I read through ten pages of sputtering threads but none seem to find a definite answer.

I have a fully built b18b...at the wastegate spring, the car pulls fine. At full boost, 16 psi, the car begins hitting the wall, almost like the wastegate is opening. Always happens at .9 bars. Can't get past that.

So I thought it was my wastegate gasket, so I removed it after reading of people running without one successfully, and bolted it back up. Same problem. Same .9 bar.

So now I am stuck. The spark plugs are brand new. The wires, distributor cap, rotor all have less than 5k on them. Timing is correct.

I'm thinking it's an ignition or fuel problem since it does not do it at the spring setting, which is about .7 of a bar. Car drives fine other wise.

Wastegate is a Tial 38mm. 5k on entire setup and engine.

Thanks for any help.

 

BUMP

 

What is the car tuned on? Do you have a wideband in the car? Was it tuned at both levels of boost? What are you plugs gapped at?.. Need some more info.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93turbo16 &raquo;</TD></TR><TR><TD CLASS="quote">What is the car tuned on? Do you have a wideband in the car? Was it tuned at both levels of boost? What are you plugs gapped at?.. Need some more info.</TD></TR></TABLE>

I forgot to include that info, my apologies.

Plugs are brand new. Copper NGK, one heat range colder. Gapped at .30.

Tuned on Neptune by Jeff Evans. Yes it is tuned on both settings.

 

There is no wideband on the car, BTW.

 

Gap your plugs tighter... try around .24-.25

I actually have mine gapped a lot tighter than that on 20 psi.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93turbo16 &raquo;</TD></TR><TR><TD CLASS="quote">Gap your plugs tighter... try around .24-.25

I actually have mine gapped a lot tighter than that on 20 psi.</TD></TR></TABLE>

Will do. But with that said, the car ran 1.15 bars for a year before this all started. I will regap the plugs, however.

 

The 16 psi is on a GT30, btw, making 330 whp. I've read that for that power, the plugs should be gapped between .28 and .32 so I went right in the middle.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pa_itr &raquo;</TD></TR><TR><TD CLASS="quote">The 16 psi is on a GT30, btw, making 330 whp. I've read that for that power, the plugs should be gapped between .28 and .32 so I went right in the middle.</TD></TR></TABLE>

That really depends on the car. It can vary a lot between each car.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93turbo16 &raquo;</TD></TR><TR><TD CLASS="quote">

That really depends on the car. It can vary a lot between each car.</TD></TR></TABLE>

OK, thanks for your input. I am going to regap them later today. Will update then.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pa_itr &raquo;</TD></TR><TR><TD CLASS="quote">The 16 psi is on a GT30, btw, making 330 whp. I've read that for that power, the plugs should be gapped between .28 and .32 so I went right in the middle.</TD></TR></TABLE>

So your car ran for 5k with them gapped at .30? If so, then this is most likely not the problem

Check and make sure your wastegate is working properly.