Help! my turbos squeeling

[Calvin]

My turbos squeeling!

Hi All

Ive reciently fitted Power FC boost kit and had it mapped to run upto 1 bar by a well respected Skyline garage in the UK, a lot quicked on 1 Bar, a lot more fun to drive! The car was fine for a couple of weeks after mapping, but now whilst running full boost, at about 4500rpm I get a squeel which is getting louder as time goes on. Is the bearing in my turbo moaning or have I sprung a leak? On 0.7 Bar the noise stops.

This is the spec of my car:-

Super dragger
decat
75mm front pipe
HKS pod filter
Greddy iridium spark plugs
Apexi PFC
Hand controler
Boost kit
boost up to 1 bar
Mapped at RBs

Anyone any ideas


Calv

[SkylineUSA]

I would tear into it. Take a look yourself. You really cannot diagnose over the net. We could only give you guesses. The only to make sure is physically looking at it.

Sorry, I cant be more help. Get the wrenches out, and have some fun

[hybridsol]

Originally posted by SkylineUSA
I would tear into it. Take a look yourself. You really cannot diagnose over the net. We could only give you guesses. The only to make sure is physically looking at it.

Sorry, I cant be more help. Get the wrenches out, and have some fun

he's right it could be lie 10 different things....could be just a clogged intake manifold to a Gas leak in ducting after the turbine outlet, or simply just dirt caked on the turbine. basically something is lodged somewhere or you have an air leak, or a loose wheel and so on and so on.... but check the manifolds and check for air leaks.

[hexn8r]

i have an rb20det which i have experienced the same problem.
replace your turbo, it sounds like the wheel is scraping inside your housing?
i have an aftermarket comp, which was running abit lean, i beleive was the culprit.
i would seriously have your fuel/air mixtures inspected !!!
otherwise you'll be replacing more than your turbo.
good luck!

[RazorGTR]

Calvin I don't see a front mount listed, and the factory R33GTS25t turbos are shockingly weak. Dependant on the year of the car your turbo could have a plastic compressor wheel!

People it is so simple. I am not lecturing here only enlightening. Time and time again with members of the SDU club having the same issues. The ceramic factory turbos are designed to be light weight and thus spool quickly. They are also extremely weak. The exhaust wheel and shafts are moulded out of ceramic and at 1 bar of constant use they weaken. Now given that most of the cars are either at least 10 years old or are approaching that age those turbos are well used. Simply put run 14.5 psi and they WILL die and some rather quickly. It has nothing to do with fuel mapping or ignition timing. It is all about pressures and age.

If you want to run more than say .9 bar get an aftermarket turbo with steel shaft and wheels or have your factory one hi-flowed with bushed bearings and steel wheels and shaft.

[Calvin]

Got the problem susses now, it turns out that an exhaust manifold stud has snapped, thus when running higher boost pressures, the gasget blows like a reed making the squeeling noise, goes in next month to get it sorted. Hopefully coming home nice and quiet, may fit a bigger turbo in the process, anyone got any recommendations.


Calv

[RazorGTR]

Give me an idea of what power and boost you are realisticlly looking to run and make.

You could go with a Trust GT30 and dependant on the A/R rating of the exhaust housing you could see 500hp.

Another good one from HKS is a 28-35 to say 30-37 for good power. Both are ball bearing turbo's so should spool nicely on the RB25DET mill. You will see a bit of lag say to around the 3,700 rpm mark before you break into boost thresh hold for the bigger turbos.

I would also upgrade your fuel delivery system including fuel pump to a bosh 044 WITH non-return valve, and some RX side fed injectors say around the 550cc mark min. You will need other bits to make it all work properly but I have seen quite a few R33 GTS25t's pushing over 400 hp at the wheels with simular combinations at only 1.1-1.2 bar of boost. It is all in the setup and tuning.

