Rb25. weird issues.

[smoked240]

Alright I just got my rb25 swap done and drove it this past week. For the most part it ran great.

The first issue I am having is I cannot boost over .5bar. The only time I hit past .5 bar was when, my hose running from the intake to the BC slipped off and I hit 1bar. How the vacuum lines are ran for the bov and bc are. Straight from the Intake to the bov. then from the second port on my bov to the intake tube. Then I teed off my vacuum going to my FPR to my BC then from the BC to the wastegate. After I ran it this was I noticed the boost was stronger and stayed at .5bar when I stepped it down and didn't back off some. But I still can't go over .5. anyone know?

Then another thing. If I give it about half throttle maybe a little more and i'm not at .5bar it's about .2bar lets say maybe .3 my engine seems to cut out and loses power, but then I step it down and it hits .5bar and just goes with no hesitation. Could this be from lack of fuel? I am currently running the stock FPR and stock pump. I am ordering a Walbro and Adjustable FPR, but for now it's just stock since it's winter and I don't drive the car.(with the exception of trying out the motor)

Now the next is if I rev it up and just let it drop it will shut down. I was told this could be from running my BOV atmospheric dump rather then recirculation. I have heard it's kind of a hit an miss with running it atmospheric. If I have to recirculate it I don't really care just as long as it doesn't shut down.

If I start it when it's really cold and go to release the clutch,with it in neutral it will start to go forward and will shut off. I have to rev it up while releasing the clutch so it will idle. But this only happens when it is cold out and the car has been sitting, once it's warmed up it doesn't do it.

The only thing I can think of is, the thick gear oil is spinning along with the shaft in the tranny and is causing the car to act like it is in gear. but given enough rpms it spins the fluid faster, cause it to warm up and not engage it. Does this make any sense?

I also have a belt that will squeak at random times and it is driving me fucking insane! I think it's the Alt. belt being too loose,or tight. Just not sure.

Thanks for the help!

[Touge Whore]

I would definately look into getting the fuel pump and pressure regulator. This way you can control the fuel supply and can be sure it is getting adequate flow.

As far as the BOV goes, yes, I would have it recirculate. Just remember to have it go back in after the MAF. I am going to be doing this as well to my RB swap. Good luck with it!

[smoked240]

I would definately look into getting the fuel pump and pressure regulator. This way you can control the fuel supply and can be sure it is getting adequate flow.

As far as the BOV goes, yes, I would have it recirculate. Just remember to have it go back in after the MAF. I am going to be doing this as well to my RB swap. Good luck with it!

Oh yeah I for sure will be getting them, I don't need them yet since I can't really drive the car,but i will probably pick them up soon. I am looking for a FPR but I want a good one, but can't really afford an AEM. I looked at the megans but I have heard bad things about them. My next option is the ISIS one.

I plan to recirculate one day haha, I just got to get to it.

Thanks man!

[P-Funk alot]

well 1bar is 14.5 lbs and im sure if this is stock thats not what your runnin so with that said .5 should be around 7lbs which is stock. i never had an issue with the bov issue just make sure your bov is adjusted to a stiffer position

[Sileighty_85]

well 1bar is 14.5 lbs a

14.7 psi



What BC are you using?

[Goodlucks7even]

You got tuned ? What ecu ? Stock turbo ? If u got an aftermarket wastegate it might be the spring, if it's to stiff you wont have all the boost.

FPR + fuel pump is a good idea, make sure to have more than 11V(between12 and 14 is good) to the fuel pump. When you go from idle to WOT, does it hesitate ?

[smoked240]

You got tuned ? What ecu ? Stock turbo ? If u got an aftermarket wastegate it might be the spring, if it's to stiff you wont have all the boost.

FPR + fuel pump is a good idea, make sure to have more than 11V(between12 and 14 is good) to the fuel pump. When you go from idle to WOT, does it hesitate ?

Stock turbo, Stock ecu. Series 2 engine. from idle to WOT there is no hesitation at all. I have Greddy style intake,FMIC.
14.7 psi



What BC are you using?

IsIs.
well 1bar is 14.5 lbs and im sure if this is stock thats not what your runnin so with that said .5 should be around 7lbs which is stock. i never had an issue with the bov issue just make sure your bov is adjusted to a stiffer position

I'm not running 1bar, that is just what I hit when the vacuum line slipped off. I am at .5bar which should be stock. I wanted to run about 8-9psi.

That makes sense. I had to loosen the spring tension some so I will tighten it up and go from there!


I also noticed when I hit 1bar it cut out. I'm not sure if that was lack of fuel or safety switch in the ecu. I would never push 1bar with the stock turbo, just something I noticed.

Thanks for the help!

[P-Funk alot]

yea it probably detonated and the knock sensor shut it off for a couple of seconds. and yea 14.7 is one bar. ive seen bone stock rb25 hang with one bar of boost. i wouldnt recommend it but it has been done.