T25 Flapper vs 16G Flapper

Fmstrat · 03-26-2004, 07:06 AM

I'm going to port a T25 wastegate tomorrow. We have a die grinder bit that works perfect for 14B's and 16G's, which is just a big ball that we push through the wastegate and it ports it perfect.

Does the T25 have the same size wastegate? If not, anyone know the flapper's actual measurement?

Thanks.

ShapeGSX · 03-26-2004, 07:25 AM

Why on earth would you port a T25's wastegate? That won't do anything for power. In fact, it will probably hurt power.

Fmstrat · 03-26-2004, 07:40 AM

Because it's running a 3" exhaust, and has massive boost creep. It's basically a fix to get rid of the creep until the car gets the bigger turbo.

ShapeGSX · 03-26-2004, 07:42 AM

Quote:

Originally posted by Fmstrat
Because it's running a 3" exhaust, and has massive boost creep. It's basically a fix to get rid of the creep until the car gets the bigger turbo.

What is it creeping to?

Fmstrat · 03-26-2004, 08:28 AM

16psi on a low rpm pull
19-20psi on a 3rd gear drop on the highway

I consider that last spike bad enough to warrent porting. Especially since it's not hard to do.

ShapeGSX · 03-26-2004, 08:37 AM

That is a spike, not creep.

Porting the wastegate won't solve that.

That is a boost control issue, not a wastegate issue. The boost controller isn't reacting quickly enough. Having a larger wastegate port isn't going to speed up his boost controller.

I had the same thing happen with my T25, btw. I never did anything about it. I don't think it is a problem. It isn't as if the T25 is going to flow a damaging amount of air in that circumstance.

Fmstrat · 03-26-2004, 09:05 AM

Interesting point. I've actually read about zip tieing the vacuum line to make it smaller to open sooner. Mine's pretty bad though, it sustains after it spikes. I've hit fuel cut once b/c of it, and my EGT's get pretty high.

CanadianTSi · 03-26-2004, 09:48 AM

If it is actually boost creep then Port out your 02 Housing

kpt4321 · 03-26-2004, 10:17 AM

Quote:

Originally posted by CanadianTSi
If it is actually boost creep then Port out your 02 Housing

Wrong.

Porting the O2 housing does nothing for creep. Creep comes from the restriction of the WASTEGATE, not the O2 housing, so you would need to port the wastegate.

blcknspo0ln · 03-26-2004, 08:31 PM

then why is it suggested by everyone to get a larger o2 if you have creep?

DSM mechanix · 03-26-2004, 08:50 PM

Quote:

Originally posted by blcknspo0ln
then why is it suggested by everyone to get a larger o2 if you have creep?

Not a larger o2 housing but one that vents the wastegate gases. It just so happens that the o2 dumps come in larger than stock sizes.

NickMOSU · 03-26-2004, 11:23 PM

Quote:

Originally posted by ShapeGSX
That is a spike, not creep.

Porting the wastegate won't solve that.

That is a boost control issue, not a wastegate issue. The boost controller isn't reacting quickly enough. Having a larger wastegate port isn't going to speed up his boost controller.

I had the same thing happen with my T25, btw. I never did anything about it. I don't think it is a problem. It isn't as if the T25 is going to flow a damaging amount of air in that circumstance.

Yup, I had the same thing happen to me, my T25 spiked to like 20 lbs in third, before I put in my profec B.

DSMJim · 03-27-2004, 06:08 AM

Quote:

Originally posted by kpt4321
Wrong.

Porting the O2 housing does nothing for creep. Creep comes from the restriction of the WASTEGATE, not the O2 housing, so you would need to port the wastegate.

Another thing guys have done to fix their creep problem is port out a straighter path for the wastegate too. The exhaust has to do a pretty hard 90deg turn when coming out the wastegate so one guy sloped the side of the housing into the wastegate hole. He removed material from the side of the housing going downtowards the hole as well as making the hole larger. Apparently this all be eliminated his creep problem.

1fast97gsx · 03-27-2004, 08:22 AM

does anyone know the answer to the original question?

Fmstrat · 03-28-2004, 05:37 PM

No answer as of yet, but I have found that the spike is actually related to the BCS. When the BCS is connected, it slows down the actuator's response, and causes it to open to slow. It sustained the boost, and porting would fix that, but once I fixed the spike, it didn't matter.

As a temporary solution I've blocked off the vacume line so it goes just from the turbo to the actuator. I now hold 12psi on the nose until near redline it drops off.

So, putting together a ball and spring MBC that shoots the air through fast should let me get the 14psi I want easy enough.

DeezNutsForYou · 03-29-2004, 11:30 AM

I have a bleeder valve, and even when I have it closed, so all of the air is going directly to the wastegate I still have creep. I have a bad valve seal which is causing me to burn oil like a muther. So I think all the crap might be cloging up my wastegate hole. Also I just found that I have been running with only one nut on my downpipe, so I don't know it that would effect anything, I haven't heard any exhuast leak. And buy the way, my creeping seems to be rpm dependent. Anytime I spin above 5500 is starts creeping and the higher I spin the farther it will creep. It will go to 20 pounds if I let it.
I really don't know whats up with my car

Fmstrat · 03-29-2004, 11:53 AM

What turbo and exhaust? I had a full 3" no-cat on my 1G and the only way to eliminate creep for me on the 14B was porting.

Ben K · 03-29-2004, 12:30 PM

Quote:

Originally posted by Fmstrat
Does the T25 have the same size wastegate? If not, anyone know the flapper's actual measurement?

Thanks.

33.5mm

Fmstrat · 03-29-2004, 12:50 PM

Wow, that's almost as big as the upgrade flapper (34mm) for the 16G. What is the stock 16G size?