I was wondering, is there a Supercharger lag in the V or no lag at all? Especially at low RPM

There is definitely a lag in the V2 but not in the normal sense. Since a blower is belt driven there isn't much inherent lag because it can start spinning as soon as the engine cranks over. Changing the size of the crank pulley or blower pulley along the belt can change the speed at which the blower spins, increasing its effectiveness (albeit with the necessary supporting mods and tune).

Turbos can lag significantly because they are generally gas driven and therefore need to wait for exhaust cirulcation to occur before building boost. A lot of guys use a "two-step" when they run large single turbos to spool them up in advance of acceleration. This said, turbos are generally more efficient than blowers and can make more power all things equal.

As far as the V2, you are probably asking this question because the boost seems to only kick in under harder acceleration (which is most easily noticeable when you are in an overdrive gear). I will defer this to the tuners here, but I assume that has more to do with the tune than it does the blower. All late modern cars can bypass boost, and I assume that is what Caddy does for gas mileage but I'm not sure. I have driven three cars with roots style blowers and none of them kick in boost as late as my V2 does.

s/c lag???
Turbo lag, Ive heard of.

F

I own both a '09 CTS-V (supercharged) & a mildly modified '87 turbo Buick (*turbocharged*) and I feel that if there is a supercharger lag on the Cad '09 CTS-V's it is insignificant or just plain non-existent. There is a turbo lag on turbo cars, the amount of lag depends upon quite a few variables, including, but not limited to: how well the size and type of the *turbo* is matched to the car, amount of boost, downpipe size, *exhaust* characteristics, cat or no cat, headers or none, intercooler size, front mount or stock mount intercooler, & how well & how much the car is tuned to match the motor mods that it has.

turbo and supercharged motors will rarely ever have the instant response of an na motor.

turbo and supercharged motors will rarely ever have the instant response of an na motor.

what? Your saying FI is not equal to NA response? Im not buying it. Turbo, I'll buy but not FI.
Id like to hear your thoughts on why NA is more responsive.


F

Blower lag? :bonkers:

Bypassing boost? :bonkers:

NA quicker throttle response than a blower? :bonkers:

:hmm:

Blower lag? :bonkers:

Bypassing boost? :bonkers:

NA quicker throttle response than a blower? :bonkers:

:hmm:


:werd:

Blower lag? :bonkers:

Bypassing boost? :bonkers:

NA quicker throttle response than a blower? :bonkers:

:hmm:

NA = Naturally-Aspirated engine (No Supercharger or Turbo).

Boost Bypass = When boost is not needed a by-pass valve allows air that is being forced down the throat of your motor to be by-passed back into the supercharger or into the atmosphere.

I don't know about SC lag, but my V2 has power whenever I need it regardless of engine RPM. This would be a very fast car even without FI.

I don't know about SC lag, but my V2 has power whenever I need it regardless of engine RPM. This would be a very fast car even without FI.

actually it would probally be a dog w/out the blower because of the compression

what? Your saying FI is not equal to NA response? Im not buying it. Turbo, I'll buy but not FI.
Id like to hear your thoughts on why NA is more responsive.


F


Equal? No, I don't believe FI and NA are equal.

Close? Definitely, but my experience is that there definitely is a subtle difference between the two. Not sure I can explain it, but it's been in both my blown Vs, as compared to my NA cars.

Turbo clearly is the lag king though

Equal? No, I don't believe FI and NA are equal.

Close? Definitely, but my experience is that there definitely is a subtle difference between the two. Not sure I can explain it, but it's been in both my blown Vs, as compared to my NA cars.

Turbo clearly is the lag king though


The term lag has more than one meaning in this post.

-there is actual mechanical blower lag
-then there is perceived lag due to tune potentially bypassing blower for mpg
-then there is acceleration lag, which can be a combination of both.

consequently, the sts-v has the worst acceleration lag of any car i've ever driven. the cts-v has great throttle response, it's just not necessarily from boost.

consequently, the sts-v has the worst acceleration lag of any car i've ever driven. the cts-v has great throttle response, it's just not necessarily from boost.

I gotta agree...but I suspect it's due to the glass rear and 470HP on a 4k+ beast. There are WAYYYYY too many tq nannies on the STSv.....
You dont hear of many grenading rears on the STSv like the V1s, though.....


