SR : Weird surging problem - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

YoungGun · 05-30-2008, 02:43 AM

I had a boost leak at the bov flange because the gasket was paper thin. I put liquid gasket on and let it dry until the next morning. When I went to drive it the boost leak whine was gone, but then at high boost my turbo would surge. Tonight driving home I noticed if I slowly build boost the bov blows off correctly. Any input on what the problem could be? I want to fix this before my turbo seals give out again. Could it be that some sealer got into the air pocket for the bov?

Engine specs:
Redtop SR
3" turbo back
Intake
FMIC
1g DSM bov vented to atmosphere

tt99ol · 05-30-2008, 03:39 AM

it would surge under throttle?
or just when the bov is supposed to be working?

YoungGun · 05-30-2008, 09:40 AM

It surges after I let off of WOT. Partial throttle under boost it blows off correctly.

((sr)) kelly · 05-30-2008, 10:02 AM

get a new bov

YoungGun · 05-30-2008, 01:40 PM

Any other suggestions?

tt99ol · 05-30-2008, 02:21 PM

how much boost are you running
and what vacuum source is the bov getting

Forge_55b · 05-30-2008, 02:50 PM

if nothing changed other then u putting on the gasket maker, try another bov is the only way i can think of to really check

oh and u probably didn't give enough time to let it cure completely

YoungGun · 05-30-2008, 03:08 PM

Stock boost, but it must be creeping some because of my exhaust I don't have a gauge to check. I have a t connector going from the intake manifold to the bov to the turbo wastegate like how it's supposed to be.

Well I gave it enough time to cure because it sealed it and took care of my boost leak issue. I guess i'll try to borrow another bov, I think i'm gonna just take it off and try to reseal it tonight and use less sealer?

If anyone has any other suggestions i'm all ears.

Thanks to those who have responded.

kamikazekid · 05-30-2008, 03:21 PM

dont run the vacuum line fom the mani to the wastegate, run it from the pressure source (hot pipe/ cold pipe) witch ever. its surging because when you let off the throttle at high boost and the throttle plate closes, theres no more pressure to open the wastegate so it has no releif. remember the wastegate is actuated by pressure, bov actuated by vacuum. You get what im saying right?

YoungGun · 05-30-2008, 04:28 PM

Read what I wrote again, I have it set up correctly.

kamikazekid · 05-30-2008, 04:33 PM

Im reading that you have the wastegate vacuum hose going to the mani correct? is the turbo internally actuated? stock turbo right? you can run that set up that you described but like you were saying if your exhast is choked you're gonna get some boost creep. nissan has it set up from the factory to have the pressure source running to the wastegate for a reason think about how the wastegate is gonna function when you put that vacuum hose behind the throttle plate. you said you were all Ears right? just try the set up i said its cheaper than a blow off valve. if it doesnt work than no big deal.

YoungGun · 05-30-2008, 04:39 PM

Yeah stock turbo there a line that goes from the intake manifold then t's off. One line goes to the bov and the other line goes to the wastegate, the setup isnt my problem. I'm thinking that the bov is messed up now.

kafanylovesme · 05-30-2008, 04:44 PM

CS solves all problems...

Wish I could help Cody, but compressor surge ftw!

kamikazekid · 05-30-2008, 04:46 PM

im just saying try that setup first, just a suggestion but the way you have the vacuum lines set up is incorrect. you need to run the pressure side to the wastegate. when you run it to the mani and the throttle closes it creates vacuum witch will not open the wastegate. people run your setup yes but its not a good idea for hard driving ,on off throttle situations. you will get boost creep.

YoungGun · 05-30-2008, 04:59 PM

Quote:

Originally Posted by kafanylovesme

CS solves all problems...

