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View Full Version : Can you get BOVs for an S3? If so, where in Melbourne?



April 12th, 2004, 03:59 PM
I went to Easternats with my sister yesterday. A commodore went past with this wicked Puh-chish. I had a laugh and said "would you like one of those on your car?" She said, "ohr yeah..." So I said, I'd get her one.

Pardon my ignorance, but this is what I understand:
- that sound comes from the blow off valve;
- getting a blow off valve isn't too expensive (my guess is about $150, but I really have no idea);
- BOVs don't add to performance, they simply amplify the sound from the standard unit;
- they are not particularly difficult to fit.

Am I right? If so, how much would it cost to get one?

Kris
April 12th, 2004, 08:41 PM
Matt, I advise against it.

Few reasons:

Our cars require that vented air for the MAF to work correctly
Vented BOV's will throw a code on the ECU
They sound horrible (in my opinion)
They are around $300+

April 12th, 2004, 08:59 PM
Matt, I advise against it.

Few reasons:

Our cars require that vented air for the MAF to work correctly
Vented BOV's will throw a code on the ECU
They sound horrible (in my opinion)
They are around $300+

Fairy nuff. I guess it's money that should really be spent on a chip anyway. I've promised Lex that if she gives up smoking for a year, I'll buy her one.

Thanks again for the response. :_b:

Kris
April 12th, 2004, 09:13 PM
:)

Definately best keep that $ for the chip.. Its the best value mod you can do!

bitemebw
April 12th, 2004, 11:41 PM
anything you can do to help someone stop smoking is a good thing.

BM.

All Outta Angst
April 13th, 2004, 07:27 PM
I think you can get GFB's cheapest BOV for around the $200 mark...

But as was said above, you shouldn't get one, they may make the car run a little rough, particulaly on the gear change (when the venting happens) as the car runs rich for a second.

I have heard you can get the hybrid valves that allow you to vent a little bit of the air and plumb back the rest. S oyou get the noise and the car still runs ok. But these are quite expensive. Its around the $400 mark if i remember correctly.

Mr_SilverA41.8tq
April 13th, 2004, 07:38 PM
i have forge valve in good condition just needs new ring and that will do the job...email me usfo@optusnet.com.au if your interested...

April 13th, 2004, 09:15 PM
GFB Hybrid valves are $309.00 and plumback valves are $250.00.

WOBGTI
May 7th, 2004, 02:51 PM
Our cars require that vented air for the MAF to work correctly
Vented BOV's will throw a code on the ECU



This IMO is not true... Although I do say this and keep in mind I am not a qualified mechanic...

If the MAF is between the airbox and the air inlet pipe and the return air from the OEM valve is after the MAF, then how does this effect the MAF?

[/quote]

Lima
May 7th, 2004, 10:29 PM
Our cars require that vented air for the MAF to work correctly
Vented BOV's will throw a code on the ECU



This IMO is not true... Although I do say this and keep in mind I am not a qualified mechanic...

If the MAF is between the airbox and the air inlet pipe and the return air from the OEM valve is after the MAF, then how does this effect the MAF?



The MAF expects air to be sent back to it via the stock DV, so if some, or all of that air is released into the atmosphere instead of the air box the MAF's calculations will be inorrect.

Well that's my understanding anyway. :wink:

WOBGTI
May 8th, 2004, 02:30 AM
Our cars require that vented air for the MAF to work correctly
Vented BOV's will throw a code on the ECU



This IMO is not true... Although I do say this and keep in mind I am not a qualified mechanic...

If the MAF is between the airbox and the air inlet pipe and the return air from the OEM valve is after the MAF, then how does this effect the MAF?



The MAF expects air to be sent back to it via the stock DV, so if some, or all of that air is released into the atmosphere instead of the air box the MAF's calculations will be inorrect.

Well that's my understanding anyway. :wink:

Ok I would have agreed with you but only if the DV return was before the MAF...

If the DV is after the MAF, then how does the MAF sense this venting air back? Does'nt make any sense to me! The MAF will only sense the amount of air passing through it from the air box, the DV does not vent air back into the air box, so how will the MAF sense the air that is vented back into the inlet pipe which is after the air box and after the MAF?

ribena
May 8th, 2004, 10:28 AM
U can buy my forge diverter valve for $150 if you like... Its 1 week old....

All Outta Angst
May 10th, 2004, 01:46 PM
Our cars require that vented air for the MAF to work correctly
Vented BOV's will throw a code on the ECU



This IMO is not true... Although I do say this and keep in mind I am not a qualified mechanic...

If the MAF is between the airbox and the air inlet pipe and the return air from the OEM valve is after the MAF, then how does this effect the MAF?



