Leeroy94

What type of ECU do you run?

Nah he had an aftermarket turbo.. It's his daily and he has no money so I'm just going to help him out. The rb25 turbo I have doesn't have the stock 5psi spring, it has an aftermarket 10psi spring. Yeah I went and talked to a turbo rebuilder and he said 14psi on the rb25 turbo through an rb20 engine is fine as long as I don't limiter bash all the time. I usually keep it third gear around 5-6k rpm so should be fine. Plus my rb20 is super tired.. As for the spikes ill have to look out for it. I might run it 12psi for a track day to see how much it spikes.

Yeah I've fitted the turbo with the rb25 actuator (came with a 10psi spring attached). I'm going to weld a brass nipple onto the intercooler piping and run a MTBC off it. I've been informed that the boost controller should run 13psi fine on the rb25 actuator with a less than 2psi boost spike. Does that sound about right? My mates turbo just blew on his rb20 so I'm going to give him my old one as it is in really good condition.. Hence why I didn't swap the actuators.

Jacking the car up works great or if you have a steep driveway that works fine too. Just in case someone is unsure of how to bleed a cooling system here is a basic guide: - Jack the front of the car up or park on a steep hill as suggested earlier. - Make sure the radiator hose and heater hose clamps are tightened securely. - Set the heater control lever to hot position but leave the fan off. - Release the radiator cap and bleed valve bolt (pictured below). - Fill the radiator gradually (filling speed: slower than 2L per min) to the top of the spout with coolant. - Fill the radiator until the coolant in the reserve tank reaches the MAX level line indicated. - After closing the radiator cap and bleed valve bolt, start the engine and allow it to idle. - The engine will continue to idle until the thermostat opens. (Touch the radiator flow hose and make sure hot water is flowing). - If a large volume of air remains the water temperature gauge needle will move past the middle as the engine temperature rises abnormally. If this occurs, stop the engine wait until it cools and add water to the radiator repeatedly as described above. - After the thermostat opens, race the engine for 10 seconds at 2500rpm two or three times. - Check that the water temperature does not rise excessively. - Stop the engine and allow it to cool, Release the radiator cap and check the fluid level. If the fluid level lowers, return to step 4 and repeat the process.

Im a Design Engineer, Hydrology. I didn't really put that much thought into it, just went off the top of my head.. But I'm sure the more information he gets the better. Just trying to give the bloke some ideas that don't cost him hundreds of dollars. Not a competition. To JordansR32: Take my advice if you want, It worked for me. But I wouldn't be driving around without adding more concentrate if your car is reaching those temps. Its not a long term fix.. But it will give you time to figure out what it is and possibly save up for what is needed to fix the problem.

Okay thanks for your help GTSBoy!

I don't know what coolant you guys use but the one i buy has got glycol in it. Which is twice as resistant to boiling than water... Therefore adding more concentrate (glycol) reduces the chance of boiling. Seeing as your car is reaching 95-100 degrees you want more glycol. If you run premix coolant chances are your engine won't get damaged but if you are planning on running it hard then yes add more glycol. You don't want your coolant to boil!! Kind of on the right track but majority wrong. Ability to move heat: Glycol has a 15% increase in circulated heat flow than water. Which is handy for when your coolant decides to pass right next to your exhaust manifold and turbo. Heat capacity: Both water a glycol see the same results up until and beyond 122 degrees. Therefore pointless in 95-100 degree ranges - Boiling point of water 99.98 degrees - Boiling point of glycol 197.3 degrees Without doing any calculations a 50/50 mix of the two will give you a boiling point of around 110 degrees. Which is great for you! I agree with this!! Because of my intercooler piping I can't run a clutch fan and therefore am running 2x12 inch thermos (far less superior to a clutch fan) At the end of the day, you should research yourself and find out what works best for you and your cars setup. Or go and see a professional and get their opinion.

Thank you GTSBoy. Mods are: - FMIC - JJR bell mouth dump - walbro 255 fuel pump Soon to be rb25 turbo My compression is low but the motor refuses to die. Cylinder 1 - 135psi Cylinder 2 - 120psi Cylinder 3 - 120psi Cylinder 4 - 124psi Cylinder 5 - 126psi Cylinder 6 - 135psi I'm going to run it till it blows and then upgrade to an rb25det. Is it worth getting a tune on the stock ECU if I can't afford a nistune?

