Manufacturers putting turbo 4-bangers in SUVs

[Ws6]

Originally Posted by madRiver
Originally Posted by Brigadier
I will still take my V6 over an overworked, overstressed turbo 4 any day. But then again, I run 30W oil in my engines that call for CAFE 20W oils.......So I guess I am a neanderthal....


The idea that turbo engines are overstressed is a bit dated. The majority of modern turbo applications are light pressure and geared for efficient power not brute force.power with little regard for economy.

It's understandable with your thinking which is dated by around 10-15 years on turbo applications. VW and Saab seemed to pioneer the efficient turbos.


Agreed. Mine spends most of its life below around 3000rpm. 310# of torque available by 2000rpm. No need to rev the snot out of it like a V6.

 

[Ws6]

Originally Posted by UG_Passat
Originally Posted by BMWTurboDzl
Do any of these I4's in SUV's use variable vane turbos or are they fixed vane?


Unless it is a Diesel, no. It's rare for a gas turbo to use a VNT/VGT turbo.

The old RDX turbo did have a dual path turbine housing to minimize drag.

Some gas engines have twin scroll turbos.

The one in my CX5 GT-R has a variable exhaust path which is managed by the exhaust manifold. The result is almost zero turbo lag (I cannot discern any), and 310# torque by 2000rpm.

 

[BMWTurboDzl]

Originally Posted by madRiver
Originally Posted by Brigadier
I will still take my V6 over an overworked, overstressed turbo 4 any day. But then again, I run 30W oil in my engines that call for CAFE 20W oils.......So I guess I am a neanderthal....


The idea that turbo engines are overstressed is a bit dated. The majority of modern turbo applications are light pressure and geared for efficient power not brute force.power with little regard for economy.

It's understandable with your thinking which is dated by around 10-15 years on turbo applications. VW and Saab seemed to pioneer the efficient turbos.



Unless my memory serves me wrong I'm going to disagree. Today's turbo applications are all about using small turbos to generate lot of low end torque with as little lag as possible and then relying on reduced rotational mass to obtain FE targets at highways speeds. Take a look at the TQ/HP curves below. Notice how much lower in the rpm range the BMW 4 cylinder engine reaches max torque vs the 4 cylinder SAAB.

 

[Jarlaxle]

Originally Posted by madRiver
Originally Posted by Brigadier
I will still take my V6 over an overworked, overstressed turbo 4 any day. But then again, I run 30W oil in my engines that call for CAFE 20W oils.......So I guess I am a neanderthal....


The idea that turbo engines are overstressed is a bit dated. The majority of modern turbo applications are light pressure and geared for efficient power not brute force.power with little regard for economy.

It's understandable with your thinking which is dated by around 10-15 years on turbo applications. VW and Saab seemed to pioneer the efficient turbos.


Volvo. The "light pressure" turbo 5 cylinder in the 850. 200lb/ft from 1800RPM from a 2.4 litre engine.

 

[oilpsi2high]

America has been brainwashed into thinking a car-based hatchback with increased ground clearance is an SUV.

 

[ekpolk]

Originally Posted by oilpsi2high
America has been brainwashed into thinking a car-based hatchback with increased ground clearance is an SUV.

They'll do anything -- ANYTHING -- to avoid the dreaded W-word*. . .

You know, w-a-g-o-n! Too lazy to check tonight -- I think even our auto-censor takes it out!

 

[Andrew1972]

Originally Posted by oilpsi2high
America has been brainwashed into thinking a car-based hatchback with increased ground clearance is an SUV.


I think it's more people like the look and configuration of the vehicles. I remember when truck based SUVs existed and 97% of owners never went off pavement.

 

[ekpolk]

Originally Posted by BMWTurboDzl
. . .
Unless my memory serves me wrong I'm going to disagree. Today's turbo applications are all about using small turbos to generate lot of low end torque with as little lag as possible and then relying on reduced rotational mass to obtain FE targets at highways speeds. Take a look at the TQ/HP curves below. Notice how much lower in the rpm range the BMW 4 cylinder engine reaches max torque vs the 4 cylinder SAAB.


