Nameless Downpipe: Official 5th Gen GT Install Thread

[eckseleven]

Perhaps a longshot, but has your turbo ever been rebuilt maybe before you bought the car or did you buy it new?

Bought new.

[fahr_side]

I'd be surprised if the flapper was still touching that tube. With the switch from bolts to studs like everyone else has used and considering the good wack with a hammer I gave that tube, it just doesn't seem possible to me. There would have to be a serious manufacturing defect to cause things to be off still.

Yes, I agree it's an unlikely scenario. Not impossible, but not that likely.

Perhaps there could be an actuator issue but since I've never had a problem in 38k miles and my tuner has never pointed out any odd behaviors in the past it just doesn't seem possible to me.

Also unlikely, but again not impossible. Easy to test though.

fahr_side, I know you've mentioned this in the past, what do people typically gain with a CBE? I'm curious what I'd loose if I were to go back to that. Maybe I'd loose some peak HP but gain TQ when compared to stock DP plus 3" CBE?

Nothing to gain. We've run cars back to back with our TD05H-18G hybrid on stock exhausts vs. 63mm and 70mm systems with straight thru and turbo-style cans. All we saw as a difference was boost creep, even on cars with meth injection running at 335whp. This is when I started hand porting the wastegates!

I need to consider my options. It sounds like you'd just port the WG but unfortunately I don't have the resources in my area to do that. Switching exhaust components is the only thing I'm willing to do.

Ultimately you're going to get out of this what you're prepared to put into it. I understand your frustration though. I fully expected this very nice J-pipe to fix all issues with boost creep but it seems harder to crack than that. Yes I would just port the WG but then I have the means to do it myself. I also could not guarantee you porting the WG would solve your problem.

Edited December 14, 2015 by fahr_side

[Starks]

I guess what I'm not understanding is, all of the other guys doing builds and all with full tbe's. Why aren't they experiencing boost creep? What about the wrx's?

 

Sent from my DROID RAZR HD using Tapatalk

[FLlegacy]

I guess what I'm not understanding is, all of the other guys doing builds and all with full tbe's. Why aren't they experiencing boost creep? What about the wrx's?

 

Sent from my DROID RAZR HD using Tapatalk

The wrx uses a different turbo, ours is special!

 

Sent from my SAMSUNG-SGH-I337 using Tapatalk

[jojorios]

Nothing to gain. We've run cars back to back with our TD05H-18G hybrid on stock exhausts vs. 63mm and 70mm systems with straight thru and turbo-style cans. All we saw as a difference was boost creep, even on cars with meth injection running at 335whp. This is when I started hand porting the wastegates!

 

So would both stock midpipe & mufflers be needed? Or can it be one without the other?

[FLlegacy]

So any chance of making a video how to on porting the waste gate?

 

Sent from my SAMSUNG-SGH-I337 using Tapatalk

[eckseleven]

So would both stock midpipe & mufflers be needed? Or can it be one without the other?

I'm giving my options some thought. I may put my stock mid on and keep the AVO mufflers and see what happens.

[fahr_side]

I guess what I'm not understanding is, all of the other guys doing builds and all with full tbe's. Why aren't they experiencing boost creep? What about the wrx's?

Other people do have creep, they just don't start 30-page threads about it

 

The new WRX has a hotside with a better design, where the wastegate dumps into a nice chamber at a converging angle to the turbine flow. It's also a 2.0l motor, some 25% less exhaust volume to deal with...

So would both stock midpipe & mufflers be needed? Or can it be one without the other?

Depends on the design of the catback, but if the flanges for the cans are in the stock location you could mix and match as you like.

So any chance of making a video how to on porting the waste gate?

Sure, next time I do one. Don't hold your breath while waiting!

I'm giving my options some thought. I may put my stock mid on and keep the AVO mufflers and see what happens.

Yes, give that a try. If it still runs away then swap the mufflers too, or keep the midpipe on and replace the stock cans.