I've read 1000 topics on this and haven't got a clear answer. I have an rb25 turbo with hardly any shaft play. It is stamped 45v4 on the compressor housing and 21U on the exhaust housing. It's going on a track car but will not be limiter bashed (6000-6500 max). Running a JJR bell mouth dump pipe to no exhaust. Is 13psi okay to run? Also, I have a manual boost controller. Can i run the boost controller off the stock 7psi actuator or will should I just get a spring for 13psi? Edit: I was told the rb20 puts less strain on the turbo than the rb25 and therefore can run more boost. Is this true?

Another thing, when you add more coolant concentrate to your radiator make sure you bleed it properly. Air bubbles in your system will decrease its ability to cool. Post results when done and we can go from there.

Yeah I think it may have slightly ceased up. I soaked it overnight but no luck.

Is the alloy rad from ebay? Lol You could try adding more concentrate to your coolant. Seeing as your motor is sitting higher you could try putting washers underneath the rear bolt of the bonnet hinges (check with state law). 3mm clearance for air to escape does make a difference to under bonnet temps, it will also cause more air flow in the engine bay. A heat shield is a good idea too. I'm just pumping ideas out here. What motor did you upgrade to?

Daily driving, after a mountain run, track? In my track car I run two thermos with a brand new radiator etc and see temps of 95-100 degrees after a hard run. Everything is running fine. I have 50% anti-boil and 50% demineralised water in my radiator, rather then 33% anti-boil/anti-freeze they use in premixes. How hot is your car getting? When does it get hot? Idling at stand still, on the highway etc..

I took it down to the turbo specialist. He said rb25 turbos are sealed inside (ball bearing) and therefore there is no point in taking it off to clean. I ended up getting a tooth brush and getting the excess soot out of the exhaust housing, apparently the only area that needs to be sut free is around the actuator flap. Edit: there was about 2mm thick soot everywhere, hence why I tried to take it apart to clean.

How do you remove the exhaust housing of an rb25 turbo? There's 6 bolts, 3 of which came out. The other 3 can't fully unbolt because the oil line screw holes are in the way. Ive soaked it in wd40 because apparently your suppose to twist it? What what does it twist, where do I hit it with a mallet?

Yeah I agree, the previous owner installed it there. I've already gone through one set of melted hoses will need to secure them better. What does recirculating the blow by to the intake do exactly? Pros and cons. What's the best way to set up your intake manifold?

I would suggest posting a photo of your engine bay. I rebuilt a turbo daily and it was having similar problems. Turned out there was an air breather on my rocker cover that acted like a valve, but it was installed backwards, causing my engine to puff smoke similar to when yours does.

Black smoke or white smoke?

Excuse my engine bay..

Okay so I understand the hose between the catch can and the intake before the turbo. Both of my cam covers have one breather each with two sides to them. Are you suggesting I block off one side of each breather, then connect hoses from both the breathers into a T-piece which then connects to the catch can? Just trying to clarify.

Okay. Ill try switching the hoses around both ways suggested to see which one works the best. Ill post pics once done.

My engine is on its way out already. I knew that from the start but it refuses to die (rb20det) Compression test results Dry test: Plug 1 - 135psi Plug 2 - 120psi Plug 3 - 120psi Plug 4 - 125psi Plug 5 - 126psi Plug 6 - 135psi Leak down test (roughly 10ml oil down each spark plug hole): Plug 1 - 142psi Plug 2 - 144psi Plug 3 - 145psi Plug 4 - 150psi Plug 5 - 145psi Plug 6 - 154psi I've taken all my intercooler pipes and intercooler off. They have all been cleaned thoroughly. I removed my stock rb20 turbo. Next to no shaft play, nor is there any oil besides the dripping oil lines. Exhaust housing wasn't even that fowled. I have an empty catch can with no breather on it. Two hoses go from the top of the catch can. First hose runs to a breather on the left rocker cover (closest to the intake) which is then blocked off on the other side. Second hose runs to a breather on the right rocker cover which then has another hose on the other side running to my intake, before my turbo and after my AFM. I didn't install the catch can. I bought it like that. Does anyone know of a good catch can setup? It's a drift car so I don't need to abide by any laws. Also, in terms of my compression, I have no plan on rebuilding the motor. I have a rb25 turbo stamped 45v4 on the compressor housing and 21U on the exhaust housing. Can I bolt this turbo on until my motor blows up? And what effects will the motor blowing up have on the turbo?

Yeah there is a pipe running from my turbo inlet to one of the breathers on my rocker cover.. Could that be the cause?

It's just an empty catch can, two hoses going to it from each side of my rocker covers

I'm running a catch can