BamBam

iTrader: (4)

Kelly, I still have my stock cats and whatever other stuff AAM gave me after putting in all my custom stuff if you want it..... (except for the nismo muffler)That is if you are interested.

Ping me man

MIAPLAYA

iTrader: (3)

He needs an exhaust. Any other y pipe back exhaust would do I think. Kelly I have a downpipe with a cat on it. That should create SOME backpressure. I can send it to you for testing also if need be.

ActionJackson

iTrader: (1)

I have a stock exhaust & Y-pipe in my garage for sale... No bolts or gaskets though but you can probably get those from a nissan parts store for like $35

35ounces

iTrader: (5)

I dont see how an exhaust could cause that. The wastegate is designed to open at a certain pressure that is triggered by the signal line (and spring). If the signal line is good and the spring is the right weight then it should open (unless something is physically keeping it from opening).

Is there something in that dump pipe that is interfering with the wastegate maybe? Is there a way to temporarily take that dump pipe out of the equation and vent to atmosphere?
What exactly is in that funky connection where the wastegate/dump pipe connect to up pipe?

If the problem goes away with the stock exhaust then what exactly does that mean? I mean in theory at least you should be able to run without any exhaust and still be able to control boost. Using backpressure to control boost doesnt sound too good to me.

MIAPLAYA

iTrader: (3)

I agree completely....Heres the thing. So far two people have had this happen. Kelly and BlueBlrr are both running a modified Greddy Evo2 exhaust and both of them are getting upwards of 11 PSI of boost and their AFR is in the 9s. The only common things are the kit and the exhaust. BlueBlrr is going to bolt on a different exhaust next week and see what happens there. Kelly is running a 5 PSI spring and regardless of boost controller is getting 11 PSI even after the wastegate has been changed. The funny thing is that even at 11 PSI before the Emanage Kelly's car was in the 9s AFR at 11PSI!!!! At 10.5 PSI my car was in the 12s AFR. The only difference between me and him is the exhaust. I don't begin to understand how it could be the reason for this but its something to try.

kcobean

iTrader: (2)

Yeah, I'm kind of of the same mindset. The wastegate is basically a diaphragm connected to a plunger. The pressure signal from the compressor housing pressurizes the chamber on the bottom side of the diaphragm. The diaphragm pulls the plunger open, allowing exhaust gas that WAS heading towards the turbo to flow into the dump tube and pass into the downpipe/exhaust. The only things that should be a factor here are if a) the diaphragm is torn, so the lower chamber can't pressurize (it's not, I inspected it when I put the 5 lb spring in) b) the gate is not getting an accurate pressure signal from the compressor housing (indicating a leak or blockage in that vacuum system), or c) there is something blocking the dump tube such that when the wastegate opens there is nowhere for the exhaust gas to go to once it passes through the gate.

Does this sound right?

Z BOY

iTrader: (41)

i understand none of this technical turbo stuff, but from what i've read on this thread, disturbed had the same problem and was able to solve it.

MIAPLAYA

iTrader: (3)

You are absolutely correct. What all of that does not explain however is why even at 11 PSI you had AFRs in the 9s. I know for a fact at 10.5 PSI those injectors run 100% duty cycle and the car runs lean above 5500. Turbonetics did it several times on mine and their car. How you can run 11 PSI and still have AFrs in the 9s is insane. And I know your fuel pressure is spot on too.

BoOsTedz33TT

iTrader: (1)

then something is leaking, sounds like your running an disconnected wastegate, my old integra got messed up because of the TN wastegate, it was a deltagate. I dont know if thats what you have, but man that thing would spike boost when it was cold like crazy, blew a motor up because of it.

GurgenPB

iTrader: (2)

Hmm...so where does the out from the compressor housing go, if you've got the IN conected to a manifold tap and out to the wastegate IN port?

Lets make sure we are on the same page. A typical boost controller solenoid/stepper motor must have 3 inputs. You need to have your compressor housing OUT go to the IN of the solenoid, the OUT of the solenoid got to the IN of the wastegate, and a manifold tap go to a third connection on the solenoid, for boost pressure monitoring purposes (or for closed loop control in some more advanced boost controllers).

I won't go into this further, just to make sure you didn't misspeak or I didn't misunderstand you in your explanation above. The point is that you don't want to have a manifold tap go to the IN of the boost controller, although that may seem logical. The best way to ever do it is to havee the singnal line go from a pre-TB location close to the TB.

Sharif@Forged

iTrader: (92)

aaarrrrrrggghhhh..

I was really hoping that that new wastegate would fix this issue. The bizzard, thing, like you said, is that even without a boost controller hooked up, you are overboosting.

I wish I had something more to add, but you and me have had lengthly conversations on this and I am totally at a loss.

The exhuast issue that Robert mentioned is a possibliity, but when we had Peking's car in the shop, we completely disconnected his exhaust system for testing, and even without an exhaust, he never overboosted. Could your modified Evo2 exhuast be more free flowing that no exhuast? But I have seen stranger things happen on the VQ35, so it might be worth a shot.

disturbed2483

iTrader: (9)

i was just thinking, which whole do you have the signal line connected to on the wastegate cause when i first installed my kit that is another mistake i made, i connected to the wrong hole. at this point you might wanna check anything cause i know it can get pretty frustrating.

kcobean

iTrader: (2)

The routing is exactly this:

1. There is a vacuum line from the turbo compressor housing to the lower port on the wastegate. It is this line that is responsible for opening the wastegate by pressurizing the lower chamber so that the diaphragm pulls the plunger open. (this line has been replaced and is brand new).

