Here's a little definition session.

Turbo lag: Decrease in turbocharger efficiency and response due to high charge temperatures.

Boost threshold: The time it takes for the turbocharger to begin producing boost after throttle is given.

Most people refer to boost threshold as turbo lag. These are two different things entirely. Turbo lag is most commonly caused by an incorrect turbocharger system. By incorrect, I mean that things like turbine impellar size, intercooler efficiency, etc. are not capable of keeping up with the rest of the system. As w/ most things in life, you're only as good as your weakest link.

Just thought I'd share that just in case some of you didn't know.

 

S2000's dunna have turbos... just an fyi

 

Say Knowledge, it is not most people who use lag that way. It is everyone I every talked to or read. Language is defined by common usage. Witness Homer's "d'oh!" making it into a dictionary. Seems to me lag is an acceptable word for that purpose since the layman interprets it that way. I'm curious though and I assume you are technically correct but what is the source of your definition?

 

Some do, some also have superchargers. Of course, they're aftermarket systems but you get the picture.

 

Read Corky Bell's Maximum Boost or talk to anyone who really knows their turbocharger systems. They'll tell you the same thing that I did. I know that lag is accepted by most but when you start dealing w/ a "serious" turbo guy, it'll make things a little easier by using the correct terminology. If you want me to get ultra-specific, I can explain why intercoolers are actually aftercoolers.

 

[QUOTE]
Turbo lag: Decrease in turbocharger efficiency and response due to high charge temperatures.

 

Knowledge,

Mabye you meant...

Turbo lag: Decrease in turbocharger efficiency and low RPM response due to high exhaust pressure required to spool the turbo.

 

Phantom, what you are describing is called boost threshold. Turbo lag is most often an issue while the engine manifold pressure is becoming positive. Boost threshold describes the time and/or rpm needed to attain positive manifold pressure (boost).

 

[QUOTE]
Turbo lag is most often an issue while the engine manifold pressure is becoming positive.

 

It is an interesting subject. I used to ride a 1982 Honda CX500 turbo motorcycle, the world's first factory turbocharged cycle. I would twist the wrist, wait about two seconds, and hold on when the boost threshold (see I'm learning) was finally reached. Yeah, I know all modern sportbike riders are unimpressed with 75 HP in a 500+ lb bike but it still hit with a big rush (and grin). It remains the most challenging bike I ever rode.

I know a few really fast RX7TT auto-X drivers who still complain about "turbo surprise." One of them (a married couple actually, the Lynches) recently switched to a Z06 vette because of this. They haven't finished sorting it out yet but it still looks like a fast beast to me.