Jump to content
SAU Community

Recommended Posts

Need some ideas.

 

R34 GTR.

 

Car had 354rwkw with -9s at 24psi on e85. N1 manifolds, full 3.5 exhaust with no cat.

 

Added 4bar sensor and kelford L182-A 264 cams and BC springs.

 

Car is making less power than before and is laggier to make boost everywhere.

 

345rwkw or so on 19psi and will not make anymore boost, solenoid is max duty. I knew max boost would come down but not that much.

 

Spikes to 25psi midrange but once the engine starts to breath it just falls away.

 

Have tried lots of adjustment of cam timing, bench test wastegate actuators, and checked all the connections.

 

I'm gonna go over and boost leak test it with him again and I considered bypassing BOVs for testing. I'm also going to remove intakes and inspect Comp wheels and free play.

 

Given I'm sure I could hear a new turbo bearing/whistle type sound when it comes on boost, is this symptomatic of failing turbo bearing?

 

The car had 2 boost leaks previously and I did a track day not knowing it had those leaks, worried I've cooked a turbo bearing?

 

Other ideas welcome.

 

Yes I know I should have put a single on it.

 

 

Link to comment
https://www.sau.com.au/forums/topic/470243-lack-of-powerlack-of-boost-rb26/
Share on other sites

Yes it idles perfectly as I also suspected that maybe the timing had been thrown out. He said it is revving cleanly it is just a boost issue.

 

And if you remember from my build thread I was chasing a boost leak and that whistling sound before the cams went in.

 

Would stuffed blow off valves have this kind of effect? Or does the vented pressure just end up back in the intake anyway and have no bearing on Max boost?

 

 

If it's an oil seal yeah I guess?

I'm talking more about bearing wear/pending failure.

I can hear a whistle/whirring that wasn't there previously.

Sounds like the whistle a turbo diesel 4wd makes as they spool.

They only had 7k on them when purchased and play was fine then, they have only done another 1000ks since.

 

I will check them again tomorrow.

 

My thought was that running a track day with a boost leak may have had them working too hard and caused an issue.

 

What would I see from faulty BOVs?

 

 

Test for boost leaks by blocking off the pipe (do you have 2 into 1?) and installing a tyre valve. Apply pressure - first up to 30 psi and then 40 psi and you will see if there is a leak. What kind of wastegate and what spring are you using?

Do you mean testing the BOVs?

All piping to an from BOVs is factory.

These are standard garret actuators that come on -9s so I think they are 1bar.

They were both bench tested fine.

If the BOVs were leaking I would've thought it wouldn't make 25psi in the midrange?


Dose Pipe suggested actuators. 

I think they are the standard 15.6psi ones that ship with those turbos. Tuner bench tested them, they both crack at 17psi, is that too early for a target boost of 24ish? 

They "were" working fine.

This was them at purchase, those are the actuators. 

I will test BOVs, actuators preload, and shaft play tomorrow. 

Anything else? 
 

received_10153163034151771.jpeg

My suggestion for pressure testing was for the whole induction system - not just the bovs - also the piping, intercooler - all the connectors.

I take it your boost control is by an aftermarket ECU and Mac valve. When you say the solenoid is at max duty - that should mean fully closed so no boost should be getting to the actuators...are you sure you have that right? I forgot you were using IWG. Maybe you need some heavier duty actuators such as the HKS ones.

I had pressure tested the entire intake previously when chasing boost leaks, up to 40psi. Will do it again to be sure.

 

One thing a static test doesn't show is BOV leakage as anything going past is still in the same pipework, I'm just not sure what the symptoms are with faulty BOVs when the leak is past the seat and recirculating back into the intake.

 

Haltech with 4bar sensor and Mac solenoid.

 

If need be I'll wire the actuator flap shut to test it.

 

 

 

 

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

    • Knowing how slow their other compressors are that connect to the cars battery, you'd want to hope it's one hell of a slow leak!
    • So why can’t the front pipe just be listed as custom make? why does everything have to have a brand name to it? or if you have bought the car like this and have no idea about anything at all or no knowledge what so ever of parts how are you supposed to inform them of what it is you have exactly?
    • Yep, I'd be interested to hear how it works out in the end.
    • Because all parts that are put into your papers usually are assigned a badging if they did not come with one. So other people can just check that badging to tell if it is the parts your papes outline. But my pipe has NOTHING on it whatsoever. No idea why this even passed as a Mines pipe to begin with. I see this going two ways: -nobody cares and it's a non-issue, but that is unlikely -the pipe will just have to be assigned a bagding, for sake of argument, a Mines logo, and the papers corrected accordingly If it interests you I will post what the actual solution ended up being. All I care about is that it has to sound equal length and nobody can screw me later on because of a pipe being illegal.
    • The fasteners to the pipe are not subject to TÜV I guess, if we really start putting nuts and bolts through technical tests I'm going to hang the people responsible and then myself. Usually on a modern-ish EU normed car, you would just replace the pipe. Because if you start hacking away at it and welding new pieces on the cops will definitely find a reason to tow your car. That is just how it is sadly. On old cars and imports with no clear "standard" stuff like that won't matter too much. Most cops or inspectors probably won't even really know what they are looking at. But there is experts for this stuff even among cops, and some of them know the rules to a T and even have extensive knowledge about many vehicles. For "just a pipe" to be legal it usually is included in a set of parts, like a complete intake kit or a full exhaust. For example my exhaust needs to pass a noise test, meaning they have a standardized test track with a set of instructions and they run the car through there 3x for an average noise value that is 75dB(a) at point x of the test track. If it's above that, fail. For a turbo setup to be put in your papers you have to do dyno runs, emissions testing etc. So quite costly
×
×
  • Create New...