Wish I could help Cody, but compressor surge ftw!

lol CS! no man at least not for me whenever I surge smoke comes out of the exhaust! lol

Quote:

Originally Posted by kamikazekid

im just saying try that setup first, just a suggestion but the way you have the vacuum lines set up is incorrect. you need to run the pressure side to the wastegate. when you run it to the mani and the throttle closes it creates vacuum witch will not open the wastegate. people run your setup yes but its not a good idea for hard driving ,on off throttle situations. you will get boost creep.

pm'ed you.

tt99ol · 05-30-2008, 05:17 PM

wastegate should always have its own source
always
the bov should be t'd in with the fpr
what kamikaze is trying to say is to run your wastegate from a nipple on the hotpipe
or coldpipe
it will keep the wastegate open until the bov relieves all pressure this way
running it from the mani gives you more boost
it also slams the wastegate shut on throttle lifts causing a spike
just try it and see if it works

kamikazekid · 05-30-2008, 05:27 PM

Quote:

Originally Posted by tt99ol

wastegate should always have its own source
always
the bov should be t'd in with the fpr
what kamikaze is trying to say is to run your wastegate from a nipple on the hotpipe
or coldpipe
it will keep the wastegate open until the bov relieves all pressure this way
running it from the mani gives you more boost
it also slams the wastegate shut on throttle lifts causing a spike
just try it and see if it works

thanks brotha.
good luck with the surge hope we could help.

((sr)) kelly · 05-30-2008, 10:38 PM

im going to be selling my HKS ver 2 bov/hot pipe kit from enjkuku soon... lmk if you are interested. Pull type bovs FTW

YoungGun · 05-31-2008, 01:13 AM

Ungh, YOU GUYS! I have the bov on the hotpipe! my friend is going to lend me his greddy rs, i'll see if the bov is faulty or not.

jonathan12uiz · 05-31-2008, 11:25 AM

what I was wondering from your post is...
1.Is your BOV recirculated?
-I've driven a few SR's and non-recirculated BOVs with no Fuel controller seem to have this surge/skip/bogging slightly after a shift because the air that was calculated through the maf was released. Now this is not valid if you are running a blowthru setup on your maf.

2.What are your vac lines routed like. Redtop sr is...
the top left on the throttle body goes to the FPR. This is also where you can T for a Boost gauge.
the top right (larger diameter one) goes to the BOV. Make the line as short as possible.
and the bottom vac nipple is usless, just cap it off.
Now for the wastegate you have to have a line coming off your hotpipe straight to your wastegate (line as short as possible). If your hotpipe didn't come with a nipple for this, just go to home depot or lowes and go to the plumming section. buy a brass threaded nipple that can fit a vac line. Drill a hole in your hotpipe. tap the hole to fit the threads of your new nipple. insert your nipple and jb weld it. run your vac line and VOILA! done.

3. Timing is 15* advanced right?
-Timing plays a good role in a lot of weird problems.

Lemme know.

YoungGun · 06-01-2008, 12:15 AM

Uhhh not sure what your description of the vacuum routing is but anyways I FIXED IT! yay i'm so happy, never going to touch my engine again. Stock SR FTW.

Oh those who are wondering, I put too much liquid gasket shit on and it got in this little hole which I guess prevented it from blowing off? Well I scraped it off and now it works. No boost leak, no surging, OKAY!

kafanylovesme · 06-01-2008, 12:17 AM

Nice! Good to see you fixed it Cody!

Now I have a problem of my own =/

Griffith Park owned my intercooler and piping today!

05-30-2008, 02:43 AM	#1
YoungGun Post Whore! Join Date: Nov 2007 Location: 818-951 SoCal Posts: 3,961 Trader Rating: (23) Feedback Score: 23 reviews	SR : Weird surging problem I had a boost leak at the bov flange because the gasket was paper thin. I put liquid gasket on and let it dry until the next morning. When I went to drive it the boost leak whine was gone, but then at high boost my turbo would surge. Tonight driving home I noticed if I slowly build boost the bov blows off correctly. Any input on what the problem could be? I want to fix this before my turbo seals give out again. Could it be that some sealer got into the air pocket for the bov? Engine specs: Redtop SR 3" turbo back Intake FMIC 1g DSM bov vented to atmosphere

05-30-2008, 03:39 AM	#2
tt99ol Zilvia Addict Join Date: Jan 2005 Location: quartz hill CA Age: 38 Posts: 644 Trader Rating: (8) Feedback Score: 8 reviews	it would surge under throttle? or just when the bov is supposed to be working? __________________ Need automotive work done in the antelope valley? Ask me how i can help.

