Can Someone Explain This To Me?

"K-Roll-PorscheTamer" (k-roll390)
05/20/2014 at 22:36 • Filed to: Turbo

WTF is turbolag??I haven't a clue what it is, what is does, when it happens and why! I feel like I should know this seeing as I haz turbocharged car. Have Focus ST for your troubles.

DISCUSSION (62)

Brian Silvestro > K-Roll-PorscheTamer
05/20/2014 at 22:37

The time it takes for the turbo to spool up from the exhaust gas

K-Roll-PorscheTamer > Brian Silvestro
05/20/2014 at 22:39

Is there any way for me to know how much lag I've got by just driving? Can you feel it?

AM3R > K-Roll-PorscheTamer
05/20/2014 at 22:39

It's pretty much the time it takes for the turbo to spool up and "kick" in.

Brian Silvestro > K-Roll-PorscheTamer
05/20/2014 at 22:40

Yeah, you'll notice a distinct sense of torque after you hear the turbo spool up

K-Roll-PorscheTamer > AM3R
05/20/2014 at 22:41

oh is that where "V-tec kicked in yo!" Came from? Does this mean that Honda has crappy turbos?

Logansteno: Bought a VW? > K-Roll-PorscheTamer
05/20/2014 at 22:42

I don't know much about it either. But it's the delay between you accelerating and the turbos spooling up to give you boost. Not that that effects me.

N/A car life!

PowderHound > K-Roll-PorscheTamer
05/20/2014 at 22:42

turbo uses exhaust gasses to spin. Under low throttle there is less exhaust gas so the turbo isn't working to its full potential. Until it fully kicks in at the right rpm, which depends on the size of the turbo, piping length and a multitude of other things, is the region of lesser power known as turbo lag.

naallday > K-Roll-PorscheTamer
05/20/2014 at 22:42

It's like A lag that is felt between pushing on the gas pedal and having the turbocharger create boost So the period of time it takes to make boost. Sometimes if your car has a large turbo then the lag is very noticeable.

Burrito de EJ25 > K-Roll-PorscheTamer
05/20/2014 at 22:43

Nope. That's variable valve timing.

The Daily Hoon > K-Roll-PorscheTamer
05/20/2014 at 22:47

Throttle lag occurs because turbochargers rely on the buildup of exhaust gas pressure to drive the turbine. In variable output systems such as automobile engines, exhaust gas pressure at idle, low engine speeds, or low throttle is usually insufficient to drive the turbine.

Textured Soy Protein > K-Roll-PorscheTamer
05/20/2014 at 22:47

Reading is your friend.

http://auto.howstuffworks.com/turbo.htm

naallday > K-Roll-PorscheTamer
05/20/2014 at 22:48

not even a little. You have much to learn.

CRider > K-Roll-PorscheTamer
05/20/2014 at 22:48

Jeremy Clarkson explains turbo lag

Racescort666 > Burrito de EJ25
05/20/2014 at 22:49

Well... V-tec is variable lift too so there's that. But yeah, the moral of the story v-tec =/= turbo lag.

PetarVN, GLI Guy, now with stupid power > K-Roll-PorscheTamer
05/20/2014 at 22:49

Ok, so "Turbo lag" is the amount of time it takes for the PSi the turbo makes to increase. Since you have a FoST, take a look at the turbo pressure gauge when accelerating. look at it when you hit the gas at ~4000rpm in 2nd, and look at it when you're in 5th/6th and you hit the gas. You'll see a noticeable difference in the amount of time it takes for the turbo to produce it's optimal power

That, my friend, is Turbo lag.

the "V-tec" thing comes from valve timing Honda uses, that engages some magical trickery in the camshaft of a V-tec equipped car, allowing it to produce (quite a bit) more power. It happens at a set RPM. every time. Turbo lag can happen in any gear, at any RPM's at any time.

K-Roll-PorscheTamer > Brian Silvestro
05/20/2014 at 22:51

Right! That does make sense.

Racescort666 > naallday
05/20/2014 at 22:52

Or a poorly designed system. Turbo size is just one factor to lag which is affected by many things.

K-Roll-PorscheTamer > Logansteno: Bought a VW?
05/20/2014 at 22:52

There are times I wish I was still about that life.

AM3R > K-Roll-PorscheTamer
05/20/2014 at 22:52

not exactly, pretty much every turbo car will have turbo lag, some less than others. Even NA V6 Honda accords have V-tec, trust me I've spend enough time hooning my dads :)

K-Roll-PorscheTamer > naallday
05/20/2014 at 22:53

would a FoST turbo be considered large or small?

