Wow. seems like an old thread. still looking for turbos?

You remember the matrix? not the crappy ones after the first one. the actual matix? where what's his name is talking to the little bald kid bending spoons? and the kid looks at him and goes, "There is no spoon."

Well... that's what lag is. No such thing. Their is starting at the wrong RPM, or the wrong gear, or whatever you do wrong to ask the car to go fast, but their is no lag.

With a larger turbo even when you make less "boost" chances are pretty decent that you are moving just as much or more air. worry less about what boost you hold to redline, or where your turbos are making 15 lbs of pressure, and more about getting as much air into the engine and out after it's spent as possible.

I don't care what kind of turbos you run, but don't decide based on lag.

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Bad decisions make good stories.
Look at it! LOOK AT MY @SS AND TELL ME IT'S PRETTY!

...and don't pic a turbo that'll only be fully spooled at 6000rpms too. Doesn't leave much room for fun before you hit redline.

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06 Blue EVO 9

but for those two seconds... man what a ride...

_________________
Bad decisions make good stories.
Look at it! LOOK AT MY @SS AND TELL ME IT'S PRETTY!

I didn't realize how old this thread was, whoops.

Yeah I agree with both G-ELL and TT, I think you're both right.

For basically any TD04 turbo, ttangel is right, I mean, as far as TD04 and even TD05 turbos (with some head porting), there is no such thing as what anyone else in the import world would call "lag". We're just extremely spoiled by our advantageous cam profile, displacement (compared to most turbocharged imports), our DOHC heads and our 9B's. Stock, EVO's hit full boost by like 3500 RPM... with one stinking 16G. And theirs are DUAL SCROLL! We hit full boost with TWO 16G's around that RPM. So, yeah, complaining about lag anywhere below, say, 550 WHP turbos is pretty silly.

But I agree with G-ELL too, after a certain point, the mass of the compressor wheel becomes great enough where, yes, at the same RPM, it is not pushing the same amount of air, because more exhaust flow is required to push the wheel at a lower speed at an equivalent exhaust CFM. This becomes obvious on 1400 WHP Supras with gigantic semi-truck single turbos. They make less horsepower at 4000~4500 RPM than even some BPU VR-4's at that RPM. That's due to a combination of top end cams and enormous turbos. Some of these are even stroked, and still making relatively low HP at those RPMs.

It's not as important during maximum linear acceleration, but lag is a big factor when you're upshifting and downshifting on a track or in the city. Sometimes you want to modulate or hang at a certain RPM, at which point your turbos will taper off in spool. If you hit the throttle again, it will take much longer for your turbos to spool if they're enormous and laggy, described as the "responsiveness" of the engine. Most people don't want to have to shift at 6,000+ RPM in the city just to be in the right area of the powerband in the next gear.