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Discussion Starter · #1 ·
I was getting on it a little today and I noticed that the car would pause slightly after I switched gears and then pull. I know some people have said to keep the rpms up between shifts but that is for normal driving. It almost feels as if there is no boost for a second and then it hits boost. Whats the deal?
 

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I have also felt this when I have slipped the clutch a little. To me, it feels like the car is all of a sudden kicking you back in your seat. This only happens when I'm trying to make an extremely smooth transition into second, or when I want a smooth launch from first. Its a little bad for my clutch, but I try not to do it.
 

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do you have a bov vta?
 

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do you have a bov vta?[/b]
Used to have this problem.. installed my fujita cai and its gone... its almost instant after i shift from 1 - 2 2 - 3 etc etc... its amazing how much it changed the car and how it responds that much better... Sound is just an added bonus ;)
 

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You know, I was coming home from work tonight, and as I went from one highway to another, a high speed entrance ramp, I punched it and i got powerloss, and then a split second later, the car jerked violently and it kicked in, and I thought, ok, this is twice in 3 months since ive owned the car...wtf? Could this be a similar problem to the one the original poster is discussing?
 

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Discussion Starter · #6 ·
do you have a bov vta?[/b]
No, the car is bone stock. It's strange that this is happening because when I shift gears at wide open throttle, the turbo should be spooled and the response should be instantanious.



Used to have this problem.. installed my fujita cai and its gone... its almost instant after i shift from 1 - 2 2 - 3 etc etc... its amazing how much it changed the car and how it responds that much better... Sound is just an added bonus ;)[/b]
So with your cai there is no more delay right after shifts? Is the sound loud under normal driving? I want a cai but I'm trying to keep this car civil. The Vette is already far gone.
 

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I was getting on it a little today and I noticed that the car would pause slightly after I switched gears and then pull. I know some people have said to keep the rpms up between shifts but that is for normal driving. It almost feels as if there is no boost for a second and then it hits boost. Whats the deal?[/b]
If you are meaning after every shift there is a slight hesitation before acceleration, what you are experienceing is boost lag. Even a tiny turbo such as ours will have a slight amount of lag unless you are powershifting. If you had a boost gauge hooked up you would see that as soon as the throttle plate is closed it goes instantly to vaccuum and after you get back on the throttle there is a 1/2 second lag before boost builds back up.
 

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If you are meaning after every shift there is a slight hesitation before acceleration, what you are experienceing is boost lag. Even a tiny turbo such as ours will have a slight amount of lag unless you are powershifting. If you had a boost gauge hooked up you would see that as soon as the throttle plate is closed it goes instantly to vaccuum and after you get back on the throttle there is a 1/2 second lag before boost builds back up.[/b]

exactly. you can counteract the lag by staying on the throttle as you shift. It's like a sling shot effect where you just keep the car in boost and it keeps pulling and pushing you back in your seat. but i think this will shorten the life of your clutch for sure.
 

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No, the car is bone stock. It's strange that this is happening because when I shift gears at wide open throttle, the turbo should be spooled and the response should be instantanious.[/b]
Thats not true, while the BOV helps with spool for the duration of closed throttle the turbo is puching (or trying to) 16 psi with NO EXAHUST to power it. It is GOING to slow down some no matter what, that bit of lag is common for any turbo car, it may be more pronounced in our car as our motor is more boost dependant that say a 4g63 where they rely on only 11 psi. Some people shift and only drop to 1/2 throttle between gears and this seesm to help, although i dont se the risk/reward value beign worth it!
 

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I'd say that your just shifting below the power band and catching it before the turbo is starting to boost. Plus with this electronic throttle it throws a whole new deal into this, because i don't think any of us knows what the ecu is doing to the throttle under different conditions.
 

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I've noticed the same thing - little bit of turbolag after shifts. Same thing happens when moving along and I floor it - takes .5 to 1 sec to really start pulling.
Don't have a boost gauge installed, but as far as i've been able to tell, it feels that even if i'm in boost rpm range, the turbo isn't really pressured up unless the engine is under load, which would make sense... So even if i'm going along at 4 grand or so in second and can it, still takes a bit to really catch. Did feel almost like clutch slip at first, so I tried some agressive launches from stand still and rolling starts in boost range in the lower gears. Clutch seemed to work fine so I just assumed it was just the turbo spooling up. Was nowhere near as bad as what I experienced on my friend's non-STi WRX when I drove it, but reminded me of a Conquest and Talon I used to have.
 

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Discussion Starter · #13 ·
I am talking about speed shifting. The rpms stay high but after each shift there is a hesitation and then full power. If I wrap the rpms out to 6,000 and then shift the next gear probably falls between 4,500 or 5,000 rpms. Should there still be lag at that point?
 

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to a minor degree yes it will still be there, it is to be expected.
 

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I am talking about speed shifting. The rpms stay high but after each shift there is a hesitation and then full power. If I wrap the rpms out to 6,000 and then shift the next gear probably falls between 4,500 or 5,000 rpms. Should there still be lag at that point?[/b]
If you're speed shifting, then it could possibly be you touching the rev limiter. Also if you didn't turn off DSC it will be your traction control kicking in.
 

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I've been hesitant about posting this but it could also be the throttle by wire taking a split second to catch up as well. The TL has a throttle by wire system and it's non turbo engine takes a second to make power after shifting similar to doing full lift shifts in the ms6. So my vote is throttle by wire or a combination of that and turbo lag. Who really knows for sure?
 

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I've been hesitant about posting this but it could also be the throttle by wire taking a split second to catch up as well. The TL has a throttle by wire system and it's non turbo engine takes a second to make power after shifting similar to doing full lift shifts in the ms6. So my vote is throttle by wire or a combination of that and turbo lag. Who really knows for sure?[/b]
That is a good point. While the info posted in CP-E's thread shows a much closer correlation between pedal input and throttle response in the MS6 vs. the MS3 there is a possibility that the ecu modifies the throttle when the clutch sensor activates. That being said, I still believe that what the OP is experiencing is turbo lag. Even when you powershift there is a split second depending on how fast you shift that there will be a drop in boost pressure. Keeping your foot in the throttle helps but unless the engine is under load it will not spool up the turbo as much as if it was.
 

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Discussion Starter · #19 ·
I can tell you that my Vette has absolutely no delay in response and is also throttle by wire. There is no way I'm hitting the limiter as I know what that feels like and I only shift at 6,000 rpms max. I'm beginning to think it is due to the computer.
 

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It is probably a combination of the E throttle and turbo lag, without an anti lag system (which shortens turbo life exponentially) your GOING to have some hessitation until the intake pipes are pressurized....
 
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