Aahj

I have a 97 civic EX. I just got finished putting my engine and turbo back into my car. Everything runs great, except I have one little problem. The blow off valve isn't working properly.

When I let off the throttle after boosting, the valve doesn't lift open all the way. It probably lifts up like 2 or 3 mm. And it makes this fluttering noise.

I am pretty sure I am not leaking on a vaccum line somewhere because at idle my boost guage reads 22 psi.

But recently, I had my blow off valve apart for about a month. Do you think the spring could have stretched itself out and that makes it too tough to open up all the way?

I need some suggestions please.

thanks in advance,

aj

turbocoupe

I have the same problem. . .it sounds like a HKS SS BOV right? From what I have been told we are surging. . .which is bad for the turbo. . .I justs had mine (turbo) rebuilt. . .so if you find a remedy for the problem let me know.

Aahj

it sounds like crap. There is not chirp from the blow off valve at all. It does sound like the HKS SS takin' a ****

I have posted this thread on two other boards.

I will let you know when I get an answer.

thanks,

aj

SagaGSR

give the bov its own vacuum source.. you probably have too many things t'd off into one vacuum source..

the same exact thing happened to me..

Aahj

Well, that would make sense.

But I have the same number of fittings when the blow off valve worked and now when the BOV doesn't work.

I will try it though.

I will try anything at this point

thanks,

aj

turbocoupe

ajn- - -have you tried adjusting it? When I adjust mine hard or soft it makes the fluttering noise then it makes the normal whistle sound. It sounds like **** so I just "tuned" it to where it makes the fluttering noise alone. . .like I said if you find a remedy let me know please.

SagaGSR

the type s isn't suppossed to flutter

turbocoupe

I know. . .we need to know how to remedy the problem.

Ri5e

If it flutters, try softening it up a bit.

turbocoupe

I did that but it made a fluttering followd by the normal whistle you should get. . .

maxim

Where do you guys have your vacuum hose for the bov taped into? If you have all of your hoses t'd into the fpr vacuum try tíng into the brake booster line vacuum, you will probably need a bigger t though.

Aahj

I have mine Tee'd into the FPR along with my boost guage.

I softened it so much that I REMOVED the adjusting allen set screw and it still fluttered.

I have a feeling that it's the spring some how.

I did remove it once, and it was apart for about a month, do you think that it might have stretched itself out?

thanks,

aj

cann

hey ajn, i got the same problem, i tried 2 bovs, the HKS Racing BOV, and the Blitz Super sound dual drive (coz 20% percent air sounds promising) but none solve the problem, this is because (too much boost, too little air)
honda has a low rev limit, if u go from 1st gear to 2nd gear at like 4k rpm or above u get the straight out air noise.
if u are lower rpm than 4k, u get the snake sound, it's not really a flutter
1. try taking ur intake out and move the rod that the turbine is in, see if it's shaking around really loosely, tightened it.
2. take off the intake on the turbo, try pulling the throttle cable and feel if there are any air coming out from the air intake side without the intake (this proves if the theory is correct)
a. rev it, if it snake sound (air come out from inlet side of turbo) + air out from bov, IF more air from bov than turbo, u're fine.
b. rev it, if more air from turbo inlet side than bov, then we'll talk.
coz usually that sound is normal especially on an Automatic transmission, that snake noise.

Aahj

I don't know, because I can see the blow off valve not opening up all the way when I rev the engine. It used to lift up about 1 whole inch. Now, it only lifts up about 1-2 mm. I don't understand why. I will try teeing into another vaccum line though.

later,

aj

cann

hey ajn, i have the same dang problem, some told me it's okay, some told me it's not okay, and i think my next step in tackling this problem is putting some grease on the valve itself

u can read my thread (f-max kit flutters)
i hope we both solve this damn problem.

BlueShadow

for all the people that are having the fluttering problem click this link.
https://honda-tech.com/zerothread?id=103060

you guys probably know more about turbos in a whole than me but. I looked up the exact definition of "COMPRESSOR SURGE" in a book and there are 2 types of surge.

here is a cut and paste from the link

I quote BlueShadow (me)

I was wondering at what RPM do you start hearing it? and what boost are you at at that RPM?

I was answering an unrelated question and I had to look up the exact definition of compressor surge. There are 2 kinds of surge:

#1 throttle shuts turbo is still compressing air against closed throttle air oscillates BOV not opening or not present.

I think you fall under reason number 2
#2 too much boost pressure not enough airflow through the system. The chirping sound heard from the turbo when lifting off the throttle while operating under boost results from the oscillating air volume.


quote:
--------------------------------------------------------------------------------
so i guess low throttle, i get that flutter, snake, che che che che...... sound and full bost i get the deep swoosh

--------------------------------------------------------------------------------

so maybe your hitting too high of a boost setting at a low RPM (low airflow), thats what it sounds like to me.

EDIT: as for getting a recommended fix, what size turbine A/R do you have? and what size is your compressor? I dont think adjusting your BOV will help any, cause if I'm right, your surge is caused by LACK OF AIR


END QUOTE

before you flame me or anything read the whole post in the link
EDIT: If I'm right about the kind of surge you guys are describing. its reason #2 which is not harmful, just annoying with the "che-che-che" sound it makes.



[Modified by BlueShadow, 5:46 AM 1/9/2002]

turbocoupe

ttt

FBP Ex-T

damn....should i get another BOV? or do i just have to pass a certain amt of rpms...

question: when you are just crusing. like driving normal( i kno its hard..but try and understand ) when u start off on first gear and u take it up to 3000 rpm slowly...are u boosting.? cause if not there shouldnt be any problem..i mean there isnt that much more air than a regular car...and annyways...theres abunch of i/c piping plus the i/c for the air to go through.... see my point??/ anyone?

turbocoupe

On my greddy kit I don't start boosting till about 3.5k-4k rpms. . .you don't have a boost gauge?

Aahj

I haven't been boosting now because of my blow off valve, but when I do, the blow off valve sounds like crap.

I am going to start working on it tomorrow. I haven't really had anytime to look at it because of homework and other problems with my car.

later,

aj

BlueShadow

CANN tried using 2 different BOV's when he got the snakelike "che-che-che" sound but he could hear it even on the different BOV's and at their tightest and loosets setting.

only thing you can do is make sure all your lines are hooked up right. but other than that the noise is just something you'll have to get used to.

Ri5e

Replace the vacuum hose that conects from the BOV to the vacuum source. Could be a dirty line... OR your BOV could be dirty inside. Clean it out. And next time, use an INLINE filter for the vacuum line. That way no dirty stuff gets into your BOV.

FBP Ex-T

ok filter....ihave no clue wat ur talking about....theres a filtter in the vaccum lines?? never heard of that...i thouhgt iwas just a line that connected to the fmu...that teed off to go to the BOV....? anyone

turbocoupe

need more info. . .

maxim

Hope this is ok, I pulled this off from one of the guys on this board, maybe he will see this and be able to explain it better. I believe what he is referring to is something that looks like this:

close up


wider view



[Modified by maxim, 7:29 PM 1/10/2002]