I know it's been covered in searches, but it still hasn't answered my question. My setup boosts to 10psi on a 7.43psi spring, my boost cutoff is set at 10 psi so chances are it will continue to spike past 10psi.

I originally thought it was my greddy profec, but completely disassembled it still spikes.

Now, I heard that drag manifolds are known to cause crazy amounts of spiking.

I checked and re-checked my vaccum sources and they are fine.

My question is, aside from a manifold, are there any other factors that can play a roll in boost spike. ex. wastegate. ect

thanks guys for any input

 

Generally a couple psi fluctuation is alright, I mean its only a spring and its not like all springs are perfect. However, the drag manifold is more than likely the problem for you. Rev-hard manifolds work well for keeping spikes away. Or get a log style manifold.....ooooor just get an equal length. But whichever way suits you best I would do it.

 

thanks for the input Dunc, but the thing is it never, and I mean never boosts it at 7.43 psi it always goes straight to my cutoff.

 

that's weird i never got spikes when i used the stock setting on my tial...with the drag kit on a gsr....i plugged the tap on the turbo housin and hooked up the tial WG to my vacuum mani that ran off the brake booster line before the check vavle....i ran all my vacuum sources from their ...bov/boost gauge/e-01/WG/fpr....and no problems at all....it held 7psi hardcore no spikes on the analog autometer boost gauge or on the e-01 boost controller...also i used a good size vacuum line for the wg...good luck

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 95GSRT &raquo;</TD></TR><TR><TD CLASS="quote">thanks for the input Dunc, but the thing is it never, and I mean never boosts it at 7.43 psi it always goes straight to my cutoff.</TD></TR></TABLE>


I would check your wastegate spring then....double check. Perhaps you have one that is a higher pressure than what you think. It's happened before to people who come in for tuning, and once they buy another one or a lower pressure one then it's all good. Just food for thought.

 

also....check your wastegate rubber diaphragm for rips/tears!

for about a week until today, my car was spiking to 14psi and wouldn't come down. I double-checked all of the vacuum hoses for possible leaks,etc. but then decided to take apart the wastegate for the hell of it to see what was going on inside.

once i took off the top hat, lo and behold, i had a nice tear,about 1/2'' long on one of the edges.

I used some Permatex hi-temp copper gasketmaker and band-aided the rip until i purchase another wastegate.

test drove it and boost held at 7psi and none higher.

 

I checked my spring and it is the small green spring, which is 7.43psi.

i took apart the wategate and the diaphragm lifts on the edge when vaccum or boost goes into the side port.

Should the diaphragm be completely sealed?

 

yes. There should not be any pin holes/tears/etc.

 

alright, I checked the wastegate diaphragm and there are no rips or tears. I also checked my spring and it functions properly.

I'm really confused. The wastegate controls all the boost, but everything is fine in the wastegate what the hell else can it be?

Someone must know.

 

bump

 

anybody