Yumcha

But, to think...I'll need a VW expert...but, did they have some low-end Polos that were NA and diesel out in Europe?

charliemike

Yeah. The old VW Rabbit diesel was NA. So were the domestic diesels in the 80s. Most heavy duty diesel engines in trucks were NA until recently as well. I know because I drove a trash truck that was diesel

oonowindoo

If the old trucks were NA diesel, and they were able to carry heavy stuff. That means it does have the torque advantage over gas even without turbo.

So why does it need turbo?

more importantly, why were you driving a trash truck???

charliemike

I drove one in college. The community I grew up in didn't have county trash service ... So we had our own. I worked on the maintenance crew and drove the truck on rounds and out to the landfill.

According to a diesel shop that services these things:

Aman

Per Wiki:

I guess since diesels are always technically "pinging" or knocking by design, it's not something you have to worry about when going FI compared to gasoline engines, where knock is bad.

oonowindoo

Diesel is such a mystery, i love it.

Yumcha

So is Acura.

00TL-P3.2

My 1982 Merccedes 240D was an NA 2.4 4cyl diesel.
The 1982 Mercedes 300SD I had after that was a 3.0t 5cyl diesel.
Mercedes also sold the 190E with an NA diesel.

Costco

My old high school instructor told me that diesels strength is low end torque, but are lacking in top end. That's where the turbo comes in.

I am not sure if diesel exhaust has any significant effect on turbo spool... possibly?

Yumcha

Well, oonowindy...hope that answers your most excellent question.

AZ's knowledge base to the rescue!

oonowindoo

That is why cartalk > other sections.

ttribe

Yumcha

Indeed. I'm also partial to Car Talk's sister sub-forum, Automotive News...but, I'm biased.

oonowindoo

Automotive news is like an extension of cartalk.... full of haters.

ttribe

Like me!

Yumcha

That's cuz most of the world are full of ignorant peeps who don't know the full powah of the IS350 and the RLX with upgraded rubbers.

ttribe

Yumcha

*in Kanye West voice*

Yo, Germans, I'm really happy for you, I'ma let you finish, but RLX had one of the best 0-60s of all time! One of the best 0-60s of all time!

Rick_TL-S

Oh lord, what thread did that originate from?

oonowindoo

when SSFTSXX said RLX will be faster than M5 because it has superior all season tires?

i miss him....

Aman

I wouldn't be surprised, considering their exhausts tend to be significantly bigger in diameter compared to their gasoline counterparts. For trucks, anyways.

SamDoe1

I did a lot of work on diesel engines in skool, I'll try and answer some of these...

Yes, you can run a diesel without a turbo. Many larger applications of diesel engines running for max torque rather than max power (ships/trains/generators for example) will run a diesel without a turbo.

Many older cars/trucks came without a turbo diesel. These are the super smoky and smelly cars that gave diesel a bad name to begin with. The non-FI diesel engines tend to not burn as cleanly because of lower combustion pressures, adding a turbo increases that pressure and provides a more complete fuel burn.

In the automotive world, a diesel all but needs to come with a turbo. A N/A diesel motor will produce a lot less power than a similarly sized N/A gas engine and because the diesel motor weighs a lot more due to component weight, something needs to be done to bring the power to weight ratio more in line with a gas engine. Turbos aren't all that heavy and can add a ton of power, hence why they are included. Add to that the fact that you can basically run a diesel up to max operating pressure in terms of boost and it doesn't make a whole lot of sense to not run a turbo. There doesn't need to be any knock sensors or timing changes because the fuel is injected at the time of combustion and...well there's no spark plug to adjust timing on...

Low end torque is inherent to any diesel, the turbo aids in the high end power. Turbos were added in the late 60's to early 70's to long haul trucks because that's when the interstate system was ramping up to what it is now. Before then, a lot of transport was by train and trucks didn't need to travel at high speeds, that's what requires horsepower as I'm sure you know.

Your instructor is absolutely right. The turbo just helps the higher end of the rev range by shoving more air and fuel into the combustion space.

An exhaust path has an effect on any engine regardless of fuel choice. The biggest part of a turbo system is exhaust pulse timing, you want the engine to send a pulse of exhaust gas at the exact time a turbine blade is in position to take full advantage of it. If the system is timed between blades, you lose power. If the system is sometimes between blades, you lose power. Downstream of the turbo, the bigger the better since you want to evacuate the gas as fast as possible. The reason that large trucks have large exhausts is simply because they have a large volume of expelled exhaust to get rid of. A 1.8L diesel engine in a passenger car doesn't have a whole lot of exhaust gas to expel. A 15L+ diesel engine in a semi truck has a hell of a lot more to push out.

Hope this helps.

oonowindoo

Thank you sir!

Mr. Maker

iTrader: (4)

Got 2013 ZL1 Camaro in the shop. Supercharged 6.2L V8. 580hp.

srika

you know what to do.











pictures would be nice.

Mr. Maker

iTrader: (4)

Mr. Maker

iTrader: (4)

Also just had a DB9 and GLK 55 AMG.

srika

looks sinister even in white - thanks for the pix.

charliemike

I just priced out a 228i X-Drive M-Sport and it's $43,620. No nav but has the lighting pkg, Harmon Kardon, heated and power seats, bullshit Bluetooth Plus, metallic paint and leather.

If you build a similar A5 with the Sport, Sport Plus, and S-Line Competition package you're at $48K ...

The next A5 is going to have to be cheaper to compete with the 2-series unless Audi plans to bring over a smaller coupe.

oonowindoo

You can get a M235i for pretty much the same price since it has more standard features.

I built a M235i, it was a lot cheaper than i thought if you don't go crazy with all the unnecessary craps. Based on my experience with the HK in F30, it still sucks.

and i don't think A5 is competing with 2 series, more like 4 series.

ttribe

Hey! One man's "unnecessary craps" is another man's "critical gadgets." My M235i build is about $52k.

Yumcha

And IMHO, 4-Series > A5...

SamDoe1

They make an A3 convertible but not a coupe...I'd imagine it's not far behind.

I'm a bigger fan of Audi's styling both inside and out over the newer BMWs and MBs. At least Audi's interior doesn't look like they finished it and then said "oh shit we need a nav screen, lets just stick this iPad on the dash and hope no one notices..."

charliemike

The M235i X-Drive is $6,125 more and all I added was H/K, heated seats, and streaming blueteef.

Yeah, it's only $120/mo more but that's a lotta money. The M235i RWD is still $48K. Cheaper than an A5 and a better value but still a lot more than a 228i X-Drive M-Sport.

speedemon90

Sometimes I wonder if he did it cause he was an attention whore or actually believed what he was saying.

what happened to him??

charliemike

I stuffed him in a trash can and shot it into the Sun.

ttribe

I saw him make a couple of posts in the 5G forum recently.

Yumcha

oonowindoo

i didn't realize X drive was a must.

Streaming blueteef is standard... unless you want to add those BMW apps and etc...

for $6000, you also get 100 more HP/XX torque and the sound/feel of I6 instead of diesel.


but 225 is very capable and probably.. most likely faster than TLX V6.

Yumcha

I dunno...I'd say, good rubbers are more important than AWD?

There could be a few bucks savings there?