Canadian

iTrader: (1)

I just got my car back from having the trans built, and I had my torque converter upgraded to a smaller, higher stall converter. Read below, and I'll explain why I mentioned this.

The day we finished the car and went to test it out, I was seeing boost creep up to 11psi. The only thing that was touched on the while the tranny was out is the exhaust. I had an oil change done, and the trans was put back in. I got a new exhaust as well. I went from the HKS to the FI Intimidator.

I was getting worried, so we went back and adjusted my manual boost controller. Then it hit 9psi, and it was adjusted some more. Then it went up to 14psi. We kept adjusting it but we were not seeing any consistent numbers. We saw 14, 11, and apparently even 20 (as far as I know the JWT turbos are no where near capable of 20psi, right??). This is what my boost gauge was saying. The car DEFINITELY felt A LOT faster. A LOT. So, the boost was up. What confused me is I'm still on stock injectors, and I have just the upgraded fuel pump the JWT 530bb kit comes with. Not a 255lph Walboro. My A/F was fine, it was low 11s and high 10s. When it supposedly hit 20lbs, the car went into safe mode. I got no response from the gas pedal. I stopped the car, but then it continued to drive. I thought I blew the motor or something.

How is that possible with double the boost on stock fuel for the most part? So we bypassed the manual boost controller, and decided to go back to the wastegate springs, and we went for a drive. It seemed to be okay, but I would see it spiking to 10 and 11lbs still. It was getting late at night, so we just called it a night.

I went home, and the next day I went driving and got it it in 2nd gear, and it did the same thing when I hit 20lbs. I haven't been getting on it at all since then, I'm scared I might blow something up..

I was told by my tech to order a better boost controller, as my manual one sucked. So I have one already, and putting it in this weekend.

Now, about the torque converter he also said that this could cause more boost because it is smaller and spinning up quicker. How likely is this? Also, would my new exhaust cause this big of a difference? I hope I can get this resolved quickly. I spoke to Jim at JWT last night and he offered some help, and told me a few things to do. I haven't done what he said yet, hopefully will do this weekend.

Anyway, does anyone have any other ideas? Thanks...

Jay'Z

iTrader: (118)

WOW.. How is she running now? Still in limp mode?

ToastZ

iTrader: (2)

What did Jim [JWT] tell you to do ?

Dynosty

iTrader: (27)

Ordering a better boost controller will do nothing for you if it is spiking to 20psi even on wastegate. No boost controller can lower boost below wastegate. Have you checked over your vacuum lines to the wastegates - make sure they have not melted through, torn, gotten crimped, etc.

boostedmaxima

IMO the high stall converter and the exhaust helped the turbos spool faster so it would be easier to hit boost than before. Technically if the exhaust was less restricted the turbos would hit higher boost. In regards to the wastegate spring it depends on what spring you used. On a stock motor I would say you should be using a 5 lb spring. Even on a 5 lb spring if you floored it real quick you can hit 9.5 psi. On an 8 lb spring your boost would normally be around 11 psi.

wannabuy350z

iTrader: (27)

i have the same kit. you didnt mention anything about TP or HFC, i assume you have test pipes. the wastegate spring on JWT on the 530s is 6.8 PSI. and that what I used to get when I had HFC on. the reason I say this, is because the kit was designed to have that. once you alter the flow. you will see changes.

going to 10 11 psi. is what I see when I went to TPs and greddy TD ti exhaust. I think the downpipes of this kit is giving boost creep. I am going to have my welder custom make me a downpipe from the turbo 3" and we will see what happens.

but I think you have a leak in your vacuum system. do a pressure test.

chopperman

iTrader: (9)

That doesnt explain the boost jump up to 20 psi? Anyone know where that can be coming from or maybe that was a mistake on the boost controller's part?

arizzee

iTrader: (28)

For testing, I'd suggest removing the boost controller and check your wastegate control lines from the intercooler fitting back. Also check that the wastegate actuators have the proper clearance, especially the driver's side.

Why your motor didn't blow on stock ejectors @ 20psi - the JWT FMU would have had the fuel pressure around 108 psi at that boost level. To quote Jim regarding the fuel system and high fuel pressures, Jim said "If the A/F is in the 11.5:1 range at full boost, leave the pressure alone, the EV14 style injectors are designed to operate up to 118psi without problems." Still, I wouldn't press your luck hitting 20psi.

rcdash

iTrader: (18)

+1. Your answer is right there. Wastegate lines...

You have no overboost protection? And on a stock motor? 20 psi

Canadian

iTrader: (1)

Thanks guys. I'm going to get all the lines this weekend. Hopefully we'll find something.

My exhaust setup before was Megan v2 test pipes, and HKS exhaust. All I changed was the exhaust, I still have the Megan test pipes. The car ran fine before, and hit 7psi, no higher. Now with the tranny done and torque converter and the new exhaust it is doing this.

I hope I find something this weekend, as we're going to be installing a new boost controller (whether or not that will help isn't the point, at least it will get us to check all the vacuum lines). I'm going to have my manual one removed completely.

Sharif@Forged

iTrader: (92)

Doesnt sound like a trans issue causing that huge of a spike. I would double check all the lines. It's funny how things can come loose, or be moved around when taking out the trans. I bet you will find it an easy fix.

Canadian

iTrader: (1)

I hope so! I cant even enjoy the freshly built trans yet

At least it shifts beautifully

thom000001

Seeing that much boost sounds like you have no boost control at all. Check you boost controller setup (vacuum/boost lines) and wastegate lines in general like Hal said.

Creep is 1-3psi......catastrophy is 11psi too much.

Tom

iStan

iTrader: (29)

We bypassed his POS manual controller, expecting to get wastegate boost, but that isn't working out apparently. We'll be installing the EBC this weekend and following all of his lines.

Blwn_By_Twins

iTrader: (6)

I can't believe he hit 20psi and didn't pop! WOW!

Good luck on finding the problem bro!

rcdash

iTrader: (18)

I don't think the 530bb flow that much more air at 20 psi compared to say 14-15. If it had been a Greddy, APS, or 700bb, I suspect it would have been really bad news...

Blwn_By_Twins

iTrader: (6)

Oh, didn't realize. I thought 20psi would be 20 psi with any kit. I know when I was having the boost creep problem 11.7 was scaring the sheet out of me!

thom000001

The 530bb's would be producing mucho heat at those boost levels

GTM

iTrader: (12)

Double and triple check all vacuum lines as stated.

It seems that either 1. something was moved or became loose while installing the new trans. or 2. the new exhaust is not providing enough back pressure giving you boost creep, although it shouldn't be this severe. That is one of the problems with internal waste gates

If all the vacuum lines are routed correctly, and there are not any leaks. I would suspect the exhaust is causing the internal gates to keep building boost.

Hopefully its a simple fix!

-George
GT Motorsports

rcdash

iTrader: (18)

precisely and hence very little additional mass air. ideal gas law ftw! lol - well it saved Canadian's motor at least. An oft unrecognized benefit of small turbos.