ixfxi

I wanted to start a thread that has to do with turbo components and hardware. It seems there is a lot of confusion & mixed opinions in regards to the following:

1) Turbo Gasket. The two most problematic gaskets are:
- Turbo to Exhaust Manifold
- Turbo Outlet Housing

A well known & respected company in the industry suggested NOT to use a gasket between the Turbo & Exhaust Manifold. I thought that was odd. Their belief was two fold:
1) Keep the heat transfer even between turbo & manifold. No gasket = better heat transfer
2) The manifold must be (machined) flat to ensure proper seal.

NISSAN obviously uses a gasket with locking hardware (clips), which brings me to my next issue:

2) Secure Turbo Hardware. Again, same problem areas:
- Turbo to Exhaust Manifold
- Turbo Outlet Housing

I have read so many weird methods that people have discussed over the years on various different forums. Lets start with what I think are the best ways:
1) NISSAN's method is use high-grade (OEM = Inconel?) fasteners. No one has been able to confirm that the OEM hardware is inconel, but I think we all can agree that the OEM hardware is indeed up to the job. So if I am correct, NISSAN uses Inconel studs & nuts, then secures the hardware with the locking tab/clips we all know. I personally hammer the tabs around the nuts to make damn sure that the nut has no way of rotating.

2) Tack welding the hardware. Some people have simply tacked the nuts to the studs, and that keeps the nut from spinning obviously. This method sounds good and is easily serviceable, at the expense of replacing your studs/nuts if/when you ever decide to remove and/or replace the turbo. Not a big deal if you ask me.

3) Safety wire. I purchased some nice inconel safety wire but ran into a big problem when it came to locating drilled nuts. Hardware that has been drilled for safety wire is typically found in aerospace and acquiring this hardware does not seem easy, metric especially. With that said, the only solution I found was to take a batch of nuts to the machine shop and have them drilled with holes for the safety wire. I purchased a jig online that would allow me to do this on my drill press, but the OEM hardware is just impossible to drill through no matter what grade of drill but I was to use.

4) WELD the turbo to the manifold. This does not seem like a wise choice for various reasons. Anyone familiar with welding understands that cast iron is not an ideal metal to weld. The results are questionable and I wouldnt be surprised if the components are susceptible to cracking.

5) Fancy shit such as Nord Lock nuts, Stage 8 fasteners, or Resbond high temp thread locker.

To be honest, the first 3 methods seem to be the best. Either use OEM hardware, or if thats insufficient then switch to safety wire or fucking tack that shit down.

LAST item has to do with the EGT. Not everyone cares about gauges or monitoring their temps, but I do. With that said, where and how are people mounting their EGT?

1) Before the turbo (ie: turbo inlet temp) means that you must drill into your cast iron manifold.

2) After the turbo (ie: turbo outlet temp) means that you must install the probe into the Turbo Outlet Housing.

Obviously, if you have a tubular type manifold then welding a provision on there is much easier. But if you're using the OEM cast iron manifold, then obviously welding is not an option as you risk cracking. You would have to find an area where you can drill and tap the exhaust manifold, or, you would have to install it after the turbo.

Feel free to chime in. Except you, Kingtalon.. I dont want to read a 10-page dissertation on how we need a fucking clean room or any of that bullshit. :-)

KoukiMonsta

I had some thoughts, then laughed and said fuck this.

okay..I have never heard any mention of the hardware being inconel, though yes it is very up to snuff. Interesting you couldn't drill the nuts, this helps confirm that idea as inconel is extremely hard.

you forgot an option I would consider to be the clear winner, fucking JB Weld all that shit together.

yea im too lazy to finish typing my thoughts

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jorge1190

I have always used lock washers with copper nuts. It is what a lot of big diesels use and I've never had a problem.

I have found that the best gaskets are OEM gaskets. I have never blown out an OEM nissan gasket. I can't say the same for mr. Gasket.

This is experience with stock manifold/turbo, tubular manifold with greddy T517Z, and now my top mount set up.

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KAT-PWR

Many performance applications use no gaskets. However you literally have to have a perfect surface on BOTH surfaces. (Do you want to take your head off to get machined?)
I think quality OEM nissan gaskets and CLEAN surfaces area big starts. Followed by hardware which gets tricky. Personally i like to try and keep up on the torque of the manifold nuts, no its not fun... but it ensures they arent backing off.