2. There is a line from the "out" port of the boost controller solenoid that connects to the upper port of the wastegate. This line is responsible for "countering" the signal pressure and holding the gate shut to pressures greater than the spring would normally provide.

3. There is a line from the "in" port of the boost controller solenoid that connects to the tap on the upper plenum. This line is responsible for providing the pressure that the solenoid uses on the "out" port to hold the wastegate shut.

4. There is an additional line from the plenum tap (it's on a T fitting that is being shared by the "IN" port of the solenoid) that goes to the boost controller main unit. This line provides the "intelligence signal" that is used by the main unit to control the operation of the solenoid.

Line 2,3 and 4 are for boost controller operation only and are not part of the basic turbonetics kit. Only line #1 is mandatory for the wastegate to operate properly at spring pressures. With a 5 pound spring in the gate, the compression signal from line #1 should overcome the spring and open the gate when the turbo generates roughly 5-7 Pounds of pressure in the lower wastegate chamber. The kit overboosted as it does now before the boost controller was installed and only line #1 was present. Because of this condition, the boost controller is rendered useless because the controller cannot cause the gate to open *sooner* than it normally would.

The gate has been replaced, the signal line has been replaced and the gaskets for the gate have been replaced.

Peking

iTrader: (2)

Man this is so weird, really really weird.

kcobean you know that there is a gasket for the discharged sized of the wastegate... But it is not needed to have on on the inlet side... But I have one there since I had a leak... Though not enough to cause any boost increases that large... So that isn't to much help I guess... But a change like that along with the suggestions on the exhaust... Maybe can help


1. There is a vacuum line from the turbo compressor housing to the lower port on the wastegate. It is this line that is responsible for opening the wastegate by pressurizing the lower chamber so that the diaphragm pulls the plunger open. (this line has been replaced and is brand new).

What if there is a possible issue with the fitting into the compressor housing? Strange I know to say, but what if something it blocking that (maybe some thread sealent, bad fitting) and the pressure isn't being built correctly causing you to boost much higher.

kcobean

iTrader: (2)

I wondered about the whole gasket thing because the new wastegate only came with one gasket, but the old one had one on each port when we took it off. I wasn't figuring it would make a difference though, since the hole in the gasket is as big as the opening in the wastegate. Yes? No?

I too thought about the fitting in the compressor being blocked. I took a section of vacuum line and blew through it to get an idea of how much resistance it provided by itself. Then I installed it on the compressor fitting and blew through it again. The resistance was almost identical and so I don't think the fitting is blocked. Taking the fitting off of the compressor to visually verify would be quite difficult since it appears to have been thread locked in place and I have very little angle to reach it either with a tool or by hand.

35ounces

iTrader: (5)

Right. Thats why you should T it and run a line to your boost gauge so you will know exactly what pressure it is seeing.
The other thing you could try is running a line to the port connected to a pressurizer like the type used to find intake leaks. Run it with the car off so you can see if the WG opens/closes at the spring pressure rating or at a higher pressure.

D350Z10

iTrader: (20)

I dont think it can be the exhaust.... I am also using a Greddy Evo 2 and have no problems with overboosting. I still think that the bolts or hardware some where near the wastegate or the compression housing are loose.

Peking

iTrader: (2)

Well you don't nor is it suggest to use one per the directions for the wastegate since the valve is supposed to seal the opening. But the shop that installed my kit used one (gasket they had around the shop that fit) because they worried about having leaks. I told them to take it off cause there wasn't supposed to be one there in the first place... The flange is machined so you will have a good fit... But I guess since they placed a gasket there and after a week or so of driving, when they took it off... There was air leaking through, so they placed the gasket back.

Also yeah it is a weird angle and most likely not possible unless you remove the turbo completely then remove it with some force (breaking the thread sealent). Though I can't see what else it can be since you have already stressed other possible alternitives (well not the exhaust one yet)... But I don't see how that alone would change so much in the psi (more than one or two psi). Maybe that fitting is supposed to freely flow air more than the line that connects to it.

kcobean

iTrader: (2)

So I got mid-evil with the car tonight. I pulled off the strut-bar, engine cover, MAF sensor/housing, the black-chromed pipe that connects to the lower end of the maf, and EGT Sensor probe. Upon visual inspection and what I can get to with my fingers, here's what I see:

The bolt that attaches the turbo to the support bracket and turbine feed pipe (left-rear bolt as you view it from the front of the car) is finger loose, thought it appears the other 3 are tight enough to keep this joint from leaking because there is no sign of exhaust leak on the flanges).

There is a DEFINITE leak where the dump tube attaches to the down-pipe. The frame-wall near that joint is covered in exhaust residue. The b!tch is that you can't get to these bolts to tighten them up or install a gasket because they are on the underside of the downpipe. I don't know how in God's name these were torqued in the first place.

All this said, I still question how an exhaust leak could cause the issue I'm having. It's effectively the same as having some mixture of recirculation and atmospheric dump....

Regarding the theory that my exhaust could be causing this because it's too free flowing, what do you think of this: What if I block off one of the mufflers some how. This would effectively reduce my exhaust system to be a single 2.5" (or whatever each side of the EVO2 piping is) exhaust post downpipe and would reduce the flow rate by 1/2. Practical or complete lunacy?

Thanks to everyone for all the thoughts/suggestions.

disturbed2483

iTrader: (9)

i though the same thing but its do-able but only out of the car, as crazy or stupid this may sound you can actually attach the dump tube to the down pipe out of the car and put it in the car as one whole piece but it must be done from the top, believe me its possible thats how I did it it just took some tlc. if you have any questions let me know.