !sharkster Is a GOD !sharkster Is a GOD !sharkster Is a GOD !sharkster Is a GOD !sharkster Is a GOD !sharkster Is a GOD !sharkster Is a GOD !sharkster Is a GOD !sharkster Is a GOD !
Originally Posted by carendt242
my car has an HKS bov routed back into the intake. Sharky doesn't like it but it works for me

supposedly, the previous owner vented it to the atmosphere w/o any trouble; but what Ruiner explains is definitely true in most cases. to expand a touch, when the ECU dumps in the extra fuel, your car is likely to stall in near-idle situations (coming to a stop, etc.)

i'll probably try this soon - the car would love another noise

- chuck
LOL I do actually like it- had it on my EVO but if you want I'll dig out my GFB adjustable one and it seemed to work way better. I have to say yours actually settled down more now with the new program Todd gave you. Idle isn't as rough for some reason

Mine wasn't too loud with the stock intake. Once I cut open the box and/or put the EVO conical style intake in I obviously got more sound...
 
  #8  
Old 03-17-2006, 11:12 PM
Ruiner's Avatar
Registered User
Join Date: Dec 2005
Location: Atlanta, GA
Posts: 1,321
Rep Power: 71
Ruiner is on a distinguished road
Originally Posted by tom kerr
Ruiner nice explaination sent ya some kudos!!
Thanks! It comes from hard lessons learned in my previous years of modifying Japanese turbo cars...
 
  #9  
Old 03-17-2006, 11:12 PM
Ruiner's Avatar
Registered User
Join Date: Dec 2005
Location: Atlanta, GA
Posts: 1,321
Rep Power: 71
Ruiner is on a distinguished road
Originally Posted by carendt242
my car has an HKS bov routed back into the intake. Sharky doesn't like it but it works for me

supposedly, the previous owner vented it to the atmosphere w/o any trouble; but what Ruiner explains is definitely true in most cases. to expand a touch, when the ECU dumps in the extra fuel, your car is likely to stall in near-idle situations (coming to a stop, etc.)

i'll probably try this soon - the car would love another noise

- chuck
You are 100% correct on that point.
 
  #10  
Old 03-18-2006, 10:23 AM
SR996's Avatar
Registered User
Thread Starter
Join Date: Nov 2005
Location: miami
Age: 40
Posts: 221
Rep Power: 0
SR996 is an unknown quantity at this point
Thnks to all you guys for the help. Anyone have sound clips or now where I can get em


Thanks again
Sam
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
turbotuner20v
Automobiles For Sale
20
09-11-2015 12:02 PM
Money2536
GT3/GT2
4
09-01-2015 04:56 AM
jmbmm
991
4
08-28-2015 02:01 PM
vividracing
Ferrari
0
08-24-2015 04:35 PM
ECS Tuning - VW
VW Vendor Classifieds
1
08-19-2015 08:58 AM



You have already rated this thread Rating: Thread Rating: 0 votes,  average.

Quick Reply: Blow off/diverter valve questions 996tt



All times are GMT -6. The time now is 10:41 PM.