Major Lag!

[s13kris]

Thanks scott will try tonight.im running an emanage blue which is a piggyback ecu so the standard computer should still be controlling the vct..

[Trozzle]

flapper is closed up. next on the list is testing the VCT. spoke to Tao today(hypergear) and he strongly believes thats the problem so its deffinetley worth a try since theres nothing else left to check

I can't work out how VCT will cause a boost graph to look like that. RB26 does not run VCT. RB20 does not run VCT. Nistune on an RB20 board will not have VCT unless you're running a controller. Having seen comparisons of people running VCT on and off back to back, even their power curve isn't that lazy - their boost curve barely looks different to what it should be.

Please tell me you still removed the actuator rod and opened/closed wastegate by hand? I'm not even kidding, DO IT. The words I got from my tuner were almost exactly "It's very laggy when it's warm, but when it's cold it boosts like a f**king monster". This was because when cold, the wastegate parts weren't binding up and jamming. Once it was boosted for the first time (read: COLD), the actuator would open the wastegate. As the actuator pulled the wastegate closed again, it would jam just before closing. Because of this, the next time it boosted (which is when they considered it WARM) it would take FOREVER to come on boost. If they turned the engine off and let the exhaust/turbo cool down, as the metal shrunk that tiny bit again it would free up and close (since the actuator was still pulling against it), hence the next time they ran it the turbo would boost correctly again.

What pressure actuator are you using? I later experienced issues with my 14psi actuator causing a similar problem though not as bad....I put this down to repeated heating and cooling of the actuator itself while being held in a partially open position...

In regards to your issue Kris, I would be trying to tie the gate shut and run it without the vac line connected. Remove and block the line that goes to the actuator, then use some steel wire or similar to tie the gate shut also. Be careful not to boost to infinity and beyond because im confident your motor wont like it.

Do the simple test on your VCT also, its a good avenue to check. With the comment noting that you didnt have the problem prior to installing the turbo, I am assuming you also didnt have whatever is tuning it prior to your turbo install either. You have not noted what ecu you are running? At the moment it is fair to assume you may not even have VCT connected, please elaborate on this particular item first.

Yes, what he said. Also, please confirm your ECU. If you're still running AFM, doing the test of removing the boost source and/or holding the gate shut could be bad if not done on a dyno. It was safe for me to do as I'm running a MAP sensor and the engine would cut out if boost reached a certain level - which it certainly did very quickly.

With no vacuum source for the actuator, you will still boost very hard if it's working correctly - regardless of it's pressure rating. It will take a LOT of exhaust pressure against the wastegate to overcome the actuator on it's own. If this fixes the issue (read: if it boost correctly) it doesn't necessarily confirm the cause of the problem, only that the turbo CAN boost correctly. It could still be the wastegate being a prick, or the actuator could be very soft/faulty and opening very easily

Bottom line, having had the EXACT SAME PROBLEM AS THIS, I can say first hand that it will be the wastegate not closing or a boost leak. If you're sure you don't have any leaks before your manifold, then it's the wastegate. End of story.

[Trozzle]

Thanks scott will try tonight.im running an emanage blue which is a piggyback ecu so the standard computer should still be controlling the vct..

Start engine, open bonnet, place your head right down near the oil filler cap, Using your hand, open the throttle very gently and increase the revs. As they pass 1500rpm, you should hear an audible *click* from the VCT solenoid. You should be able to hold the revs at the right point where you're just activating the solenoid, so you can make it click repeatedly.

Hear that click? VCT is working. don't hear it? Doesn't necessarily mean it ISN'T working - mine might just be noisy or it's just the fact I have a VERY good ear for out of place noises from my engine.

[Trozzle]

Here's the dyno plot overlaying my first tune with damaged wastegate (again, fark you Aust Post - NOT Stao) with the tune once wastegate issue was sorted.

GREEN LINES are older, RED LINES are newer. This is boost vs power.

[Crans]

I have lag issues on my 43G3, Took turbo off and noticed the wastegate was also stuck gave it a wiggle sent it back to Stao he updated the wheels installed turbo and no difference. So thinking my wastegate is also stuck.

How exactly did you fix it? Did you need to take the turbo off?

[Trozzle]

I have lag issues on my 43G3, Took turbo off and noticed the wastegate was also stuck gave it a wiggle sent it back to Stao he updated the wheels installed turbo and no difference. So thinking my wastegate is also stuck.

How exactly did you fix it? Did you need to take the turbo off?

How did I fix my problem? Well yeah the assembly where the wastegate goes through the housing (going from outside turbo to inside) had become loose from the damage, so Stao just rebuilt that part. Simple fix, but yes turbo needed to be removed. Once removed, I took off the actual wastegate adapter plate and sent that back for repair.

Just making sure everyone realises, what was wrong with my turbo was NOT STAO'S FAULT. It wasn't faulty, it was damaged. Stao was not liable for the damage, as it was done during postage and no doubt after my package had been opened, inspected and repacked.

[SimonR32]

I would also say it's not a issue with the VCT...

It's either a issue with the internal gate or a boost leak!

