hello all,

Often when i start to accelerate and than lift my foot from the paddel, you hear and feel a shock or a hiccup in the engine. You can also hear a muttering sound in the exhaust. It is difficult to describe.

it only happens between 2000 and 4000 rpm. But when i accelerate beyond 4000 rpm it is normal.

Before i had my car chipped i noticed it a few times, but now after chipping i have it almost all the time. But not all the time.

Also when it happens you don't hear the turbo blowing of in the air intake.

my octavia RS is chipped and the exhaust is replaced by a simons exhaust with no middle demper. I still use a stock DV.

Does anybody know what is wrong.

When you accelerate is there a slight reduction is acceleration going through 3krpm.

Also I guess when you lift off the accelerator around 2.5k - 3k you get a slight surge?

If so, sounds like overboost to me......when you accelerate you'll get overboost but when you reach 3krpm boost will return to the normal levels hence the drop.

For coming off the accelerator vice-versa is true.

As for the noise is it more "durrrr"? Perhaps waste gate chatter.

Who did you get the car chipped by?

Sounds like overboost to me too. Also could the stock DV be on the way out?

I concur, tis Overboost.

But when the car was not chipped yet, i also noticed it sometimes.

My car is chipped by RICA a dutch chipper which is well known here.

My car has no reduction in acceleration arround 3k, it's higher when this happens, past the 4k.

If it is a overboost is this bad for my engine, and how can i fix it.

I can also notice that when it happens the turbo has to spin up again.

Can't it be that my DV is stuck in closed position so the boost pressure isn't released?

But when the car was not chipped yet' date=' i also noticed it sometimes.

My car is chipped by RICA a dutch chipper which is well known here.

My car has no reduction in acceleration arround 3k, it's higher when this happens, past the 4k.

If it is a overboost is this bad for my engine, and how can i fix it.

I can also notice that when it happens the turbo has to spin up again.

Can't it be that my DV is stuck in closed position so the boost pressure isn't released?[/quote']

Not sure the rpm range of the overboost facility...perhaps it can be set?

If so your chip may well have it's upper limit at 4kprm.

Mines been remapped by Jabbasport and like a few people hear had the overboost scenario which occurs at around 3krpm

Your tuner should be able to turn the amount of overboost down.

I can also notice that when it happens the turbo has to spin up again.

This is an interesting comment.......can you hear the turbo whistle, you then hit 4k get the drop in acceleration then get the whistle and acceleration back?

If so then your hitting the boost limiter. You wouldn't have an N75J valve fitted would you?

Either way you should have a chat with your tuner.

Not sure about the DV...I also thought when they failed the couldn't hold boost??

HTH.

one other thing that i noticed was that when it happens the turbo isn't running at it's highest speed. So when you just start to accelarate and you go over the 2k rpm. and just lift the accelarator you hear and feel the hiccup.

Also i noticed that when the engine get's hotter the problem doesn't occur as often. But it never goes away completely.

also what i think is strange is that i also noticed it when the car wasn't chipped yet, but than i only saw it than a few times.

I'm a little confused now??

You firstly said it occurs between 2k-4k and said above 4k it is fine.

Next the hiccup occurs past 4k?

Then it's 2k?

When I say "dip in acceleration" it's only a very slight reduction but I can be detected.

Best take it back to your tuner and explain.....I still think it's overboost.

Stil got the same problem, i've been out for een few weeks, so have had no time to talk to my tuner.

Could this be the surging problem people are talking about? Or do i have a different problem. When does surging occour? What i understand is that surging is when you accelarate and not when you come of you're accelarator.