Wastegate issues?

[lethe]

I have a few things going on that im not really sure if it's normal or not. First off my setup is a single comp 6765 w/billet wheel, on3 WG/BOV.

1. Under partial throttle if i let me rpms slowly climb to 4k rpm my boost will go from 0 to 5psi almost instantly. This is under maybe 1/4-1/3 throttle so there's not really a load on it. Not sure if that's normal or not.

2. Im not seeing full boost until 4k+ rpm. I can hear the turbo spooling around 3k rpm and it will start building boost but its not consistent. I'll see the gauge hit 4-5psi then sit there for a moment before the boost goes up to 8-9psi for another moment before it finally peak at 11 psi around or above 4k rpm.

Im running off the wastegate only still. Once my tune is a little more dialed i'll add my boost controller.

 

[CPRsm]

Where is you boost gauge hooked up? After throttle body?
Yes, no tomorrow load can go to 6k and not see boost. That's normal

 

[RED09GT]

What turbine housing are you using?

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[lethe]

Where is you boost gauge hooked up? After throttle body?
Yes, no tomorrow load can go to 6k and not see boost. That's normal

Boost gauge is hooked up to the FPR vacuum hose. I'm thinking about moving it to the unused port on the FRPP intake where the drivers side breather hose used to go. Wastgate pressure source is directly from the compressor housing.

 

[lethe]

What turbine housing are you using?

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.68 AR

 

[Stinger]

I betting the cause for #1 is that your throttle body position isn't staying in the same location even though you're not moving your foot. I'm betting the ECU is opening the throttle more which brings in the boost.

 

[CPRsm]

^^ there's one. Also makes sure it's not traction control. It does wierd shit w turbos and the throttle body. Mine wouls spool like ass w traction control on. TB would start to close and lessen the load.

 

[Stinger]

Yeah, traction control gets me too if I forget to turn it off.

I know mine does the same spontaneous spool when RPM gets high and I've logged it and verified the throttle is opening even though my foot never moves. I guess the ECU assumes if you're revving that high you're trying to get somewhere in a hurry and opens the throttle accordingly!

 

[lethe]

Its the same with or without traction control on.

 

[michael.konor]

Few questions:
1. You're running the on3 WG, what spring(s) are you running? Did you physically diassemble it to verify springs?
2. Where are you hooking up your boost reference that connects to the WG? It should be the port on the turbo.
3. Are you ditr you have no leaks on your boost reference line that could cause erratic symptoms?
4. Was the valve on your WG completely closed and sealed during installation? Possible any debris might have gotten in there that are keeping the valve partially open?
5. Ports hooked up right?
6. Have you tried disconnecting the boost reference, capping off the vac line, and slowly reving (under load) your engine to see if the turbo responds better? BIG NOTE: Do NOT overboost!

 

[lethe]

Few questions:
1. You're running the on3 WG, what spring(s) are you running? Did you physically diassemble it to verify springs?

I have the black spring and blue spring in it.
2. Where are you hooking up your boost reference that connects to the WG? It should be the port on the turbo.

Like i said above, the Wastegate reference is on the turbo housing.


3. Are you ditr you have no leaks on your boost reference line that could cause erratic symptoms?

Line is brand new
4. Was the valve on your WG completely closed and sealed during installation? Possible any debris might have gotten in there that are keeping the valve partially open?

Fully sealed as far as i remember
5. Ports hooked up right?

Using bottom port on wg
6. Have you tried disconnecting the boost reference, capping off the vac line, and slowly reving (under load) your engine to see if the turbo responds better? BIG NOTE: Do NOT overboost!

Have not tried that yet.

 

[W3bb3r04]

I don't like the stacking springs idea. I am using a Tial 8.7# spring in my on 3 wastegate. I'm at full boost between 3000-3500 depending on the gear. Mine also goes full boost at partial throttle at high rpm but I don't really ease the car around at 4000 rpm

 

[lethe]

Once i install my boost controller Ill go back to a single spring.

 

[W3bb3r04]

Okay I think Tial makes up to a 12# single spring

 

[Full_Tilt]

2. Where are you hooking up your boost reference that connects to the WG? It should be the port on the turbo.

I completely disagree. It should be on the cold side charge pipe (after the intercooler but before the throttle).

 

[JoshK]

I have always had the signal to the wg off the compressor housing. Also rann all year last year with stacked springs in my on3 gate. Would make 11lbs on the springs, had the boost controller set for 12lbs and 18lbs. No issues at all, I do have a .81 ar turbine housing though

 

[lethe]

I have always had the signal to the wg off the compressor housing. Also rann all year last year with stacked springs in my on3 gate. Would make 11lbs on the springs, had the boost controller set for 12lbs and 18lbs. No issues at all, I do have a .81 ar turbine housing though

What rpm are you seeing full boost?

 

[JoshK]

3k with the on3 piping.

 

[Full_Tilt]

I have always had the signal to the wg off the compressor housing. Also rann all year last year with stacked springs in my on3 gate. Would make 11lbs on the springs, had the boost controller set for 12lbs and 18lbs. No issues at all, I do have a .81 ar turbine housing though

Is that also where the boost controller is reading boost?

Unless you have an oversized intercooler, if youre using the compressor housing as a reference, you will get boost "sag" at high rpm.
Thats why I say to do it post-intercooler, so it compensates for the pressure drop across the intercooler when flow increases.

Some say to just use a vacuum port on the intake manifold, but the danger there is that you could over-spin the turbo when boosting at part throttle since the boost drop across a cracked throttle could be huge.

 

[JoshK]

Boost controller is T-ed into the line coming off the compressor housing. Boost gauge that is wired for datalogging boost in livelink is off the FRP sensor vac line. Both readings are within 1-2lbs at all times. I have a 31x12x4 intercooler. Boost does peak at 3k and then starts falling off to about 1lb under peak at redline. IE, 19lbs at 3000-3500rpm then down to 18lb at 6000-6500rpm