I would not blend the front side of the housing where the flapper seals, mainly because I believe you should increase the diameter to the point where you won't be able to blend it and let it seal.

Port volume increases exponentially with diameter, blending does not. You can also blend the port while increasing the diameter, in fact it's kinda a necessity to do so.

What do I know though, my **** don't creep and my turbo has thousands of miles.

Here's my port, and here's a VD plot similar to Scott with massive flat low boost with no hiccups.

 

interesting. that's promising--especially given you have a similar setup.

there is always a worry that the exhaust can push open the flapper and you dont want that, but looks like it's working nicely for you. My boost held flat at 10psi as well.

 

I've actually ran less wastegate preload and run more like 6-7 psi pretty flat, spool does not move that much.

Here's before I played with EBC. I turned my wastegate preload way down because I can't remember, it still does not blow the gate open, nor does it creep. There's boost DC changes in this log, but the signal to the solenoid is interrupted.






This is my first or second run with EBC enabled, settings I pulled from my bum. I was super amazed, no overshoot and plenty of quick reaction in relation to boost DC.

I believe that is port volume, not porting, but that's just my opinion

 

Ported a bit more but still not enough. I still haven't increased the diameter and it is about 20mm or just over 3/4". I wonder if anyone has a measurement of a Garrett port diameter.



12.5 psi at 6000 with wastegate wired open.<br/>13.5 psi at 6000 with 10 half turns preload referenced post IC from about 9 psi when the wastegate ckacks open around 3250.

 

When I get back from the beach I am going to try porting a turbo like deezums and see how it works for me.

 

There is another way.

 

I mean external wastegate is doable, it would just add another $300-400 onto the price of the setup, which sort of goes against this being the budget setup.

 

I feel you, but it is one of the few ways to run a true low boost setup.

 

I run a td04 off a Saab. Hit 14psi on the dyno and run 3-4 psi on the track. I did a session with the wastegate all the way open this weekend and I couldn't build boost at all.
<br />I can't find any pictures of mine but look how the wastegate is angled and merges back into the flow instead of being at a right angle:
<br />

 

Do you mean to tell us that not all turbo's are designed the same?

whoa

 

Just adding fuel to the fire Where is leafy with maths and stuff about hole sizes and how much pressure it takes to blow them.

 

yeah thats a lot better of a design, that's why the EFR ones work well.

 

20yr old turbo ftw!

 

And the flapper actually gets to open more than 5 or 10 degrees like on the Churbos so it's easier to flow through the wastegate hole. I suspect that's the real problem and deezum sort of hit on it in his picture where he relieves some of the material to let it open more although not as much as the SAAB style.

Just my opinion.

In 20 years the Chinese foundry will introduce this new design.

 

Or we could just have shuiends build 2.5" exhaust.

 

I discussed that in a PM with him in the beginning (not because of this issue). Not sure if that's sufficient to create enough back pressure before the turbine to change the flow though. I measured the opening angle when I got the turbo and IIRC it only opened about 7 degrees and was still going to be a blockage in the air flow. I think it's the reason the turbo flows 11.5PSI without the flapper. Without all the data it's hard to do any sort of modeling anyway.

I've ordered some parts to fab up a new flapper housing and should have them to the welder by Thursday. Another way is to modify the cheap ebay housings (like deezum's) but even more severe.

EDIT: Remember the downpipe is 2.5" to 3" so there's about 24" where it's 2.5" IIRC.

And I could be all wrong anyway...

 

Are you all really going to make me go jack with my preload?

I am nearly positive I could run 4 pounds or less pretty flat. If my gate is wired open, I don't get but 2psi or so near redline, I know because I unhooked it for a week when I popped the head gasket.

Something is terribly wrong if you can't run less than 11 pounds with the gate wide open. Having a 3" exhaust is not a problem. Having a tiny *** wastegate hole and trying to force all the waste down it is a problem, that causes pressure differential, that makes boost.

You all are still so fascinated on blending the gate to the flow, yet nobody mentions that Aiden's gate is literally double or more the size of this turbo, look at that ****, it's the size of the turbine... I have sooo much flapper angle now, yet my wastegate can can't even use it all, not enough range of motion without binding.

Volume before flow, always. Make the diameter as large as you reasonably can then blend.

 

I'm never quite sure in these threads if someone's responding to my post without quoting it or not so I'll ask.

I should've referenced sonofthehill's (Carlos) earlier post where he wired his WG open and got 11.5psi.

Otherwise, the reference to you was actually complimentary on the way you modded the area behind the flapper to let it open more.

If your just making general observations, carryon... Sorry!

 

General observations towards nobody in particular, just seems like the point of port diameter keeps getting glossed over.

If you are suggesting exhaust backpressure is necessary, then I disagree. More backpressure just lowers the pressure differential on both sides of the turbo. You should be able to lower the pressure differential using the wastegate, that's it's sole purpose. Shoving restrictions in the exhaust is a very corky way to fix creep.

 

What you did there.
I seez it