Cars and Turbochargers

[Obi Heed Kenobi]

I'm thinking about buying a turbocharged car (either gas or diesel) and wanted to see if anyone had experience with them. I'm concerned primarily about reliability and maintenance - I do most of my auto work myself, but have absolutely no experience with turbochargers.

Also, I'm curious about performance at altitude. Obviously, the turbo provides better performance than a NA engine can. Regardless, I haven't been able to find any information regarding the critical altitude (to borrow an aviation term) of auto engines. If anyone has experience or knowledge, what is the general elevation where turbo'd car engines start to lose power (I'm sure it varies from car to car, I'm just looking for a rough idea)?

Thanks for the help!

 

[tonycondon]

i dont know but i want a turbodiesel volkswagon. good tow vehicles with good gas mileage, from what i hear.

 

[ScottM]

i dont know but i want a turbodiesel volkswagon. good tow vehicles with good gas mileage, from what i hear.

Really they tow gliders with them? What type of altitude do you get with a turbo VW?

 

[t0r0nad0]

i dont know but i want a turbodiesel volkswagon. good tow vehicles with good gas mileage, from what i hear.

A friend of mine has a 2005 Jetta TDI with a 5-speed. He gets about 45 mpg, which is convenient, because he has a 60mi commute to work - each way.

I also had another buddy of mine in college that had an older Jetta TDI, and he did the grease car conversion. It literally ran on old deep-fryer grease! He used to go around to restaurants to collect the used grease, and they usually donated it since they had to pay to have it removed, typically. He'd take it home and filter it, then put it in an auxiliary tank he had in his trunk. He had to start the car and stop it on diesel, but once it was running he just flipped a switch to grease. He delivered pizzas, so it was really nice that he only had to buy gas once every two months or so. He said that the only downside is that your car smells kind of like french fries .

 

[Tom-D]

I'm thinking about buying a turbocharged car (either gas or diesel) and wanted to see if anyone had experience with them. I'm concerned primarily about reliability and maintenance - I do most of my auto work myself, but have absolutely no experience with turbochargers.

Also, I'm curious about performance at altitude. Obviously, the turbo provides better performance than a NA engine can. Regardless, I haven't been able to find any information regarding the critical altitude (to borrow an aviation term) of auto engines. If anyone has experience or knowledge, what is the general elevation where turbo'd car engines start to lose power (I'm sure it varies from car to car, I'm just looking for a rough idea)?

Thanks for the help!

I drive a turbo charged Cummins Diesel truck (2500 Dodge) and have over 100k on it with out any problems, Work on them?? Ya don't have to. I run AMSOIL do the oil samples every 10k and changed oil at 45k, and again at 90, I tell every one that the cummins will do every thing except sneek around cause that diesel is LOUD. I haul stuff over the mountain passes and have yet to see any loss of power at altitude.

Gal at work has a diesel Golf, says she gets 55 per gallon. WE drove a new Jeep Cherokee with the Mercedes Benz diesel it was very smooth, and quite.

 

[sbonek]

..snip..

He said that the only downside is that your car smells kind of like french fries .

I'm not seeing the downside

 

[Keith Lane]

I've got a 1983 Mercedes 300D Turbo. As far as I know (I have the maintenance records from previous owners) it has never had a turbo problem in the last ~~ 400K Miles.

Mark Shilling (NC Pilot) has 3 or 4 Mercedes Diesels as well. Maybe he can add something.

 

[LeonardMack]

Most car computers have altimeters in them so that if you drive up in the mountains then down to sea level, it will adjust the engine for best performance (Fuel flow, etc). The same goes for the turbo charger. The computer controlling it will adjust it based on several factors for best performance.

 

[NC Pilot]

I've got a 1983 Mercedes 300D Turbo. As far as I know (I have the maintenance records from previous owners) it has never had a turbo problem in the last ~~ 400K Miles.