Grindintosecond > K-Roll-PorscheTamer
05/20/2014 at 22:53

Back in the day or early turbo cars, Foot goes down, engine gives some power. Turbo spins up to finally give enough boost and then wham!..you have assloads of power but only at 4k rpm on up because it took that long for the big pumpkin turbo to generate pressure....Today, we have high compression boosted engines and engine management that makes boost at a much lower rev range. Way back when, the porsche 930 of the late 70's had a low compression engine and big boost. So you stepped on the gas and nothing happened until the engine spun up fast enough to create exhaust pressure, and then the turbo ws big and heavy and that took a bit and finally spun up to speed and it suddenly pumped air in and your power suddenly came in at 4k rpm. So in that car with all that weight hanging out the back in a corner when you put your foot down on exit......it spun off into the giggly bushes from sudden power a second after you wanted it.

K-Roll-PorscheTamer > AM3R
05/20/2014 at 22:54

Would a CAI reduce the lag?

K-Roll-PorscheTamer > Grindintosecond
05/20/2014 at 22:55

I liked this history lesson, especially because you used a 930! Thanks for the lesson!

Grindintosecond > K-Roll-PorscheTamer
05/20/2014 at 22:56

Yup! that was the first big turbo car and it scared everyone in the rain. I think the MR2 gen-2 has a bit of that issue too...in the rain.

Nick, Drives a Cobalt LT > CRider
05/20/2014 at 22:57

Reasons why I brake boost and have antilag......

YSI-what can brown do for you > K-Roll-PorscheTamer
05/20/2014 at 22:57

Turbo lag is when you are off throttle and then go on throttle again, it is the time it takes for the turbo to spool back up to its original psi. It has nothing to do with power delivery. Larger turbo has more mass so it requires more force to spool back up. Boost threshold is something completely different from turbo lag, which is the amount of boost produced by the turbo at a given RPM.

AM3R > K-Roll-PorscheTamer
05/20/2014 at 22:58

Honestly just getting a tune (Cobb, etc.) would help tremendously. I know a lot of 335i owners who got downpipes and a tune to get rid of lag. It worked well for them!

Logansteno: Bought a VW? > K-Roll-PorscheTamer
05/20/2014 at 22:58

I like my torque served at 2500 RPM with no lag, thank you very much.

K-Roll-PorscheTamer > Grindintosecond
05/20/2014 at 22:58

I want to ride in a 930...in the rain! :)

YSI-what can brown do for you > CRider
05/20/2014 at 23:00

That is boost threshold!!!!

K-Roll-PorscheTamer > Logansteno: Bought a VW?
05/20/2014 at 23:00

Do you?

Milky > K-Roll-PorscheTamer
05/20/2014 at 23:00

In my friends 9-3 Areo one time he floored it and the tires spun at like 2500 - 3k rpm instead of right away. Thats turbo lag.

CRider > YSI-what can brown do for you
05/20/2014 at 23:02

Hello there, my pedant friend.

YSI-what can brown do for you > CRider
05/20/2014 at 23:03

THIS SHIT IS IMPORTANT!!! IMPORTANT!!!!!!!!!!!!!!!!!!!

It's a "Porch-uh" > K-Roll-PorscheTamer
05/20/2014 at 23:04

All of you who say that it's the "build-up" or "spool-up" time are incorrect.

You're thinking of boost threshold , which is the surge of power during acceleration as the engine speeds up and finally puts out enough exhaust gasses to spin the turbine fast enough to then provide significant intake pressure to make the car zoom.

Turbo lag is the reduction in throttle response that occurs once the turbine is operating above the boost threshold. So you're at WOT then shift, taking your foot off the accelerator briefly, then back on. The turbine slows as the exhaust output is reduced and takes time to spin back up to full speed, causing a delay in throttle response. If you've heard an anti-lag system popping on a WRC car, it's between shifts, or as the car is banging on the rev limiter while waiting to start.

Somehow, somewhere in the past, boost threshold started being called turbo lag. I'm not sure why, but it's not up to y'all to politely correct your friends and the rest of the car community.

It's a "Porch-uh" > YSI-what can brown do for you
05/20/2014 at 23:08

Kinja'd!!!

It's a "Porch-uh" > K-Roll-PorscheTamer
05/20/2014 at 23:09

Except that's not right. He's talking about boost threshold.

CRider > YSI-what can brown do for you
05/20/2014 at 23:09

Kinja'd!!!

It's a "Porch-uh" > CRider
05/20/2014 at 23:11

Except he's technically correct. The best kind of correct.

