Restrictor Ring / BC

Just out of interest, with double de-cat, can you have a Boost Controller fitted with no restrictor ring?

Just out of interest, with double de-cat, can you have a Boost Controller fitted with no restrictor ring?

Boost controllers can only raise boost, not lower it.

Boost controllers can only raise boost, not lower it.

Perfect answer mate! Ta!

Just out of interest, with double de-cat, can you have a Boost Controller fitted with no restrictor ring?

Yes but really they are two separate entities. The restrictor ring is to stop the car from over boosting (spiking) higher than you would like. The BC is to raise the boost from the level which the restrictor ring is holding.

Just to throw the cat amonst the pigeons, I am still to be convinced that a restrictor ring works properly as my experience in the past shows that the boost used to spike way higher than the restrictor ring should have allowed it to.

Just to throw the cat amonst the pigeons, I am still to be convinced that a restrictor ring works properly as my experience in the past shows that the boost used to spike way higher than the restrictor ring should have allowed it to.

I know what you mean mate, my experiance would say that a RR seems to be too constant, it works fine at lower speeds, but when your in 3rd / 4th (auto) and the revs are higher for longer and th cars under more load, boost seems to raise way past the limit of the RR.

For example, my RR is a 1.2 bar, but when im at 120+ leptons it raises higher, ive seen over 1.4 bar at 160+ leptons, but i do have hybrids so its not as bigger a deal as it would be with stocks T's.

What are the alternatives to RR's then if your double de-cat CJ?

Ta

Matt

I am still to be convinced that a restrictor ring works properly as my experience in the past shows that the boost used to spike way higher than the restrictor ring should have allowed it to.

The boost that a restrictor plate will allow is purely guessed at. And the boost level for any particular restrictor plate aperture will vary from car to car and also with atmospheric conditions.

There is no such thing as a (say) 1.2 bar restrictor ring that will always hold boost steady at that level. It's just a crude device for limiting flow.

my RR is a 1.2 bar

See above.

What are the alternatives to RR's then if your double de-cat CJ?

In my experience, it didn't work as expected. By that I mean that the ring purchased was supposed to be to keep the boost at 1.2 bar and yet, when I changed to TTC, it went up as far as 1.5 bar.

Now, if an item is sold as a "restrictor" to stop boost spike above a certain level then I expected it to do that but it didn't - hence my comment regarding I am yet to be convinced.

Or am I being obtuse?

In my experience, it didn't work as expected. By that I mean that the ring purchased was supposed to be to keep the boost at 1.2 bar and yet, when I changed to TTC, it went up as far as 1.5 bar.

 

Now, if an item is sold as a "restrictor" to stop boost spike above a certain level then I expected it to do that but it didn't - hence my comment regarding I am yet to be convinced.

 

Or am I being obtuse?

Thats fair comment mate

The only thing that could truly restrict the boost to a setpoint would be a valve in the exhaust downpipe that varies according to the boost pressure.... i.e. the EGCV

TBH I'm surprised that no one has made the EGCV work in this way to limit boost pressure on de-catted J specs as the equipment is already in plave, all thats needed is a controller.

In my experience, it didn't work as expected. By that I mean that the ring purchased was supposed to be to keep the boost at 1.2 bar and yet, when I changed to TTC, it went up as far as 1.5 bar.

 

Now, if an item is sold as a "restrictor" to stop boost spike above a certain level then I expected it to do that but it didn't - hence my comment regarding I am yet to be convinced.

 

Or am I being obtuse?

Good point, i may as well put my restrictor ring in the bin!

Restrictor rings can keep you from over boosting to a certain boost level, but it can not vary boost according to engine RPM and load, it is not a boost regulator.

So what you find is that you may boost to 1.1 in second gear and 1.2 in third and upto 1.4 in sixth.

I'm one of the lucky ones, as my J spec is fully decatted and does'nt over boost and thus i use a Blitz ID3 to control my boost.

The only way round it, is to get a 0.9-1.0 Bar ring (i.e the max boost you see is 1.1-1.2 ish) and to then use a B/C to maintain desired boost levels.

Or single Decat.

Restrictor rings can keep you from over boosting to a certain boost level, but it can not vary boost according to engine RPM and load, it is not a boost regulator.

 

So what you find is that you may boost to 1.1 in second gear and 1.2 in third and upto 1.4 in sixth.

 

I'm one of the lucky ones, as my J spec is fully decatted and does'nt over boost and thus i use a Blitz ID3 to control my boost.

 

The only way round it, is to get a 0.9-1.0 Bar ring (i.e the max boost you see is 1.1-1.2 ish) and to then use a B/C to maintain desired boost levels.

 

Or single Decat.

That doesn't make sense to me at all.

People buy a restrictor ring to stop the car from overboosting / boost creep when they decat. The ring they buy is supposed to be set for (as an example) 1.1 bar. It isn't purchased on the understanding that the car could boost higher at certain gears because, if it was, what would be the point of fitting it?

I was always led to believe that the ring held the boost at a given level and that a BC was then fitted to increase the boost to the desired level.

My restrictor ring always worked for me, without it in the boost spiking was ludicrous. It was also pretty spot on for 1.2bar.

Going TTC is prone to causing boost spikes anyway, if you were taking your reading off a peak hold figure then you'll find it would have spiked as the turbos came online and then dropped down to more reasonable levels.

Also, higher gears = higher load = more boost production. I've got tweaks in my boost controller to lower the solenoid duty cycle as the gear I'm in gets higher. So a mechanical device like a restrictor ring is susceptible to this fluctuation, as are bleed valves. However if it's sized for restricting boost in the higher gears, like 4th or 5th, it'll stop high load creep. You can compensate for not hitting target boost in lower gears with a boost controller.

-Ian

That doesn't make sense to me at all.

 

People buy a restrictor ring to stop the car from overboosting / boost creep when they decat. The ring they buy is supposed to be set for (as an example) 1.1 bar. It isn't purchased on the understanding that the car could boost higher at certain gears because, if it was, what would be the point of fitting it?

 

I was always led to believe that the ring held the boost at a given level and that a BC was then fitted to increase the boost to the desired level.

I see what you mean, i guess their should some sort of clause stating that,

But what people also need to understand is that with ambient temps getting colder and with higher engine loads i.e higher gears, the boost will increase more so than in lower gears.

Even the Blittz ID3 cant iron out this problem unless you have speed maps activated (Boost maintained regardless of engine load).