2.3 boost creep issues

[Terry Posten]

Can someone confirm my thoughts?

The EIII turbo I have still has the smaller flapper. It is ported. Can I be just generating too much exhaust pressure that the WG can't bypass enough to keep it at a steady level?

The turbo flys right up to 13 and then as the revs go up, so does the boost. I have my MBC bypassed. By 2500 I am at 13 and by 4000 I hit 23. way too much for 93 pump.

My MBC does not seem to matter to much. I did not spend too much time on this issue but I can't pull the motor past 5500 due to hitting 25psi. and on pump gas, that is hitting about 15 counts of knock and she does lay over a little

What do you think I can do? Please keep in mind that I just got done spending well over $3500 in this rebuild and I do not want to spend anymore (niether does my wife). I also want to be able to drive her for a while before I take something apart.

I want to go to the track but the boost creep is worring me, however I would run 105 race gas and want to run 25 PSI anyway. /ubbthreads/images/graemlins/devil.gif

 

what about meth injection? you could let it go to 25 and have way more fun. you know what they say if its fun at 13psi it will be twice as fun at 26psi.

 

I know you don't want to pull it all back apart but you need to port the exhaust housing for creep. That will solve your problem and won't cost you much money or time. If you have everything to do the job you should be able to have it all done in 4 hours and back together.

 

[Terry Posten]

Chris Beran ported the JDM mani, the complete turbo I bought from you and I took the 02 as far as I could. I also have 2.5 down to 3" all the way back.

I can't port it any further. The limit is now the flapper (I think).

 

There is another technique to use when you're porting for creep. Call me if you're still up or catch me tomorrow. I needed to let you know that I sent you another couple ecu's too.

 

[CP]

I understand the thinking behind opening up the WG hole, but wouldn't a bigger flapper tend to blow open more easily due to it's larger surface area?

I've got a severely ported EVO3 as well (SBR mani with ported 2G O2), and run it at about 23-24 psi with mostly no knock. I'm 2.5" all the way back though, with a cat.

 

[turboaddict]

Put in some leaded race fuel, and see how far is goes. With the e316g and a 2.3 with cams you should run out of compressor as well as the turbine. (I don't think you would be able to make any more that 24-26psi with the 2.3)
Do you plan on keeping that turbo?

 

[atc250r]

You need to port the inlet of the turbo. From the factory they are cast so that the wall of the inlet shrouds the WG hole and directs exhaust gasses away from it. If you lay that portion of the wall back you'll cure the problem. I used to have a picture of where to port, I'll see if its still on the PC.

John

 

Make sure your MBC is working and gets a direct vacuum/boost source. AMS machined a channel in the wall between the wastegate valve chamber and the main exhaust chamber on the outlet side of the turbo. They told me it helps eliminate creep because it lets the gases that are released by the flapper have additional access to the main outlet.

I also suggest that you install a larger wastegate flapper, too. CP: your concern is not actually an issue.

 

[Terry Posten]

OK. I am confused and excited at the same time.

I had a brain storm this morning and removed my MBC from the hoses and used my air compresor to set it.

I turned the regulator down to 20psi and used my airgun to set the MBC to where it was just allowing a very little air pass (it was way to lite). I then installed it back into the hoses and did the same test with 20psi with the air gun.

The WG actuator was very sluggish and would not open more than a fraction of an inch. So I "loosened" the MBC up so that 20PSI had a good openning push of the WG and had it wide open.

I took it for a quick run and so far it is going great. It snaps to 20ish psi and holds it for atleast 5500 revs.

I need to do some more runs to see where 20psi is obtained (rev wise) and how steady it is up to 6500.

WOW, is it more snappy than last night. It would only go to 12psi and then slowly climb as the revs gained.

20psi at low revs is a kick in the pants.

Why did my "lower Shores Performace" MBC screw with the boost setting with it really loose? I bet I turned the course adjustment knob "tighter" atleast 4 turns before it was limiting it close to 20psi.

Lower Shores Performance This really is a good unit. I have used it for 2 years and it still works great.

 

[jepherz]

So what you're saying is you had creep with NO boost controller hooked up, then you hooked the boost controller up for 20 PSI and it fixed your creep? As I told you, I'm having creep issues with my wastegate hooked directly up to the J pipe, which I would have assumed would open the wastegate as soon as possible??

 

[Terry Posten]

I am also confused.

I did hook my air hose up to the WG and "exercised" it for about a minute. The first few times, it was openning slowly and not all the way. By the time I had everything hooked up and was testing it with the air hose, the WG as snapping wide open. Maybe I had a sticky WG chamber/flapper.

I don't know.

 

[jepherz]

So your creep problem is solved?

 

[Terry Posten]

Mostly. I am hitting 22 around 6000 when it is set for 20. I can live with that for now.

 

[Mark]

Do they have different springs for the MBC you have? Perhaps the spring in the MBC needs to be stiffer..

 

With a 2.3 on a 16g I really don't think you are going to get away from creep. There is just way to much exhuast gasses and you just can't vent them with that small of a wastegate. You are at the point where you need to get a bigger turbo with a bigger flapper or you will need to buy an external wastegate. Jesse, I cut the divider in between the wastegate hole and the turbo outlet, if thats what your thinking I needed to do. I opened this thing up as much as I could. Jeff thats what you need to do on your 02 housing to fix your creep issue. I will give you a call later Terry.

 

[Hertz]

Quote:

Lower Shores Performance This really is a good unit. I have used it for 2 years and it still works great.



+1 The problem would probably be worse with a lesser MBC.

 

[Struc]

Bringing this back up from the dead...

Terry: Has your boost problem stayed under control? Did you ever find any other issues.

I have a brand new EVOIII-16G on 56/1000, which has recently had a 2.35l stroker transplant. It's straight out of the box, no porting, etc. I'm having similar boost creep as to what you were describing. I get to a certain RPM, and the boost just keeps climbing. I took my boost controller (also a Lower Shores Performance) out of the picture, and just attached the wastegate actuator to the boost nipple on the turbo outlet pipe. It holds 10psi or so until 5500rpm, and then it starts climbing until I hit fuel cut (stock ECU and stock MAF at this moment).

Any suggestions / advice / expirences would be appreciated. I was going to pull the turbo off and hog out the wastegate hole some, but it sounds like maybe that isn't necessary?

 

[boostedinaz]

Quoting atc250r:
You need to port the inlet of the turbo. From the factory they are cast so that the wall of the inlet shrouds the WG hole and directs exhaust gasses away from it. If you lay that portion of the wall back you'll cure the problem. I used to have a picture of where to port, I'll see if its still on the PC.

John



Exactly!!

A huge majority of people who have creep issues just open up the step in the turbine housing. Almost no one goes through and ports the "turn" to the WG for a nice smooth path.

 

[belize1334]

^^ I have an E3 exhaust side w/ s16g compressor and the exhaust housing was ported as described. The inlet to the wg passage was opened up and there's a little ledge to promote flow. The outlet is also opened up to promote the transition to the o2 housing. All the port work was done by fp. With that setup and a 2.5" mandrel catless exhaust I'm getting creep to 20psi at sea level by redline.

Here's an interesting read/procedure ... clicky