Interesting Bits Of GM Info From The SAE Mag

[Gateclyve Photographic]

I interviewed an EcoBoost engineer at SEMA one year. He explained the harsh reality of OEM turbo engineering. There are a handful of basic parameters, which are essentially in the following order:

1. Cost (including parts and assembly costs)

2. Packaging (with emphasis on ease of production-line assembly)

3. Emissions and fuel economy

4. Torque curve (on a consumer-grade street car -- where turbos need to closely emulate a big-cube mill and stay relatively invisible to the customers -- you want the turbos to build torque down low where small-inch 'plants need the most help)

5. Mass air flow requirements.

Small, water-cooled turbos are now relatively cheap, reliable, and quick-spooling. They are easily managed with electonics and tamed with GDI.

The giant oil-cooled racing turbos that get all the ink and page views in the performance world mostly aren't. Nobody but a gearhead or racer will put up with a turbo that's just along for the ride until 4,000+ r.p.m., even if the "bragging rights" peak numbers are much higher.

[silver_bullet]

Thanks for that insight...I kind of figured that much!

[SuperBuickGuy]

I interviewed an EcoBoost engineer at SEMA one year. He explained the harsh reality of OEM turbo engineering. There are a handful of basic parameters, which are essentially in the following order:

1. Cost (including parts and assembly costs)

2. Packaging (with emphasis on ease of production-line assembly)

3. Emissions and fuel economy

4. Torque curve (on a consumer-grade street car -- where turbos need to closely emulate a big-cube mill and stay relatively invisible to the customers -- you want the turbos to build torque down low where small-inch 'plants need the most help)

5. Mass air flow requirements.

Small, water-cooled turbos are now relatively cheap, reliable, and quick-spooling. They are easily managed with electonics and tamed with GDI.

The giant oil-cooled racing turbos that get all the ink and page views in the performance world mostly aren't. Nobody but a gearhead or racer will put up with a turbo that's just along for the ride until 4,000+ r.p.m., even if the "bragging rights" peak numbers are much higher.

I figured that in the current state of affairs, number 3 would be the first consideration.

[DanStokes]

From my work experience, 1 & 3 are about a tie. They won't do it if it costs much and of course they CAN'T do it if it drives the emissions too high. They have a pretty good handle on emissions these days and generally can get turbo engines to pass with no problem but they still, of course, keep an eye on it.

Dan

[RockJustRock]

Where's Durability?

I mean..... Trucks? Turbos?

My original stance, those two little boxes making 20 Lbs. of ANYTHING looks sketchy. But I'd DRIVE it, yes I would.

[Beagle]

Where's Durability?

I mean..... Trucks? Turbos?

My original stance, those two little boxes making 20 Lbs. of ANYTHING looks sketchy. But I'd DRIVE it, yes I would.

Durability? When was the last time you saw a diesel truck without a turbo?

My purchase decision was Reason 4. Torque. Between GDI and a couple of turbo's , it's hard to believe how much torque these little bassturds make and how low they make it. They still have a little bit of lag but it's certainly not like a carb'd 3.8 turbo from 1978. It's almost like they spent 40 years kind of figuring some things out...

[Deaf Bob]

I'm thinking the world's lightest street rod. Make the frame out of junk NSX and Vette alloy items.... 'Course that would be wasted on me or DB, but PDub would FLY around a road course in it. He'd take up autocross just to show off!

I'dda be ballast to keep it from rolling over!

[Deaf Bob]

Yep.. I want a turbo in a couple rigs I got... Flatbed or dualie, 350 gas motor. All done by 5k rpms. Make me weird?

[SuperBuickGuy]

Yep.. I want a turbo in a couple rigs I got... Flatbed or dualie, 350 gas motor. All done by 5k rpms. Make me weird?

yep, turbo motors like long stroke, small bore - it's how the manufacturers make motors that are tiny yet usable. You can turbo a 350, but a turbo 4.8 would eat its lunch - all for less money. It's also the second reason why I sleeved the 455 Buick. You bring up an interesting conception that persists - that new motors are basically the same as old motors, in that they burn gas - they're the same - but we're talking flathead era where manufacturers made long stroke small bore. The 'tech' that came in the 50s and 60s was big bore short stroke to my hp - a turbo motor hates that because you have all that mass working against getting the motor to spin up and make the turbo efficient.

[pdub]

I'm thinking the world's lightest street rod. Make the frame out of junk NSX and Vette alloy items.... 'Course that would be wasted on me or DB, but PDub would FLY around a road course in it. He'd take up autocross just to show off!

Misplaced confidence. There is the element of "driver skill" involved, that's a parade rainer every time.

[RockJustRock]

But the package would be SO light you couldn't POSSIBLY kill the brakes on it!

And honestly I didn't even know you had started autocrossing already.

[pdub]

But the package would be SO light you couldn't POSSIBLY kill the brakes on it!

And honestly I didn't even know you had started autocrossing already.

Red's done AX about 4 times previously with SCCA, nearly-local events. We got ass last in Novice Class every single time. It's harder than it looks from standing there watching. At least it sure seems hard to me. Because it is. That's hard. You can stand there and watch and you don't even know what you're watching until you go out there and try it.

Standing around watching and waiting the next run in Chattanooga, I was standing there with some AX guys who were dreaming out loud about doing a real road course someday. I'd already done that, I did that "first," so I didn't understand....so, go do a road course, why limit yourself? I think AX is actually harder to do well than a full blown road course. It looks goofy, but AX is hard to do well. I see the draw in it but I'm not drawn to it, per my own lack of ability.

[RockJustRock]

You keep forgetting one thing Rusty. Only one thing stopping me from doing most events. I'm a dazzling urbanite who doesn't own a car. At this albeit long extended moment in time.

[pdub]

You keep forgetting one thing Rusty. Only one thing stopping me from doing most events. I'm a dazzling urbanite who doesn't own a car. At this albeit long extended moment in time.

Dayum. Ok, I apologize. You've got even less car than WE have. Shit, my bad.

[RockJustRock]

No biggie, just let me ramble on about what I HAD. When they were CHEAP. If you follow the details of my personal life you know it looks like things will be looking up financially sometime. Right now I see the best BangShift worthy bang for the buck would be a P71 Crown Vic. I'd PREFER a Cop Charger, but hardly ANY Cops did so they are few and more expensive.

In the meantime I'll keep trying to amuse you guys with stories of my youth and my youthful music tastes or lack of same. And my admittedly loutish opinions on cars. Feel free to give the attaboys and SHUPs as anyone wants to. Been doing the Message Board thing since the 90s and always amazed at how friendships and enemyships build and even flip flop into each other.

Hope you find all the 'lil easter eggs I left scattered around in recent threads while you were on the road.