Jump to content
SAU Community

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
Link to comment
https://www.sau.com.au/forums/topic/475966-boost-pressure-loss-over-time/
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 
 

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.

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
  • 2 weeks later...

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

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

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
  • 1 month later...

Finally  got around to changing the gasket and washers. I found out that not only was the gasket super swollen but one washer was completely missing and pressure wouldn't have been applied in that section of the plenum. Since changing the gasket the cars been running great, idles awesome and no more significant boost pressure loss

 

Thanks for everyone's input and help :) 

  • Like 1

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

    • For once a good news  It needed to be adjusted by that one nut and it is ok  At least something was easy But thank you very much for help. But a small issue is now(gearbox) that when the car is stationary you can hear "clinking" from gearbox so some of the bearing is 100% not that happy... It goes away once you push clutch so it is 100% gearbox. Just if you know...what that bearing could be? It sounding like "spun bearing" but it is louder.
    • Yeah, that's fine**. But the numbers you came up with are just wrong. Try it for yourself. Put in any voltage from the possible range and see what result you get. You get nonsense. ** When I say "fine", I mean, it's still shit. The very simple linear formula (slope & intercept) is shit for a sensor with a non-linear response. This is the curve, from your data above. Look at the CURVE! It's only really linear between about 30 and 90 °C. And if you used only that range to define a curve, it would be great. But you would go more and more wrong as you went to higher temps. And that is why the slope & intercept found when you use 50 and 150 as the end points is so bad halfway between those points. The real curve is a long way below the linear curve which just zips straight between the end points, like this one. You could probably use the same slope and a lower intercept, to move that straight line down, and spread the error out. But you would 5-10°C off in a lot of places. You'd need to say what temperature range you really wanted to be most right - say, 100 to 130, and plop the line closest to teh real curve in that region, which would make it quite wrong down at the lower temperatures. Let me just say that HPTuners are not being realistic in only allowing for a simple linear curve. 
    • I feel I should re-iterate. The above picture is the only option available in the software and the blurb from HP Tuners I quoted earlier is the only way to add data to it and that's the description they offer as to how to figure it out. The only fields available is the blank box after (Input/ ) and the box right before = Output. Those are the only numbers that can be entered.
    • No, your formula is arse backwards. Mine is totally different to yours, and is the one I said was bang on at 50 and 150. I'll put your data into Excel (actually it already is, chart it and fit a linear fit to it, aiming to make it evenly wrong across the whole span. But not now. Other things to do first.
    • God damnit. The only option I actually have in the software is the one that is screenshotted. I am glad that I at least got it right... for those two points. Would it actually change anything if I chose/used 80C and 120C as the two points instead? My brain wants to imagine the formula put into HPtuners would be the same equation, otherwise none of this makes sense to me, unless: 1) The formula you put into VCM Scanner/HPTuners is always linear 2) The two points/input pairs are only arbitrary to choose (as the documentation implies) IF the actual scaling of the sensor is linear. then 3) If the scaling is not linear, the two points you choose matter a great deal, because the formula will draw a line between those two points only.
×
×
  • Create New...