F

Didn't thought there would be so many answers :)

In fact, having owned a NA Z06, SVT Cobra, Jeep Srt-8, V8 S4, i'm looking in the V to have similar throttle response to the cars/truck I mentionned... When I was stating a "lag", I was meaning when you are for example at 15-20mph and you floor it, if it's similar to a NA engine or you can feel a "lag" between the time you floor it and the time it reacts compared to the vehicles I mentionned! I loved my Jeep SRT-8 when I was flooring it... I didn't liked the truck feeling though so I kept it only 6 months.

Just my .02, but the motor wants to run like a raped ape. My auto is the limiting factor. It hesitates throughout the powerband. Some more than others, but it does it regardless. If you are concerned with power I would recommend the manual if it is feasible. I only bought an auto out of necessity.

There is a very small lag with the supercharger.

Turbo-lag = the time it takes for the turbo to spool up to speed to generate boost. A turbo not making boost will have to increase 10k or 15k RPM, or more.

Supercharger lag = the time it takes for the boost-bypass valve to disable bypass. The valve is controlled by intake manifold vaccuum, and when vaccuum is decreased or not present (as in open throttle positions) the valve moves to direct boost to the manifold. SInce it is belt driven the supercharger is essentially always making boost, it just needs to be directed to the intake manifold. Without the bypass valve the engine would always be under pressure, consuming large amounts of HP and fuel to pressurize the intake manifold for no reason.

The supercharger lag is very small though, very short. Vaccuum is reduced almost simultaneously with throttle opening, and the mechanical delay is very short as well, so it is almost not noticeale (unless there is a computer nanny/intervention - think torque management). This is why most people say a supercharged engine has the same throttle response as a NA engine.

Search for the related threads on the "P-port". Disabling the P-port on the boost bypass valve eliminates the computer (and mechanical) ability to govern boost pressure and response via the bypass valve. Vaccuum control still applies via the V-port, and in my non-scientific experimentation I found disabling the P-port offered seemingly faster boost response (reduced supercharger "lag"). But this could be placebo, hard to say for sure since the lag is so small anyway. FYI I do have the manual trans, no torque management nannies...

NA = Naturally-Aspirated engine (No Supercharger or Turbo).

Boost Bypass = When boost is not needed a by-pass valve allows air that is being forced down the throat of your motor to be by-passed back into the supercharger or into the atmosphere.

Looks like I didn't choose my emoticons properly. Thanks for your response to my poorly structured post. I didn't mean to imply that I didn't 'understand' the terminology. Rather, I was questioning the veracity of the statements.

If there is such a thing as blower lag, I haven't experienced it in the roots type blown engines that I've owned. Do you (a collective, you) define lag as something measured in milliseconds?

If a NA motor provides quicker throttle response than a blown motor, are we again speaking in terms of milliseconds?

If I lose the quarter mile run by a thousandth of a second, it will not be because of "lag" in my FI engine but rather because my reaction time sucked.

When I was stating a "lag", I was meaning when you are for example at 15-20mph and you floor it, if it's similar to a NA engine or you can feel a "lag" between the time you floor it and the time it reacts compared to the vehicles I mentionned!

There is definitaly a lag between when I floor it and when the automatic transmission decides to pick a gear ........ I am guessing it is tuned this way from the factory to allow for the 100K mile warranty.

There is definitaly a lag between when I floor it and when the automatic transmission decides to pick a gear ........ I am guessing it is tuned this way from the factory to allow for the 100K mile warranty.


:yeah: I am experiencing the same thing.

:yeah: I am experiencing the same thing.

A factory tuning issue. A clean tune will improve the performance throughout the curve.

One aspect of a blown engine that may be perceived as "lag" is due to the fact that the blower has a significant inertia to it ( magnified by the pulley ratio ).

The feel is similar to comparing 2 identical engines - one with a very light flywheel the other with a very heavy flywheel.

The lighter one will feel lighter/freer revving, overshoot less engine accel, etc.

the heavier one will feel laggier - since it is less closely coupled to the throttle (timewise)

When I was stating a "lag", I was meaning when you are for example at 15-20mph and you floor it, if it's similar to a NA engine or you can feel a "lag" between the time you floor it and the time it reacts compared to the vehicles I mentionned!

There is definitaly a lag between when I floor it and when the automatic transmission decides to pick a gear ........ I am guessing it is tuned this way from the factory to allow for the 100K mile warranty.

factory tuning issue. A clean tune will improve the performance throughout the curve.

