My plan for a fast spooling turbo on a 2.0

[bnr32jason]

Haha! Would that really work? Even with no identifying marks on the engine other than stamped engine codes and part numbers?

[Xusia]

Hahaha! I've actually done that before to avoid late fees when registering new vehicles (I went past the 30 days allotted).

[sponaugle]

I read a post by Clark Turner on nasioc about a car he tuned running a 2.5L with TD04 and external wastegate (ewg) vented to atmosphere. He said it was one of the funnest cars he's ever driven because spool was so fast and the EWG (along with not being plumbed back into the exhaust) helped with top end power. Obviously there are downsides to that setup (noise, pollution), but I'd love to take a test drive.

Edit: Here's the post from 2005.

I tuned a similar WRX back in 05, but it had also been converted to rear wheel drive only. It was pretty amazing at drifting sideways. The torque came on so fast you really could drive it like a large displacement car. The same owner switched to a 20G a few months later, made about 350whp, and wrecked it on the first test drive. Massive torque onset with rear wheel drive only is a great way to learn about end swapping.

Jeff

[Evan78]

Wow, that's too bad. Glad to see you here Jeff.

[sponaugle]

Wow, that's too bad. Glad to see you here Jeff.

Yep.. I think over all the cars that I tuned, that was the first and only one to crash on the first drive. At least some people had the decency to give it a week.

It will be interesting to see what other Subaru people we get over here. This is kind of a neat project for someone who has been in the Subie world for a while... and a good use of those EJ20s lying around!

Jeff

[longislandwrx]

Well it arrived on Monday. Super happy with it.

http://thefactoryfiveforum.com/entry...t-s-Turbo-Time!

[Frank818]

Beautiful piece! I hope you'll achieve what you're looking for.

[Frank818]

I have a question.

Gut feeling, what do people think is the maximum torque achievable with any turbo that full boosts anywhere under 3000rpm?

For 2.0 and 2.5, plz specify which.

I know there are compromises with turbos, if you want full boost at 1500 you probably won't have 500wtq on a 2.0. So I was wondering the approx max torque output achievable on a very good tuned 2.0 and 2.5 engine (parts and map) if its turbo hits full boost under 3000.

[Evan78]

I'd suggest looking at dyno charts for OEM turbos. They typically hit full boost in that range and there will be plenty of data. A TD04 (2002-2007 WRX) will typically do 220-230 ft/lbs at the wheels on a 2.0. On a 2.5, they'll make over 300, but fall off quickly since they are pretty small for a 2.5. Various VF series stock turbos on 2.5L engines (STi, Legacy, Forester) will typically make torque in the low 300's on a 2.5L. When I say typical, I mean using the most common modifications of an aftermarket downpipe and engine management in the form of a reflash of the Subaru ECU.

Additional modifications may squeeze out a little more, but the gains are going to be pretty small for the money spent unless you're using something other than pump gas.

[Frank818]

Yeah I have seen a bunch today. I admit I prefer the 2008+ dynos, lots of torque in the low and it keeps it up until redline. But considering the price of a donor, minus the engine, + buying a 2008 engine and trying to make it fit (may not be bolt-on), etc., not worth for me.

It seems in the dynos I have seen a 2.0rarely full boosts under 3000 or if it does, it has not much torque in the low and all of sudden it blasts some good torque. But that typical high slope or steeper slope is common on smaller displacements.

I also have seen that a better flowing IM (like Cosworth) and big valve head, ported stuff, twin-scroll, blue printed engine, excellent AVCS and map tuning, all this seems to add up to reduce spool time, full boost rpm and peak tq/hp. It also adds up in the wallet too.

Like we all say, there are always compromises with turbos (assuming using one turbo).