Twin Turbo Kit- Internal wastegate rattle sound

NOBLE|370Z

I have a 2009 370z, with a GTM stg2 TT kit recently installed on it. I have a boost controller with set points at 7psi (wastegate spring baseline) and 10psi. An issue that I am noticing when I take it to 10psi on the highway is that I hear a loud rattle noise above the 7psi. It sounds almost like a detonation sound (rattling metal popcorn).

There may be a reason for that since one of the actuators on one of the turbo's internal waste gate is having some issues. Apparently there's not enough clearance for it to open and close properly, so Sam and my mechanic are looking into whether or not I have a 350z bracket on it. As a result I have to set the boost controller ~2psi higher than the set point Id like to see. Therefore I dial in 12 psi if I want 10psi to show on my boost controller read out.

I'm beginning to wonder if the rattle could just be the internal wastegate rattling. However, its a really loud noise that I can hear when I'm going high speeds, so I'm not totally sure a waste gate rattle is the cause since its so small.

Could this in fact be some kind of detonation? My mechanic and I will be hearing back from Sam at some point this week to tell if we have the wrong bracket on the turbo. I'm just not sure I should be driving my car at all in case there's a more serious problem here. I don't hear the sound at the 7psi setting, so hopefully I can drive it at lower boost in the mean time.

Has anyone else had any issues with this?

COSMO

I would wait until you speak with sam before driving it. He's prob going to have you run a data log and email that to him.... Please keep us informed...

SAM@GTM

I have called the shop and spoke to the technician and what is happening does not make a lot of sense. I think you have two separate issues here and they are not linked to each other. The tech stated that when he tested the actuator with a vacuum pump on the bench, it took 20psi for the actuator to move. If that is the case, then you should not be having any boost target issue or your engine should have been destroyed by now. Keep in mind that the HKS boost controller works off of boost target and is very critical for the learning process (base boost pressure) to be done precisely so the boost controller can achieve what you are asking it to do.

So here's what I suggested to him. Remove the boost controller out of the equation and just run the wastegate actuators to a pressure port to establish what kind of boost we have. That should really give us a good idea how well the preload is set on the actuator (whether it is too tight or too loose). As for the noises you are hearing, I would not drive the car until you find out the exact source of the noise. I can't see the car making a rattling noise at 10psi unless you have a fuel delivery issue and the car is running lean.

As for having the wrong bracket, we do have the right bracket as verified with the tech.

Sam

Mitco39

What fuel are you running from where? Everyone I talk to says stay away from Husky and anything lower than 94 octane, especially if you are running boost.

__________________
2007 Chevy Duramax - EFILive Tuned By Me
2010 40th W/ Nav - Boosted Performance - UpRev Tuned By Me
The Mrs. Ride -2012 335XI N55 BMW - Cobb Tuned By Me, Built by her
My Build --> http://www.the370z.com/members-370z-...39s-build.html

Motion Lab

The IWG turbos are known to have a "flutter" but it should not be making a noticable pinging noise. Its hard to explain but some noise from the flapper can be expected depending on the set-up itself. A lot of our subaru customers freak out this first time they hear it after upgrading to an aftermarket downpipe. Having said that, there are a lot of other factors that can determine how the kit performs boost wise. I always like to try and pull a vacuum reference off the manifold itself to provide most accurate reading for boost controllers/boost gauges.

Good luck tracking down your issue, the guys at GTM are always helpful but its really damn hard to diagnose something when its not there infront of you haha.

Thanks,
Alex Goodwin
AlexG@motionlabtuning.com

NOBLE|370Z

Sam provided me with a couple different maps. One for Octane 93 and one for 91. The only fuel that I use is the "Ultra" octane 94 which Petro Canada sells.

During the HKS boost controller Initialization&Startup it finds the baseline for you. In other words you can enter it in manually, or drive it ad accelerate to get the feedback from the intake pressure. The springs are supposed to be around 7psi, and that's what I can, so I entered that in as the baseline.

