Big Daddy Turbo TD05

[Subaru_Nation555]

My turbochager has over 115,000 miles on it and untill recently it has been trouble free. Lately, however, it has been making all kinds of noises. Before I blame the turbo I still need to get a boost gauge but the sounds it is emitting is like metal on metal almost. Anyway, just wanting to keep my options open I was looking at the TD05 with the special 90 degree inlet from Deadbolt. I e-mailed them and they said that I might need some fuel mods to handle the new turbo. But isnt the boost of the turbo contoled by the ECU via the wastegate soleniod? So if the was the case the boost would remain at 8.7 or close to that? Or is the boost level control by the pre-set on the external wastegate? I know there are posts handling other aspects of the TD05. Thanks.

[DeadboltEnterprises]

Pressure and volume are not the same function. If the TD05-16G is producing 350CFM at 8.7PSI, while your old turbo was only producing about 190CFM at the same pressure, your injectors are having to work much harder to keep up. While the stock injectors can handle stock boost levels from the TD05, if you even think about upping the boost you will need bigger injectors.

[Subaru_Nation555]

gotcha. thanks for the info. I dont plan on raising the boost at all, so would you not even run at TD05 with out larger injectors or is it safe to do so?

[vrg3]

The stock boost control system was calibrated around the stock wastegate actuator. It won't be able to work right with the TD05-16G's wastegate actuator. So "stock boost" with the TD05 would be if you just hooked the compressor outlet nipple directly to the wastegate actuator with a little piece of hose, and I believe that yields you around 9 psi.

9 psi is a similar pressure to stock boost with the stock turbo and stock boost control system, but as Deadbolt says it is significantly more air because the TD05 makes that boost more efficiently (though it won't actually be 80% more as the CFM numbers might suggest). If you have an intercooler between the compressor and the engine, that may actually reduce overall airflow or increase it, depending on the intercooler's efficiency and restriction. Note that if you do have an intercooler you'll see less than 9 psi at the manifold -- with a Saab intercooler, for example, you're likely to see around 7 psi.

I won't guarantee it, but at the TD05's minimum boost level you should be able to run with the stock engine management. The stock MAF sensor is good to up around 200 horsepower. Beyond that, it maxes out. The ECU appears to be smart enough to notice when this happens, and when it does it throws the injectors open at 100% duty cycle. This isn't good for the injectors, but it can supply enough fuel for around 240 horsepower.

It looks like with moderately restrictive intercoolers (Saab or early WRX) you hit the MAF sensor's rail around 10 psi with a TD05-16G. Realize that that's probably around 12-14 psi at the compressor outlet.

So it looks like if you keep to minimum boost with the TD05 you should be able to use stock engine management. It won't be ideal, of course, and you'll have to be careful, of course, but it should work for the moment.

Things you should do:

- Install a high-flow fuel pump.
- Make sure all your sensors and injectors are healthy. - Have a laptop handy to check things out with my scantool if necessary.
- Install extra instrumentation (like an EGT gauge and an real (i.e. wideband) air/fuel ratio gauge).
- Pay very, very close attention to your engine and what it's doing. If you ever notice what seems like overboost, detonation, misfire, high EGTs, high air/fuel ratios, or other weird behavior, back off immediately and diagnose and repair.

[Subaru_Nation555]

Thanks alot vrg3, thats exacply what i wanted to know. So just to get your personal opinion; would you upgrade to the TD05 or rebuild/replace the stock IHI? Right now all my money is going into making the car look better and some suspension stuff. Some performance upgrades will come later.

[vrg3]

I would upgrade to the TD05 if and only if you're already saving up for engine management upgrades.

Having experienced the TD05 in Matt's car and in Phil's car, as well as in limited capacity in Jason's car, I say that it's the turbo that our cars should have come with from the factory.