[eckseleven]

Log it and post the actual boost curve.

 

Here's the log. First 40 lines or so.

 

https://drive.google.com/file/d/0BwoQtejdZCJmQXVsb1RqWlUyNnNEcG1KYmpBS2J4YTU0U0Vr/view?pref=2&pli=1

Edited December 15, 2015 by eckseleven

[Starks]

Ooooh, so the member here who ceramic coated his dp may have really flubbed up because the temperature difference may be even greater?...

 

Sent from my DROID RAZR HD using Tapatalk

[GotthatGT]

So far with the Cobb OTS stg 2 high waste gate tune I only get 16.5 psi. I really need a pro tune so I can actually feel a difference.

[jojorios]

Ooooh, so the member here who ceramic coated his dp may have really flubbed up because the temperature difference may be even greater?...

 

Sent from my DROID RAZR HD using Tapatalk

 

Don't think so because..

 

[ripstik]

Don't think so because..

 

that header is pure sex

[Starks]

Don't think so because..

 

[ATTACH]221337[/ATTACH]

Holy balls!! Good stuff!

 

Sent from my DROID RAZR HD using Tapatalk

[GTEASER]

Is it possible that the MAP sensor could be bad, or the voltage go accidentally re-scaled improperly, resulting in a boost reading that is higher that it really is? Do you have a stand alone boost gauge to cross-check the AP reading from the ECU? Sorry if this was covered already.

[fahr_side]

I've never seen a MAP sensor fail without throwing a code, or the scalings change themselves.

 

 

Sent from a device using some software.

[eckseleven]

Do you have a stand alone boost gauge to cross-check the AP reading from the ECU?

 

I do not but this experience may be the push to finally get one. I have been wanting one for years.

[GTEASER]

I've never seen a MAP sensor fail without throwing a code, or the scalings change themselves.

 

 

 

Is there a MAP voltage that could be logged in comparison to MAP pressure reading, and that compared to stock? The reason I brought this up, is perhaps there is a tiny possibility that the tuner intended to rescale the MAF and accidentally rescaled the MAP, or did so completely accidentally.

[fahr_side]

MAPv is not defined in every ROM for the Opensource logger but I have no idea in Cobb.

MAF scale is not linear so that's a 2D look-up table, MAFv vs. air flow value in g/s.

The MAP sensor is a linear relationship between MAPv and pressure, so there's a per-volt value for pressure and an offset value to apply.

No tuner worth the title could possibly mistake one for the other!

 

 

Sent from a device using some software.

[Tuning Alliance]

I do not but this experience may be the push to finally get one. I have been wanting one for years.

 

I would next try, to disconnect the flap so its flopping and open. See if it persists or give you no boost. Sorry if you have already tired this I didn't go back and read all the posts.

[Dreizehn]

So far with the Cobb OTS stg 2 high waste gate tune I only get 16.5 psi. I really need a pro tune so I can actually feel a difference.

 

 

Same here. I have the normal wastegate setting though and at 5280'. My max psi is identical.

 

 

Sent from my iPhone using Tapatalk

[eckseleven]

I would next try, to disconnect the flap so its flopping and open. See if it persists or give you no boost. Sorry if you have already tired this I didn't go back and read all the posts.

 

Can that be done easily with out removing a bunch of stuff?

[Starks]

If it's like the Evo 16g and its internal wg it's easy. Just remove the cotter pin holding the actuator arm to the wg.

 

Keep it mind though your pin may be rusted, and the preload of the arm. New pins are at your local autoparts store.

 

Sent from my DROID RAZR HD using Tapatalk

[Tuning Alliance]

Looks like the c-clip is on the underside if the pic im looking at is accurate. Might be a pain but doable.

[mcg_]

Looks like the c-clip is on the underside if the pic im looking at is accurate. Might be a pain but doable.

 

It does appear to be a c-clip on the underneath (looking at my VF54 hybrid turbo on my desk) but good luck actually accessing that with the turbo on your car....