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lok

You need to have good drill bits.

My friend did this with just a corded drill and good bits.

I have used stage 8 and there hard ware did not hold up.

ixfxi

You are referring to the wrong gasket.

Not exhaust manifold to head. When the fuck have those ever failed?

I am talking about the hotspot, the most common being the TURBO to EXHAUST MANIFOLD gasket. These are ALWAYS blown out. Even when I purchased my front clip, I removed the stock parts and that gasket was blown apart.

One thing I will add is that during street use, this will never be an issue. Hardware failing and coming apart WILL happen at the track, and this is a fact.

No matter how hard I drove on the street, I never generated enough heat & abuse to have issues. However, in a matter of minutes at the track where you are basically 100% throttle _forever_ -- things get hot and come apart quick.

ixfxi

I saw that photo recently of the drilled hardware.
Thing is, the hardware does not appear to be OEM inconel. Maybe I am missing something.

I have some Norseman "Magnum" drill bits and couldnt drill through shit, and at low RPM too.

Oddly enough, the inexpensive "spot weld" seems to be the best solution, no?

KoukiMonsta

If you have a welder, yea it's dirt cheap. Easy/quick as hell and not permanent.

Agreed on street vs track use, for a street car some quality copper nuts have worked done for me many times.

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lok

I had the previous turbo secured with spot welds too. Worked great and never had an issue with the bolts/nuts coming loose. Just kind of a pain to disassemble when upgrading turbo but it does work well.

Also, spot the top of the studs if you can too.

Def

I tried everything from a fancy hardware and gasket setup and nothing could make the gasket survive. The nuts were actually getting hot enough to deform/creep on the sealing face. I forget how many Nissan gaskets I blew out, maybe 5? I would get 1 weekend where the nuts (OEM, fancy Grade 19 titanium, metric inconel non-OEM etc.) would start deforming, then next weekend the gasket would let loose on the first day.


This wasn't a problem until I was really pushing that little bit harder on track. The OEM stuff in my experience can handle novice/intermediate track driving, as there's enough off throttle time to keep things cooler.

So tack welding just the nut isn't going to solve the issue, you have to help support the nuts with weld between the turbine housing and manifold. It welds just fine with a MIG welder, and I've had my welded setup hold up for many years. You can still service the turbo by pulling the CHRA off the turbine housing. Don't use a gasket in this obviously, just run a bead all around. Done and done.

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Sileighty_85

Man, Ive never had an issue with the stock locking tabs on multiple SR's and RB's. Ive used the locking tabs on my 2871R for the last 4 years with out an issue.

I do Method #1 you listed.

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1989 Built SR GT2871R -363whp
1998 S14 W/RB25- 250ish (For Now)
1986 SR86 - 200ish
1990 R32 GTR - 320hp
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S14DB

My word, What are your EGT's at to make your Nuts and bolts fail?

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e1_griego

The other piece to prolong the lift of the gasket is to run the exhaust hanger from the downpipe to the trans mount.

I'm running stage 8 fasteners now on my setup, but I think vband is my next step lol. I've only lost 2 t2 gaskets in 6 years though, but the last one came apart half way through a track day.

ixfxi

I think one of the main improvements that is under looked would be to change the M8 hardware to M10. I am not sure how possible that is though. Again, one thing to note is that this really only applies to people who are full-throttle and tracking for long times.

Another guess, and I'm just thinking out loud here, is what level of boost the turbo is being run at. If you run push a smaller turbo to the limit, there is a good chance it will create more heat than its designed to deal with, hardware included. This wouldn't be noticeable if you're just occasionally raping people on the street -- but it will be immediately noticeable when you go to the track and try that shit for 5-10 minutes straight.

Besides my main 240 resto-mod project, I have a few other side projects I am working on. One is converting this `99 Miata to turbo. Some of the info I've read from that community doesnt seem to have been discussed on Zilvia, so I'm curious what the thoughts are here. Miatas are commonly running the Garrett GT2560R (S15 turbo). People are complaining that the turbine outlet needs to be ported otherwise you run into boost creep issues. My SR20DET was fitted with a Spec-R turbo and never had boost creep issues.

