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+--- Thread: Turbo lag with manual trans? (/showthread.php?tid=347)
Turbo lag with manual trans? - JB3 - 05-04-2009
Last fall I took a 5500 mile road trip through the midwest and california in my trusty 300. I enjoy national parks, so while I was in denver, I headed north and west to Rocky Mountain national park which has a pretty spectacular 30 miles high altitude road if you've been there or passing through.
The car ran normally until about 7000 feet, then I started to notice an advanced turbo lag, which increased the higher I got. At 12000 feet, it was necessary to floor the gas pedal and then slowly let out the clutch in order to even move forward slightly. It felt very much like a bad clutch, but the problem then decreased as I dropped out of the rockies.
At one point I even had to roll down hill to get the car moving and then whip around to continue above the treeline. I also had some severe deceleration bucking as well coming down the other side.
What could be the problem here? Do I need to replace the ALDA? I had similar problems in the high sierras, but none so bad as in the rockies.
I have been told that the problem is the manual trans swap, but I don't think so, especially with all the other cars out there converted.
RE: Turbo lag with manual trans? - ForcedInduction - 05-04-2009
Thats just normal high altitude oxygen starvation. At 7k feet you have 25% less air pressure than sea level, 35% less at 12k feet. Not only do you have less air to burn before the turbo kicks in, the turbo has to spin faster to make the same boost pressure.
Here is how altitude affected my performance at the 14k ft Pikes Peak (40% less air).
http://www.youtube.com/watch?v=QtEvPIBq9OU
RE: Turbo lag with manual trans? - JB3 - 05-04-2009
Interesting, Once the turbo kicked in, it ran pretty normally, even way up high. The boost seemed to hover around 5-8 since I was driving pretty slowly. Heres a pic of mine as well, I was going about 10mph gawking.
I was able to compensate, but several times I made the mistake of parking on a steep incline to sight see, which caused most of my problems when I tried to move forward again.
I guess I wont worry about it too much then.
thanks
RE: Turbo lag with manual trans? - kamel - 05-06-2009
The problem is you still have a alda.
RE: Turbo lag with manual trans? - winmutt - 05-06-2009
ALDA help keeps the bucking down.
RE: Turbo lag with manual trans? - GREASY_BEAST - 05-06-2009
(05-06-2009, 07:30 AM)winmutt ALDA help keeps the bucking down.
If by bucking, you mean a jarring start from a stop light, you should try driving a Subaru with auto trans. All the throttle response is in the first inch of pedal travel, the other 70% really doesn't do much at all. Even without ALDA, the Benz is far more dignified than that...
If that's not what you meant, could you elaborate?
I agree, though, the ALDA is what's killing the turbo at high alt., however driving at altitude with no ALDA would result in a HUGE cloud of black smoke until the turbo kicked in... Worth it IMO...
RE: Turbo lag with manual trans? - ForcedInduction - 05-06-2009
(05-06-2009, 07:30 AM)winmutt ALDA help keeps the bucking down.
Other way around, a restrictively adjusted ALDA makes bucking worse.
RE: Turbo lag with manual trans? - GREASY_BEAST - 05-06-2009
does "surging" = "bucking" ...?
RE: Turbo lag with manual trans? - JB3 - 05-06-2009
I was trying to use the engine to slow the car down on grades, and it would surge/buck heavily unless you were on the gas. It would not act normally unless you were completely out of gear and just idling using the brake, or actually accelerating downhill. In other words, you couldn't just coast downhill using the engine. About 5 thousand feet lower, it became normal again.