When I shift at high RPM under hard acceleration the car does a wierd surg/studder and normals out after a second or two.

I have a stock IX MR. could this be because the boost has tapered down because of the stock setup?

Help please.

 

Hard to tell from your description, but my guess would be that you're not timing the clutch, shift, and gas properly. It should be a seamless transition with no jerking.

No, it has nothing to do with the boost tapering.

 

Its hard to discribe, if I shift sooner it won't do it but if im over 5500 or around 6000 and shift it surges like it wants to go but its being held back, but it doesn't feel like a bad shift (almost but its deffinatly not) its not as violent as a bad shift.

 

Does this also happen if you blip the throttle at high RPM? If so, I would guess your compressor bypass valve's spring tension isn't set right.

 

He's stock, so that is doubtful.

How many miles on the car? I'm hoping it's not the clutch, but I've never heard such a description of a problem before, and I've never experienced anything like it in my Evo at any level of modification. You're not just talking about turbo lag are you?

 

Nah not turbo lag because it only happens at high RPMs around 6000k?, I have about 600 miles on the car, but I got it from the dealership with about 130-150 miles on it so god knows how the test drives went before mine.

 

I thought you said it happens AFTER you shift, which means you're in the next gear at much lower rpm. Are you saying it happens while still in gear at 6000rpm? If so, then that would be a whole different story.

 

oh man, say If I shifted around 6000-6500 rpms say from 2-3 or 3-4 would I have fallen out of the boost range?

EDIT: actually Im sure its not boost lag cuz after I shift and it does its wierd surg thing I don't feel the boost come back on, its deffinatly high RPM AFTER shift. its like after 6000 RPMs the power is instantly gone.

 

No, why? Boost taper is not an issue here.

Does the studder occur while still in gear at 6k rpm, or after you shift from 6k rpm? Is it when in the previous gear, between gears, or in the next gear at a lower rpm after re-engagement?

 

Its AFTER the shift, its like after 6000 the power is GONE and there just nothing to keep up the momentum.

 

So when you're NOT in gear after the shift, you lose power? I really don't understand.

 

You may be describing the clutch not engaging fully (right away) due to its restrictor pill. I find it most noticeable at high revs. If you play around with various techniques - ie. the amount of throttle input, how quickly you let go of the clutch, etc - this can be avoided. I hope that made sense.

 

it can be avoided by timing how quickly you let go of the clutch. I also experienced it at first but quickly adjusted how quickly i let go of the clutch.

The trick is not to hasten when shifting fast...that worked for me.

 

Is it like this?
http://www.steven-laura.net/Steven/Videos/Evolution.wmv
This was my car and problem when I got it. Boost leak + crushed 1G CBV solved it.

 

Based on the description in the first post and the video by 56Hotrod... if they're describing the same thing, then I think I know what you're talking about. It typically happens when doing an aggressive 1-2 shift at a higher rpm. I think it's more with shifting technique, since it doesn't happen all the time and it happened more when I first got the car (since I was trying to figure out the car's dynamics). I remember the first time it happened, the CD case shot out of the little storage thing under the HVAC controls during the shift.