Only thing I can think of is that maybe there is a variation between the turbo Garrett sells vs the Spec-R from NISSAN. I know it has the wastegate divider. You guys think there are any variables here that not everyone is aware of?

ixfxi

Or even better yet, run a piece like this:



Currently, I have a combination of the Greddy Turbine Outlet w/ HKS Downpipe and I can while nothing has ever cracked, I can say that this above piece is very tempting!

e1_griego

Yeah I have PBM downpipes in both my cars, just saying that it's important to run the rear hanger.

The turbo miata guys all go for inconel studs and all that stuff, but 99% sure the factory nissan stuff is inconel already.

I looked to go m10 when I blew my last t2 gasket this summer but it seems pretty iffy on actually having enough room to do that on a t2 turbo.

Top mount is the answer lol

Matej

Is there any advantage to using studs on the turbo, other than it probably makes it slightly more convenient to thread on a nut in a couple of the hard to reach places?
I automatically replace any turbo studs with bolts. When used without washers, they never came loose. Plus they are a lot less likely to snap, which is a really common and unpleasant problem on T2 turbos and manifolds.

Dealing with the locking tabs or any type of locking contraption on a bottom-mounted manifold is a huge pain. I am having an adapter plate made to have the stock manifold flipped upside down and use it as a top-mount, only due to how annoying it is to work with a bottom-mounted turbo. Though I am still undecided about using it, because on the other hand the bottom-mount setup does look much cleaner in the engine bay and makes for a lower center of gravity.

ixfxi

Convenience and grade are the two factors I can think of. The question is, where are you going to find high-grade (inco) screws?

Personally, I think we're better off modifying the manifold and turbo to use 10mm fasteners. The bigger 10mm fasteners are guaranteed to secure better than the bullshit 8mm hardware, regardless of what they are made of.

I am going to look into drilling/tapping the manifold and turbo for M10.

Matej

The two manifold-mounting bolt holes in the rear are the most unpleasant to get to, I am not sure how it would be with M10 hardware. If using an aftermarket manifold where all the manifold studs can be accessed from the top, I would just tap the holes on the turbine housings for M10 and use bolts/studs to fasten the turbo from the top, similar to how RB26 turbos are.


As for hardware, I am using ARP, though I do not intend to any racing, I am sure inconel would be best.

ixfxi

I see, I did not know the RB turbos had the studs installed on the turbo as opposed to the manifold. Interesting.

But still, fuck this aftermarket nonsense. All I care about is CAST IRON. Remove the OEM studs, drill and tap to M10. I will report back with my results.

KoukiMonsta

my only concern, without referencing any parts, would be reducing the wall thickness on both manifold and turbo. which in turn leads to loss of structural integrity. I don't think it will be an issue, especially since we are talking about the cast iron stuff but other then that I dont see why this wouldn't be a great solution.

side note, can anyone verify p/n OEM nuts?

stud: 14064-01m00 EDIT: stud part number replaced by 01151-00161

All this talk of inconel and all I see is copper..are the nuts inconel too?

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ixfxi

I've been researching this on and off for several years now. The (inconel?) studs I have acquired and used over the years has been:
NISSAN 14064-N4200

As for the nut, I actually ordered the OEM nut and returned them because they looked identical to the stainless nuts I've purchased from McMaster in the past. Here is the PN:
NISSAN 14432-0B700

So YES on the studs, NO on the nuts.

With that said, some of the big names are pushing to sell COPPER nuts which doesnt really make sense to me since copper is soft.

Here is a very similar thread that I've been following on the Evo forums:
http://www.evoxforums.com/forums/showthread.php?t=78114

I checked my turbo & manifold today, M10 hardware should work on the turbo to manifold. The only area I see problematic is the Turbine Housing Outlet. My Greddy turbine housing does not have much room for that larger M10 hardware, so I dont think that is possible. However, on my S13 I used those NISSAN lock-plates on the turbine housing. I modified them a bit, but it worked.

Edit: Here is a video that beautifully shows the problem:


Good to know that safety wire isnt the solution here, its the hardware stretching.

KoukiMonsta

Therefore, the only solution involves larger hardware that can better take the conditions.

No lock nuts, safety wire, spot welds...blah blah will solve issues related to the studs

Edit, until your larger hardware needs the aid of some previously listed stuff to further help prevent issues.