Mark Shilling (NC Pilot) has 3 or 4 Mercedes Diesels as well. Maybe he can add something.

Glad to - The current crop of diesel cars and the 80's Mercedes diesels seem pretty good. My daughter drives a '85 300D with almost 400,000 miles on it and it just keeps going.

The earlier gasoline turbo's had issues with the oil coking if the car was driven and shut off without allowing the turbine to cool down (good practice with aviation turbo's as well) which caused a few turbo's to end their lives pretty early.

Since I live in the flat lands, I really cannot comment on performance up high, but I do know my turbo benzes have waste gates to limit boost pressure, so I imagine their performance stays pretty good at altitude. I always wanted to drive one of them up Pikes Peak.

If and when I get another one it will probably be a '98 E300D, but the prices are not down to my level yet.

 

[kevin47881]

David, all post 1996 (OBD-II) vehicles have a MAP (or similar) sensor. MAP stands for Manifold Absolute Pressure. As such, fuel distribution is automatically compensated for altitude. I have driven turbo charged vehicles at about 8k feet without incident.

As for working on them, really not much different than a normally aspirated engine. There is a turbo mounted somewhere on the engine with a couple oil lines, air tubes and maybe an intercooler. The only advise I offer regarding turbos is to allow about 45 seconds after a hard run before cutting the engine off. This allows the turbine/impeller to slow down before you lose the pressurized oil source. Lack of oil (primarily from coking in the feed line) is the number one killer of a turbo.

 

[Obi Heed Kenobi]

Thanks for all the comments, fellas. I've never even seen a turbo before. I know it spins. :/

As far as driving up Pike's Peak, this car will be driven daily at 10,000'-12,000' (I-70 and Loveland Pass) and occasionally higher, so I'll let you know how it does.

Great advice about letting the turbo cool down, too...I wouldn't have thought of that. Along the same lines, when the weather is cold, I always let my car idle for a minute or two after starting it up before revving the engine - it gives the cold, thick oil (that has run down into the base while it is still warm and runny) a chance to warm up, thin out, and get back up in the cylinders. I don't know if it actually makes a difference, but it might.

 

[bstratt]

Back in '90 I had the Eagle (Mitsubishi) Talon, 5 spd, turbocharged. It went like a bat outa hell. IIRC the real issue with preserving the turbo was not to miss a scheduled oil change and to let it cool down before turning it off. Had it for three years and sold it when I got married (what was basically a two seat sports car didn't fit the new mission!).

 

[Obi Heed Kenobi]

Back in '90 I had the Eagle (Mitsubishi) Talon, 5 spd, turbocharged. It went like a bat outa hell. IIRC the real issue with preserving the turbo was not to miss a scheduled oil change and to let it cool down before turning it off. Had it for three years and sold it when I got married (what was basically a two seat sports car didn't fit the new mission!).

How does the oil system for the turbo work? Is it connected to the engine oil system, or does it have its own independent system?

If the latter, what does it take to do it yourself?

 

[kevin47881]

How does the oil system for the turbo work? Is it connected to the engine oil system, or does it have its own independent system?

If the latter, what does it take to do it yourself?

The oil system is part of the engine oil system. No seperate system on any turbo vehicle I've worked on over the past 20+ years.

 

[bstratt]

How does the oil system for the turbo work? Is it connected to the engine oil system, or does it have its own independent system?

If the latter, what does it take to do it yourself?

IIRC it was one and the same with the engine oil, hence the need to change it right on schedule. I gave up changing my own oil when I could pay someone else $25 and get it done in 15 minutes and stay clean!

Interestingly, the lady I sold it to told me she went 10,000 miles before remembering to change the oil the first time - turbocharger went TU after she put about 30,000 miles on it.

 

[kevin47881]

Back in '90 I had the Eagle (Mitsubishi) Talon, 5 spd, turbocharged. It went like a bat outa hell. IIRC the real issue with preserving the turbo was not to miss a scheduled oil change and to let it cool down before turning it off. Had it for three years and sold it when I got married (what was basically a two seat sports car didn't fit the new mission!).

