turbo lag what car has the MOST

Flerbizky

I am SO lost right now...... That was not a very clear clarification...

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I will make a video so you understand better lol hang on...

thegreatms

It looks like almost everyone here is not using the term "turbo lag" correctly. You must clarify if you are talking about boost threshold or turbo lag. They are different and often confused.

from Wiki: (http://en.wikipedia.org/wiki/Turbo_lag)
"Lag is not to be confused with the boost threshold; however, many publications still make this basic mistake. The boost threshold of a turbo system describes the minimum turbo RPM at which the turbo is physically able to supply the requested boost level. Newer turbocharger and engine developments have caused boost thresholds to steadily decline to where day-to-day use feels perfectly natural. Putting your foot down at 1200 engine RPM and having no boost until 2000 engine RPM is an example of boost threshold and not lag."


To be clear:
Putting your foot down at 1000 rpm and waiting til XXXX rpm to get boost built is boost threshold.

Putting your foot down at 5000 rpm (or anywhere above boost threshold) and waiting X.X seconds for boost to build is turbo lag.

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I know boost threshold is what where taking about and its the "technical term" but really every one knows it as turbo lag, especially when I talk to people that have turbo's (real life cars) they usually say the "turbo, lag" instead of boost threshold.

thegreatms

It looks like almost everyone here is not using the term "turbo lag" correctly. You must clarify if you are talking about boost threshold or turbo lag. They are different and often confused.

from Wiki: (http://en.wikipedia.org/wiki/Turbo_lag)
"Lag is not to be confused with the boost threshold; however, many publications still make this basic mistake. The boost threshold of a turbo system describes the minimum turbo RPM at which the turbo is physically able to supply the requested boost level. Newer turbocharger and engine developments have caused boost thresholds to steadily decline to where day-to-day use feels perfectly natural. Putting your foot down at 1200 engine RPM and having no boost until 2000 engine RPM is an example of boost threshold and not lag."


To be clear:
Putting your foot down at 1000 rpm and waiting til XXXX rpm to get boost built is boost threshold.

Putting your foot down at 5000 rpm (or anywhere above boost threshold) and waiting X.X seconds for boost to build is turbo lag.

Click to expand...

Thank you. I knew I was right. 👍

Boost Threshold is also "Boost Response".

Everyone I've talked to and everything I've read describes the the delay between full-throttle from idle and boost as "turbo lag," and not "boost threshold."

Why on earth would a delayed reaction be called a "threshold," anyway? That conflicts with the meaning of the word.

"Boost threshold" is just the point where a turbo actually begins spooling up. "Turbo lag" is any delayed reaction between putting your foot down and getting boost, regardless of what RPM you're at.

the option z stream.....not sure whats wrong with it...

Wolfe2x7

Everyone I've talked to and everything I've read describes the the delay between full-throttle from idle and boost as "turbo lag," and not "boost threshold."

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Thank you very very much - It's not just me then.... 👍

Wolfe2x7

Everyone I've talked to and everything I've read describes the the delay between full-throttle from idle and boost as "turbo lag," and not "boost threshold."

Why on earth would a delayed reaction be called a "threshold," anyway? That conflicts with the meaning of the word.

"Boost threshold" is just the point where a turbo actually begins spooling up. "Turbo lag" is any delayed reaction between putting your foot down and getting boost, regardless of what RPM you're at.

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Actually, it is a common wording mistake.

http://www.xmission.com/~dempsey/shelby/turbo101.htm

People make this mistake commonly. Lag means something going slow, so if their turbo is "working slowly", they automatically call it "Turbo Lag" when in fact, what the discussion is about is boost response, not turbo lag. When you feel turbo lag, it feels a little like the car is about to stall out, then you get a sudden boost of response when normally driving. This is not simulated in GT4, since if I am cruising at a certain RPM, and gas it, the car does go, and doesn't have a momentary stall, or jolt feeling.

I don't care if GT4 doesn't simulate it. There are many, many things it simulates incorrectly.

A lag is a little bit more than something going slow. It is a pause, a period of time between two related actions/reactions. Namely, flooring the throttle and getting turbo boost. In that sense, boost response and turbo lag are synonymous -- they both represent the amount of time it takes for a turbo to spool up and provide boost.

I fail to see how different RPM ranges necessitate the need for two separate words, but I guess the terminology has already been decided. If I were you, though, I wouldn't expect many people to apologize for using the "wrong term" to describe this phenomenon. I certainly won't.

Wolfe2x7

I don't care if GT4 doesn't simulate it. There are many, many things it simulates incorrectly.

A lag is a little bit more than something going slow. It is a pause, a period of time between two related actions/reactions. Namely, flooring the throttle and getting turbo boost. In that sense, boost response and turbo lag are synonymous -- they both represent the amount of time it takes for a turbo to spool up and provide boost.

I fail to see how different RPM ranges necessitate the need for two separate words, but I guess the terminology has already been decided. If I were you, though, I wouldn't expect many people to apologize for using the "wrong term" to describe this phenomenon. I certainly won't.

