VQ35HR engine series: more power, better economy.

[lemming]

http://www.autoweek.com/apps/pbcs.dll/article?AID=/20060829/FREE/60828028/1041

just thought i would post this because i will go on the record as someone who would prefer BMW rollout a 3.5litre six again. not that the 3.0T isn't a nice engine --it probably is.

but hp to hp, i'll always, for the rest of my life, prefer naturally aspirated power to turbocharged power.

[lupinsea]

Very intrguing.

Like you I'd prefer a N/A engine, if for no other reasons than a lack of turbo lag (though BMW's new 3.0 turbo is said to have virtually non-existant lag) and it's mechanically simpler, and thus theoretically there are fewer things to go wrong.

[iateyourcheese]

Very intrguing.

Like you I'd prefer a N/A engine, if for no other reasons than a lack of turbo lag (though BMW's new 3.0 turbo is said to have virtually non-existant lag) and it's mechanically simpler, and thus theoretically there are fewer things to go wrong.

Hah, BMW has a little trouble with the whole variable valve timing thing. They actually simplified these things (got rid of Valvetronic) before adding the turbo. Maybe it won't be so bad. :crossfingers:

[lemming]

in my own experience with turbocharged cars, they're really fun on cold days. but on humid and hot days, when the engine heat soak is at its greatest with the a/c compressor also running, they're really not a lot of fun.

i swear i can feel the ECU dialing back the timing to save the engine. heat soak affects them to a greater degree than n/a engines. not that n/a engines are immune, but 3.5litres still has sufficient punch even with heat soak.

[ZBB]

in my own experience with turbocharged cars, they're really fun on cold days. but on humid and hot days, when the engine heat soak is at its greatest with the a/c compressor also running, they're really not a lot of fun.


Although our Cooper S has a supercharger instead of a turbo, I've also experienced it, especially in the AZ summer heat. I've been commuting in it over the last couple weeks -- and I usually see ~10-degree temperature differences between my house and work (although 2 weeks ago it was 19 degrees cooler at home than when I left the office 30 minutes earlier!). In the morning, its typically ~80 degrees when I leave the house, and about 90 when I get to the office. On the way home, its usually low 100s to 114 or so (although rarely above 105 since >110 usually only lasts a week or two), but its anywhere from 95-102 by the time I'm home.

Here's what I notice -- and its all during off the line acceleration (at speed you really don't a huge difference). The S is nice and peppy when I leave the house, and slightly less so when I get near the office. But on the way home, the S is really sluggish off the lines -- and it needs more throttle to accelerate adequately (until your above ~2500rpm in 1st). Then its better closer to home. But man does it struggle when the temp is over 100!!!

Its one of the reasons we haven't sold it yet (we replaced it with the X3) -- I think it will be easier to sell once we get out of the hot season in the next few weeks. On a side note, I'm glad we kept it for a couple extra months -- helped me realize that we do not need a 3rd car, even though I've thought about having a fun weekend car at some point... I'd rather just make sure at least one of the daily drivers is fun enough...

[lemming]

Although our Cooper S has a supercharger instead of a turbo, I've also experienced it, especially in the AZ summer heat. I've been commuting in it over the last couple weeks -- and I usually see ~10-degree temperature differences between my house and work (although 2 weeks ago it was 19 degrees cooler at home than when I left the office 30 minutes earlier!). In the morning, its typically ~80 degrees when I leave the house, and about 90 when I get to the office. On the way home, its usually low 100s to 114 or so (although rarely above 105 since >110 usually only lasts a week or two), but its anywhere from 95-102 by the time I'm home.

Here's what I notice -- and its all during off the line acceleration (at speed you really don't a huge difference). The S is nice and peppy when I leave the house, and slightly less so when I get near the office. But on the way home, the S is really sluggish off the lines -- and it needs more throttle to accelerate adequately (until your above ~2500rpm in 1st). Then its better closer to home. But man does it struggle when the temp is over 100!!!

Its one of the reasons we haven't sold it yet (we replaced it with the X3) -- I think it will be easier to sell once we get out of the hot season in the next few weeks. On a side note, I'm glad we kept it for a couple extra months -- helped me realize that we do not need a 3rd car, even though I've thought about having a fun weekend car at some point... I'd rather just make sure at least one of the daily drivers is fun enough...

good lord.

how do all of the rubber moldings and tires deal in that heat day in and day out?

[ZBB]

good lord.

how do all of the rubber moldings and tires deal in that heat day in and day out?

Its only for a couple months of the year :dunno:

Most cars made in the last ~20 years with silicone-based "rubber" parts do fine, especially through warranty/lease periods. You also have to remember that the automakers hot-weather testing isn't only to test engine cooling -- but it includes parts durability testing, including withstanding heat.

But my '65 LandCruiser was a case study in what can go wrong with rubber parts after so long in the desert. I had it from '88-'92, and by the time I received it, most of the door seals were hard and starting to crumble. My TLC had the older-style windshield (narrower, with windshield wipers at top on independent motors, and a vent you could open up below the windshield (but still within the fold-down frame). The vent was held on by a rubber gasket -- and the gasket acted as a hinge. It was partially torn by the time I receieved the car, and completely tore within a year -- so I just closed up the vent and never used it after that.

Then there were the engine gaskets. Over the last year we owned the TLC, it developed an oil leak. Over a ~120 mile trip, it would lose 1 quart of oil, with ~1/2 of that seaping through the firewall and ending up in the passenger footwell (fortunately, the footwell was just metal). On a side note, that engine (a 4L I6) held ~12 quarts of oil, so a 1 quart drop barely register on the dipstick. Over 3-4 visits, our mechanic replaced almost every gasket in the engine, yet had only managed to stop about 1/2 the leak. The final repair fixed it -- and that was the gasket between the engine and transmission. Since he had to drop the transmission, he also replaced the clutch, which was only ~50% worn after 90k+ miles...