Yep, I worked for a Mitsubishi regional office for 13 years (late 80's forward) and remember when the Eclipse came out. It was one fun, fast ride as long as there were only two of you. We use to refer the rear seat as the torso seat (you couldn't sit back there if you had legs ).

Oil changes and cool down are imperative to prevent coking in the oil feed/return lines.

 

[Obi Heed Kenobi]

Once again, thanks for the comments!

 

[Anthony]

As far as driving up Pike's Peak, this car will be driven daily at 10,000'-12,000' (I-70 and Loveland Pass) and occasionally higher, so I'll let you know how it does.

David,

Do you commute to Denver from Frisco? That's a haul and yes at some very high altitudes. I use to get up to that area a lot when I lived in Lone Tree (Highlands Ranch/Littleton area).

 

[Obi Heed Kenobi]

David,

Do you commute to Denver from Frisco? That's a haul and yes at some very high altitudes. I use to get up to that area a lot when I lived in Lone Tree (Highlands Ranch/Littleton area).

I was going from Denver to Georgetown (where my office is). A few good friends lived in Denver when I moved out here, so naturally I said I'd live with them. It was about 50 minutes to an hour.

I just moved up to Frisco a couple of weeks ago, so now it's Frisco to Georgetown. About 25 miles.

Most people might mind the drive, but I love it!

 

[Anthony]

I was going from Denver to Georgetown (where my office is). A few good friends lived in Denver when I moved out here, so naturally I said I'd live with them. It was about 50 minutes to an hour.

I just moved up to Frisco a couple of weeks ago, so now it's Frisco to Georgetown. About 25 miles.

Most people might mind the drive, but I love it!

Oh cool! Your office is in Georgetown! I use to do a lot of wheeling with my Jeep on some great trails around Georgetown and Frisco/Breckenridge for that matter.

 

[Obi Heed Kenobi]

Oh cool! Your office is in Georgetown! I use to do a lot of wheeling with my Jeep on some great trails around Georgetown and Frisco/Breckenridge for that matter.

No joke! One thing I'm going to do this summer is borrow/rent a 4wheeler and take a tent (along with a rifle for cougars) and explore some of the roads/mines around here. For some reason, I'm fascinated with them. Probably because I'm convinced my future lies in prospecting instead of the law.

My office is right next to Clear Creek. I tell everyone that at lunch I'm going to start panning for gold.

 

[Henning]

I'm thinking about buying a turbocharged car (either gas or diesel) and wanted to see if anyone had experience with them. I'm concerned primarily about reliability and maintenance - I do most of my auto work myself, but have absolutely no experience with turbochargers.

Also, I'm curious about performance at altitude. Obviously, the turbo provides better performance than a NA engine can. Regardless, I haven't been able to find any information regarding the critical altitude (to borrow an aviation term) of auto engines. If anyone has experience or knowledge, what is the general elevation where turbo'd car engines start to lose power (I'm sure it varies from car to car, I'm just looking for a rough idea)?

Thanks for the help!

Don't buy any diesel without a turbo. New turbos rarely are problematic.

 

[bstratt]

No joke! One thing I'm going to do this summer is borrow/rent a 4wheeler and take a tent (along with a rifle for cougars) and explore some of the roads/mines around here. For some reason, I'm fascinated with them. Probably because I'm convinced my future lies in prospecting instead of the law.

My office is right next to Clear Creek. I tell everyone that at lunch I'm going to start panning for gold.

We are heading to Breckenridge for 5 days on July 31st. Have a condo rented in town. We're hoping to do some of that back road stuff ourselves - old mines and ghost towns. Any suggestions?

 

[Obi Heed Kenobi]

We are heading to Breckenridge for 5 days on July 31st. Have a condo rented in town. We're hoping to do some of that back road stuff ourselves - old mines and ghost towns. Any suggestions?

