Just plain weird

[JAP63]

Car..VR4
-Ported E3 16G
-Full 3 In. Exh,
-Haltech..pump + injectors
-big cooler and piping
around 200 kw @ wheels

Car had a stainless tuned length manifold that was cracked..today i removed it and fitted a stock one until i sort out the repairs to the manifold etc..and thats where it got weird...went for a drive and the car would only make around 1 bar and bled back to 7 pound at redline...checked the setup and the vacline had slipped off the wastegate actuator.not conencted at all!!


So without the vac line connected the car does this.
10 psi in 1st
13 psi in 2nd
18 psi in 3rd
20 psi in 4th
25 psi in 5th...and then...in every gear the boost spikes to the above pressures then tapers off to around ten pound..what the hell...!!

No vac line should mean it would free boost..not lose boost!!

Could the wastegate be faulty?

 

[Jonson]

I dont think you should worry about losing boost :shock:
I hope you have a good headgasket and a strong bottom end :shock:

 

[brisvr4]

Is this on Paul's car?

 

[JAP63]

Is this on Paul's car?

yeah ive had it for a while now

i dunno wat the story is...
Even when its on 15 pound it feels like 5...

 

[JAP63]

I dont think you should worry about losing boost :shock:
I hope you have a good headgasket and a strong bottom end :shock:

You noticed the 25 psi bit didnt you...
Might i add the car has ben tuned for this boost.
Im not just poing a stick at it and picking boost levels.

 

[Jonson]

Ohh haha. Thats ok then.
I would say exhaust leak at manifold or turbo to manifold but it would be a constant power loss. I would say go get your wastegate checked. Maybe the diaphragm is faulty?

 

[AUSVR4]

Just to toss in an idea: BOV?

 

[rob323]

But how was it running before you changed the manifold?
Was the boost bleeding off before the swap?
What BOV is it running?

My bov (std vr4 one) was leaking. I would get what ever boost level I had it set at initally, but by about 5000 rpm upwards, the boost would bleed back to 7psi. If its a standard plumb back bov, just put something in the return line to block it off and you will soon be able to tell whether its the bov causing the leak or not.

 

[JAP63]

Interesting thoughts

Yeah it was still spiking around the joint in a similar fashion with the cracked manifold..just at higher levels....

Im sus on the bov.

its some sort of HKS SSQ with twin vac ports/lines or some ****..

 

[CLuTZ]

One of these??

This was the first b.o.v I ever bought (back in 1999)

I got it cheap, and the reason why was because the diaphram was fuxored. They havent been making these for years, so if it is one of these, i'd be looking real close at it. All it takes is a slight leak and vac press is all over the show.

You should try and suss a newer series 2 'SSQV' to borrow- put on that flange, and if your problems go away, you know what your problem is........

 

[JAP63]

yeah thats it
It only has one of the 2 vac lines connected at the moment....the attatchment for one of them is broken.