*Turbo "fluttering" while boosted*

[ArcherV20]

Hey guys,

I've had this strange problem come up very recently, I took the car out early spring so I attibuted it to cold weather, but now that it's warming up, the "problem" is still there.

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S14 SR20DET

Everything is normal, until I start boosting (around 2500RPM and beyond) the turbo sounds like it's fluttering when I accelerate. However, after about 5 minutes of driving - the noise goes away and everything sounds the same. Under the same conditions I get that nice little hissing noise as I build boost.

Is this the signs of my turbo about to blow? Boost leak?

I'm not too expereinced with this kind of stuff, so any help would be appreciated. I know "fluttering" is pretty vague, but it doesn't sound like the regular hissing noise I'm so used to.
Modified by ArcherV20 at 8:22 PM 7/12/2008

[IanS]

I would guess that you have a leak in your turbo to manifold gasket. They can leak and make all sorts of weird noises when they leak. Mine used to sound like a super loud, high pitched, twittering bird. Once the engine, and the exhaust warm up, the metal expands, and the leak goes away.

[DrifterProdigy85]

Sounds like T25 Inlet Gasket to me.

[ArcherV20]

Ugh. So the best fix now is to pull the turbo off the engine? I guess it's time to service the whole snail.

Is there a better way to do this? Or am I right in just assuming the whole turbo needs to be pulled. I'm reading through the FSM and man it looks like a process.

[IanS]

You can just take the nuts off and drop the turbo down, then replace the gasket.

The most common cause of that gasket failing is loose turbo to manifold bolts, check them to be sure.

[0wn3r]

FYI- you may want to tig weld the as many of the bolts as you can (might be like 7 that you can actually get to). This will prevent them from backing out on you and ruining gaskets or having your turbo fall off. Of course this may mean draining your coolant and taking it all off...I'm sure you could check the condition of the turbo while you're at it.

I just had a leak, my turbo eventually made a noise, but it wasn't like a compressor surge noise, it was a lower-pitched "wooooo wooooo wooo wooo" noise as it was building boost.

Stay out of boost and get it fixed...you don't want pieces of a gasket getting sucked in.

Gaskets aren't cheap

[ArcherV20]

I still haven't fixed this problem, I've put my car on super light duty (emergency transport only) and it's been sitting in my garage waiting for me to get off my arse and do it.

Anyway, I've been researching into this (I'm fairly new to working on engines, and I've barely touhed my SR20 besides routine matinence so please bear with me ) And it looks like in the FSM, the removal of the turbo is QUITE a process. Now all things remain the same - if I simply wanted to replace this turbo to exhaust manifold gasket that you pro's seem to think it is.

FlatBlackIan mentioned that I can simply drop the turbo down and replace the gasket. But I want to make doubly sure I know what I'm getting into before I start unbolting crap.

1. Remove exhaust mani-heat sheild2. Remove all the intake piping and hot pipe.3. Now from the FSM it looks like the exhaust mani is held to the turbo by 4 bolts. (It's inbetween these two where my possible leak is right?)4. Remove the 4 bolts, pull apart, inspect, clean, replace, rebolt.5. Reassemble and celebrate on NICO?

Is there something I might be leaving out here?

And a final Q.

This is the part I should be ordering in?

http://www.frsport.com/Nissan-....html

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Thanks guys! I appreciate all the help, I hope you can appreciate someone who searches before he posts!

[IanS]

^^^ Sounds like you've got the gist of it.

A few things to watch out for. There are tabbed washers on the nuts that hold the turbo to the manifold, they are meant to keep the nuts from backing off, but they don't usually work, they just make removing the nuts a pain.

If you plan to remove the turbo entirely, make sure to unbolt the two coolant hard lines, the oil feed line, and the oil drain from the turbo.

Also, you will need to remove the down pipe and dump tube from the car to get the turbo out.

If you dont want to spend $20 on that gasket from FRsport, you can do what I do. Drive to your local Saab dealership. A whole bunch of Saab's use turbos with T2 flanges, so they keep those gaskets in stock. IIRC the gaskets cost me about $4 a piece.

[0wn3r]

A few things to watch out for. There are tabbed washers on the nuts that hold the turbo to the manifold, they are meant to keep the nuts from backing off, but they don't usually work, they just make removing the nuts a pain.

If you plan to remove the turbo entirely, make sure to unbolt the two coolant hard lines, the oil feed line, and the oil drain from the turbo.

If you dont want to spend $20 on that gasket from FRsport, you can do what I do. Drive to your local Saab dealership. A whole bunch of Saab's use turbos with T2 flanges, so they keep those gaskets in stock. IIRC the gaskets cost me about $4 a piece.

