Atmospheric Blow off Valves - good or bad?

Atmospheric Blow off Valves - good or bad?

Author
Discussion

speedmachine

Original Poster:

366 posts

214 months

Thursday 1st March 2007
quotequote all
I've been reading up a bit about Blow off valves. I've come across a number of places where they say that the BOVs that get rid of the pressure into the air cause problems like stalling. It appears that its best to stick to a Recirc BOV.

However, you gotta have the Pshhhht! Of the atmospheric BOV

What are your views and experiences with BOVs?
Have you had problems and if so how have you sorted them?

I will be getting a an R33 GTS-T in the next couple of weeks so can any of you recomend a BOV for it?

Thanks!

turbo-tastic

973 posts

251 months

Thursday 1st March 2007
quotequote all
That sound you crave will beome annoying very quickly.

Dont bother getting one, they're tacky and pointless. Money could and should be spent better elsewhere IMO

shadowninja

77,494 posts

289 months

Thursday 1st March 2007
quotequote all
The R33 GTS-T has a perfectly good recirc valve. If you do have a BOV installed then you will need to get it remapped or the Skyline will have fueling problems.

Mr E

22,127 posts

266 months

Friday 2nd March 2007
quotequote all
turbo-tastic said:
That sound you crave will beome annoying very quickly.

Dont bother getting one, they're tacky and pointless. Money could and should be spent better elsewhere IMO


Hasn't annoyed me yet, but then I do few miles. I changed the DV once the diaphragm stock recirc unit gave up...

If the car has a MAP sensor it should cope perfectly well.

speedmachine

Original Poster:

366 posts

214 months

Friday 2nd March 2007
quotequote all
What is an MAP sensor?

So if I do go for a BOV for the GTS-t, is it a little more complicated then just switching it over?

Mr E

22,127 posts

266 months

Friday 2nd March 2007
quotequote all
speedmachine said:
What is an MAP sensor?

So if I do go for a BOV for the GTS-t, is it a little more complicated then just switching it over?


Mass Air Pressure rather than the somewhat simpler Mass Air Flow (MAF) sensor.

(I think)

I have no idea what a R33 Liner has.

cactussed

5,303 posts

220 months

Friday 2nd March 2007
quotequote all
The R33 GTST (and GTR) have Air Flow Meters (AFM) and recirculating BOV's.
Crudely put, AFM's work by having a flap that opens as air is sucked into the engine. The angle of the flap dictates how much air is going in and thus how much fuelis required.

When you lift off, the BOV vents pressure into the intake manifold, closing the flap and cutting fuel. withouth the recirc BOV, the flap stays open and you tend to overfuel a bit. your fuel economy will get worse but more importantly, you also get bore wash (neat fuel stripping the thin layer of oil from the cylinder lining). Not catastrophic but can give you increased wear over time. It'll also run a little rougher, but nothing really noticable, perhaps slightly worse at idle.

The ideal option is to get a hybrid valve, that has a partial vent to atmosphere, so you get to have your cake and eat it too. Like this:

www.gofastbits.com/index.php?parentid=products&option=products&sub_option=bovs&sub_sub_option=hybrid

koh

28 posts

213 months

Friday 2nd March 2007
quotequote all
i(and alot of other gtst owners) have a hks ssq bov on my spec 1 gtst,i dont have any stalling issues with it,an ssq is your best bet for avioding comon bov problems

The GMan

2,508 posts

262 months

Friday 2nd March 2007
quotequote all
I would not bother with one.

Save your money and get a bigger turbo and an external wastegate, than add a screamer pipe if you want noise.

More money but trust me if you want a smile on your face when you floor your car that's the way to go.

steve bowen

1,268 posts

231 months

Friday 2nd March 2007
quotequote all
speedmachine said:

the Pshhhht! Of the atmospheric BOV




= CHAV is my opinion.

but

If the cars got and AFM it'll run badly after every pshhhht as it suddenly doesn't have enough air to burn the fuel

If its got a MAP sensor then it'll run ok

speedmachine

Original Poster:

366 posts

214 months

Friday 2nd March 2007
quotequote all
Each to their own

speedmachine

Original Poster:

366 posts

214 months

Friday 2nd March 2007
quotequote all
koh said:
i(and alot of other gtst owners) have a hks ssq bov on my spec 1 gtst,i dont have any stalling issues with it,an ssq is your best bet for avioding comon bov problems


Was it fairly straight forward to fit? How much did it cost?

