Dang. Pwn3d.

I tried to be nice;) Beer is a cool dude, he just doesnt realize that trim and a/r are not the same thing.

He has the same thing I do, its just a stage 3 wheel in a .48 a/r housing. How cute, we have matching turbos.:gay:

I know what AR is, everyone just calls it trim for turbines. Slip of the tongue. Anyway there definitely is a T3 housing with .48 A/R stage 3 turbine wheel. I didnt think my imprecise language would be that big a deal.

Anyway, I spent like 8 hours and finally got it installed. I swear like 3 of those hours were spent dropping tools into the engine bay and not being able to find them again. And finding that I didnt have bolts to attach the oil drain line and having to find replacements from elsewhere in the garage/engine bay.

And the results?

For the record:
compressor housing: T04e 50AR
compressor wheel: 50 trim (?)
turbine housing: T3 .48 AR
turbine wheel: stage 3

I didnt mean to get on you about it, but I honestly cant stand when you say a stage 3 48 trim....because someone reading that might take what you say as the correct terminology. Just trying to keep people smart around here;)

I know how you feel about dropping tools down in the engine bay, it happens to me all the time and then i cant find where they went. its like they have dissappeared forever.

Ok just got back. The car makes 15 psi around 4000-4200 rpm and makes solid power all the way up to 7000+rpm with zero puke and die.

With the old turbo, I made a lot more boost down around the 2000-3000 rpm range but it would make a big lump of torque around 5000 rpm and then taper off and die. In hot weather it would heatsoak fairly quickly driving it to redline. Very inefficient.

With this turbo it feels completely N/A below 3000 and only like a strong N/A from 3000-3500. 3500-4000 rpm you can feel the turbo starting to feed back on itself and from 4000 onwards it just surges forward. I can tell I'm not even scratching the surface of what the turbo is capable of.

Sick.


OK, educate me. The new hotside (hows that for terminology? :hs: ) is larger. Thus: less restrictive, spools later, and results in less heatsoak/better efficiency?

Man, if boost onset is that much later, you should be able to feed back in some timing, eh?

What would timing have to do with it? I'm running a Link. And I make full boost over nearly the exact same RPM range- the only difference is that I dont make the same "partial boost" over the low RPM range. I also can't roll into the boost with partial throttle. I have to actually mash the throttle all the way to get full boost.

The bigger hotside lets me flow more exhaust, which lowers EGTs and lowers backpressure. Basically a small turbine backs up the exhaust and forces the engine to spend a lot more effort during the exhuast stroke. The downside is that I have to open up the throttle all the way to get boost instead of just having to crack it halfway. This is a real small downside. I am finding that I downshift a lot more instead of just mashing the pedals waiting for the turbo to spool

The heatsoak is from the compressor inefficiency. The T04B is basically a tiny island of so-so efficiency in a sea of really bad inefficiency (73% island, 50% at fringes). The T04E is a giant ocean of high efficiency (78% in the island down to 75% if I ran a ton more boost and RPM). Basically the more heat you make in the compressor, the more work the intercooler has to do. The T04E doesnt get the intercooler as hot as the T04B which means that intake temps stay lower, especially when you drive hard for more than 10 seconds.

Well, because you've got less of a restriction in your exhaust and your boost doesn't build as easily, you should be able to add have more timing advance during the boost-building RPM range. In addition, you've lowered you surmise that you've lowered intake temps due to the higher efficiency range.

So, do all these factors not add up to a little more timing (or boost...or leaner mixture?)?

beer - pull some datalogs of your boosted runs and post 'em- do some screen dumps of the runs for those who don't have link lab. Do you have any from the old B turbo? That's the best way to compare- and adjust.

ok but here's the big question... I've read several places and maybe Stephanie can chime in here with Corky's opinion...

PULLING timing in the pre-spool area of the map can heat up the exhaust gases and IMPROVE spool.

Discuss.

pulling timing can actually increase EGT's and that means more heat to get the turbine up to speed. So yeah, I could see it improving spool.

but then you have to live with poor out of boost performance due to unadvanced timing....

Trade-offs.

well the point is to spool sooner so you wont be out of boost :)