[Patjza80]

Ok so my tuner just got started on the car today. My set up is a 6265 turbo, cast manifold, and a precision 39mm wastegate. I have NOT taken apart the wastegate at all. Precision says there is a 1 BAR spring from the factory in the wastegate. My tuner began tuning today and boost shot to 20 PSI... But the thing is at 20 PSI boost flat lined like it had a 20 PSI spring in it. Before pulling of the wastegate we made sure that the 1 BAR spring wasn't in the box ( peice of mind that there is more than likely a 1 BAR spring in the wastegate) He is currently pulling of the wastegate so maybe I'll know something tonight.

My question is... Is it possible that it does have a 1 BAR spring in it, but its not dumping enough and its pulling 20 PSI? Maybe I can put a 10 PSI spring in and I can bring it down to 15 PSI or so?

Has anyone else had this issue?

Here is the downpipe I'm using for my set up.. I don't know if this will have an effect or not.

Also what do you guys usually use to block this off? I know, I know I should have welded it shut when I had the chance, but I didn't. I don't think this rubber cap is going to hold...lol.

 

[Wreckless]

That's a classic example of boost creep. Boost creep is what happens when the wastegate cannot bypass enough exhaust energy to stabilize boost.

Basically, good boost control is a balance of turbine housing, WG size, and manifold/dp design. Generally speaking, the less boost you want to run, the bigger the WG you'll need.

In your situation, I think you need a larger wastegate.

From your DP design I'm guessing that you're using a Turbonetics/PHR style cast manifold. That manifold frequently sees boost creep issues with larger turbine housings, and needs extensive WG porting and a custom adapter made to go from 2-bolt to a V-band 44mm Tial (or other suitable V-band WG) in order to avoid boost creep.
The fact that your WG dump is recirculated (albeit in a very good way for exhaust flow) is also likely to add to the problem, particularly if you have a catalytic converter downstream of the WG recirc, or are running only a 3in exhaust.

You might be able to run a weaker (lower psi) WG spring and have less of a problem, but the problem ultimately is that when your WG is open, it is NOT bypassing enough exhaust to keep the boost down. A weaker spring is only going to make your WG open sooner, not open wider.


As for your plug, When I can't get to it to have it properly welded to be blocked off, I use a short piece of appropriate coolant hose with a piece of nylon or aluminum bar stock stuffed in one end and hose clamped into place, and hose clamp the other end over that port.

If you don't have nylon or AL bar stock, an appropriate sized leftover bolt with some RTV also works great.

 

[Patjza80]

I had the manifold ported to match the 39mm wastegate, and I have no cat. Looking through this thread it appears people are running the same wastegate or a 38mm and there results are fine? That's where I'm super frustrated.
http://www.supraforums.com/forum/sh...5-Stock-Engine-300wtq-2800-RPM&highlight=6265

http://www.youtube.com/watch?v=MBi7F91JClI&sns=em

http://www.supraforums.com/forum/sh...ing-single.-PT-6265-questions.&highlight=6265

 

[vr4bats]

In your situation, I think you need a larger wastegate.

From your DP design I'm guessing that you're using a Turbonetics/PHR style cast manifold. That manifold frequently sees boost creep issues with larger turbine housings, and needs extensive WG porting and a custom adapter made to go from 2-bolt to a V-band 44mm Tial (or other suitable V-band WG) in order to avoid boost creep.
The fact that your WG dump is recirculated (albeit in a very good way for exhaust flow) is also likely to add to the problem, particularly if you have a catalytic converter downstream of the WG recirc, or are running only a 3in exhaust.

For a sample of another similar setup;

I have the same WG, I'm recirced, complete 3" exhaust, Turbo (1.0 A/R), QSP, and a Treadstone cast manifold. (I do not have a cat either).

My minimum boost is 16psi. I have NO creep issues.

 

[Patjza80]

Well bad news... Here is the boost on a 10 PSI spring..

