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Old 04-26-2005, 07:56 AM   #1
fish
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turbo lag

keeping in mind that you've got a complete idiot here when it comes to cars...

what exactly is turbo lag? and like why does it happen?
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Old 04-26-2005, 10:04 AM   #2
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Quote:
Originally Posted by fish
keeping in mind that you've got a complete idiot here when it comes to cars...

what exactly is turbo lag? and like why does it happen?

Delay between pressing the accelerator pedal and the engine getting sufficient boost to increase the output power level above normally aspirated levels at whatever rpm.
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Old 04-26-2005, 01:41 PM   #3
theman352001
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The reason it happens is because it takes some time for the impeller in the turbo to "spin up" to the speed necessary to provide the boost mentioned above.
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Old 04-27-2005, 02:04 AM   #4
fish
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ok i think i get it (somewhat)...so how do you get around it? is there a way or do you just have to live with it?
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Old 04-27-2005, 02:18 AM   #5
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Quote:
Originally Posted by fish
ok i think i get it (somewhat)...so how do you get around it? is there a way or do you just have to live with it?

Turbos will always have turbo lag, no matter how big or how small it is, it's just how much there is. The idea behind sequential twin turbos is to lower turbo lag, by having a small turbo that spools up first, then the larger one spools up, hence you have boost over the entire power range. There will always be turbo lag though. Some ways to lower it;

-Ball bearing turbo
-keeping the turbo properly lubricated
-Sequential twin turbos
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Old 04-27-2005, 03:19 AM   #6
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A couple of things:

theman352001 spooling is not necessarily the problem, for instance when gear changing the turbine/impellor can actually spin faster because it isn't doing much work, it's stall that causes the problem. The stall occurs after stall flutter and is the air stream breaking away from the blade contours; the compressor impellor does not actually physically stall, the air does.

Godlaus there are lots of ways to reduce lag. The most obvious method is to make a hybrid that suits the application. Other common things are dump pipes, long radius up pipes, plenum resizing, etc. A method some of us use is to run the fueling lean at lower revs in certain circumstances so that the throttle is more open and flow through the turbine higher, thus earlier spooling.
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