05-30-2008, 02:21 PM	#6
tt99ol Zilvia Addict Join Date: Jan 2005 Location: quartz hill CA Age: 38 Posts: 644 Trader Rating: (8) Feedback Score: 8 reviews	how much boost are you running and what vacuum source is the bov getting __________________ Need automotive work done in the antelope valley? Ask me how i can help.

05-30-2008, 02:50 PM	#7
Forge_55b Zilvia Junkie Join Date: Jun 2007 Location: OC Age: 43 Posts: 414 Trader Rating: (2) Feedback Score: 2 reviews	if nothing changed other then u putting on the gasket maker, try another bov is the only way i can think of to really check oh and u probably didn't give enough time to let it cure completely Last edited by Forge_55b; 05-30-2008 at 02:52 PM.. Reason: added a line

05-30-2008, 03:21 PM	#9
kamikazekid Leaky Injector Join Date: Jul 2007 Location: california Age: 36 Posts: 140 Trader Rating: (0) Feedback Score: 0 reviews	dont run the vacuum line fom the mani to the wastegate, run it from the pressure source (hot pipe/ cold pipe) witch ever. its surging because when you let off the throttle at high boost and the throttle plate closes, theres no more pressure to open the wastegate so it has no releif. remember the wastegate is actuated by pressure, bov actuated by vacuum. You get what im saying right? __________________ Drifting is not a crime

05-30-2008, 09:40 AM	#3
YoungGun Post Whore! Join Date: Nov 2007 Location: 818-951 SoCal Posts: 3,961 Trader Rating: (23) Feedback Score: 23 reviews	It surges after I let off of WOT. Partial throttle under boost it blows off correctly.

05-30-2008, 10:02 AM	#4
((sr)) kelly BANNED Join Date: Jun 2007 Location: Zebulon... NC Posts: 1,035 Trader Rating: (6) Feedback Score: 6 reviews	get a new bov

05-30-2008, 01:40 PM	#5
YoungGun Post Whore! Join Date: Nov 2007 Location: 818-951 SoCal Posts: 3,961 Trader Rating: (23) Feedback Score: 23 reviews	Any other suggestions?

05-30-2008, 03:08 PM	#8
YoungGun Post Whore! Join Date: Nov 2007 Location: 818-951 SoCal Posts: 3,961 Trader Rating: (23) Feedback Score: 23 reviews	Stock boost, but it must be creeping some because of my exhaust I don't have a gauge to check. I have a t connector going from the intake manifold to the bov to the turbo wastegate like how it's supposed to be. Well I gave it enough time to cure because it sealed it and took care of my boost leak issue. I guess i'll try to borrow another bov, I think i'm gonna just take it off and try to reseal it tonight and use less sealer? If anyone has any other suggestions i'm all ears. Thanks to those who have responded.

05-30-2008, 04:28 PM	#10
YoungGun Post Whore! Join Date: Nov 2007 Location: 818-951 SoCal Posts: 3,961 Trader Rating: (23) Feedback Score: 23 reviews	Read what I wrote again, I have it set up correctly.

05-30-2008, 04:33 PM	#11
kamikazekid Leaky Injector Join Date: Jul 2007 Location: california Age: 36 Posts: 140 Trader Rating: (0) Feedback Score: 0 reviews	Im reading that you have the wastegate vacuum hose going to the mani correct? is the turbo internally actuated? stock turbo right? you can run that set up that you described but like you were saying if your exhast is choked you're gonna get some boost creep. nissan has it set up from the factory to have the pressure source running to the wastegate for a reason think about how the wastegate is gonna function when you put that vacuum hose behind the throttle plate. you said you were all Ears right? just try the set up i said its cheaper than a blow off valve. if it doesnt work than no big deal. __________________ Drifting is not a crime

05-30-2008, 04:39 PM	#12
YoungGun Post Whore! Join Date: Nov 2007 Location: 818-951 SoCal Posts: 3,961 Trader Rating: (23) Feedback Score: 23 reviews	Yeah stock turbo there a line that goes from the intake manifold then t's off. One line goes to the bov and the other line goes to the wastegate, the setup isnt my problem. I'm thinking that the bov is messed up now.

