walterwhite

is there a sweet spot for boosting?

as opposed to planting the accelerator 100%

it seems if you just engage the turbo passed the dipping point, then let the pedal back up a touch, it makes the turbo work harder.

is this true?

does anyone else do this?

Brun

dipping point - you got me

Shaun

Proper load is where it's at with enough heat in the turbo, headers and up-pipe to maximise the spool / flow and mid-range.

walterwhite

i'm talking about how much you dip the gas pedal.

by dipping point, i mean the point that you have to press in the accelerator in for your turbo to kick in (assuming you have enough revs)... like, you can still drive at 80mph without engaging the turbo if the gas pedal isn't depressed enough.

i find that if you plant the gas pedal 100%, then slowly lift the pedal, there will be a point (maybe 50%-ish) where the turbo will work harder.

...as in, feathering the gas pedal around the point where the turbo kicks in, gives you more power than simply planting the accelerator all the way.

Doobs Scoob

iTrader: (2)

Essentially what you are doing is spinning the turbo up at 100% throttle, then by coming off the 50% the turbo will slow down, but still be spinning, hence why when you put your foot back down it seems the turbo pulls harder.

walterwhite

though, i am actually letting the pedal out when this happens (slowly, just after the kick-in point), not pressing it in again - but not disengaging the turbo.

there feels like a spot you can feather to make the turbo work harder. again this is me letting off the accelerator -at this sweet spot, i can hear the turbo surge - which i normally don't hear just planting the gas pedal in 4th gear.

Shaun

I take it you know what surge is? Then it would be no surprise why you would be getting it in that scenario with the throttle butterfly only partially open. The engine can't consume the air quick enough and the surge is the backing up of the air to the compressor.

Anyway... why would you want to entice the turbo to work "harder". Efficiency is what it's all about, not making the turbo work "harder".

trevsjwood

iTrader: (2)

at max boost in 4th the turbo could be producing hot air, as much as 180c, by feathering the pedal you would be running it at a lower boost level so the turbo outlet temps would drop and it would feel more efficient.
Trev

Midlife......

iTrader: (2)

Maybe at WOT the map is throwing in a bit too much petrol and it's running a bit rich and down on power a tad. Lifting off may lean out the mixture for a more efficient burn and better power..,...... just a guess.

Shaun

jef

iTrader: (13)

id call this lag tbh.

when you plant it, everything starts to get going, by time you lift up its got going, and because your 50% on throttle it keeps going.

Turbotits

iTrader: (2)

I tend to agree. mines mapped rich at wot. but i also find if i sometimes use 3/4 throttle of of a roundabout it feels more torquey although wont rev as hard.

Id guess this is what the op is referring to