The MAF expects air to be sent back to it via the stock DV, so if some, or all of that air is released into the atmosphere instead of the air box the MAF's calculations will be inorrect.

Well that's my understanding anyway. :wink:

Ok I would have agreed with you but only if the DV return was before the MAF...

If the DV is after the MAF, then how does the MAF sense this venting air back? Does'nt make any sense to me! The MAF will only sense the amount of air passing through it from the air box, the DV does not vent air back into the air box, so how will the MAF sense the air that is vented back into the inlet pipe which is after the air box and after the MAF?

Simple - The MAF measures the total air that has entered the air box.... If the Air is circulated using the DV it doesnt have to remeasue it, as the total air is the still the same.

If you vent the air to the atmosphere then the total air in the system is now less.

WOBGTI
May 10th, 2004, 08:23 PM
Our cars require that vented air for the MAF to work correctly
Vented BOV's will throw a code on the ECU



This IMO is not true... Although I do say this and keep in mind I am not a qualified mechanic...

If the MAF is between the airbox and the air inlet pipe and the return air from the OEM valve is after the MAF, then how does this effect the MAF?



The MAF expects air to be sent back to it via the stock DV, so if some, or all of that air is released into the atmosphere instead of the air box the MAF's calculations will be inorrect.

Well that's my understanding anyway. :wink:

Ok I would have agreed with you but only if the DV return was before the MAF...

If the DV is after the MAF, then how does the MAF sense this venting air back? Does'nt make any sense to me! The MAF will only sense the amount of air passing through it from the air box, the DV does not vent air back into the air box, so how will the MAF sense the air that is vented back into the inlet pipe which is after the air box and after the MAF?

Simple - The MAF measures the total air that has entered the air box.... If the Air is circulated using the DV it doesnt have to remeasue it, as the total air is the still the same.

If you vent the air to the atmosphere then the total air in the system is now less.

Alright - I see the light - thank you for clearing that up for me!

The MAF has calculated the amount of air and the the ecu calculates the mixture.... Alright - thankyou All Outta Angst...

This means the a/f mixture may run a little richer when the throttle is released...

b5turbo
May 11th, 2004, 06:50 PM
I've seen the GFB Hybrid and GFB Stealth FX on Audi 1.8T's and they didn't throw codes. Hell, I've even seen a Stealth FX at full vent (names have been deleted to protect the innocent) and it caused the engine to stall but still no codes. I sometimes think that people get a little too paranoid about these things. If your sister loves the sound, get her a GFB Hybrid. Personally I think a K&N filter does more damage to your engine...

ea2001
May 11th, 2004, 07:26 PM
I've seen the GFB Hybrid and GFB Stealth FX on Audi 1.8T's and they didn't throw codes. Hell, I've even seen a Stealth FX at full vent (names have been deleted to protect the innocent) and it caused the engine to stall but still no codes. I sometimes think that people get a little too paranoid about these things. If your sister loves the sound, get her a GFB Hybrid. Personally I think a K&N filter does more damage to your engine...

I've found exactly the same b5. I think its a bit of a beat up. It does do as the above post says, make a rich mixture momentarily, but I've never seen any adverse affect from it. Might try to measure it some day soon.

Derek

Lima
May 13th, 2004, 02:15 PM
Personally I think a K&N filter does more damage to your engine...

Care to elaborate on that?

Agree that there are plenty of people running BOVs on 1.8Ts in Australia to make a reasonably safe assumption that nothing major, if anything, will come of it.

b5turbo
May 13th, 2004, 06:35 PM
Personally I think a K&N filter does more damage to your engine...

Care to elaborate on that?

I was waiting for someone to pickup on that one. I find it funny how people are worried about the fuel mixture running rich during shifts but they don't car if a free flowing filter allows more dirt into their engine. Please understand this was just an example and I don't want to create hysteria.

ea2001
May 13th, 2004, 08:20 PM
Also some people have said that their MAF sensor has failed because of oil from a K&N/BMC/FK/Green Cotton type filter has contaminated the hot wire in the MAF. I think this is likely from an overoiled filter but not one that is oiled correctly.

WOBGTI
May 15th, 2004, 02:41 AM
Also some people have said that their MAF sensor has failed because of oil from a K&N/BMC/FK/Green Cotton type filter has contaminated the hot wire in the MAF. I think this is likely from an overoiled filter but not one that is oiled correctly.

Hey thats funny, I installed a K&N in my wifes car about 2 years ago. The MAF screwed up and was replaced about 4 months ago. I might revert back to the OEM as the K&N didn't make much of a difference, a part from some additional induction noise.