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I wish I could give you more Reps.. Thanks ! 👍

Wolfe2x7

I don't care if GT4 doesn't simulate it. There are many, many things it simulates incorrectly.

A lag is a little bit more than something going slow. It is a pause, a period of time between two related actions/reactions. Namely, flooring the throttle and getting turbo boost. In that sense, boost response and turbo lag are synonymous -- they both represent the amount of time it takes for a turbo to spool up and provide boost.

I fail to see how different RPM ranges necessitate the need for two separate words, but I guess the terminology has already been decided. If I were you, though, I wouldn't expect many people to apologize for using the "wrong term" to describe this phenomenon. I certainly won't.

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Not expecting an apology. Just trying to let people know what the proper term is, there is a difference, and although small, it is still a difference.

Flerbizky

I am SO lost right now...... That was not a very clear clarification...

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I see that this has already been discussed, but I wanted to clarify. Hopefully I can also explain why if it important to have two different terms.

This example is based off my car in real life (90 eagle talon GSX, with stock 14B turbo).

If I floor it at 1000 rpm in 3rd gear I will accelerate without boost, then at about 1800 rpm I just start building boost, by 3000 rpm I have full boost of 15 psi.
The time from when I floor it to when it builds boost is the boost threshold/response. And in reality it is solely based on the minimum rpm to build boost. You could floor it at a variety of rpms 500, 1000, 1500 and not get boost.

Turbo lag: Let's say I'm on the highway, at 75 mph in 4th gear (about 5000 rpm). I floor it. The boost gauge goes from vacuum (-16 hg/mm) to boost (15 psi) very quickly, maybe .3 seconds. That is turbo lag; it is very low on my car with its small turbo.

One case illustrates the difference in these terms. Lets say I'm towing a heavy load in my car, or going up a really steep hill. If I floor it in 4th gear at 1500 rpm, I may not accelerate; I make very little hp at 1500 rpm. So I may stay at a constant speed, and I will make no boost, therefore my boost response will be undefined. It would take an infinite amount of time for me to reach 15 psi.
In that situation if I am smart and downshift to 2nd, I will get up to a rpm where I make boost, and it will come on very fast, as described above (~.3 seconds).



Turbo lag is an important factor with pure racecars. When they shift they will still be above the boost threshold rpm but if the turbo lag is high, it will take time for the turbo to spool. Only a mis-shift or exiting the pit lane would put them in an rpm range where boost response comes into play.

I've also wondered (and I posted this in another thread but didn't get a response to it) if cars like the Option and others with "lag" are actually suffering from turbo related lag, or boost response like Thegreat mentioned above, or if it is a matter of the car being designed to run at high rpm and thus running extremely lumpy cams? I say this because a stock 350Z makes close to 300hp. Thus, the Option should also be making the same power a stock Z would (well, close to it at least considering the tuning involved with turbos being different from NA tuning) when not on boost. That makes me believe that the cars being described as laggy are actually just cammed up.

There is hardly any lag when in the upper revs on any car in GT4. From the time you go WOT to closed throttle to WOT again there should be a little bit of time for the turbo to spool back up but it is not noticeable. Also the laggy cars will develop full boost from idle with full throttle according to the boost gauge. That almost makes it seem like the gauge just changes depending on throttle position, but some cars do lose boost at higher rpm like the kei cars.

Could the way turbos operate in GT4 be flawed as well?

Ebiggs

I say this because a stock 350Z makes close to 300hp. Thus, the Option should also be making the same power a stock Z would (well, close to it at least considering the tuning involved with turbos being different from NA tuning) when not on boost. That makes me believe that the cars being described as laggy are actually just cammed up

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That right, but its not just cams. Lots of tuning options will lower your hp at low rpms to get a gain at high rpms. In a stock turbo car, swaping in a big turbo will be the most obvious case of this. In addition to cams, your intake manifold shape/size and you exhaust system will move your power band. This is one reason new cars are working on varible length intake manifolds.

Also with the Option Z a turbo car often has lower compression pistons than a NA. So the NA version will make better power until the turbo starts making boost. That is one way many people damage their engines, they take a NA car with high compression pistions, and throw on a turbo. Not realizing that they should have swapped in lower compression pistions.

Yeah, it took that into consideration when I said "(well, close to it at least considering the tuning involved with turbos being different from NA tuning)." I just don't know the specifics of the tuning to have explained it more.

Any Group B beast is going to win the "Scariest Turbo Spool-Up" award easily. The Lancia Delta S4 has got to be the worst (or best) at this, it's absolutely impossible to take even a minor sweeper at WOT because when the turbo kicks in, it's like getting drop-kicked by a mule. Even with permanet 4WD, it oversteers like a Corvair when in the boost range.

And don't get me started on the EVO 2 Peugot....

Well, I think I have the answer.

Chapparal 2J (with BIIIIG stage 4 turbo), 1st gear "tweaked" to run to about 380 kays...

Lets just say I got whipped by a Ford Ka up to about 120 km/h

You used to have late '70's Le Mans Porsches with 3 second turbo lag, so the drivers would put the throttle down three seconds early. That is turbo lag.

xjr-9