There is a pretty good website that lists places to go, and details how to get to them. I can't remember what's it called, but if you google something along the lines of "Colorado mines" or "abandoned Colorado mines," you should find it.

 

[Dave Krall CFII]

).

Oil changes and cool down are imperative to prevent coking in the oil feed/return lines.

Would using synthetic oil be advantageous? My engine is the 4 cylinder Suzuki off a Geo Metro with a Bocsh (sic) turbo & intercooler.

 

[kevin47881]

Would using synthetic oil be advantageous? My engine is the 4 cylinder Suzuki off a Geo Metro with a Bocsh (sic) turbo & intercooler.

Personally I'm not a proponent of synthetic primarily due to cost and lack of changing the oil filter as a result of extended oil change intervals. As long as you change dino oil every 3-5k all will be well.

 

[Henning]

Personally I'm not a proponent of synthetic primarily due to cost and lack of changing the oil filter as a result of extended oil change intervals. As long as you change dino oil every 3-5k all will be well.

As long as you change filters every 3-5, you can change dino every 30,000-50,000 and all will be well. Oil doesn't break down, it gets dirty (which the paper filters keep under control) and the additives load up/break down (which the top up oil during filter changes takes care of). I ran a tug that had 3 20-645 E6 EMDs, 3600hp each, over 1,000,000 hrs each, none had ever had an oil change, filters every 200hrs. Continuous oil analysis at every filter showed no issues. No service issues any different than any other tug I had operated with those engines.

 

[JRitt]

If you are looking at the current crop (for 2008) turbo diesel cars you only have 3 choices. The Merc. Benz C320 (good room 200hp 6cyl and 35mpg hwy 50K). The Merc Benz C220 (smaller with a 170hp 4 cyl and 42mpg hwy 35K) and the Volkswagon Jetta CDI with a 140hp 4cyl and 45mpg hwy 25K. I sure wish I could get the C320 for 30K

 

[gibbons]

Don't fear the turbo (unless you're running against one).

 

[Dave Krall CFII]

Personally I'm not a proponent of synthetic primarily due to cost and lack of changing the oil filter as a result of extended oil change intervals. As long as you change dino oil every 3-5k all will be well.

I'm not concerned with the small additional cost IF synthetic would actually be BETTER against coking up under higher turbo temps. I'd be changing out everything at regular intervals, not extended times as well.

I never have, nor do I intend to start going for longer oil change intervals either.

 

[James_Dean]

. I ran a tug that had 3 20-645 E6 EMDs, 3600hp each, over 1,000,000 hrs each, none had ever had an oil change, filters every 200hrs.

Ah, Henning? That's 114 years of continuous operation. That be some good oil.


James Dean

 

[kevin47881]

I'm not concerned with the small additional cost IF synthetic would actually be BETTER against coking up under higher turbo temps. I'd be changing out everything at regular intervals, not extended times as well.

I never have, nor do I intend to start going for longer oil change intervals either.

Dave, here is an interesting and informative web site on dino and syn oil analysis
www.bobistheoilguy.com

 

[Ghery]

I was going from Denver to Georgetown (where my office is). A few good friends lived in Denver when I moved out here, so naturally I said I'd live with them. It was about 50 minutes to an hour.

I just moved up to Frisco a couple of weeks ago, so now it's Frisco to Georgetown. About 25 miles.

Most people might mind the drive, but I love it!

Georgetown Loop Railroad still running? That was a fun excursion, but it was about 25 years ago.

 

[gismo]

Oil changes and cool down are imperative to prevent coking in the oil feed/return lines.

Cool down isn't really a problem with most turbos today as the automotive mfgs went to water cooled turbos quite a while back and that pretty much eliminated the problem. you do need to allow time for the turbine to stop turning before shutting down if you've been much above idle, but that only takes a few seconds, unless you were near WOT just before stopping for a shutdown.