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ixfxi

well, thats my hunch. but again, i think this comes down to what particular turbo you are running and at what boost levels PLUS how hard you drive.

street car, occasional tom fooler = stock hardware OK
street car, lots of street racing = stock hardware OK

anything more than that, then you will need to take measures to prevent shit from falling apart.

ive been researching this to death and will continue to do so. my findings so far is that either you spend the money on inconel and fancy hardware -OR- you step up to larger fasteners. me personally, i am going to attempt the larger m10 hardware and see what happens.

with that said, ive been digging through many big companies install-guides and what not, and stumbled into this:
http://www.airpowersystems.com/gto/i...ts04_guide.htm

the well respected APS does not use ANY fucking gaskets between turbo and manifold. instead, they use permatex copper which has a rating of about 700f. sounds like bullshit, but people are saying that it works like tits so i am going to give it a rub. other old-schooler alternative is to smear the mating surfaces with some bearing grease, which burns off and leaves a tough carbon seal. again, it is critical that all mating surfaces be machined flat or as flat as possible.

keen eye will notice the lack of inconel ANYWHERE in the aps guides, they're using stainless with copper self locking nuts. no locking clips, no nordloc, no threadlocker, no safety wire. jeeeez.

e1_griego

There is a guy on NRR just using copper permatex and stage 8 fasteners. I think he's been running it a year now with lots of autox and track days.

KoukiMonsta

Interesting, I wonder if it is based on the same type of effect you get from the old-school bearing grease method? where its not so much that the sealant keeps the seal but the effects of heat cycling it forms something with a stronger bond.

Also, based on the first post, we have not discussed turbine outlet at all. I personally have only had issues with the inlet (4 bolt gasket). Mike do you have any thoughts/plans for changing your methods there? stick with M8 inconel and SS nuts?

EDIT: this p/n NISSAN 14064-N4200 has been replaced (according to a couple nissan parts pages) 14064-N420A
EDIT(2): it seems this p/n references an m10 stud, can anyone verify?

My next question, excuse my ignorance, when talking about studs inconel vs. (high grade/10.9 steel?) what color are the inconel ones? I am familiar with the studs being black, is the inconel stuff more gold/silver.

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S14DB

It looks like stainless but a little more silver/white(bright). Almost like chrome when polished. It only turns gold when heat cycled.

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ixfxi

Both, turbine outlet housing AND turbo to manifold bolts had come loose on my SR20DET. This is why I am researching this so hard, I want a sure-fire fix to this problem. I was under the impression that wire-wrapping would be one of the fixes, but after seeing the hardware stretch... the only fix I can think of is larger fasteners.

When I examined the turbo to manifold, it looks do-able. The only issue I found was that I could not use the OEM MLS gasket without enlarging the 4 bolt holes. Google "turbo manifold" and "no gasket" and you will find a shit ton of people (old schoolers included) who can vouch for the "no gasket" setup working and working WELL. As long as both surfaces are machined flat, the saying "no gasket = no gasket to fail." Guys are even referring to the old chrysler turbos that came from the factory with no gasket.

As for the color if inconel, there was a thread about that too and in the end its all bullshit. Color doesnt mean shit. The only thing that matters is that the studs are not magnetic. I checked all the OEM NISSAN studs I have and they were all very mildly (as in barely) magnetic. I think someone sent out some BMW fasteners for testing and the results were NOT inconel but basically stainless steel.

So take this for what its worth. I'm going M10 for the turbo to manifold. As for the turbine outlet, I dont think I can fit M10 hardware. Its just too tight.

KoukiMonsta

I am under the impression all OEM NISSAN studs are stainless, not inconel, at this point. At least referring to m8 size.

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Def

M8 stuff and permatex didn't work for me. Same story of the face of the nuts deforming - I.e. High temp creep. There's no gasket to blow out, so it wasn't as bad as the stock gasket letting loose, but it still noticeably leaked and gave a 600-900 rpm later spool and generally down on power. Not to mention all the exhaust on that side boiled my clutch fluid in the line on the straights.

Have you thought about trying to fit M10 bolts, or 3/8-24 A286 socket cap screws? You can drill large safety wire holes and use that to torque the bolts with a screwdriver or something through the holes.

That said, you're making this too hard. Just weld the damn turbine housing to the manifold and never worry about it again. There's so much weld area, it will not crack.

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