Rb26 Boost Problem

[endless]

Thanks for the pic. Well certainly near the same amount of adjustment left on yours as i have. The springs in my actuators must just be weak. Will look at replacing them, although i may look into shortening the arms for a little more adjustment.

[MrStabby]

Justin's suggestion is good. Wire them shut and see if they build boost properly. If they do then yeah the actuators are the problem.

CRD found a bunch of crap in my intercooler when they installed my turbos..... WhereTF did that come from??!!

[endless]

I've always heard that term but never needed to put it into practice until now. How do i wire them shut tighter than the tension the actuator is already holding the flap closed?

[endless]

Well update time... STILL no good!

I have installed brand new 1 bar actuators and i am still having the same problem. Really thought it was solved as the actuator arms i pulled off the turbos were much much easier to pull on than the new ones.

In 4th at ~4k it will only make 0.6 - 0.7 bar... if i rev it more it continues to rise very slowly before i back off.

So...

- I have disconnected the actuator lines and had a run = exactly the same. So it is certainly NOT the ebc.

- Oil pissed out of both lines when the feeds were taken off to change the actuators so turbos are getting oil.

- There are NO leaks in the cooler piping & definitely no blockage/rags in there.

Basically there is nothing left but the tune..? I was under the impression i should be able to make the boost spike using the previous method regardless as its mechanical?

Could incorrectly set up nismo AFM's cause this somehow? Injectors were also upgraded pre-tune.

Starting to really regret not just slapping a single on!

[snozzle]

my gtr is running on a base map atm with barely any timing in it and its still building over a bar of boost before 4300rpm lol

i doubt its your tune, good luck finding your issue

[Beer Baron]

yeah I doubt it's the tune too. if you have tried the unlimited boost trick it should boost hard and fast. it's possible a REALLY bad tune could do this but it would have to be so very, very bad.

[snozzle]

how does it drive when u remove the vac hose from the actuators ?

[endless]

Drives just as well as with it connected.

I am starting to wonder if my base timing is out. I did ask the tuner to set it originally, obviously he should of before the tune... but i am running out of things to try here as you can see.

I swapped my engine covers when i swapped the turbos and was unable to set the timing right as it would hunt at idle post injector install. In fact i tried last night and it is still hunting?

Setting the pre-load up on the gates made a HUGE difference to low end, but it was tuned without this.. and possibly with timing out also. Hence suspecting tune.

[snozzle]

that is definitely wrong then, your wastegate flaps must not have enough preload on them or arent shutting properly

[endless]

Please re-read what i have done already. I went to the trouble of swapping on BRAND NEW garret 1 bar actuators. I have the same problem!!!!!!

[snozzle]

Yes, i read the whole thread.

I will repeat myself, have you made sure the wastegate flaps on both turbos are fully closed/shut? pretty sure you need the dump pipes off to check this rather than checking how much the flap moves from the exterior arm that the actuator rod attaches to.

I have seen a brand new garret rear housing with a wastegate flap that didnt fully seal against the seat from factory because the hole for the arm that the rod attaches to was drilled off center. It was sent back to garrett.

Im quite puzzled as to what your problem is but thats most legitimate suggestion i can come up with dude.

It would suck to go to the trouble of taking the turbos back off and checking the flaps and seeing how they actually sit to only find that theres nothing wrong with it but i guess, you gotta do it to know for sure.

[endless]

I do remember having a look before installing and they were sealed flush. I'd imagine it would be quite obvious to the eye if one wasn't sealed correctly?

I'll try to check the timing tonight as i think i can get a steady idle from cold start & go from there. I appreciate the help guys.

Edited February 4, 2011 by endless

[DVS JEZ]

if you back the timing off in the tune down low this can help build boost quicker but by the sounds of it its more a mechanical thing.

pull the front timing cover off and check the cam timing then borrow a timing light and set the CAS timing up,

[JonnoHR31]

yep, less timing (within reason) builds boost at lower rpm than more timing. more timing will give you boost quicker time wise and make the car quicker overall but it'll be at slightly higher rpms.

[endless]

Well checked the timing ..& it's out 5 degrees.

[DVS JEZ]

good you found an issue, but have you tested it now? hows the boost issue

[endless]

I think setting the timing to 15 degrees then going for a blat would be a bad idea seeing as it has been tuned out 5 degrees, also with the turbo response like shit (which has now been solved) think i'll just take it in for tune to be safe.

[wolverine]

Where was the timing set?

GTR base timing is 20deg.

[STATUS]

Well update time... STILL no good!

I have installed brand new 1 bar actuators and i am still having the same problem. Really thought it was solved as the actuator arms i pulled off the turbos were much much easier to pull on than the new ones.

In 4th at ~4k it will only make 0.6 - 0.7 bar... if i rev it more it continues to rise very slowly before i back off.

So...

- I have disconnected the actuator lines and had a run = exactly the same. So it is certainly NOT the ebc.

- Oil pissed out of both lines when the feeds were taken off to change the actuators so turbos are getting oil.

- There are NO leaks in the cooler piping & definitely no blockage/rags in there.

Basically there is nothing left but the tune..? I was under the impression i should be able to make the boost spike using the previous method regardless as its mechanical?

Could incorrectly set up nismo AFM's cause this somehow? Injectors were also upgraded pre-tune.

Starting to really regret not just slapping a single on!

did you pre-load the new ones correctly? i like to use about 10mm preload.

another thing to check is the cooler pipe under passenger front wheel well (common leak spot)

And finally the bov pressure line often gets swapped with another close one and the BOV leaks under boost. (seen this about 5-6 times)

[STATUS]

Well checked the timing ..& it's out 5 degrees.

are you sure? check your hand controller "live" timing screen then adjust CAS so it reads the same on the balancer. i often change the base timing as do other tuners.

NEVER ASSUME IT IS SUPPOSED TO BE 20 DEGREES

If you have nistune etc then use consult to hold a particular timing whilst setting.