The old mantra used to be, "there's no replacement for displacement". I think it's still a defendable statement, though of late, the idea seems to have been discarded in the "real world." Admittedly, with better computer control and a couple decades of research (and the ever-present CAFE pressures), they've gotten a whole lot better. I remember test driving a car with the Chrysler 2.2L turbo (pretty sure it was 2.2) back in the 80s. THAT was an unrefined beast by today's standards and its longevity was anything but assured. More to the point, though, so long as the internals are designed to bear the loads involved with a small engine moving comparatively large mass, there's little reason why today's "4-bangers" shouldn't be able to hold up in the long run.

 

[Brigadier]

Originally Posted by madRiver
Originally Posted by Brigadier
I will still take my V6 over an overworked, overstressed turbo 4 any day. But then again, I run 30W oil in my engines that call for CAFE 20W oils.......So I guess I am a neanderthal....


The idea that turbo engines are overstressed is a bit dated. The majority of modern turbo applications are light pressure and geared for efficient power not brute force.power with little regard for economy.

It's understandable with your thinking which is dated by around 10-15 years on turbo applications. VW and Saab seemed to pioneer the efficient turbos.


Yet, those overworked turbo fours aren't blowing up fromLSPI........

 

[Garak]

Originally Posted by madRiver
Originally Posted by oilpsi2high
America has been brainwashed into thinking a car-based hatchback with increased ground clearance is an SUV.


I think it's more people like the look and configuration of the vehicles. I remember when truck based SUVs existed and 97% of owners never went off pavement.

In other words, AMC was simply way ahead of its time with their butt ugly designs.

 

[BMWTurboDzl]

Originally Posted by Brigadier
Originally Posted by madRiver
Originally Posted by Brigadier
I will still take my V6 over an overworked, overstressed turbo 4 any day. But then again, I run 30W oil in my engines that call for CAFE 20W oils.......So I guess I am a neanderthal....


The idea that turbo engines are overstressed is a bit dated. The majority of modern turbo applications are light pressure and geared for efficient power not brute force.power with little regard for economy.

It's understandable with your thinking which is dated by around 10-15 years on turbo applications. VW and Saab seemed to pioneer the efficient turbos.


Yet, those overworked turbo fours aren't blowing up fromLSPI........


Yep, that's because they made peak torque at a much higher point in the RPM range. The link I posted above allows you to compare the HP/TQ curves of various new and old designs.

 

[BMWTurboDzl]

Originally Posted by oilpsi2high
America has been brainwashed into thinking a car-based hatchback with increased ground clearance is an SUV.


Naw....they just prefer better riding vehicle to go along with better visibility. The vast majority of SUV's never were taken off road (Dirt roads don't count) to begin with.

 

[supton]

It's sporty*, it does all their needs (utility) and it's a vehicle. SUV applies, no?

[*ahem, I still see people slowing down for the most gentile of curves. If the vehicle can take the typical cloverleaf at posted speed, it's a sporty car, right?]

I used to call my old TDI wagon an EUV. Economical Utility Vehicle. Other than AWD and perhaps ground clearance it did all I ever wanted, including towing my 4x8 utility trailer.

 

[Kurtatron]

I think today's vehicles are just becoming more and more disposable as a general rule. Either an expensive electronic goes bad or you get nickel and dimes from all the gadgets and gizmos. That doesn't mean they won't last 200k, but they just aren't rebuilable like yesterday's cars. I don't think a turbo engine in an SUV is the big worry or concern, but all the other electronic junk around it.

I worry way too much about my Toyota Previa, which is 4 a cylinder 3700lb van. It spins at high RPM at highway speed. To OCD people like us, this thing should self destruct in 10 seconds, but the vans are routinely making 300k+ miles. Case in point, I don't think the metal wearing out in engines is the issue, but added complexity around them.