 

[Patjza80]

My difference is I have a Ebay cast manifold as opposed to a treadstone manifold.. I'm guessing thats my problem?

EDIT: I know, I know... I'm an idiot.

 

[Wreckless]

My difference is I have a Ebay cast manifold as opposed to a treadstone manifold.. I'm guessing thats my problem?

EDIT: I know, I know... I'm an idiot.

Considering VR4bats has the Treadstone manifold and is running an extremely similar setup otherwise, my guess would also be with the Ebay manifold.

Keep your Ebay unit and compare it to the Treadstone unit once you get it in - compare the WG flange areas and if the Treadstone's is significantly more open/larger, chances are that'll fix your problem.
If possible, port the WG area even more. The more WG flow you have, the more stable your boost control will be.

If boost creep issues persist, you will need to find a way to port the WG flange & accommodate a larger wastegate.


Edit : This thread might be of interest - is this the manifold you purchased?
: http://www.supraforums.com/forum/showthread.php?631394-Godspeed-cast-t4-manifold-GARBAGE-(PICS)

 

[Nick 95 6sp]

As another reference point for cast manifolds, when I was still using my Turbonetics cast manifold (along with the rest of that Induction Motorsports kit) with a PHR Stg1 60-1, I never had a problem holding a solid 17 psi which was my normal pump gas setting. It was ported out and came with a 2-bolt-to-V-band adapter to fit the HKS 60mm GT wastegate.

 

[Sfitts2380]

Not trying to thread jack, but I noticed we have a similar problem, sept instead of hitting 18-20 psi which is where I need it mines hits all over the place, 23,25 and 27.4 was the highest it hit right off the bat.

 

[marshallpre1]

Not trying to thread jack, but I noticed we have a similar problem, sept instead of hitting 18-20 psi which is where I need it mines hits all over the place, 23,25 and 27.4 was the highest it hit right off the bat.

What boost controller do you have?


Also to add to this, I have a ported and ceramic coated turbonetics manifold, 1.00 divided a/r and Tial 44mm wastegate (1 bar spring) rerouted into the downpipe and mine holds steady at about 16-16.5 psi.

 

[Sfitts2380]

what boost controller do you have?


Also to add to this, i have a ported and ceramic coated turbonetics manifold, 1.00 divided a/r and tial 44mm wastegate (1 bar spring) rerouted into the downpipe and mine holds steady at about 16-16.5 psi.

hks evc, also my AR is .85 and it's a 3" DP, the turbo is a precision 62mm with an internal WS, if any of that helps

Also the guy I bought it from said it ran great at 18psi for a long time no creep or over boost at all, and I'm running the same mani and DP as he was

 

[Patjza80]

Well after speaking with four different people with the treadstone manifold, I went a head and ordered one. I really hope this fixes the issue.

I was really looking forward to having my car back today

 

[Josh S]

Hope the manifold change solves your issues. Good luck!

 

[vr4bats]

Good luck with the treadstone, hope that works for you.

 

[Patjza80]

Got the treadstone manifold in today, it does look better inside. It is still going to be ported just incase.. Hopefully the car will be put back together by Tuesday.

 

[Patjza80]

UPDATE

Got the treadstone manifold in yesterday. From memory this does look better than the godspeed manifold. Here are some pics from taking it out of the box:

Here is after my machine shop porting it to a 39mm and cleaning it up for me.

Do you think this looks OK?

 

[Sfitts2380]

UPDATE

Got the treadstone manifold in yesterday. From memory this does look better than the godspeed manifold. Here are some pics from taking it out of the box:

Here is after my machine shop porting it to a 39mm and cleaning it up for me.

Do you think this looks OK?

How much was that mani?

 

[Patjza80]

$322 shipped from treadstones website. I was in such a rush to get it here, I only took a brief second to see if I could get it cheeper... But I didn't see anything.

 

[Sfitts2380]

Oh ok, not bad, I'm just gonna save then and get a tubular mani and bigger turbo down the road