Boost creeping...

[mulot30th]

I can't hold boost under 25psi... which is too much for me at this moment (engine break in...)

Is it possible my new double downpipe is too restrictive for the wastegate to properly function?

The wastegate side of downpipe has 1" tube that exist directly to atmostphere juste beside the downpipe itself.

Is it possible the wastegate stick close because of the 'wall' between the turbine outlet and wastegate (when metal gets very hot and expand....)

I did a cold test and its not sticking... but its rubbing somewhere I can hear it.


I would like to keep her down to 15-18 psi for the moment until engine is properly broken in.

thank you

 

[lakercr]

I can't hold boost under 25psi... which is too much for me at this moment (engine break in...)

Is it possible my new double downpipe is too restrictive for the wastegate to properly function?

The wastegate side of downpipe has 1" tube that exist directly to atmostphere juste beside the downpipe itself.

Is it possible the wastegate stick close because of the 'wall' between the turbine outlet and wastegate (when metal gets very hot and expand....)

I did a cold test and its not sticking... but its rubbing somewhere I can hear it.

I would like to keep her down to 15-18 psi for the moment until engine is properly broken in.

thank you

I'm running a double downpipe at 20ish lbs and not experiencing any creep. In fact, I've noticed that it seems to help noticeably with boost spike.

Check the line going to your actuator and the clamps for leaks.
Port the wastegate if you haven't already.

What are you running for an exhaust?

 

[DC5]

Are you using a boost controller? If so what type? There is no way that an "open dump" wastegate pipe is more restrictive then a single downpipe so I don't think that is your problem.

 

[mulot30th]

Hallman boost controller, it was working correctly before... and now I can't control the boost... sled is unuseable because of this....

This is my downpipe (dumping on side panel)





I will check if the wastegate valve does rub agains the separating 'wall'

 

[DC5]

Try taking the boost controller out. That will tell you if the problem is the wastegate rubbing or the controller.

 

[mulot30th]

Try taking the boost controller out. That will tell you if the problem is the wastegate rubbing or the controller.

great idea!

 

[lakercr]

are you venting your crank into the airfilter?

 

[woodsrider]

It might be that your waste gate is hitting the exhaust flange and not letting the waste gate fully open.

 

[mulot30th]

Okay a quick check test with air compressor hose connected to boost controller inlet.

Seems like there is a little hole to bypass some air at the exit fitting of the boost controller. So even with the boost controller set to minimum boost it take much more air to actually open the waste gate than with no boost controller...

Seems like it take about 12 psi to crack open the wastegate open... is this correct????

I have half a turn of the rod of preload on the wastegate by the way.


I grinded the separating wall on my exhaust pipe flange because I could clearly see the wastegate was rubbing against it when moving... so that may solve my problem by itself....

What do you guys think?

 

[mulot30th]

are you venting your crank into the airfilter?

no!

Why do you ask?

 

[IRONMAN IRMEN]

I had the same problem with my double down pipe and was told its only on my sled, I must be doing somthing wrong. Hahaha guess you solved yours the same way I did, grind it and allow it to dump into the main chamber, magic, boost under control. The side pipe seems to restrict the exhaust to much. At least on mine and you sleds.

 

[mulot30th]

I had the same problem with my double down pipe and was told its only on my sled, I must be doing somthing wrong. Hahaha guess you solved yours the same way I did, grind it and allow it to dump into the main chamber, magic, boost under control. The side pipe seems to restrict the exhaust to much. At least on mine and you sleds.

Oops... I only grinded it some to add clearance to the wastegate valve.... but if this does not work, I'll not was any more time and I will pierce a hole thru that wall....

 

[Quicksilver]

Do both of you guys have your heads ported, polished and do you have increased the size of your valves?? Your efficient on the head and header but too restrictive at the wastegate and drop pipe?

 

[lakercr]

I'm heading out tomorrow to do some testing. What boost level did you first start noticing the creep at? I'll see if I can replicate the problem.

 

[mulot30th]

Have everything done to my engine, but not head porting, only slight cleaning of the ports but not much.