\

Which is why the coolant was drained first when mine was done...then the bolts were welded instead of relying on the tabs.

Damn..I paid $30 (I think it was same gasket.)

[ArcherV20]

oh man, Ian, and Own3r thanks again you guys are awesome.

I looked around for Saab gaskets and found the 1995 900SE had a flange similar to ours. However... I may just go with the FRSport one, I want to be sure it's the right one, and would you believe it the Saab scene isn't exactly booming with tuners .

I'll keep you guys posted on how it goes.

[IanS]

oh man, Ian, and Own3r thanks again you guys are awesome.

I looked around for Saab gaskets and found the 1995 900SE had a flange similar to ours. However

I just brought the old gasket straight to Saab, I gave it to the guy at the parts counter and told him, I need a new one of these. He gave me a goofy look and asked what year car, I told him I didnt know, but I did know it came from a turbo, he took it, walked into the back and came back 30 sec later with a perfectly matching MLS gasket. I then explained to him what I was doing, he got a good chuckle out of it.

the T2 flange is rather common, gaskets are pretty universal, any saab dealer should be able to match it up, with or without the old gasket.

[0wn3r]

haha awesome.

maybe you can take the heat shield off first and try and see what gasket it is? you may even be able to see the gasket breaking apart without even taking it out.

oh and Archer, you should try to search for my floor mat thread i made a while back. bought some from ebay...they were a little over $100 i think but definitely pretty nice.

[ArcherV20]

I've found some floor mats since then, thanks anyway some nice OEM ones that match and say 240SX on them!

Anyway..

I HATE HOSE CLAMPS

I pulled my car in this morning and started work this afternoon, pulling off most of the IC piping was easy enough.

Removing the heatshield was a PITA for a bit, it just didn't want to slide out too nicely. Finally got that out, but now there is another shield covering the gasket and the point in which the turbo and exhaust mani meet.

ALSO it looks like I'll have to approach the 2ndary heatshield and turbo bolts from under the car. It looks like clearance for my arms and tools might be an issue. I don't have access to air tools or anything, so I'm stuck here cutting my hands apart.

edit: Now that I know at which point to remove the IC pipes, and learning to give the heatshield some tough love removing and installing... I think my next attempt will go much smoother. All this for a little gasket, I'm starting to think owner's idea of Tig Welding the bolts in is sounding like a good idea. Also it's +30 celcius outside, and I think the A/C is more of worthwhile project right now

[0wn3r]

Tig Welding the bolts in is sounding like a good idea.

you only need to do a small spot on each bolt...don't go crazy and do the whole bolt head.

and don't thank me for the idea, thank 240sxmotoring.

[jr_ss]

You may have better luck pulling the whole manifold off the head. I had the same issue and found it to be much easier to remove the whole thing off the side of the head, instead of fighting to get your ratchet /wreches into the tight area. It'll also let you get those nuts nice and tight and make sure the locking tabs are lined up right.. Buy the locking nuts from FRsport.com, think they are copper? But lock down on the threads nicely..

[ArcherV20]

Well the issue with that is, I don't want to remove the entire turbo. To be perfectly honest with you, I'm not 100% clear, or confident in doing that myself. This unbolting of 4 more bolts dropping and replacing seems to be at my level.

Otherwise you guys would have me in here posting pics and asking for more and more help. And I really hate being *that annoying forum guy*

[IanS]

Well the issue with that is, I don't want to remove the entire turbo. To be perfectly honest with you, I'm not 100% clear, or confident in doing that myself. This unbolting of 4 more bolts dropping and replacing seems to be at my level.

Otherwise you guys would have me in here posting pics and asking for more and more help. And I really hate being *that annoying forum guy*

That annoying forum guy who asks repeated questions about stupid BS, who refuses to search, and fails to treat anyone with respect.

You're just a regular who needs a little helping hand. Many of us got to where we are today with the help of friends, whether next to us in the garage, or across the country.

If you have questions, dont be afraid to post pictures and that sort of things. We are here to help, all we ask is that you at least try to return the favor.

[0wn3r]

my guess is that you may have a b*tch of a time trying to avoid taking it out.

[IanS]

my guess is that you may have a b*tch of a time trying to avoid taking it out.

Its not that tough, Ive changed the gasket without removing either the turbo or the mani.

[0wn3r]

Its not that tough, Ive changed the gasket without removing either the turbo or the mani.

did you weld the bolts though?

[IanS]

did you weld the bolts though?

