legacycentral bbs

im considering getting a td04, and its my understanding that i wont need to run some kind of engine management, but will i need a boost controller?
and how much psi does a td04 spool?
Is there anything i should know?

any feed back is greatly appreciated!

Judging by the questions you asked you dont seem to know enough

A Turbo dosent boost spool, it is spooled by the exhuast gases

you wont gain anything without any intercooler, ill be back later, too tired

Yeah. You really need to look into intercooling first.

I will try and give you a short version of what the guys are trying to say: but i WOULD recommend reading up a bit more before you start modding.

The TD04 is a slightly larger turbo than the VF-11 that is on the USDM legacy turbo. The pressure reading or PSI as you put it is set according to the wastegate actuator on the turbo and the engine boost set-up. Each turbo/actuator/car set-up is different. The Vf-11 on your car is set up to run 8-7 psi. The TD-04 is set to run about 14 lbs on a WRX. If you move the TD-04 to your car, your controller will try and keep it running at the original 8-7 lbs. The car will allow up to 11 before it cuts the fuel ( and you do not want to be there.) A Boost controller adjusts the amount of air in the lines and bleeds it off before the actuator opens. So where your car is set to run at 8-7, a boost controller will allow you a few more lbs. But you still have to deal with the fuel cut at 11-12 lbs.

So If you decide to go to a td-04, then just hook up the turbo and leave everything else stock. Since our cars do not have an intercooler, if you do not add one, then we do not recommend adding more boost as this can be very harmful to your engine.

read up and educate yourself some more.

dscoobydoo,
U just answered about 10 questions I had running thru my head!

I'm doing a swap from a '92 SS to my '90 and this is great info.

Thanks a bunch.

TD

apparently i misused the word "spool". I have a 07 intercooler all rigged up and ready to go, but my only beef was finding a better turbo. Now that i have decided to actually do a TD04, i was just wondering about how much more boost i will gain, will a boost controller be needed.

I already modded the intake and exhaust(3") like i said the intercooler is ready to go, and i have headers waiting to go on.

dscoobydoo wrote:I will try and give you a short version of what the guys are trying to say: but i WOULD recommend reading up a bit more before you start modding.

The TD04 is a slightly larger turbo than the VF-11 that is on the USDM legacy turbo. The pressure reading or PSI as you put it is set according to the wastegate actuator on the turbo and the engine boost set-up. Each turbo/actuator/car set-up is different. The Vf-11 on your car is set up to run 8-7 psi. The TD-04 is set to run about 14 lbs on a WRX. If you move the TD-04 to your car, your controller will try and keep it running at the original 8-7 lbs. The car will allow up to 11 before it cuts the fuel ( and you do not want to be there.) A Boost controller adjusts the amount of air in the lines and bleeds it off before the actuator opens. So where your car is set to run at 8-7, a boost controller will allow you a few more lbs. But you still have to deal with the fuel cut at 11-12 lbs.

So If you decide to go to a td-04, then just hook up the turbo and leave everything else stock. Since our cars do not have an intercooler, if you do not add one, then we do not recommend adding more boost as this can be very harmful to your engine.

read up and educate yourself some more.

so, just bolt the wastegate actuator from the VF11 to the td04?

Would it be realistic then to use a td04 with an 07 WRX intercooler, and maintain the OEM intake system by using a 90 degree coupler on the intake side of the turbo? If so, is it then necessary to up the boost with a manual boost controller, or could it be left as is?

its not necessary, but why go through all that trouble to not make more power?

I agree with you that it's pointless if you're not going to up the boost, I'm just a n00b at doing so. Would you just bolt the VF11 actuator to the td04 and plumb a MBC in line?

I am just unsure how it works as far as the stock injectors keeping up with more air coming in, and whether or not it would lean out the mixture too much.

The TD04 has a stock wastegate pressure of 9 PSI. You can simply run wastegate pressure if that's all you want, or you can by a manual boost controller (MBC) and adjust it to what you want.

There's no need to switch the actuators at all.

The stock injectors are good up to about 12 PSI. After that, you'll want to get bigger injectors and a fuel cut defender (FCD).

9 psi on the OE TD04?

At the risk of sounding argumentative I've found that all three of the OE WRX TD04's that I have installed on my OBS each boosted 8 psi. This is quite consistent with what I have read on NASIOC too.

was that with an intercooler?

because intercoolers cause pressure drops across your system resulting in lower boost readings.

That's with a TMIC but boost taken from manifold pressure and wastegate controlled by manifold pressure and not directly off the nipple on the turbo outlet. I have that nipple capped.

Hmmm ok. I always thought it was 9 PSI, but if you've read and even seen 8 PSI then I'll definitely admit I'm wrong on that lol.

I look at the TD04 as getting a better replacement turbo that is easier to make the intercooler work with.

That is it.

It is not an UPGRADE in the sense of running MORE boost- although it can handle more and work with it better than the VF-11.

But you have to remember that at the fuel cut point, you will have to run a FCD. And then the injectors cap out. At that point, going with a bigger turbo, injectors, and a piggy back or standalone is going to be necessary if you want to see real gains.

So I suggest getting a td 04 as a replacement for the Vf-11 and to make it easier to fit the intercooler.

Then save up for the bigger turbo, the injectors and the ECU management that you are going to need.

But SOOOOO many people forget the mods to stop and handle.
To me, those were the most important.

I got the 4/2 pots, and the springs, bars, and all the handling stufff WAY before I ever started in the engine bay.

dscoobydoo wrote: But SOOOOO many people forget the mods to stop and handle.
To me, those were the most important.

I got the 4/2 pots, and the springs, bars, and all the handling stufff WAY before I ever started in the engine bay.

Woot! ^^^^^^

+1 on the TD04 (& TD05) boosting 8psi on the actuator.

I think the brakes & handling of a stock car (in good running condition (no blown struts, or metal on metal brakes...)) are enough to control what the engine will be dishing out @ TD04 boost levels before fuel cut.

Once he decides to hold 15psi on the TD04 he will need to address the brakes @ the bare minimum as they will fade after a few stops.

Having had both turbos on my 4eat SS in the past few months I can tell you the low-midrange pull on the TD04 can be impressive, whereas the TD05 (@ 17-18psi) pulls hard from Mid-High RPMs & does not taper boost off the way the TD04 does.
With the alky working on my SS I used to spike the little TD04 to 19psi which felt nice & strong @ the lower RPM range.
Without alky I played it safe & kept boost @ 14psi....

Another TD04 question here: What CFM is the TD04 rated at? And the VF11?

Subaru TD04's range from 360-390CFM.
There is a BIG TD04 that came on Volvos that's rated @ a little over 400CFMs. My friend has one in his garage somewhere, I have to see if it will connect to a Subaru e-housing one day. One nice thing about this turbo is that it has a bov/BPV right on the compressor housing.

? CFM on a VF11.

Hmmm, interesting. I havnen't scene that before, post a pic if you have one!

&
Anyone cfm on a VF11?