How do you know the Turbo lag is kicking in?

sorry for the *** question.

Happy Fathers day btw !

 

I think Turbo Lag is the time it takes for the Turbos to create boost.

Like when you floor the car, there's normally a 2-3 second period where you hear the Turbos whistle before you feel the power.

Bigger turbo means more lag I think.

 

when I WOT at stand still or on a slight roll, it will quickly accelerate, change gear and then seems to have a 1 sec delay before it changes gears and really take off; I am assuming this is the lag but I am not sure. Its a 2008 tip and my first Turbo.

 

If you drive it in the proper rpm (power) range there is very little turbo lag if any that you would find very noticeable

However if you are lugging in third gear at 2K rpm and floor the pedal without downshifting to 2nd then you will notice the turbos kick in hard at 2800-3200 rpm

Now if you have a solid tune the turbos will come on hard at about 2500 rpm

But I go back to my initial comment. Use proper downshifts to stay in the power band and any perceived turbo lag will be minimal.

 

The turbo in your car will increase the density of air entering the engine to create more power. A turbo has the compressor powered by a turbine, thus the turbine is driven by the exhaust gas from the engine, even though it does not use a direct mechanical drive, it helps improve the performance.
Like the old turbo jet engines...the turbo requires some time in order to build up some gas pressure to generate output power, thus when you accelerate and the vehicle is not MOMENTARELY responsive (even though it is a matter of 1 to 5 seconds) you just had a turbo lag...in another words, the time required for the turbo to build up the needed pressure is called turbo lag...is noticed as a hesitation in engine response. This is caused by the time taken for the exhaust system to speed up the turbine.

I onwed a GOLF GTI 2.0 TURBO, and that car had a NOTORIOUS problems with turbo lag...

I hope this is informative...as I am not a mechanic, but I am a pilot and I suffered a lot with older turbo jet engines in the past!

Regards,
LCL

 

There's really two components to it. The thing people usually don't consider is boost threshold. If you're at 1500 rpm in third gear, it might be 5-6 seconds before the engine gets to 3500rpm and makes peak torque. If you're at 4000rpm in third gear and do the same thing, it's nearly instant.

Without getting too deep in the data, let's say the turbo system works best from 3000rpm - 6500rpm. Your boost threshold is 2500-3000rpm in this case, so you're not going to generate much torque below that RPM. If you look at a dyno chart, most people bring the revs to 2000rpm, then go wide open throttle. So what you're seeing is a response curve from that 2000rpm punch. If you do the same thing from 3000rpm, the chart is going to look different. You'll see torque rise much quicker. It's variable, because there is more exhaust energy at 3000rpm to spool the turbos than there is at 2000rpm. The other thing is that higher gears generate more load, so you will get boost at a lower RPM than a lower gear. 2500rpm in 6th can generate quite a bit of boost, but 2500rpm in 1st acts differently. It's less complicated than it sounds, after about 15 minutes of driving the car around you will get the feel for it if you know what to look for.

In essence, if you drive a turbo car with these factors in mind you can effectively eliminate turbo lag altogether. If you try to floor it at 1,500rpm in 3rd you're going to get some lag until you cross the boost threshold around 2500-3000rpm then the car is going to take off. One of the cool things about turbo cars is because the torque delivery is a little more gradual, they feel quite a bit faster than a normally aspirated car of the same power level because of the way torque ramps up.

 

^ Agree with this.

 

thanks for the explanation ! Cheers