No, but I retorqued them after they heat cycled a few times and it was never a problem again.

[ArcherV20]

Okay so today was the day I began working on the little gasket replacement here. I was pretty pressed for time so I couldn't totally finish, but I do have some questions that'll help me tomorrow..

FlatBlackIan - how in the WORLD did you get all 4 bolts off without removing the turbo or manifold? It's such a tight squeeze from any angle I come at it :\





Those last 2 bolts are really tightly snugged behind the manifold...any advice on what tool I should be using here?!

All that's left is those 4 bolts..will removing these 4 bolts give me enough wiggle room to remove the gasket? Or should I prepare myself to start pulling something else off? Thanks guys

P.S. I still hate heatshields, what a biotch.

[PhopsonNY]

Most people and the shop manual pull the turbo and manifold off first.

It is more trouble than it it worth to try and keep the manifold on while pulling the turbo.

good luck

[IanS]

I have a stubby set of wrenches, they make getting in there quite easy. If you don't have stubbies, you can always cut the end off a wrench of the size you need. Getting those bolts is kind of a pain the first time, but once you figure out a good way to go about it, they come off easy, its all about trial and error.

[ArcherV20]

Most people and the shop manual pull the turbo and manifold off first.

It is more trouble than it it worth to try and keep the manifold on while pulling the turbo.

good luck

I know it's totally recommended for human hands. I'm just not too confident in being able to do it alone. Anyway, I'm going to give it another crack tomorrow. I'm sure I'll get it this time!

[exhsturbine]

an old man used to always tell me that when you buy a japanese car that they should come with a japanese mechanic in the trunk cause their hands fit much easier than ours..... hahaha

i know it seems difficult to remove the entire manifold along with turbo component assembly. but really i always think its easier. that how ive always done it. i cant reach in between the two. i have big hands. i think the biggest pain is the coolant and oil lines. but i believe someone suggested that you are able to make sure all turbo bolts are secure, and that was my thoughts exactly the first time i decided to try that route. also, my manifold was spot welded to prevent the bolts from shaking loose. just try not to be scared. if you break it, it can always be fixed.... hah not sure thats too comforting, but its true. besides if you are able to remove and install an engine. this should be a cake walk. all in all i wish you good luck and hope your problem is fixed

[ArcherV20]

F*** This.

FlatBlackIan I have NO idea how you get all 4 bolts off without removing the entire setup. In fact I'm calling shennanigans right now! The tabs are hard to bend back while it's mounted, and the bolts are so sneaky back there, I can imagine maybe struggling and loosening them, but putting them back on would literally make my head explode. I'm going to try and remove the manifold and turbo setup. I figure I'm already half way there aside from draining the oil and coolant (pain in the ***!). Aghh...all this for a lousy gasket.

[playbass311]

Yeah, its so much easier to just pull the manifold and turbo out, thats what I did when I did my lines and stuff. In the long run, you'll save yourself more time by doing a little more work in the beginning. And all the nuts on the manifold are fairly easy to get to (some from the bottom, some from the top, yay for a lift! lol) but just be careful not to break any of studs on the manifold when you pull them off.....and while you are at it, you may want to consider a new manifold gasket, i mean, its already off right? haha.

[ArcherV20]

My biggest problem is that this is my daily driver, and I'd like to go to work tomorrow!

I'm really at a loss right now, I feel sorta useless. I'm having trouble removing the manifold and turbo now, these banjo bolts are a pain to remove.

I'm really considering just taking this to a shop and having them replace both gaskets.

[IanS]

F*** This.

FlatBlackIan I have NO idea how you get all 4 bolts off without removing the entire setup. In fact I'm calling shennanigans right now! The tabs are hard to bend back while it's mounted, and the bolts are so sneaky back there, I can imagine maybe struggling and loosening them, but putting them back on would literally make my head explode. I'm going to try and remove the manifold and turbo setup. I figure I'm already half way there aside from draining the oil and coolant (pain in the ***!). Aghh...all this for a lousy gasket.

Hahahahaha, Im sorry, I couldn't help but chuckle a little, you said the word shenanigans.

It can be done, and I can prove it, I removed my manifold without removing the turbo, it just so happens I documented the whole thing, check my sig.

I am a mechanic, I make my living by getting my hands into places normal people cant/wont. Let me just say that the tabs are the biggest pain, the inside ones are best gotten at from the underside of the car, you need to use your fingers to feel them, then use a small screw driver to pry them away. The reason I did not recommend removing the manifold is the likeliness of breaking studs, I broke three when I did mine. Ive had my turbo out 4 times, there are a handful of people who can vouch for me.