Jump to content
SAU Community

Recommended Posts

So, ive had a catch can installed on my car for a few months, and it feels like my oil pressure is too high. I did a oil flush when i installed the can as well, 5w40 (maybe thats the cause?). If it isnt the oil thats causing high oil pressure, im thinking maybe the can setup?. Its non atmospheric, 1 way valve still connected to plenum, and plumbed from exhaust side to can, can baffled with loose steel wool, and plumbed back into intake before turbo. before putting on the can and oil change, at idle it would sit at between 1-2 (on the stock oil pres gauge), but now it sits at 4, and at pre 4500 rpm boost, its at like 5-7 on stock gauge. it seems way too high than before.

And for the second issue, the 2 stage boost is still active, its a jdm rb25 swap with what appears to be using the rb20 harness. According to the R33's, the ground for the boost solenoid needs to be grounded to the body, but since i don't have the rb25 harness looms im guessing the ecu is acting like its still an rb20. the wastegate is directly connected to the i/c pipe but it still stays at 3-5 psi until 4500 rpm then it gets to 7 psi. How can i disable the rb20's 2 stage boost? or is it not possible with rb25 turbo?

what sort of oil pressures are you getting?

have you tried venting the catch can to atmos and see if theres a difference?

if stage 2 is too high just install a stage 1.

what sort of oil pressures are you getting?

have you tried venting the catch can to atmos and see if theres a difference?

if stage 2 is too high just install a stage 1.

Im going by the stock oil press gauge on the dash, but it goes from 1-8 increments. im seeing idle pressure of "4" and WOT 6-7 almost max. Before it used to idle low psi at like 1-2. Sorry im not familiar with the measurements that the dash reads at i wish i could give more accurate numbers. I believe 6 on the gauge is 75 psi. and 4 on the gauge is 56 psi.

and i want the 2 stage boost removed, so i get max stock psi at low rpms instead of only at 4500+

so yeah, majority of the time my idle pressure is 50-60 psi. thats way over the normal threshold. would 5w40 be too thin or thick? or is my crank case not venting enough pressure. it ran the same psi when i had the can running atmospherically

I see anywhere from 20-30psi at idle running 10w40 and with a Nismo oil pump and restrictors fitted. I cant really see how a catch can would worry it but seen as its the last thing you have done wouldn't it make sense to vent the catch while its idling and see what happens to oil pressure? How is the catch can set up anyway?

What state is the oil filter in? Trying to think of things that would cause an issue if all you have done is add a catch can. Do you have an oil cooler fitted?

If your wastegate is plumbed directly to the intercooler pipe you don't have a 2 stage boost and your solenoid is doing nothing (presumably its not connected to anything). If you want more boost get an RB20 actuator which should give you around 10 psi.

I don't see how your catch can has anything to do with your oil pressure.

5W40 is not too thick.

I re routed the pcv lines back to a stock setup and it seems a little better now. i had the can plumbed in properly considering i researched it for days to be sure. i think one of my pcv hoses may have not been strong enough and collapsed under vacuum

And even though i have the WG connected directly to the i/c pipe it still has 2 stage. i dont feel 7+psi until 4500 rpm exactly which is the stock rb setup, but R32s didnt have a boost solenoid. so im guessing either the wastegate has its own way of increasing boost, like dual spring or something like that. I feel like theres a wire that should be coming from the ECU to what should be the rb25s solenoid, but as stated before since the R32s never had a solenoid, and i have a Mines refurbished ecu for the engine swap something mustve been left out. If anyone knows the wire number for the solenoid i want to trace the wire if there even is one.

Unless some rb20 Gtsts had a boost solenoid? However i dont see the plug that would've connected to it. I'm so confused

Edited by GTSTLOVE

No way can a wastegate on its own have a 2 stage setup.

The mines ecu would be doing you no good. Put it in the bin and get a proper ecu for it before you kill the engine.

The car could be very lean, or rich, or have too much or not enough timing causing the issue you describe.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • You just need to remove the compressor housing, not the entire turbo. I would not be drilling and tapping anything with the housing still on anyways. 
    • So, I put my boat on a boat. First of all, I'm going to come out and say it. Why is Tasmania not considered a holy goal, an apex that all road-legal modified cars go to, to experience? This place is an absolute wonderland of titanic proportions. If people are already getting club runs for once in a lifetime 30 person cruises to Tassy then I've never seemed to see it. It is like someone replaced the entire place with an idyllic wonderland for cars, and all of the people living there with paid actors who are kind, humble, and friendly. Dear god. After doing a lap of almost all of the place I've found that it's a great way to find out all of the little things that the car isn't doing quite right and a great way to figure it all out. All in all, I drove for 4 hours a day for a week and nothing broke. I didn't even need to open the engine bay. This is by all means a great success, but it has left me with a list of things to potentially address. I also now have a 3D printed wheel fitment tool which annoyingly hasn't got any threads in it to actually assemble it. I might be able to tape it together to check the sizing I actually want to use, but it'll likely involving pulling the shocks out to properly measure travel at least at the front, and probably raise the car while I'm at it, at least in the rear. I scraped on quite a few things and I'm not sure how else to go about it. I was taking anything with a bump at what felt like 89 degree angles. And address those 10 other tasks. And wash the car. God damn it is dirty. And somehow, the weather was perfect the entire time - And because I was on the top of Mt Wellington it turns out it was very much about to freeze up there. I did something I typically never do and took some photos up there in what must have been -10 and the foggy felt like suspended ice, rather than mere fog. If you own a car in Australia, you owe it to yourself to do it.
    • Damn that was hilarious, and a bit embarrassing for skylines in general 😂 vintage car life ey. That R33 really stomped. Pretty entertaining stuff
    • Hi, I have a r32 gtr transmission. Does any of you guys have an idea how much power it will hold with the billet center plate and stock gearset? At what power level and use did yours brake with or without billet plate? Thanks, Oystein Lovik
    • Saw this replica police car based on a Mitsubishi Starion XX parked next to a 'police box' (it's literally a box) in Hirohata, Himeji City in Hyogo prefecture the other day. It's owned by Morii-san who is a local Mitsubishi Starion enthusiast. According to a local radio station blog post, he always wanted to make a police car himself based on ones he saw in his favourite Manga comics.  As it's illegal to modify a car to look like a police car and drive on the road, Morii-san tried many times to get permission from Aboshi police station headquarters nearby. They refused initially by after they got tired of that they granted him permission. However, the car can only be displayed on private property and obviously can't be registered as long as the police livery is present. The car was completed at a cost of 1.5 million yen (US$ 10,000) in addition to the car cost. A location was chosen outside Hirohata Police box where the car can easily been seen from the street. Morii-san has two other Starion road cars, both widebody GSR-VRs.
×
×
  • Create New...