My boss's S7 turbo did fail recently however. It is an $8k repair! The car is only 5 years old and has 55k miles on it. He bought it used, and has no warranty for the vehicle. I think the great saying is this: choose any 2 of the three: cheap, reliable, high performance

 

[Andrew1972]

Originally Posted by BMWTurboDzl
Originally Posted by madRiver
Originally Posted by Brigadier
I will still take my V6 over an overworked, overstressed turbo 4 any day. But then again, I run 30W oil in my engines that call for CAFE 20W oils.......So I guess I am a neanderthal....


The idea that turbo engines are overstressed is a bit dated. The majority of modern turbo applications are light pressure and geared for efficient power not brute force.power with little regard for economy.

It's understandable with your thinking which is dated by around 10-15 years on turbo applications. VW and Saab seemed to pioneer the efficient turbos.



Unless my memory serves me wrong I'm going to disagree. Today's turbo applications are all about using small turbos to generate lot of low end torque with as little lag as possible and then relying on reduced rotational mass to obtain FE targets at highways speeds. Take a look at the TQ/HP curves below. Notice how much lower in the rpm range the BMW 4 cylinder engine reaches max torque vs the 4 cylinder SAAB.

I was referencing the Saab engines of early 1990's with less then 2000rpm and peak torque. https://en.wikipedia.org/wiki/Saab_H_engine#B204_&_B234

 

[BMWTurboDzl]

Originally Posted by madRiver
Originally Posted by BMWTurboDzl
Originally Posted by madRiver
Originally Posted by Brigadier
I will still take my V6 over an overworked, overstressed turbo 4 any day. But then again, I run 30W oil in my engines that call for CAFE 20W oils.......So I guess I am a neanderthal....


The idea that turbo engines are overstressed is a bit dated. The majority of modern turbo applications are light pressure and geared for efficient power not brute force.power with little regard for economy.

It's understandable with your thinking which is dated by around 10-15 years on turbo applications. VW and Saab seemed to pioneer the efficient turbos.



Unless my memory serves me wrong I'm going to disagree. Today's turbo applications are all about using small turbos to generate lot of low end torque with as little lag as possible and then relying on reduced rotational mass to obtain FE targets at highways speeds. Take a look at the TQ/HP curves below. Notice how much lower in the rpm range the BMW 4 cylinder engine reaches max torque vs the 4 cylinder SAAB.

I was referencing the Saab engines of early 1990's with less then 2000rpm and peak torque. https://en.wikipedia.org/wiki/Saab_H_engine#B204_&_B234



Gotcha. The current 4 cylinder made by BMW B48 (current) 255 hp makes over 295 ft-lbs from 1,550 rpm - 4,400 rpm. 11:1 compression ratio. The Saab made max torque of 252 ft-lbs @ 1950 rpm. 9.25:1 compression ratio. So ya boost pressure is lower on the BMW but the compression ratio is higher.

So who knows.

 

[A_Harman]

Originally Posted by Uphill_Both_Ways
Originally Posted by UG_Passat
Sequential turbos are not exactly new technology. They have been around since at least the mid-80's.
Any idea of their practicality? Cooling problems come to mind.

A 1.5-litre Fiat racing car with two in-line superchargers cranked out 350 horse power, I believe it was, in 1951, but I suppose two superchargers in an average vehicle would take up too much room.


Auto Union had two-stage Roots superchargers on their pre-WW2 race cars. (C or D-type's, can't exactly remember.) 600+ HP, they were the most powerful Grand Prix cars until the 1.5L turbo formula of the 1980's.
Tractor pullers were using two-stage turbos in the 1970's, and were up to 3 stages in the 1980's.
Cummins had 2-stage turbocharged diesels in production in the 1980's.
I don't know of any 2-stage turbocharged spark ignition engines in production.

 

[Jarlaxle]

Not in production anymore, but off the top of my head, I recall the Supra was 2-stage. The 911 was twin-turbo, not sure if it was 2-stage.