Ok I guess this is the right place to post

Is anyone on here running an overboost valve?

I have a 'High Flow' Cat with an Internal Gate!

I run an 18psi Tune and have 'logged' variations in Boost 18-24psi at the Track!

I believe an external Gate is the fix, but I'm not a Guru!

Rosie, do you have a high flowing exhaust? I found with an extremely high flowing exhaust (side pipe) we couldn't keep boost under 18psi with a 12psi actuator and no turbo mods. Easy fix to this is a restrictor plate after your cat. Basically a plate of steel with holes drilled in it. First try we netted a flat boost level of 14psi..

Bit cheaper than getting the housing ported and flapper mod. Basically you need backpressure in your exhaust to hold the wastegate shut, especially the standard flap. that's the short answer.

Thanks mate!

I have a 'VERY' high flow CAT and the Car has a 'serious' Motor running well below its capabilities with the usual Mods on the stock Turbo! The Car runs an 18lb Actuator with modified internal Gate into a 4inch dump and exhaust!

- Into Twin 2 and a half inche Pipes at the rear!

- With 3 Litre Surge Tank and twin Bosche Pumps, plus rising rate Fuel pressure Regulator!

- I log Fuel pressure and it is exactly where it should be at all points in the Rev range!

I logged the Boost variations on my Data Logger at the Track!

- It just has little Boost 'Spikes' over the preferred 18psi!

I have an 04 xr6t I did a pod filter and hybrid cooler all seamed fine but when I fitted the xr8 bonnet I changed the piping and got rid of the crossover and now it hits whatfeels like a soft rev cut is this boost cut I'm feeling the boost gauge appears to hit near 9 psi before it does this and yes it has new correctly gapped plugs

There's a good chance it is hitting boost cut mate, best bet is to get it on a dyno and check the AFR's and see what the boost is really doing - try not to give it a big bootful just incase its leaning out

From memory 9PSI is the cut out for a standard ecu car...when I had wastegate issues mine would go much harder down low but as soon as the revs built up it would just cut out and and go into limp mode...we hooked up a boost gauge to it and we noticed as soon as it held more than 9PSI of boost it would cut out...so it is very likely you sre hitting this cut out

I have an 04 xr6t I did a pod filter and hybrid cooler all seamed fine but when I fitted the xr8 bonnet I changed the piping and got rid of the crossover and now it hits whatfeels like a soft rev cut is this boost cut I'm feeling the boost gauge appears to hit near 9 psi before it does this and yes it has new correctly gapped plugs

Can be a few things. But most likely the PCM going open loop. The closed loop control has an overboost threshhold of ~2.25psi. If it hits this then the PCM will supply full pressure to the actuator and the gate will open.

hey guys this may have already been covered but I just gonna ask anyway.

I have a 03 BA XR6 Turbo ute. Now it has a NA motor with the turbo gear bolted on etc. (last owner managed to blow up motor from bad tune and wastegate actuator)

Anyway I got it retuned the otherday by LMG at warnertown SA.

the dyno readout got a max of 258rwkw at 13psi. he couldnt push more as the valve springs were starting to float at higher boost. so anyway I was happy with that. he also gave me a 250rwkw tune at 12 psi and a SAFE tune at around 8psi which also had timing backed off so was close to stock.

the car has a massive aftermarket intercooler. and dosent have the top crossover pipe anymore so am assuming the wastegate would have to have modifications. also it has 40lb injectors.

anyway yesterday I started to notice it overboosting.

so I changed to the 250rwkw tune. same deal.,

so I changed to the SAFE tune. (the one almost stock one) and it was making 10-12 psi max.

so im obviously having overboosting problems.

something to do with wastegate im guessing.

anyway anyone have any ideas as to what I should do?

might be worth spraying your boost control solenoid with INOX or wd-40, perhaps its just a bit gummy?

can you reach the actuator itself (from under the car) and check its movement also?