So ... are we now talking about transmission lag? Find a tuner. Any tuner worth his salt can eliminate that "lag" in no time. The transmission shift points and "lag", the throttle response and the numerous computer controlled whatnots that constitute the factory tune can be tweaked and/or turned off for a perfectly responding transmission and supercharger.

I drive most of the time in Sport Mode and don't have an issue with the hunt for the right gear.
About the only lag I get is "Jet Lag" from being propelled into the next time zone.
:lildevil:

I drive most of the time in Sport Mode and don't have an issue with the hunt for the right gear.
About the only lag I get is "Jet Lag" from being propelled into the next time zone.
:lildevil:

:rofl: :rofl:

So ... are we now talking about transmission lag? Find a tuner. Any tuner worth his salt can eliminate that "lag" in no time. The transmission shift points and "lag", the throttle response and the numerous computer controlled whatnots that constitute the factory tune can be tweaked and/or turned off for a perfectly responding transmission and supercharger.

Can we assume then that getting the Wait4Me transmission tune for the auto tranny would in fact almost eliminate this "lag"?

Pretty interesting the explanation of the supercharger by "backup", thanx

Can we assume then that getting the Wait4Me transmission tune for the auto tranny would in fact almost eliminate this "lag"?

Pretty interesting the explanation of the supercharger by "backup", thanx

There are a number of fantastic tuners in my area that can wake up your car so much that you won't believe it's the same car. I have a few friends that drive automatic Corvettes. Once a tuner gets his hands on these cars and installs the tune, which is for the engine AND the auto trans, the car wakes up and runs like you won't believe.

The so called "lag", that some attribute to the blower,is inconsequential. That "lag" time disappears as soon as the boost bypass valve (blow-off valve) disables the bypass. That condition disappears AS SOON AS YOU GET THE ACCELERATOR PEDAL TO THE FLOOR. Then there's the transmission ... and that's exactly where the tuner excels in making everything happen NOW and not a few fractions of a second LATER!!! :thumbsup:

Tuners are very rare in my area (Montreal)... I like the idea of getting a "handheld" that you can then revert quickly to the original setting when going to the dealer so that's why i'm considering the Wait4Me transmission tune.

Order is placed for 2010 thunder grey, automatic so far but still unsure if I will change my order for a manual but the auto vs. manual topics have been beaten to death already so it's up to me! :)

Tuners are very rare in my area (Montreal)... I like the idea of getting a "handheld" that you can then revert quickly to the original setting when going to the dealer so that's why i'm considering the Wait4Me transmission tune.

Order is placed for 2010 thunder grey, automatic so far but still unsure if I will change my order for a manual but the auto vs. manual topics have been beaten to death already so it's up to me! :)

Some tuners, including at least one locally, do mail order tunes. If you are interested and seek more info, PM me and I'll be happy to send you a contact name and phone number of one of the best tuners in the area.

Some tuners, including at least one locally, do mail order tunes. If you are interested and seek more info, PM me and I'll be happy to send you a contact name and phone number of one of the best tuners in the area.

The wonderful Cadillacforums admins gives us a wonderful bunch of infos but I cannot send a private message...! It says "we are hammered by e-mails so you need to have posted more messages or be a member for a longer period but you can send messages to admins", wich I've done asking to be able to pm people but never got any answers so I cannot send a pm but could receive them ;)

Thnx in advance

I'm a manual owner and I have also owned a few Z06s. The throttle response in the V is very good but if "lag" is the best term to use when describing a slightly less direct feeling or slightly less predictable throttle response/power delivery, then yes I do experience this lag.

If you're concerned about straight-line performance I do not think that this "lag" will hinder you in any significant way, the tires are barely holding on (from low rpm) as it is.

What has been more apparent to me (and I why I mentioned the Z06) is that while doing high speed cornering in the V I've found myself powering through a turn and not realizing how much power I had actually summoned at the time I applied throttle. What I have experienced (probably attributed to this boost valve) is an unpredicted increase in power going into the turn which has actually gotten me sideways mid-corner a once or twice. I've now learned to start to bringing on the power to help set the car before I go into the turn and be very careful with throttle input once I'm in the turn.

In the Z, the power delivery was so direct and so responsive that I could confidently modulate throttle through any turn and predictably control the attitude of the car. The V is still good but it it's power has crept up on me a few times.

I'm not sure if it is lag, but it is certainly there. and in my case cannot attribute it to transmission response.