[Superacerc]

Sounds like a good plan to me. what brand turbo are you planning on running?

 

[Superacerc]

Sweet. Mine's working great. I thought I had an issue originally but it was my inlet holding things back. I would suggest getting a better inlet while youre doing this if you can. I was having trouble pushing past 22psi on my 18g and now realize that it was the inlet keeping back my airflow. The 20g didn't want keep pressure past 20psi and would fall rapidly until i put the inlet on and now it'll hold 25psi+. I never would've thought it was that big an issue till it happened to me.

 

[Superacerc]

I don't think we have too many options like the sti intake guys have. Perrin worked great. I suggest doing it while the turbo and intercooler are out so you can get the back hoses attached more easily. You should be able to pull it through without the turbo on.

 

[Superacerc]

I'm looking at the same turbo down under in Australia, but with stock
Fuel Pump
Injectors
Air Intake
BCS
I do have a HyperFlow TMIC and TurboSmart Kompact BOV

If you plan on upgrading injectors and pump later on it sounds like a good plan. If you don't forsee yourself doing that in the future the vf52 would be a better option/or whatever the japanese Legacy GT equivalent has in your hemisphere.(I'm guessing your 08 has the LGT style intercooler).

Reason being, the 18g tends to spool about 700-900 rpm later than a vf series so you lose a bit of quick off the line turbo time. Couple with that that running out of injector/fuel on the top end and cant run the turbo as far as possible and youve limited yourself to having a bit of midrange power and not as much elsewhere. Whereas the vf series will give you a broader range of power. you'll get a full low end power and nearly as much as possible on the turbo with minimal fueling issues on the top end.

The 18g will still be better than the TD04 turbo but not as strong as a vf series without the supporting fuel mods.

Due to fueling the 18g and vf52 will have relatively the exact same upper rpm possibility.

Just food for thought.

Edit:

Here's a completely non actual graph(not real in any way, i just used paint to make it) to show you the approximate difference between having the same fueling capabilities and where you'll gain with a vf model. In the top end I only seperated the lines to show see them differently but in reality they'll be pretty much on top of each other.

 

[Superacerc]

Might be able to find a used one. The price is tough to beat though and would allow you room to upgrade.

 

[Superacerc]

With full fuel support though you'll get more top end out of the 18g. It'll definitely be quicker than the 52 with no pressure loss at redline. You'll like it.

A td05 20g will spool essentially the same as your 18g(mine actuall spools quicker with the inlet changed~3500rpm). The hot side is the same. You'll just have more air flowing through. There's no downside to a 20g vs an 18g as long as theyre both td05s. Theres no reason to move to a laggier td06 with our automatics since the spool is higher in rpm and we cant use that area anyway. A td05 and td06 20g both make the same power just at different rpm levels.

If you haven't bought a turbo yet and are going 91oct you might as well get the td05-20g. On 91oct you still won't be over the engine's power limits and itll spool the same as the 18.

 

[Superacerc]

Definitely no problem with the 18g. I loved mine. Just more future potential with the 20.

 

[Superacerc]

It seemed that manufacturers typically rated a normal td05 20g and td06 20g with the same hp rating. I'm sure there are some differences in the more specialized wheel setups, but would an auto Forrester forced to shift at 6100rpm see any real performance gain by switching from, lets say my td05 20g to a td06h sl2 version? And would it offset the fact that I would lose a fair amount more spooltime?

I figure if you put my turbo against nates, same car same psi target and timing mine should make the car a faster car having earlier spool and being able to maintain the same pressure till redline. Our cars are forced to shift so early I dont think its beneficial to go td06. There are some special turbine versions that should make some difference though I agree there. But same standard compressor turbines and housings with just different hot sides dont seem beneficial to move up.

If course im bench racing here so its purely speculation. Id be very interested to see it tested though.

Keep in mind our low redline patrick. We don't have the luxury of a manual shift SH model xt here in the states so higher shifting isnt an option at all. Were stuck at lower rpm levels where the td05 doesnt have a chance to run out of top end.

 

[Superacerc]

If its the exact same compressor wheel how would 15psi be any different though? The only difference is the 05 can get to 15psi earlier in the rev range. The standard model turbos are identical with exception of the exhaust wheel and housing, nothing changed on the air pump side.

So lets say we could artificially turn one turbo via 18 speed bicycle till it puts out 15 psi and we do the same on the other but in a different gear. they are identical compressors just one guy pedaling faster than the other to get it.

