Rasta

Man I am about to shed a tear. I just dropped more money on my ride fix it. I am not sure if you guys remember but I am the guy with the T4 turbo that has been having boost creep problems since it was built. I purchased a 44mm TIAL and I now have a .58 turbine housing on my turbo. I thought the wastegae would fix the problem but it still remains. I have changed the feed on the compressor to a bigger one, I have tried to connect the feed directly to the wastegate and tried to use the boost controller to regulate the boost but nothing has worked. I am at a loss; the only other thing I can think of is that the dump is for the wastegate is back into the 3" downpipe. I guess the only thing left to try is to dump it to the atmosphere. Do you guys have any ideas anything would be of help.
Here is a link to my last post:


https://www.scionlife.com/forums/vie...924&highlight=

toyotaracer9

maybe the wastegate pipe doesnt have access to enough of the exhausts heat energy . and it has no choice but to go into the housing .

318_tC

Which manifold do you have
why not .63 a/r
what are u tuning with
dump into atmosphere for sure.
what size down pipe.

paul_dezod

Might be your manifold design.

Rasta

I have an AEM stand alone, the manifold is some Chinese header that I modified but the wastgate is in a good place. The downpipe is 3" into a 3" exhaust. Here is a old pick of the engine. The wastegate and turbine housing is different though.

Rasta

I know a couple of people that run the same mani, the only differnece is that I modified it to fit a T4 and a 44mm TIAL.

Joe_Dezod

Have you tried porting your o2 housing?

With DSMs... Let's say you have a 3" cat-back, then you switch to a 3" DP as well, you tend to have boost creep. Only viable solutions are to switch turbos, port the o2 housing, or go back to a 2.5" DP.

Just throwing that out there.

Rasta

Porting the 02 housing? I have not tried that but I am not sure how that would affect the boost creep. I have a 3" exhaust no cat all the way back. Switching turbos is definitely not an option. Can you explain more about the o2 housing?

Joe_Dezod

Actually I just remembered you have an external wastegate like most of us here lol. The main concept behind that was to allow the flapper on internally actuated turbos to breathe better. It kept the creeping down.

I'll try to think of other options.

If your vacuum sources are all perfect and you're 100% sure, the only other thing I can think of is to dump the wastegate to atmosphere.

Rasta

Yea the source is good its all in a vac block. I even connected the wastegate direct to the turbo. I am out of ideas. I will dump it to the atmosphere. If that does'nt work I am screwed

OuterHeaven

The only thing I can think of is that dumping to the atmosphere may help or the manifold design just does not flow enough exhaust to the wastegate to regulate that big of a turbo. The only other thing is to make sure that the wastegate is working properly (which it seems you already have). What kind of pressure ratio are you running with that big of a turbo?? I think that turbo flows too well and the wastegate just is not getting enough exhaust gasses to begin with (much less the wastegate being big enough). Maybe this is why the T4 manifold that Full Race is building (http://www.full-race.com/catalog/pro...oducts_id=1049) has 2 wastegates.

Rasta

The manifold has a good design and wastegate pipe is right in the collector where is needs to be so it must be getting enough exhaust. When you say pressure ratio I am not sure of what you are asking. Do you mean the size of the compressor/turbine?

Rasta

This is my third wastegate, I had a evolution, then a TIAL 38mm and now a 44mm

318_tC

Who is tuning ur car? What have they said? That manifold looks scary

g3kko

Have you considered plugging the exhaust with a silencer? Enforce a little extra backpressure at high volumes?

/possibly too quick n dirty

Rasta

I wouldnt do that, the thing is I to get the most out of what I build, I dont want to limit the engine in anyway, there must be a way of fixing this without loss of HP's you know what I mean.

318_tC

Whos tuning your car man, and what do they say about it.

How many psi are u running? and what kinda numbers u laying down? you built block at all?

BOXMAN

Rasta how did you check your wastegate?

paul_dezod

No he does not mean that. Pressure ratio is the Y axis on a compressor map. It is (boost PSI + 14.5)/ 14.5.

Do you have any pics of the manifold by itself without it being installed? If it is the manifold I suspect it is, the WG placement and plumbing is far from accurate.

With respect to the FR stuff.....Don't get me wrong they have nice looking and some very nice performing items, but I personally have seen some friends of mine with poor results from their manifolds with respect to WG operation.

OuterHeaven

Whoops sorry I actually did not mean pressure ratio but the pressure ratio between the intake manifold and the exhaust manifold (also know as the TIP/IMP ratio). Most stock cars have a TIP/IMP ratio of 2 while race cars actually aim to have a ratio less then 1. What I am really getting at is that if your turbo is flowing well enough then the pressure in the exhaust manifold will be very little and therefore the pressure difference between that exhaust manifold and after the turbo part of the exhaust/atmosphere might not be big enough the allow enough air to pass through the wastegate.