Another Boost issue

[Jordan20vt]

Hi all,

I have just got to the bottom of my last boost issue which turned out to be a faulty N75 which has now been changed. Cars boosting fine again way over 20psi peak.

I now have a new problem when I hit peak boost in 3rd it seems to vent about 5 psi off instantly. I get a little pssssh noise like the dv is venting i can see it on the guage dropping instantly. It then goes on to hold boost as normal so i don't think it's a leak.

Could this be the dv? I'm running a green spring but never really had any problems before, and it's been recently serviced? Also it's only doing this in the higher gears presumably becaue there is more load

 

[Berg]

Isnt that what the N249 does?

Do you still have it plumbed in?

 

[-=Rob=-]

Could be a weak spring, perhaps try a yellow one from forge?

 

[Jordan20vt]

Isnt that what the N249 does?

Do you still have it plumbed in?

N249 I belive is a vaccum reserve, it opens up the DV if for some reason there is no vac at the manifold. My N249 is bypassed mechanically so it couldn't be that.

Just ordered a yellow spring from forge, i think this is most likely the problem but it's strange that the problem is gear specific.

 

[Jordan20vt]

Could be a weak spring, perhaps try a yellow one from forge?

Have you ever had this problem rob? I heard that Bill ran a green spring in his when he was running about 400bhp.

 

[-=Rob=-]

Have you ever had this problem rob? I heard that Bill ran a green spring in his when he was running about 400bhp.

Not had the same problem as you, but have been looking into getting a yellow spring myself for another reason...

 

[Jordan20vt]

oh ok, still aint got my yellow spring the one forge sent to me was for a different type of valve, ram valve or something.

 

[D--R--E--W]

Mine is running just over 200bhp and i have the yellow spring, i found the forge DV to be really quiet when dumping.

I heard something about the spring being wound a certain way quitens the DV, is this a known fact or just hear say???

 

[Jordan20vt]

Alters the noise if you plumb the DV in reverse, sounds HKS Supra style, cool for the first 5 mins then it annoys the hell out of you.

Volume of dump really depends on what filtration set up and boost level you run. Open cone with Revo is really loud. TBH DV noise does my head in, thats why I run standard airbox all be it with GC panel enlarged intake and smoothed so I still get a bit of noise.

 

[-=Rob=-]

Alters the noise if you plumb the DV in reverse, sounds HKS Supra style, cool for the first 5 mins then it annoys the hell out of you.

Volume of dump really depends on what filtration set up and boost level you run. Open cone with Revo is really loud. TBH DV noise does my head in, thats why I run standard airbox all be it with GC panel enlarged intake and smoothed so I still get a bit of noise.

Agree with you Jordan about the noise of the DV reversed, it's ok for five mins then does your head in! I ws running a similar set up to you, smoother airbox, green panel and enlarged air feed, but I moved to a large green open filter and have gained 10-12gm/s of airflow by doing this. Downside for some is the noise maybe.

 

[Jordan20vt]

Agree with you Jordan about the noise of the DV reversed, it's ok for five mins then does your head in! I ws running a similar set up to you, smoother airbox, green panel and enlarged air feed, but I moved to a large green open filter and have gained 10-12gm/s of airflow by doing this. Downside for some is the noise maybe.

I've been thinking about open cone, your right you can't beat a big dirty cone for flow lol. I think the DV noise would drive me nuts though