• Welcome to SAU Community

    Welcome to SAU Community, like most online communities you must register to view or post in our community, but don't worry this is a simple free process that requires minimal information for you to signup. Be apart of SAU Community by signing in or creating an account.

    • Start new topics and reply to others
    • Subscribe to topics and forums to get email updates
    • Get your own profile page, build reputation and make new friends
    • Send personal messages to other members.
    • See fewer ads!

    Consider joining our newsletter for the latest content updates

    Click here to register


kingtube69

Boost pressure loss over time

Recommended Posts

Hi All, 

Haven't really been active for a long time on here. Asked some questions on the R33 Owners page on Facebook and got some unhelpful responses so I thought I would try this community again (always been good).

I haven't driven my 33 much at all lately since I bought my fourby but I like to take it out for a bit of a spirited drive on weekends when I get a chance. The last couple of times I've gone out I noticed that for the first 10 minutes or so my 33 makes full boost no worries but progressively over time it struggles to make 1 bar of boost (typically 1.3). 

I understand that heat soak is an issue but it has never been this bad since I've owned it. 

Car is a R33 with RB25, ATR45SAT Hyper Gear Turbo, Apexi AVCR boost controller, 3" exhaust with Venom cat, Pod filter in an enclosure, Blitz SE return Flow, Haltech ecu, Nismo 740CC injectors. 

Things I've checked 
- Exhaust manifold studs - 6th cylinder was loose, done them up
- Turbo to manifold studs - one or two were loose, done them up 
- Changed all main vacuum lines 
- Boost leak tested, no noticeable leaks, sprayed joins etc 
- Checked over silicone joiners - no noticeable leaks or splits 

I do notice however that the upper section of the intake manifold has what looks like oil on the surface. I checked this when i used the boost leak tester and didn't hear or see anything. When I got back from the last test drive after I thought I fixed the issue, I boost leak tested it just to be sure and didn't hear anything obvious

I always thought that it might be the intake manifold expanding as the engine bay heats up or the exhaust manifold leaking as it heats up.
I thought I would ask here if anyone has any suggestions or personal experience on what I should be looking for with regards to this issue. Any help would be greatly appreciated. 

Apologies if this is in the wrong section, please let me know and I can have it moved. 

Thanks in advance for helping!

  • Like 1

Share this post


Link to post
Share on other sites

How big is your intercooler? Is hot weather a factor? How do you test for boost leak? Do you make a rig and subject it to say 20 psi and see if it can hold it?

Share this post


Link to post
Share on other sites
1 minute ago, KiwiRS4T said:

How big is your intercooler? Is hot weather a factor? How do you test for boost leak? Do you make a rig and subject it to say 20 psi and see if it can hold it?

hey mate, i think the specs for the cooler are 620 x 266 x 76mm, I noticed it before Sydney got stupid hot recently but can wait till it cools down again later this week and check again. With the tester I have a nitto connector in a step down plug from bunnings but it doesn't have a gauge on it so I can't see if thats holding pressure. To test I just pressurized it from 5 psi, checked for leaks, 15 psi, checked for leaks, 20 psi checked for leaks by spraying joiners and the manifold 

Hope this helps.. might be worth changing my boost leak tester design tho 
 

Share this post


Link to post
Share on other sites

How hot was it when you drove the car? I find you always need more duty cycle on the EBC during much hotter weather or simply set it up on closed loop which your Haltech could easily manage instead of using the AVCR.

Share this post


Link to post
Share on other sites
12 hours ago, Dose Pipe Sutututu said:

Random thought, do you want a spare ATR45SAT with ball bearing centre? 😂

 

13 hours ago, iruvyouskyrine said:

What wastegate actuator? Diaphragm may be leaking when hot

Its a Turbosmart replacement, its a possibility for sure but another reason for me to go high mount with external wastegate 

 

12 hours ago, Dose Pipe Sutututu said:

How hot was it when you drove the car? I find you always need more duty cycle on the EBC during much hotter weather or simply set it up on closed loop which your Haltech could easily manage instead of using the AVCR.

I can't rememeber because its happened a few days when I drove it. I would definitely like to test again on a long drive when the 40+ heat pisses off in Sydney. When I asked the tuner i used (going to try someone different next time - cough cough Johnny) they said that they don't use haltech to control boost because it requires adjusting in the ecu which is harder than doing it with a controller. 

Now I think of it I could always just up the duty cycle and see how it goes. 

12 hours ago, Dose Pipe Sutututu said:

Random thought, do you want a spare ATR45SAT with ball bearing centre? 😂

I thought it sold already?  I was considering it when I saw you post it lol. 

  • Like 1

Share this post


Link to post
Share on other sites

Still haven't gotten around to checking this out further. Might just find someone to smoke test it while I'm at it in case I've missed something obvious. Might also get an inspection camera under the exhaust manifold and check if its cracked anywhere obvious

Share this post


Link to post
Share on other sites
On 2/1/2019 at 7:57 AM, Dose Pipe Sutututu said:

Still have it, only sold the manifold and gate 

As much as I would seriously love this, I plan on selling the car soon enough. Haven't driven it for a while, the poor thing just gathers dust. The purpose of finding and fixing this issue is to make it more desirable to a buyer lol

Share this post


Link to post
Share on other sites

Went to see @jmknights93 over the weekend and worked out what part of my problem may be despite hearing no audible leaks. 

mvyebUc.jpg
gIuTEpm.jpg

It looks like the intake manifold gasket is blown out and probably torn and pushing itself out further. I have new gaskets already knowing this day would come so I'll probably change it in the coming days or weeks. 

Thanks for everyone's input, I'll make an update when I get around to it. 

  • Like 1

Share this post


Link to post
Share on other sites

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