dominator 3.0 yay? nay?

[nkw8181]

Ok first off I know this would be overkill if put wide open. One of the local shop guys has a used one for sale with ~5k miles in it. It had the 10mm hot side, ceramic coated, and internal Watergate closed off. The other turbos I'm looking at are like the 18g 20g size. Now the 3.0 would need an external Wastegate but for what I can get the turbo for can buy that and an up pipe for less then what it costs New. I have an 06 wrx (2.5L) and goal is 350 whp/wtq and if I rebuild the engine later maybe bump up to 400~. So what would you do? What I've found suggests spool up in low 3's.

[nkw8181]

I've been trying to learn subbie stuff now for a year and still feel lost.

[philly15]

I think that is going to be way too much turbo for this application. The Dom 3 is a 450whp easy turbo. It's going to be tough to "detune" it and keep it efficient at the same time. Plus you're going to need to contemplate some serious injectors, and larger fuel pump on top of it. Check out the NASIOC forums and search for dyno tunes of that turbo and you'll see what I mean. I would also bet it will spool fairly later than what you would want for the 818. I think with a host of factors such as porting and polishing, tgv deletes, external wastegate as you have stated, and possibly even an alternate fuel (like e85), you might be able to spool it in the early 3's. Otherwise from what I've seen, I think you're looking at closer to 4k. On a 2.5L, I don't really see any reason to go larger than a 20g, the tuning is going to be way more important than hitting a certain tq or hp number. I think with something smaller like an 18 or 20g you will have much more usable power, as well as initial torque after the turbo spools. Although that can all be achieved by a good tuner.

[nkw8181]

Thanks. I'm giving serious thought to the GT2871R. Though I'll still need injectors from what I gather spool will be quick and a good power curve. I should have added that above. I would rather a good curve then just top end numbers.

[FlatironsTuning]

If your goal is 350, you will be a lot happier with a Dom 1.5 than a Dom 3.0. the Dom 3 will make 400 hp and a little more. With a 2.5 you will most likely be waiting until 4,000 rpm for it to spool up. The 10CM hot side is pretty big if you want the turbo to spool up quickly. And to get a benefit from an external gate, you would actually want a smaller hot side to the turbo would spool more quickly.

I'd say look at a 20G, 20G XTR, or a Dom 1.5 with an 8cm hot side. That will give you a wider power band and quicker spool and still let you hit your target power.

[Hindsight]

Agree that 3.0 would be too big. In a car this light, you don't want all that power coming on in an instant. Other tuner's I've talked to have echoed Flatiron's advice above: 20G or 1.5. Still gets you a wide power band and 400whp or very close to it on '93 with a good IC.

[philly15]

Thanks. I'm giving serious thought to the GT2871R. Though I'll still need injectors from what I gather spool will be quick and a good power curve. I should have added that above. I would rather a good curve then just top end numbers.

This used to be my favorite turbo, but it's a tad outdated. There is better technology out there now. I'm going 1.5xtr when it comes time to upgrade. As far as injectors I always go ID1000's. Super smooth at idle, and should be plenty for the application.

[Wayne Presley]

The GT2871 is a good fit for what you want. The 20G with a billet wheel is another good choice.

[nkw8181]

Thanks for the input everyone. I think I'm going to table upgrading the turbo for a bit. If/when I do I think I have a handle on what I will want to do.

[scott s]

Bringing up an old thread here but I was considering the dominator 1.5 xtr until the new cobb td05 20g-8 came along. Ya the cobb is a journal bearing turbo but after doing a ton of research it seems ball bearing turbos of the same size only spool about 150 rpm sooner. The new cobb is making spool fast and holding power to redline. Also ball bearing turbo's can be pricey to fix and some are not really rebuildable. The price of the cobb sure is attractive.
My thoughts are grimspeed up pipe and xover with stock pnp exhaust manifold, cobb ebcs, cobb sf intake, perrin aos with catch can to drain bypass oil back into the oil pan. Not positive I need to pnp the intake manifold and or heads but I think tgv deletes are a must. My thinking is if everything is apart I may as well pnp the heads and intake also matching the tgv deletes runners. My goal is 350 whp and I think it can be achieved without the head and intake pnping and also not doing the tgv deletes but doing it now will make more room for more hp LOL! Oh ya and a custom turbo back exhaust. Head studs are a must. Cant decide on forged pistons? If I stay at the 350 whp limit?
Would rather put the bucks into the 5 speed gears and lsd.

PS. all supporting mods like injectors, fuel pump, fuel rails, high flow oil pump etc.
This is 2006wrx motor.