[Calvin]

Hi Mate

This is the spec of my car:-

Super dragger
decat
75mm front pipe
HKS pod filter
Greddy iridium spark plugs
Apexi PFC
Hand controler
Boost kit
boost up to 1 bar
Mapped at RBs

I also have a R34 GTR fuel pump sat by my computer doing nothing, I would like to see more (reliable) power, now running at 310bhp (estimated), rolling road at 355bhp (optimistic) I think. I am told by my tuner that my AFM is at max, injectors @95%, standard intercooler. I think I will need to replace a few more bits than the turbo to see more real power, what do you think, 400bhp would be nice


Calv

[SkylineUSA]

Off Topic it little.

Razor,

I noticed that a lot of people don't run external fuel pumps, is there a reason for this?

Tony

[moondog]

Calvin, if you want to run that kind of boost, you definitely need a front mount i/c. The standard i/c is very restrictive, especially as boost rises. When you see 1 bar (14.7 psi - pretty much max safe boost for the standard turbo) at the manifold, your turbo is probably pushing on the heroic side of 20psi - which is waaaay more than you should run the standard turbo at. My guess is that you're wearing it out, and you should reduce the boost until you get a less restrictive i/c.

[RazorGTR]

SkylineUSA actually there are some very good intake upgrades that fit the carrier quite easily. Some go to swirl pot and external pump but why spend the extra money if not needed The factory GTR pump will support 650hp easily, then you have the boshe 044, apexi, and nismo pumps which are good upgrades also though price varies quite a bit.

Calvin -
550 cc side fed injectors
Put your fuel pump in for sure
raising rate fuel pressure regulator
front mount i/c such a GTR (590X285X74). 600X300X90 to 100mm thick shall do
Get your factory turbo high flowed or if you can afford it a Trust GT30 with a .64 A/R exhaust rating or equivelant
metal head gasket 1.1-1.2mm
have your factory exhaust manifold ported to match the exhaust ports of the head (factory they are actually smaller and do cause a bit of turbulence)

Your factory AFM is not maxed out. Your turbo and fuel deliever are however. With the bits you have and include what I just listed you should see 400hp easily without running huge boost. Your factory cams are also fine. You can if you wish add some adjustable cam gears which help in tuning.


Moodog is so right in his statement. The factory i/c for the GTS-t and GTS25t are just enough for the factory setup. They are very small and no efficient at all. If you want to see how effetive your i/c is on a cool day give your car a bit of a run at at least 50k's getting it up to full boost on and off. I am not talking like a full lap around a race track. Keep air moving through the i/c and then pull over. Pop the bonnet and touch the outlet tube from the i/c. If it is warm then you are beyond efficient. After I did the upgrade on my old GTS-t the inlet was quite warm while the exit tube had condensation on it.

[SkylineUSA]

The factory GTR pump will support 650hp easily

Dammmmmn, I did not know that. Thanks Razor.

[moondog]

Originally posted by RazorGTR
If you want to see how effetive your i/c is on a cool day give your car a bit of a run at at least 50k's getting it up to full boost on and off. I am not talking like a full lap around a race track. Keep air moving through the i/c and then pull over. Pop the bonnet and touch the outlet tube from the i/c. If it is warm then you are beyond efficient. After I did the upgrade on my old GTS-t the inlet was quite warm while the exit tube had condensation on it.

Not just the cooling though. It may still be cooling ok, but the restriction means the turbo is pushing harder than it safely should. Myself, I'm more worried about the restricition - and consequences for the turbo speed - than the cooling, and that's why the i/c will get replaced as the next mod.

[RazorGTR]

It is actually a two fole effect. Both of which are bad. Yes the factory i/c produces a lot of back pressure but also it is so non-effecient that the air charge entering the engine is hot and that accounts for lost of power and could lead to detenation. That would destroy your motor as we know

[Forsteen]

Just curious, since when does a Skyline have side fed injectors. As far as I know they are top fed. I have top fed 550cc denso injectors on mine right now.