Developments in turbo technology

When I was at the SF auto show a few months ago they had an Ecoboost 3.7 V6 on display. What really stood out to me was how tiny the turbos were. It was hard to imagine those cute little things contributing to a net 420 ft. lbs. of torque. They looked like they were sized for a Miata motor. Anyway, it makes me wonder what developments in turbochargers have filtered down to the aftermarket? Let's say a fella had an older 2.0 Subbie. It's always possible to put something bigger in there, but are there newer designs that upgrade everywhere on the chart - are both quicker spooling and better top end?

I know that for a while, it seemed like VNT turbos were the way of the future. Not sure if that's still the case. Honestly itty-bitty little turbos make a lot of sense for torque figures, where the quick spool will contribute to low-end numbers without the massive lag typically associated with bigger turbos.

On a related note: Does anyone know where one can find the specifications for the IHI VF 18 and 19 turbos? The larger IHI turbo info is all over the internet, but the smaller units data is hard to pin down.

If you think about doing twin turbos on a V6, you have to size each turbo to work with one half of the engine. So 3.7/2=1.85, so smaller than a modern Miata motor, but a good size for a 1.6 or 1.8.

The Garrett VNT's used on the 89/90 Shelby Dodfes were amazing bit of technology, plaques by early adopter issues and dumbass owners. So Chrysler replaced the 2.2 VNT motor with a 2.5L motor spinning a tiny, tiny Mitsubishi TE04H turbo (it's really sized for something like a 1.5L) because it provided nearly the same or better torque curve with much less manufacturing and maintenance costs.

Nowadays with lightweight turbine wheels, ball bearings and ceramic technologies, VNT's aren't as needed as they once were, especially when combined with modern EFI and combustion chamber technology. They still have their place of course, but the market is fairly small it seems.

kreb wrote: When I was at the SF auto show a few months ago they had an Ecoboost 3.7 V6 on display. What really stood out to me was how tiny the turbos were. It was hard to imagine those cute little things contributing to a net 420 ft. lbs. of torque.

Freakin TINY aren't they? Probably couldn't get your thumb in the exhaust manifold outlet either. And it's a 400+hp engine detuned to whatever Ford felt like detuning it to for whatever chassis they put it in.

Anyway, it makes me wonder what developments in turbochargers have filtered down to the aftermarket? Let's say a fella had an older 2.0 Subbie. It's always possible to put something bigger in there, but are there newer designs that upgrade everywhere on the chart - are both quicker spooling and better top end?

Look into the Borg-Warner Sxxx series of turbos. The RX-7 and the Audi guys love 'em. Lots of flow for a given size. And as a bonus, they're pretty cheap too!

VNTs are still around, but mostly on diesels.

And to Kreb: Yes there are better turbos out there, but much to the chagrin of cheapskate Subaru owners-they cost more than a $300 chinese turbo.

Do you actually have the VF18/19s already? Not bad turbos, but I think those were the ones used on Subaru's Rube Goldberg Twin turbos. Those are old turbos but you might have better luck looking up information under "IHI RHF4".

SlickDizzy wrote: I know that for a while, it seemed like VNT turbos were the way of the future. Not sure if that's still the case.

It's not and never really will be except on diesels. One post on eng-tips put the problem with VNT succinctly. Paraphrased: "Sure, I could get 15psi at 1500rpm, but it needed 90psi of exhaust manifold pressure, and with that kind of pressure ratio across the engine, it wasn't a net benefit until the exhaust nozzles opened up more"

Plus think of the higher compression ratios in these DI motors too, that'll spin em up quicker too I would imagine.

The answer is Borg Warner EFR.

Also, in terms of vnt, Porsche is still using it as far as I know.

The ecoboost line is fitted with tiny turbos so the little engine runs like a big one, not a turbocharged monster of an engine, I.E. no lag, lots of bottom end.

The first gen acura rdx used a vnt turbo.

Agreed, EFR is the latest and greatest if you ask me. Especially the 7163 with a mixed flow turbine wheel.

Swank Force One wrote: The answer is Borg Warner EFR. Also, in terms of vnt, Porsche is still using it as far as I know.

Garrett's GTX line is pretty sexy, a redesigned compressor wheel, ball bearing, and it's available in twin-scroll. Just added one to Midlana and it's incredible... 400-500 hp (depending upon dyno type) and 1600 lbs =

The secret is to use ones not crazy huge like some of the kids do. Well selected, there's very little lag.

Yeah, I have seen reports like the GTX series flow like the GT series one number lower. So instead of a GT35 you run the '30.