05-30-2008, 04:46 PM	#14
kamikazekid Leaky Injector Join Date: Jul 2007 Location: california Age: 36 Posts: 140 Trader Rating: (0) Feedback Score: 0 reviews	im just saying try that setup first, just a suggestion but the way you have the vacuum lines set up is incorrect. you need to run the pressure side to the wastegate. when you run it to the mani and the throttle closes it creates vacuum witch will not open the wastegate. people run your setup yes but its not a good idea for hard driving ,on off throttle situations. you will get boost creep. __________________ Drifting is not a crime

05-30-2008, 05:17 PM	#16
tt99ol Zilvia Addict Join Date: Jan 2005 Location: quartz hill CA Age: 38 Posts: 644 Trader Rating: (8) Feedback Score: 8 reviews	wastegate should always have its own source always the bov should be t'd in with the fpr what kamikaze is trying to say is to run your wastegate from a nipple on the hotpipe or coldpipe it will keep the wastegate open until the bov relieves all pressure this way running it from the mani gives you more boost it also slams the wastegate shut on throttle lifts causing a spike just try it and see if it works __________________ Need automotive work done in the antelope valley? Ask me how i can help.

05-30-2008, 10:38 PM	#18
((sr)) kelly BANNED Join Date: Jun 2007 Location: Zebulon... NC Posts: 1,035 Trader Rating: (6) Feedback Score: 6 reviews	im going to be selling my HKS ver 2 bov/hot pipe kit from enjkuku soon... lmk if you are interested. Pull type bovs FTW

05-31-2008, 01:13 AM	#19
YoungGun Post Whore! Join Date: Nov 2007 Location: 818-951 SoCal Posts: 3,961 Trader Rating: (23) Feedback Score: 23 reviews	Ungh, YOU GUYS! I have the bov on the hotpipe! my friend is going to lend me his greddy rs, i'll see if the bov is faulty or not.

05-31-2008, 11:25 AM	#20
jonathan12uiz Join Date: Apr 2008 Location: Georgia Age: 38 Posts: 11 Trader Rating: (0) Feedback Score: 0 reviews	what I was wondering from your post is... 1.Is your BOV recirculated? -I've driven a few SR's and non-recirculated BOVs with no Fuel controller seem to have this surge/skip/bogging slightly after a shift because the air that was calculated through the maf was released. Now this is not valid if you are running a blowthru setup on your maf. 2.What are your vac lines routed like. Redtop sr is... the top left on the throttle body goes to the FPR. This is also where you can T for a Boost gauge. the top right (larger diameter one) goes to the BOV. Make the line as short as possible. and the bottom vac nipple is usless, just cap it off. Now for the wastegate you have to have a line coming off your hotpipe straight to your wastegate (line as short as possible). If your hotpipe didn't come with a nipple for this, just go to home depot or lowes and go to the plumming section. buy a brass threaded nipple that can fit a vac line. Drill a hole in your hotpipe. tap the hole to fit the threads of your new nipple. insert your nipple and jb weld it. run your vac line and VOILA! done. 3. Timing is 15* advanced right? -Timing plays a good role in a lot of weird problems. Lemme know.

06-01-2008, 12:15 AM	#21
YoungGun Post Whore! Join Date: Nov 2007 Location: 818-951 SoCal Posts: 3,961 Trader Rating: (23) Feedback Score: 23 reviews	Uhhh not sure what your description of the vacuum routing is but anyways I FIXED IT! yay i'm so happy, never going to touch my engine again. Stock SR FTW. Oh those who are wondering, I put too much liquid gasket shit on and it got in this little hole which I guess prevented it from blowing off? Well I scraped it off and now it works. No boost leak, no surging, OKAY!