Sam provided my mechanic a few good steps to get the troubleshooting process underway. Hopefully it will:

1) Ensure that the dialed in boost setting operate the wastegate(s) properly
2) Eliminate the rattle/detonation-like noise coming from the engine during highway acceleration. I only run Oct 94, and the fuel map is based on the MAF sensor anyway, so it "shouldn't" matter if one turbo i providing more or less boost then its twin. Therefore there shouldn't be a reason for the engine to detonate (I hope, but I'm not a mechanic so what do I know)

Sam shall I get a log for you to have a review of? Would a log be able to determine if the sound is in fact detonation? I'll change my engine map back to the Oct 91 until everything gets resolved in the coming days.

I appreciate the feedback/tips

COSMO

Make sure the intercooler piping is not hitting anything as well. If the wastegate was loose it would not make much boost. I know on my 335i the wastegate made a bit of noise at idle...

Legz

It's sad to see you having issues, is Les from ZR taking care of your problem?

I think Petro Ultra 94 has Ethanol, same as Husky's 94?
Petro-Canada Canada’s Gas Station Home Page - Petro-Points - Petro-Canada and CIBC MasterCard

__________________
GTM TT G37x coupe! Stage2 8.5psi Hotchkis | GTSpec | Eibach | PLX | Exoticspeed

NOBLE|370Z

Hmmm, so if there's ethanol in the fuel, should we not be using it? I suppose I could just use 91 Oct from now on. Shell's premium gas doesn't have any ethanol in it here in Alberta Canada.

NOBLE|370Z

Legz: Yeah Les is working on it. He's doing a good job and is determined to make it work properly

Legz

I actually dropped my car in for ZR to fix the AC and install a manual boost controller today, hope all is well for your Z. I've been using Husky94 all the time, before FI too, I'm not sure if it'll actually cause a problem, but for me it's all well.

__________________
GTM TT G37x coupe! Stage2 8.5psi Hotchkis | GTSpec | Eibach | PLX | Exoticspeed

Mitco39

I was also using husky with no issues. But after talking to everyone during my car getting tuned it sounded like I was one of the lucky ones who did not have issues

__________________
2007 Chevy Duramax - EFILive Tuned By Me
2010 40th W/ Nav - Boosted Performance - UpRev Tuned By Me
The Mrs. Ride -2012 335XI N55 BMW - Cobb Tuned By Me, Built by her
My Build --> http://www.the370z.com/members-370z-...39s-build.html

Girald

If your Wastegate is seized up, that can cause boost creep, or simple overboost till your sht goes boom. With a TT setup and a shared plenum, you could have major compressor issues on the side that is lower pressure.

The system relys on both sides working together.

A lot of these TT kits that fail are essentially an install problem...

1: the installer might not have banged out the chasis to give the new hardware enough room not to hit the chasis (your drivers side Wastegate actuator)
Result: wastegate actuator mount nuts got loose and backed off from the vibration of touching the chasis, thus causing the wastegate actuator to come loose, no preload on the wategate, and a wastegate rattle sound
Solution: Engine out, space bankged out, actuator mounts bent back, actuators properly aligned to wg

2: the wastegate actuator mount could bend and continue to bend from constant strikes against the chasis, eventually breaking the actuator arm, or seizing the actuator itself from operating at an angle greater than 2 degrees, out of spec

3: the preload setting could be so insanely hard that boost creep is inevitable at high RPMs and your car is on borrowed time every time you WOT the car

4: your PCV system could be severely limiting the amount of air that escapes the crank case under high boost, and it is fighting to either get out or push back against the pistons
Solution: get a CJM valve delete (an fitting to replace valve) plumbed to individual catch cans and to the intake ports, CCV either junctioned to the pcv lines, or vented to atmosphere

5: your fuel system could be limited in that you are running dry at WOT and 7000+k
Solution: get a fuel return system and regulator and a larger pump to meet requirements

All just general suggestions on what i think the problems could be assuming the engine is still sound. Check w mechanic that deals in FI and modified cars before doing anything

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