I would want to go for soemthing that has been tried and tested.

koh

28 posts

213 months

Friday 2nd March 2007
quotequote all
it takes about half an hour max to fit,they cna be had for les than £200,the price varie from place to place,try rhdjapan


Edited by koh on Friday 2nd March 14:51

MrFlibbles

7,711 posts

290 months

Friday 2nd March 2007
quotequote all
Mr E said:
turbo-tastic said:
That sound you crave will beome annoying very quickly.

Dont bother getting one, they're tacky and pointless. Money could and should be spent better elsewhere IMO


Hasn't annoyed me yet, but then I do few miles. I changed the DV once the diaphragm stock recirc unit gave up...

If the car has a MAP sensor it should cope perfectly well.


I agree with MrE - i never got annoyed by mine, it always made me hehe

MrsF(to be) never like it much though

Its chavvy but deep down i think i may have chav tendencies! paperbag

Mr E

22,127 posts

266 months

Monday 5th March 2007
quotequote all
MrFlibbles said:

Its chavvy but deep down i think i may have chav tendencies! paperbag


Silly "pchshhh" noises - check.
Huge wheels - check
Holes in bonnet - check
Exhaust you could lose a toddler down - check

Fo'snizzle my homies. Or whatever the hip baseball cap wearing youth are saying this week.

bint

4,664 posts

231 months

Monday 5th March 2007
quotequote all
Mr E said:
MrFlibbles said:

Its chavvy but deep down i think i may have chav tendencies! paperbag


Silly "pchshhh" noises - check.
Huge wheels - check
Holes in bonnet - check
Exhaust you could lose a toddler down - check

Fo'snizzle my homies. Or whatever the hip baseball cap wearing youth are saying this week.


more gauges than you know what to do with - check
silly sexist stickers on the dash - check
seats that women can't get into wearing a short skirt - check
a driver who speeds at every opportunity and is a bit of a tit - er no..... more like Miss Daisy here!

MrFlibbles

7,711 posts

290 months

Monday 5th March 2007
quotequote all
bint said:
Mr E said:
MrFlibbles said:

Its chavvy but deep down i think i may have chav tendencies! paperbag


Silly "pchshhh" noises - check.
Huge wheels - check
Holes in bonnet - check
Exhaust you could lose a toddler down - check

Fo'snizzle my homies. Or whatever the hip baseball cap wearing youth are saying this week.


more gauges than you know what to do with - check
silly sexist stickers on the dash - check
seats that women can't get into wearing a short skirt - check
a driver who speeds at every opportunity and is a bit of a tit - er no..... more like Miss Daisy here!


Tow Bar - check
"Stealth" dents and scratches - check
Tartan rug - check
Caravan club sticker - pending





_Batty_

12,268 posts

257 months

Monday 5th March 2007
quotequote all
left you a rspb sticker in it...

Mr E

22,127 posts

266 months

Tuesday 6th March 2007
quotequote all
bint said:
Mr E said:
MrFlibbles said:

Its chavvy but deep down i think i may have chav tendencies! paperbag


Silly "pchshhh" noises - check.
Huge wheels - check
Holes in bonnet - check
Exhaust you could lose a toddler down - check

Fo'snizzle my homies. Or whatever the hip baseball cap wearing youth are saying this week.


more gauges than you know what to do with - check
silly sexist stickers on the dash - check
seats that women can't get into wearing a short skirt - check
a driver who speeds at every opportunity and is a bit of a tit - er no..... more like Miss Daisy here!


Thanks dear.

R33GTST

69 posts

212 months

Tuesday 6th March 2007
quotequote all
I asked about this at Thor Racing the other day and it appears that if one is fitted whilst still running an air flow meter it can well and truly mess the running of the car up.

This is because the air is not re-circulated to match the correct amount of fuel in the inlet. The result is too much fuel which then causes the idleing problems and the possibility of the car cutting out when stopping sharply at say a set of lights.

This can be avoided though if you get a mapable ECU which means you can get rid of the airflow meter and have your atmospheric BOV. Though the standard re-circulating BOV is cappable up to 300BHP. Only worth it if you're having a serious power up grade IMO.