Hello All,

I have been having some trouble sustaining high boost with my turbo setup. up to 24psi boost holds relativly stable, but once i go beyond that the boost starts to jump around between 25psi and 29psi (my goal is to run 30psi). I have a 44mm tial wastegate and a turbo xs bov.

I thought it was the wastgaste spring so i put in 2 springs equalling 20psi of base boost. this did not help at all. however i did notice that the wastegat spring and wastegate spring housing was dirty. does that mean there is a leak in the diapram or is that normal?

Can this problem be caused by a faulty boost controller? Boost holds solid up to 24psi, but anything after that it goes crazy. This leads me to believe it could be the boost controller rather than the wastegate.

Any help is appreciated. Thanks.

 

some boost controllers have max psi they can withstand. What boost controller do you have?

I have a Blitz SBC-iD type R which had two soleniods and allows for higher boost control

 

I have a turbo xs single stage mannual boost controller. Im not sure if it has a max boost rating. I figured it could handle 25psi+ but maybe not.

 

Bump for any more ideas.

 

my turbo xs mbc was garbage at 15+ boost. it would fluctuate like yours. I switched to a hallman and the problem went away.

 

just reporting an update... i installed a hallman boost controller and it did not work... so i guess it could be the wastegate... could a boost leak cause it to react this way?

any other ideas are appreciated

 

Take the boost controller out of the picture.Run the pressure line to the wastegate. Then see how the pressure holds it should hold 20 lbs steady if not then the diaphragm is going bad.

 

I will give it a shot. Athough the boost controller i put it should handle the boost fine. and the fluctuation is very minimal under 25psi; within 1 to 1.5psi.

could the wastegate springs be bad both have been driven on for about 2. years.

Is dirt/dust suppose to be in the wastegate spring housing?? if it is not then my tial wastegate must be my problem.

 

ok guys I got another update.

I took the wastegate apart again and thoroughly examined it for any sign of damage, and didnt really find anything.

It looks like the metal spring cover was worn a little bit on the inside from what i can only assume to be from the wastegate opening and closeing violently from those fluctuations.

The Diaphragm was dirty and had gray dust all over it with some metal flakes from the metal sidewall wear. however, the diaphragm looked to be in perfect condition; no holes or rips. So I have cleaned everying as best I could and put it back together, and will test again tomorrow.

However, it sounds like I have a convential boost leak somewhere...but again I dont think boost would fluctuate that much from a boost leak, unless its very small I guess.

 

At that boost level, you could have anywhere from 30-50psi of pressure in your exhaust manifold. If the WG opens just a tad too much, it will drop down quick quickly, and boost level will follow.

Dust in the spring housing (top) is from not running a muffler (filter plug) in that top hole. The springs tend to fit snug around their circumference, but I prefer to have them a little loose. When a spring compresses, it spins, and can bind if it isn't allowed to.

 

Thanks for the reply.

I will keep testing for boost leaks and see what I find.

The springs only fit in there snug it seems. do you have any specific technique as to how to place them in their housing so they spin freely? It would seem that the constant compression of the springs wouldnt allow them to make much movement.

 

Ok I hooked up an electronic boost controller and the same problems occured....

These are my current theories:

++Wastegate springs gone bad?
Maybe worn too much to keep stable.
++bad source for vacuum pressure?
I have a homemade vacuum manifold connecting to the intake manifold in a larger-than-average port to the intake manifold.
++ Boost Gauge Connected to FPS
Never been a problem before but maybe it is for these higher boost levels. However, my mapping datalogs still show a fluctuation.

I still can't locate a boost leak if there is one, and redid my intake piping with no changes.

any help is welcome.

 

bump for some help

 

Ok guys, her is yet another update. I had redone my vacuum manifold and nothing changed. the same fluctuation is taking place.

however i now have some new theories:

Is it possible that my stock b18b head doesnt have the port size/design to flow 25+ psi with an updated intake manifold, Large t3/t4 turbo and equal length manifold?


My air filter on the turbo is dirty and that might cause an inconsitency of airflow when the turbo is trying to suck and compress lots of air.


any help is appreciated and please give me some insight on the things if you have dealt with any of my theoretical problems.

 

I used a different vacuum source for the boost gauge, no change. I also replaced all of my IC pipe couplers and used t-bolts on all collections, no change.

And a Bump

 

take off the filter

 

Ok guys another update,

took the air filter off and no change.

I took the boost gauge out from the cluster.... i noticed a little kink in the plastic line but drove around and could feel no leak.

I re did my a thicker vacuum lines with metal hose clamps rather than zip ties... no change boost is still fluctuating.

At this point im leaning towards finding a new wastegate spring and sticking it in there cause maybe my large blue spring is worn, and maybe my small blue isnt enough to compensate.

 

Can you give a little more insight into the setup. What size engine, turbo, back housing a/r will be really helpful among other things.

 

Sure.

Peak Boost Manifold
Eldrebrock intake mani
completely Stock b18b head
stock BORE b18b block
t3/t61 turbo

I May run it without the WG dump tube as well to see if that changes anything.

 

i dont think running without the wastegate will do much at all. If it was an issue it would have com about already.

It is possible that you are blowing the valve open due to lack of spring pressure on the valve. Do you have a dyno plot of this happening or a datalog?

What size turbine housing is it?

 

Well I pulled the wastgate dump and no change except for the fluctuate was maybe 3-4 psi of variation rather than 5.

I got a .63 A/R turbine housing.

At this point im thinking to get new wastegate springs, and see if that does anything.

As always any help is welcome.

 

Oh and yes, my datalogs are showing the fluctuation.

 

Maybe you should bring it by a place to have it checked out, I had this issue with my EVO and it was the computer cutting boost out, which was a pain and the *** cause i ripped the car apart so many times. haha

 

Update,

I got rid of my boost cut and still the same thing was hapening. I am now just going to order another wastegate spring and see what that does for me.


Could an exausht leak before the turbo cause this? I havnt checked yet but my exhaust manifold gasket might be blown somewhere as some carbon residue has been building up.

any further suggestions are welcome!

 

update,

put in a gasket between exauhst manifold and turbo... still no change....

I put new wastegate springs and still no change as well.