[hypergear]

Its a factory Nissan wastegate assembly, I didn't had to do any work on that part. It was opening and shutting fine when I had it. on the photo the gate appeared to be shut and sealed. You can test it by force it shut using actuator when its cold. Then disconnect the actautor, go for a drive (back off once reaching 15psi) and see if any differences are made. If not then the leak is not on the turbo side.

Update 16/4/11:

We've found a split vacumme hose to the boost controller lol. Boost appears to be back to normal. Car's booked in for retune.

[Trozzle]

Which is exactly why I'm baffled further Stao...the factory housing should be fine since you don't touch it, unless it's been damaged in the mail again lol. Though Kris would know if it were opened by customs or not...really strange, though definitely either wastegate or leak related. Possible that the actuator has completely shit itself, though very unlikely.

[Harey]

Possible that the actuator has completely shit itself, though very unlikely.

Yes and this can be quickly verified by disconnecting the hose to the actuator (holding wastegate permenantly closed ie max boost) and seeing when it builds boost. Obviously back off before it gets too high.

The next step would be an intake leak tester. I just used pvc caps to block off the pipe to the throttle body and used a $20 hand pump to pump air into the system. That way the engine is off so its very easy to hear a leak.

[Trozzle]

Yes and this can be quickly verified by disconnecting the hose to the actuator (holding wastegate permenantly closed ie max boost) and seeing when it builds boost. Obviously back off before it gets too high.

The next step would be an intake leak tester. I just used pvc caps to block off the pipe to the throttle body and used a $20 hand pump to pump air into the system. That way the engine is off so its very easy to hear a leak.

The black smoke pissing out the exhaust should indicate the leak, but yeah need to test it like you did.

I agree though, still needs to do the "unlimited" boost test

[paulr33]

if VCT was not working the car would be sluggish all the way to the default kick off point of 4500rpm

if the wastegate actuator is not functioning correctly boost would be laggy or sluggish boost build as PMr33 said

[s13kris]

**VCT is working tested it earlier.

*Troy i did remove the rod and open and closed it and it seemed fine but im no expert and its the first time ive done anything like this.

*im using the highpressure actuator supplied with the turbo (i think its a 17psi spring??)

*running an emanage blue piggy back so it doesnt delete the vct that will still run off the standard computer.

*my box was unopened when i recieved and was packaged really well with bubble wrap around the turbo but in saying that we send heaps through aus post at work all very well packaged and customers seem to end up with damaged goods. ive seen first hand how they handle goods and heard stories from the drivers so nothing would surprise me with them.

*With the vac hose removed off the wastgate and blocked and the flap arm tied with a metal coathanger so it doesnt move the car still behaves the same..i cant really over boost as the cars tuned to 17psi which is at my limiter.

WHAT I DID NOTICE:just going for a normal drive(nothing removed and not running any tests) i let the car warm up in the garage first then went for a drive and first couple of times i hit boost it was DEFFINETLY more responsive i didnt see exactly where in the RPM range it hit full boost but was deffinetly in the 4k range.

Troy is this the same thing that was happening to you? from what i read it seems so...

There is deffinetly no leaks in the system 110% on this

Thanks for all your responses guys and keep them comming theres some really useful info here for me and others.

hopefully ill have this problem sorted out soon and be driving the car to its full potential.

[Trozzle]

**VCT is working tested it earlier.

*Troy i did remove the rod and open and closed it and it seemed fine but im no expert and its the first time ive done anything like this.

*im using the highpressure actuator supplied with the turbo (i think its a 17psi spring??)

*running an emanage blue piggy back so it doesnt delete the vct that will still run off the standard computer.

*my box was unopened when i recieved and was packaged really well with bubble wrap around the turbo but in saying that we send heaps through aus post at work all very well packaged and customers seem to end up with damaged goods. ive seen first hand how they handle goods and heard stories from the drivers so nothing would surprise me with them.

*With the vac hose removed off the wastgate and blocked and the flap arm tied with a metal coathanger so it doesnt move the car still behaves the same..i cant really over boost as the cars tuned to 17psi which is at my limiter.

WHAT I DID NOTICE:just going for a normal drive(nothing removed and not running any tests) i let the car warm up in the garage first then went for a drive and first couple of times i hit boost it was DEFFINETLY more responsive i didnt see exactly where in the RPM range it hit full boost but was deffinetly in the 4k range.

Troy is this the same thing that was happening to you? from what i read it seems so...

There is deffinetly no leaks in the system 110% on this

Thanks for all your responses guys and keep them comming theres some really useful info here for me and others.

hopefully ill have this problem sorted out soon and be driving the car to its full potential.

If it behaved the same with the wastegate held shut and vacuum lines off the actuator, then I have NO idea hahaha...

Mine boosted first time fine, then each time after that until the turbo was allowed to "cool down" it wouldn't boost correctly (like yours) because wastegate didn't close all the way after the first boost.

Yours just sounds....weird. If you're sure the wastegate was held shut and would definitely not allow any exhaust through, yet it STILL behaved the same....I don't know. That would have to be a leak, but if you're also sure there's no leak....f**k this. lol.