K-Roll-PorscheTamer > It's a "Porch-uh"
05/20/2014 at 23:11

This is much more confusing than I thought it'd be..

YSI-what can brown do for you > CRider
05/20/2014 at 23:11

But, but, it was like 4 words.

CRider > It's a "Porch-uh"
05/20/2014 at 23:12

Kinja'd!!!

CRider > YSI-what can brown do for you
05/20/2014 at 23:12

Kinja'd!!!

Dsscats > PowderHound
05/20/2014 at 23:14

So by that logic, wouldn't a rear mounted turbo setup have incredible lag?

YSI-what can brown do for you > CRider
05/20/2014 at 23:14

So now then, shall I begin my lecture?

It all started when some asshole thought an Oldsmobile needed more power. . .

It's a "Porch-uh" > K-Roll-PorscheTamer
05/20/2014 at 23:15

Explained here: http://oppositelock.jalopnik.com/all-of-you-who…

K-Roll-PorscheTamer > It's a "Porch-uh"
05/20/2014 at 23:19

I see. Thank you for the info!

ly2v8-Brian > It's a "Porch-uh"
05/20/2014 at 23:30

Yeah that's pretty much it.

PowderHound > Dsscats
05/20/2014 at 23:46

not if the throttle body is facing backwards?

Dsscats > PowderHound
05/20/2014 at 23:57

Kinja'd!!!

There's just basically 10 feet of piping from the turbo's back to the intake manifold. I'm really not sure.

PowderHound > Dsscats
05/21/2014 at 00:18

oh! Those kinds. Yeah no idea

Dsscats > PowderHound
05/21/2014 at 00:37

I'd just guess these are pretty low boost set ups...

Garrett Davis > It's a "Porch-uh"
05/21/2014 at 01:51

I wouldn't say they're wrong, it's different use of terminology. The way they use the term is in replacement for "boost threshold," because no one knows that term. So technically they are incorrect, but it's just easier to say turbo lag so 98% know what you're talking about.

Garrett Davis > K-Roll-PorscheTamer
05/21/2014 at 01:53

Small. We don't have much spool up time, which is why we get so much torque so early.

Garrett Davis > K-Roll-PorscheTamer
05/21/2014 at 01:59

Not really. Honestly, the ST twins get boost pretty low for turbo vehicles already, and the further you go down the modification rabbit hole, the more peaky the power band gets, and once you start getting into bigger turbos, you come on boost much higher in the rev range — albeit with a lot more power.

There are some mods the reduce spool up time, but it starts getting expensive quick. Just an intake or just an exhaust will do pretty much nothing without a tune anyway, which is a big misconception with newer cars.

Garrett Davis > Logansteno: Bought a VW?
05/21/2014 at 02:14

2500 RPM you say?

Kinja'd!!!

Not my dyno run.

Illugi Arinbjörn Már Jónsson > Garrett Davis
05/21/2014 at 14:07

It doesn't change the fact that they are still wrong, and it's not "different use of terminology" either, it's two completely different things.

A lot of people in the US think Europe is a country, it doesn't make it a country though...

It's a "Porch-uh" > Garrett Davis
05/21/2014 at 14:33

The OP asked what is turbo lag, which people responded with descriptions of boost threshold. It's not a different use of terminology, it's the incorrect use of terminology. I don't think we're being pedantic about this, just correcting a misnomer.

Garrett Davis > It's a "Porch-uh"
05/21/2014 at 15:46

You're right, it is a misnomer, and should be corrected, though I probably wouldn't in normal conversation.

Garrett Davis > Illugi Arinbjörn Már Jónsson
05/21/2014 at 15:49

That's a terrible example.

This little mix up of words at least applies and makes sense. When you step on the gas and wait for the turbo to spool up while the revs build, that could accurately be described as lag — lag between when you put your foot down, and when the car really goes. Kind of like the lag in waiting for an automatic transmission to down shift. So while they may not be using the absolute correct term, it's still by far the most common nomenclature for that event.

I know the terminology, but when I'm talking to people about cars, I don't correct them, because I know exactly what they're talking about. True, yes, 98% of people use the term turbo lag wrong, but it's come to the point where it's fine in casual conversation.

It's a "Porch-uh" > Garrett Davis
05/21/2014 at 18:26

What? You don't want to be "that guy?"

Kinja'd!!!

It's a "Porch-uh" > Illugi Arinbjörn Már Jónsson
05/21/2014 at 18:27

Europe isn't a country?

Next thing you'll tell me is that Africa isn't a country.