I'm still planning on a Precision 5858 for my 2.3l Audi, mainly because I want something close to what the ten-valve Group 4/Group B cars had turbo-wise and I'd rather use a modern turbo than trying to scrape up an Audi-spec K27. I want a laggy bitch of a car. If I didn't, a V8 would have been an easier, cheaper, and lighter swap and would get me as much power.

"Sure, I could get 15psi at 1500rpm, but it needed 90psi of exhaust manifold pressure, and with that kind of pressure ratio across the engine, it wasn't a net benefit until the exhaust nozzles opened up more"

That is exaggerated to the point of being useless.

In reply to Vigo:

http://www.eng-tips.com/viewthread.cfm?qid=291709

For one example.

Kenny_McCormic wrote: The ecoboost line is fitted with tiny turbos so the little engine runs like a big one, not a turbocharged monster of an engine, I.E. no lag, lots of bottom end.

I've got an ecoboost Taurus. I can confirm that the motor doesn't feel turbocharged at all. It just feels like a bigger motor. I've opened the airbox some so I get a woosh every once in awhile but nothing crazy or cop-attracting.

Livernois Motorsports is a shop that offers a tune for the car. They state that there's not much headroom left in the turbos for tuning due to their size. Upping the boost just increases heat with no additional power. Ford has acknowledged that with a larger more free flowing exhaust you can also overspeed the stock turbos pretty easily. The solution to this is, of course, larger turbos. I haven't heard how the ecoboost motor with larger turbos performs. I have heard rumors of huge horsepower numbers made by ecoboost V6 motors while in development without a failure. Considering the stock motor puts out close to 400 hp and over 400 ft lbs of torque in the F150's the term "huge" is relative.

Anyone else have any ecoboost lore?

In reply to Xceler8x:

So if you are rounding to the nearest 100, 365hp does round up to 400. But I would not really say that 365hp is close to 400. Closer than the 355 hp that your car is rated to. Although, it's actually 365, too...

The ACTUAL power limit to the Ecoboost is the fuel pump. It can only pump the equivallent to about 420hp. But that's pretty tough to do.

Bigger turbos are no help at all- can't make more power. And more manifold pressure actually tends to make it run a little worse- spent a month figuring that one out.

To really make alot of power, one needs to 1) add a second high pressure fuel pump, and 2) totally go over the calibration- then more turbos would work well- as can be seen in the Ecoboost powered DP cars.

BTW, your SHO will easily make 400lb-ft. but someone was told that the trans would not be happy, so it's limited to 365.

The sound was a HUGE focus on the car, when calibrated. To eliminate any and all turbo sounds. No woosh, no chirps, nothing.

(anything you want to know, specifically?? I kinda know a thing or two about the 3.5l GTDI engines)

Knurled wrote: Freakin TINY aren't they? Probably couldn't get your thumb in the exhaust manifold outlet either. And it's a 400+hp engine detuned to whatever Ford felt like detuning it to for whatever chassis they put it in.

I just looked at one- you have a really big thumb. The exhaust inlet is just about 1.25" at the smallest point- my thumb is just 0.75".

It's tuned to do what it does.

In my limited time spent reading on turbos I seem to recall that these new little ones are spinning really fast- thus they are 'bigger' than than look.

alfadriver wrote: :Awesome facts deleted: (anything you want to know, specifically?? I kinda know a thing or two about the 3.5l GTDI engines)

I love these posts you make. Your insider knowledge is fantastic.

In reply to Ditchdigger:

It's insider knowledge that outsiders are allowed to know.

If not, i'd get fired. Which isn't high on my to-do list.

Knurled wrote: In reply to Vigo: http://www.eng-tips.com/viewthread.cfm?qid=291709 For one example.

And? Where is the log of this 90psi? I don't see it. It is true that a VNT changes pressure in front of the turbine. It is not true that a diesel is inherently more accepting of high pressures in the exhaust manifold/ports than a gas engine. It is not true that a production VNT implementation is ever going to hit 90 psi in the exhaust manifold, or EVEN ever cause such a high pressure in the exhaust manifold that the increased pumping losses offset the additional power created by the boost.

As i said, it's exaggerated to the point of being useless. I picked up a couple tidbits i didnt already know from that thread, but i dont see anything that meaningfully supports the quote you made.

alfadriver wrote: In reply to Ditchdigger: It's insider knowledge that outsiders are allowed to know. If not, i'd get fired. Which isn't high on my to-do list.

You do realize that Alfadriver works for the propaganda wing of Ford - and sidelines for the NSA, don't you?

Shaun wrote: In my limited time spent reading on turbos I seem to recall that these new little ones are spinning really fast- thus they are 'bigger' than than look.

That's just par for the course with turbo size. Generally speaking, you have to move the air X speed to get it to compress to Y pressure ratio. A smaller diameter turbo will have to spin faster to generate the same airspeed.