Is this boost lag, if so what will fix it...
 

I am new owner of a 2008.5 CWP MS3 and I love the car. I am new to boost and the only mod I have is a Mazdaspeed CAI. So the scenario pans out as follows:

Whenever driving aggressively the car pulls strong in each gear (all shifting is before 6k rpm). Go to change gears, pressing in clutch pedal while lifting off throttle, change to next highest gear as fast as possible, then lift off clutch while jumping back on throttle. It's at this point where I notice a harsh, although brief, delay in power when getting back on the throttle. This happens regardless of little the rpms drop bewtween shifts. Is this boost lag?

My questions:

1. Is this the effects of an aftermarket intake?
2. Is my stock BPV leaking? (doesn't seem to be at 20,000 miles and pulls trong) If so, will an aftermarket forge or HKS unit fix this sensation?
3. Am I just driving this car completely wrong?

Any constructive comments or experiences would be more than appreciated. Thanks in advance.

You actually have to drive a turbo car, not just push the go pedal. Basic driver mods are getting on the gas a bit before the clutch actually engages and, not pouncing on the accelerator pedal like stomping grapes for wine. This applies to all TC cars with 4 bangers.

It's you that creates this lag when you close the throttle fully on shifts. Even with a bypass valve, the backwash into the turbo from high speed air returning from hitting the throttle plate slows down the pinwheel markedly.

Suggest also a rear motor mount, as this engine moves around a little too much in load-unload scenarios.

Really disagree here. Close ratio trans and small turbo, this car is always in boost even after a shift. Even running stock, there's very little to no lag between performance oriented shifts. If something is causing a harsh, brief delay, something is amiss.

Claysan, could you get a video of what you're describing??? I once got this type of issue when I forgot to hook up the bypass valve return line to the inlet. Ran fine until I shifted, backfired on shift, then fell on it's face for the first part of 3rd gear as it recovered from the insane rich condition of VTA and inlet leak. :pat:

i noticed something like this before i got the step colder plugs...try that and see whats up. def not lag tho.

If you fully lift, it will do this. Mine does this too.

Try a half-lift shift; you can practice this in regular city driving until you get used to it. Obviously even shifting at 3500 you will accelerate faster than normal, so be safe about it.

Also, make sure you get off the clutch as fast as possible; I know these things have clutch position sensors that will cause a vent event if you press too far down (but don't disengage the clutch).

I tend to agree with you, not only because your highly technical explanation made me horny but also because you have it correct.

A turbo is basically an air pump. Like any pump once you have it going at certain RPMs it performs better if you keep it constant. When you release the gas pedal to shift you are slowing down the turbo causing the lag when you accelerate.

You might reduce turbo lag but it is impossible to completely get rid of it.

Can you imagine if OP had a larger turbo'd car he was to get used to? These little tiny ass turbo's spool quick as hell, there's a slight hesitation but nothing to be worried about. It should still feel and sound as though the car is pulling though... If it feels like a true stumble or hesitation, then you may have a problem...

just quit granny shifting.

I agree with the previous posters. It seems as though you may be letting the RPM's drop a little too far during shifts. it is important to keep the revs above where they need to be once the clutch is all the way out so letting the clutch out will cause acceleration. If the engine is going too slow it effectively becomes a brake when you release the pedal because the speed of the car is then being used to accelerate the engine rather than the other way around.

I'm no expert but I hope that helps (and makes sense).

I also agree with above, but this made me laugh:


:lmao::lmao:

Shift. Faster.

swapping E-boners with everybody, lol

Just to add to the discussion: For a full blast performance run, keep your foot planted firmly on the floor and power shift the car when it hits about 5500 rpm. You'll be blown away how much faster the car accelerates when you do this. As long as you have some sort of motor mount upgrade in the back, this car powershifts better than any car I've ever had, in 25+ years of racing and rodding.

Does that make anybody horny?

These are all good points guys. Not sure about the plugs though. I don't ever have any backfires. I guess I would say it only happens in an all out blast through the gears.

Would an aftermarket bpv hold more boost between shifts?

I have tried the half lift method before with much better success, but I wasn't sure if that was normal for this car. I do fully lift off the accelerator.

I'm glad I'm not the only one to experience this. Maybe I need to change my shifting like some suggested. Anyone got any other suggestions? I truly appreciate the responses.

Yes.... Very.

I have little experience with manual transmission, turbo or not, outside of this car, but I think I know exactly the sensation you are talking about. It's really only about 0.5 to 0.75 seconds of hesitation, and the half lift definitely is the key to keeping the turbo spooled. My problem is knowing how much to lift. I hate not lifting enough and jerking the car after dropping the clutch.

Yes

LOL @ some of these responses.

Theres nothing wrong with your car. Aftermarket BPVs and plugs are not going to make this sensation you're feeling go away.

Like you, this was my first turbo car. Just a few days ago marks 3 years I've had it. When I test drove my car, I told the dealership theres something wrong with it because it was hesitating between shifts.

Then I made an embarassing post over on m3f stating how the ms3 I test drove had something seriously wrong with it. They said "Uh...thats turbo lag you dumbass. Theres nothing wrong with the car". Long story short, I bought the car.

Basically you have to learn how to drive a turbo car. Its not the same as an ordinary car. I can't explain to you how to drive it properly, you just have to learn on your own. Those who said its simply turbo lag are right. Turbos spin at amazing speeds, and it takes time to get them up to that speed. Its not instant. When you lift off the gas the turbo slows down and it has to build boost all over again.

Also, relatively speaking, the turbo on this car spools FAST and lag is almost non existent. To a noob you may be thinking what the fuck are you talking about, but just try driving a car with a big turbo, lol. You think you have trouble with lag now...

Bottom line...stop thinking about it. And just learn how to adjust to driving a turbo car. Thats all. I promise you there's nothing wrong.

the only way to get around the turbo lag you're experiencing (or to minimize it) is to use some of the aforementioned tactics such as keeping on the throttle while shifting (no-lift shifting) or power shifting. if this is your daily driver, though, i'm not sure if i'd recommend that kind of abuse to your powertrain.

turbo lag just goes with the territory on turbo cars. for the MS3, it's insanely short on the stock turbo. if you want to reduce it further, a real quick/cheap way would be a test pipe.

here's an example of lag:

wow......that's some funny shit

This sounds exactly like what I am experiencing. I guess it is my shifting after all. Fail on my part I suppose.

Realizing your failure is step one in this process. Soon you will overcome this problem, don't worry Clay.

http://www.chicagonow.com/blogs/adve...group-head.jpg

http://blogs.pinkelephant.com/images...iefprocess.jpg

he's just past denial. we'll need to support him as he progresses through anger and negotiation.

08 - singly noted, dually agreed. We will deal with Clay one step at a time.

Beef with Clay?

I hope not!

I am actually surprised at the number of positive responses here. I admit I am a noob, but I've done my fair share of searching prior to posting.

The support thing is actually kind of funny, but welcoming at the same time. Makes me feel right at home. I can't say the same for many other forums that I have participated in.

So @ everybody,

thanks for all of your help and I can honestly say that this is a great forum with a wealth of knowledge!

I wish I could triple thank you Claysan, you get the message :D

Mind linking me to a 2009 rear motor mount thats nice :eek2:

After reading a few of the posts I have come to the conclusion that most of the members in this forum are a bunch of weirdos potheads... OK moving on.