I'd say that your main two power adders at this point is going to an cone filter/hard pipe intake and a tubular manifold like from Full-Race. I'd rate the ported intake mani 3rd.

 

The wastegate doesn't make more boost if it's "bigger", the wastegate opens to divert exhaust gases away from the turbine, which makes less boost.

In this application, he wants the wastegate to stay closed as much as possible up top so the turbo would make more boost.

I would not touch the wastegate hole at all, this can actually make the turbo make less boost. It needs to be sealed up nice and tight to make more boost.

Porting the turbine area would make more power. Power can be had from porting the machined lip right by the turbine blades to match the turbine hotside area.

From this:



To something like this:

 

razor surely at peak power the turbo is being supplied enough exhaust gas to make it produce the desired boost?
if your theory was the case the wastegate would be redundant!
hence why you can extract more power from the same turbo when using external
over internal wastegate setup!

 

More power is extracted when using an external wastegate over an internal because you seperate the turbine and wastegate gases, which decreases turbulance and backpressure at the turbine, not because the wastegate is flowing more exhaust gases.

 

we'll have to agree to disagree slightly
whilst turbulance is a condition i beleive its negligible at modest outputs,
in the case where the wastegate gases are exhausted through its own exit pipe
and not rejoined to the exhaust a little downstream yes a backpressure reduction will be realised to the turbo,
but more importantly more flow of exhaust gas can escape from the engine
when using external, hence the availability of ever bigger and bigger external gates
my 2 pence

 

Well now you are moving further away from the stock turbo dynamics and into larger turbos which are much different as far as exhaust flow. Bigger wastegates on larger turbos are used more to control creep, as the larger turbos are rarely close to having closed wastegates. The larger wastegates prevent "boost creep" since the exhaust gases flow much more than the stock turbo, if the wastegate can't keep up with moving certain amounts of exhaust gases away from the turbine, the turbo will produce more boost than is desired. A wastegates primary function is boost control.

If he wants more boost up top on the stock turbo, in a perfect world, he would want the wastegate welded shut. Of course this would increase boost at the low end to a possible unfavorable level. This is why the higher rated wastegate actuators work well on the stock turbo, they keep the wastegate flapper closer to closed much better than the stock actuator. The stock actuator can actually be blown open by exhaust gases.

To agree with you however, is that having the wastegate fully shut on the stock turbo will increase turbulance and backpressure as only so much exhaust gases can flow through the small turbine on the stock turbo.

Either way, porting the actual stock turbo wastegate hole is not something I would recommend. I have seen a bunch of people do this and it actually decreases boost and decreases power on the stock turbo.

 

there is always more but is the cost worth it?

 

dont overspin the stock turbo

 

Care to comment on that?

 

I guess what he means is He has a cobra with a supercharger. And he knows that if you overspin the turbo. It will grenade and kill a city the size of Houston!

 

1. UICP (less bends more power)
2. Intake and with filter (Buschurs is nice but i have the ETS with recirc pipe)
3. ported/aftermarket intake manifold AND 65mm throttle body (at da same time)
4. maybe an evo9 bov (im not sure if the 05's hold boost like the evo9's/jdm)
5. stand alone??? (ive heard that ur able to gain more hp because of more opts)
6. maybe cam gears to fine tune it and grab every ounce of power)
7. maybe larger injectors (dunno if that will help but maybe)
8. the only thing after that would be evo9 turbo, etc

youre making great numbers but your prolly starting to push out some hot air now. you can do meth but i personally like 93oct for daily and race gas on the track days. eitherway great numbers homie!

 

about 22 psi, on boost gauge..

Thanks everyone for the input, seems like there's a few ways I might be able to get the power up top... one thing I have not done YET is porting of any kind, but I think the intake work might be first...

I also was wondering on that hotside porting... my turbo came with the 10.5 ('05) hotside, but I think that is a big choke point also.

So I'll do intake and see what happens, probably in evoscan... quite a drive and $$ to dyno so might have to wait until I do the porting and everything to go back, but at least I can try for a before and after intake in data log labs.

 

Isnt the EVO 9 Turbine housing bigger?
You could change to a bigger E9 turbine housing, get more top end power, and still call it stock (of course "stock" is in the eye of the beholder, but most people fall for political BS wording anyway)

 

Evo 9 compressor housing is larger, turbine is the same.

 

thats interesting that u taper all the way down to 20.... i didn't know it robs u like that.... i mean i know its not a beast but from 29 to 20 is pretty crazy... good info for me to know haha