Thread: Turbo Lag
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      04-02-2013, 05:02 AM   #11
HighlandPete
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Drives: BMW F11 535i Touring
Join Date: Mar 2007
Location: Scotland, Highland Region

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Is some of this lag issue, simply an "on off" throttle style? Both affecting the engine and the transmission management.

I'm in an N55 engined car and as long as we are using the engine with the turbo spinning, there is virtually no delay to achieve boost.

But if you are, (as has been said), on the rundown or coasting down to 1,000rpm and then boot the throttle, where is boost coming from? You are really building in the potential for turbo lag, also most likely below the boost threshold. But if you have down changed to keep the turbo spinning and spooling, virtually instant shove when you add throttle.

Try different techniques, try and picture what the turbo is doing.

I'll give an example, I'm driving along in a 30mph zone, engine just running about 1,100rpm. Zone ends you boot the throttle, rpm too low to get instant response. Same situation but a few yards before the zone ends I paddle 'down change' a gear or two, rpm increases, then as zone ends boot the throttle and instant urge. Have eliminated both any engine boost threshold/lag issues, plus the gearbox is 'sorted' and no transmission delays either.

HighlandPete
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