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"Thud" on full throttle changes 2nd-3rd (99MY)

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Old May 7, 2002 | 07:46 PM
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I get this sometimes if revved hard and changed quickly from 2nd to 3rd. Is it back pressure or what ? Goes well and just serviced - is this just a characteristic ?
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Old May 7, 2002 | 07:52 PM
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sounds like the diff to me but I am probably wrong. I think this thread is heading towards drivetrain forum .
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Old May 7, 2002 | 07:53 PM
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They all do that sir.

I found it got better with a K&N induction kit + practice.

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Old May 7, 2002 | 07:54 PM
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Only had mine 5 months (my00), and it does the same, hope t is just a characteristic.
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Old May 7, 2002 | 07:54 PM
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Sounds unusual to me

When I had it my MY99 only used to occasionally jerk (sudden hesitation) after changing up after 6000 rpm + from 2nd to 3rd.
Sounds a bit like transmission to me but I could be wrong.

Yorkie
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Old May 7, 2002 | 07:57 PM
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See here also.. http://www.scoobynet.co.uk/bbs/thread.asp?ThreadID=93903



[Edited by AlanG - 5/7/2002 8:01:58 PM]
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Old May 7, 2002 | 07:57 PM
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Get this sometimes aswell try not to be so brutal when dropping the clutch on gearchanges
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Old May 7, 2002 | 08:27 PM
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Could it be the clutch plate sticking slightly on the splines, so that one surface grips fractionally before the other at which point full power is delivered with a slight thud?

I noticed a similar thing on my MY00, especially when cold, along with the dreaded clutch judder - another feature.

No such problems yet on my MY01 though!

mb
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Old May 7, 2002 | 08:54 PM
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Mine does this - exactly as per your description.

I think it's pretty normal, as I've noticed it in other Imprezas I've had track day passenger laps in...

Rich
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Old May 7, 2002 | 08:56 PM
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Mine dit it also.

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Old May 7, 2002 | 08:58 PM
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Yup, they all do it.

Its just the slack in the drivetrain being taken up.

You'll soon learn to drive around it.

D
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Old May 7, 2002 | 09:52 PM
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Thanks - mind now at rest. I think the Legacy Turbo I had 5 years ago did the same, come to think of it.
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Old May 7, 2002 | 09:58 PM
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My MY00 Sport and MY02 WRX both have the "thud" when changing gears and lifting the clutch fast ( quite often

I always thought that it's the back diff engaging... Anyway, it's nothing to worry about. Just tells you that the traction is there
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Old May 7, 2002 | 09:58 PM
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Try driving more PROgressively, and not so AGGressively.
Helps for me, you don't get anywhere by being brutal with it, so don't be!
Ron.
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Old May 7, 2002 | 10:09 PM
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**********
Try driving more PROgressively, and not so AGGressively.
Helps for me, you don't get anywhere by being brutal with it, so don't be!
Ron.
**********

Right, just that the going feels .1 secs faster when dumping the clutch
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Old May 8, 2002 | 01:35 PM
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Nah this is the overboost problem. clean out your pipes with barke cleaner and it'll subside a bit, or drive round it, or change your ECU for a 801 / Ecutek...

JonW
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Old May 8, 2002 | 05:22 PM
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JonW

Can you tell me what the overboost problem is / or where I can read about it ?
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Old May 8, 2002 | 05:27 PM
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Jon,

No it's not m8 - I'm not certain if it's diff wind up or not as it feels more like a fuel stutter to me but it certainly isn't overboost

Matt
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Old May 8, 2002 | 11:30 PM
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Not overboost for sure! (Unless someone installed a turbo to my sport

I have the "thud" on both my sport _and_ wrx so...
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Old May 9, 2002 | 12:05 AM
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FFs, you post the answer and nobody believes you

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Old May 9, 2002 | 12:28 AM
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Agree with Diablo. Definitely drivetrain shunt.

D.
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Old May 9, 2002 | 08:58 AM
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I believe you... although it does feel 'pressure related' as though the ECU reins things in for a split second.
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Old May 9, 2002 | 09:36 AM
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<consoles diablo>

I believe you.

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Old May 9, 2002 | 11:18 AM
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Whilst i believe Diablo, how can you get shunt when the drive has everything all lined up and you shift quickly which should keep things all lined up wheras shifting slowly doesnt do it? You'd have to agree the longer you leave it the more outa linethe drivetrain would be...

I was told by numerous people this is overboost and once id cleaned up the pipes it was much reduced, go figure??? :-)

JonW.

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Old May 9, 2002 | 07:08 PM
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I noticed this when I first got my Scoob. However, with the passsage of time it seemed to disappear. Until I got new tyres, super grippy ones, then it returned. So drivetrain it is I recon.
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