RR size

[JasonR24]

No idea just that it's supposed to be a 1.2 bar RR? Maybe it's a 1 bar and that's why it doesn't hit fuel cut.

[ScottC]

Ok so I've got a 1.2 bar restrictor ring in place on my VVTI. Why doesn't it try boosting to 1.2 bar and then hit fuel cut at 1 bar? I'm totally confused

 

Sounds like you are having a similar problem to me. After putting the sequential system in TTC mode it immediately boosted to 1.2 bar and highlighted a problem with the VSV's. Installing a boost gauge would help in diagnosing the problem quicker.

[Nic]

No idea just that it's supposed to be a 1.2 bar RR? Maybe it's a 1 bar and that's why it doesn't hit fuel cut.

 

There isn't such a thing as a 1.2bar restrictor ring, a restrictor ring with a certain size hole in it may make 1.2bar on one car and only 1bar on a different car, depending on how free flowing the exhaust systems are. A 4" exhaust with a single silencer will be less restrictive than a 3" exhaust with 2 silencers, some cat back exhausts follow the path of the stock exhaust under the car, others follow almost a straight line from the 2nd decat to the bumper.

 

Peak boost pressure also varies depending on what gear you are in, in 1st and 2nd gear you may only see 1bar but in higher gears when the engine is under more load you will see higher boost pressures.

 

If you are not making the boost pressure you want, then you could either increase the size of the hole in the RR (which will make it less restrictive), or you could fit a boost controller and up the boost that way.