 

[gismo]

I'm not concerned with the small additional cost IF synthetic would actually be BETTER against coking up under higher turbo temps. I'd be changing out everything at regular intervals, not extended times as well.

I never have, nor do I intend to start going for longer oil change intervals either.

Synthetic based oil definitely stands up to turbo temps better than mineral oil AFaIK, and that's what I've been using in my cars for years. It's also less prone to shearing and thus maintains it's viscosity longer.

I've been driving nothing but turbocharged cars since my first one bought new in 1978, until recently when I went with a normally aspirated Audi S4. The first (a Saab Turbo) is the only one that had any turbo related problems. My wife's last three cars were turbocharged as well. It's definitely very important to keep the oil clean. Consider using the "severe service" oil change intervals even if you don't do much stop and go driving. Keep an eye on induction system leaks too. If you have a significant leak downstream of the compressor, the ECU is likely to spin the turbo faster than it was designed to go (at which point it may be destoyed) in an attempt to produce normal manifold pressure. Personally I think it's worthwhile to add a MAP gauge if the car doesn't already have one as this allows you to detect such a problem much sooner.

Turbocharged cars I've owned:

1978 Saab Turbo
1984 Mitsubishi Cordia Turbo
1988 Toyota Celica All Track
1991 Mitsubishi Galant VR4
1995? Eagle Talon AWD
1993 Audi (uR) S4
1998 VW Passat
2001 Audi S4
2005 VW Passat Wagon

Now I'm driving a 2005 Audi S4 which no longer comes with a turbocharged engine.

 

[mikea]

The earlier gasoline turbo's had issues with the oil coking if the car was driven and shut off without allowing the turbine to cool down (good practice with aviation turbo's as well) which caused a few turbo's to end their lives pretty early...

Yep. I had a 1982 Saab 900 Turbo and later got a 1986(?) Saab 9000 with turbo.

The manual in the 900 said you needed to let the engine idle for a few minutes when you stopped, particularly after hard driving.

The 9000 didn't have that requirement. I think they fixed that with check valves on the oil lines that kept the oil in the turbo after shutdown.

I didn't have any problems with the engine or turbo in either car. I had the automatic transmissions in both turn to soup because they were crap.

 

[AirBaker]

Turbo is muy fun. I've only owned a supercharged car (98 BMW M3 Dinan).

Water cooled Turbos?

 

[flyingcheesehead]

I'm thinking about buying a turbocharged car (either gas or diesel) and wanted to see if anyone had experience with them.

Bought my first one a bit over a year ago (Volvo S60 T5) and no problems yet. My first question was "Do I need to let it run for 3 min when I shut down" like I do with the truck, but thankfully someone got smart and started water-cooling the turbos.

I really like it - It's still efficient, but it's got power when I need/want it. Best of both worlds.

 

[kevin47881]

Cool down isn't really a problem with most turbos today as the automotive mfgs went to water cooled turbos quite a while back and that pretty much eliminated the problem. you do need to allow time for the turbine to stop turning before shutting down if you've been much above idle, but that only takes a few seconds, unless you were near WOT just before stopping for a shutdown.

You are correct Lance. I wasn't sure what year vehicle we were discussing so I took the conservative approach to responding.

 

[gismo]

The manual in the 900 said you needed to let the engine idle for a few minutes when you stopped, particularly after hard driving.

The 9000 didn't have that requirement. I think they fixed that with check valves on the oil lines that kept the oil in the turbo after shutdown.

I'm pretty sure the "fix" was a water cooled turbo bearing housing. The check valves are to prevent starting (and spinning the turbo) with air instead of oil in the bearings, another failure cause.

BTW, according to GAMI's George Braly, idling an aircraft engine on the ground provides no benefit WRT turbo life or oil coking as the turbo will normally be coldest right after touchdown and will warm from there as you taxi and/or sit idling. Coming down final at low power provides the most cooling for the turbo.