Don't get me wrong, if I had an sti or a manual tranny and planned on shifting at 7500 rpm, the td05 wouldn't be effective at that point and td06 would be needed. Just not for us auto guys who'll never see those engine speeds.

 

[Superacerc]

Also think about this, both being the exact same compressor they both will make 15 psi at the same rotating speed. Meaning the turbos have to spin the same rpm to achieve 15psi. The only difference being on the exhaust fan and how effecient at turning vs exhaust speed it is. The td05 will turn quicker with lower exhaust speed and the 06 will take a bit mpre exhaust speed to get it moving. When blouch used to carry a standard TD05 and TD06 20g, they rated both at 440hp and 44lbs/min. If they're the same compressor they have the same potential for power making. Just depends on how fast you want to get there.

 

[Superacerc]

So the compressor is actually different on that model then and that makes sense. But if the turbo were to have the same cold side compressor and same max flow rating it stands to reason that it would do no better just flow differently at different rpm levels.

That being said nate, do you think with the quicker spool and 60ft time would give you more advantage over the td06 housing you currently have at the drag strip?

For what it's worth, my TD05 20g seems to be capable of making the same pressure through the rpm range as your TD06 without falling off any different. In fact I'm hitting 21-22psi at redline with only 34% wastegate duty.


Sorry for the thread hijack.

 

[Superacerc]

I deviated my off topicness back to your journal Nate. Sorry wudabum for the side track. Continue on and let us know how it goes.

 

[Superacerc]

now you guys got me wondering if i should do vf52 or H 20g

If you have the fuel pump and injectors upgraded, The (another shameless plug) TD05 20g doesn't spool much slower than the vf52(although still noticably so) and you'll get all the power you can handle on pump gas without running out of psi at redline. The 18g is so similar to the vf 52 it's not really worth comparing the two but the 20g definitely will give you some lovely go power. Either way, if you plan on buying a new turbo, consider the Kinugawa and it's cheap price and pick up the 16/18/20g for 400 dollars cheaper than a new VF52.

 

[Superacerc]

I wouldnt say unseen. Its not like the switch from td04 to something else but its noticeable for sure. Its probably gotten me close to where I was on e85 on the 18g. Probably a bit shy. Maybe 30-40 more hp than gasoline and 18g combo.

 

[Superacerc]

The good thing about breaking things (take note everyone) is you get a perfectly legitimate reason to tell your wife you need to buy an upgrade. If they didn't make cars so feeble in the first place I wouldn't have to replace this stuff right? All cars should be built with minimum 500hp in mind.

My Outlook from the start when I do some of the stuff I do is with full understanding that ill probably end up breaking something and im prepared to deal with it. I dont want things to go wrong but because of things going wrong I've ended up with a built motor, inlet (because of a tear), up pipe(from diagnosing low boost) and in the future I will be surprised if my transmission doesn't fail.

 

[Superacerc]

Make sure you get the 2.4" inlet and not 3 inch unless you plan on buying an adapter or bigger inlet. 8cm housing.

 

[Superacerc]

They look to be identical minus the devil logo. Same parts, actuator, covers etc... I wouldn't hesitate to use them. Probably exact same factory and assembly line. Id be curious to see how much better the ball bearing Garrett style do. You could be the Guinea pig for us and explore the unknown. Should be better spool.

 

[Superacerc]

Here, ill unconfuse you.

There are two sets of blades. Compressor blades and turbine blades. Both are on the same turbo. Turbine is exhaust side and compressor is intake side. The gtx has 9 blade turbine and 11 blade compressor.

The 2863 flows like a mix between 18g and 20g but calling it 18g isnt correct because 18g is mitsubishi heavy industries terminology. 2863 is proper Garrett terminology.

Like Nate said. 8 cm(referring to turbine housing/cover size) and ported are your options to add.

Aem isn't too loud but noticable kind of like a jet turbine sound. When not in boost though you cant hear it.

 

[Superacerc]

Dont forget you need legacy gt/08wrx fitment unless you have a process west intercooler or are buying one of the cnt or fast motorsports copies.

 

[Superacerc]

The stock intake works ok till about 300hp. I like the aem one, ray sells em and has good base tunes for the aem airflow so it makes things easier. Aem is also one of the only true cold air intakes locating the filter down in the bumper behind a cover to keep out engine bay heat. It stays pretty much at ambiant outaide temps according to the intaje temp sensor.


It would benefit you as well to get an inlet at that point as well. I realized even my 18g should have had one to help it I out. Too much volume for stocker and youre likely to tear that one anyway with an install on your turbo.