[Mk2] [Turbo] Will compressor surge be the death of my ceramic CT20

[SrSilkie]

Hi guys,

Just installed a Phoenix Power Intercooler and it came with a Greddy Type R Bov, Im experiencing alot of chatter and im reluctant to give it full boost purely because im worried it will damage the turbo.

Anyone ran no bov on a ceramic turbo before?

As essentially thats what im doing because the bov wont open.

[bobhatton]

Hi guys,

Just installed a Phoenix Power Intercooler and it came with a Greddy Type R Bov, Im experiencing alot of chatter and im reluctant to give it full boost purely because im worried it will damage the turbo.

Anyone ran no bov on a ceramic turbo before?

As essentially thats what im doing because the bov wont open.

The CT20 is not a strong turbo, the shaft is smaller than CT26.

The type R is a racing bov for higher pressures so may not be the best to use on a road car.
I would go back to a stock BOV and sell the type R, in fact I am after a second one if you do want to get rid of it.

[SrSilkie]

The CT20 is not a strong turbo, the shaft is smaller than CT26.

The type R is a racing bov for higher pressures so may not be the best to use on a road car.
I would go back to a stock BOV and sell the type R, in fact I am after a second one if you do want to get rid of it.

Yeah Ive read they have a stiffer spring as standard so not really what im after and would rather not add excess stress to an old turbo.

The Phoenix Power Intercoolers flange is specifically for a Greddy BOV so I will have to either get myself another Greddy (type s or similar) or sort myself out with some adapters for an ssqv.

Either way Id be willing to consider selling my Type R, perhaps give me a pm at somepoint and we could try work something out

[jimGTS]

It is doing it at full boost? Or just at light loads and low boost?

Low boost and revs not a problem.

Sure you cant adjust it so it vents at full boost? It is adjustable.

Many many on the US forums have adopted to running no bov on the ct26 and ct20 with no problems reported.
All report positive boost response.
I ran no bov for 15k of hard miles on my old car (granted not a ct20), at 1.4bar with no negatives, only positives.
Though it takes a lot to convince people!

It's on boost surge you want to be worried about, not off boost 'flutter' which is what you have.

Whether you choose to get a type s for peace of mind is your choice.

[SrSilkie]

It is doing it at full boost? Or just at light loads and low boost?

Low boost and revs not a problem.

Sure you cant adjust it so it vents at full boost? It is adjustable.

Many many on the US forums have adopted to running no bov on the ct26 and ct20 with no problems reported.
All report positive boost response.
I ran no bov for 15k of hard miles on my old car (granted not a ct20), at 1.4bar with no negatives, only positives.
Though it takes a lot to convince people!

It's on boost surge you want to be worried about, not off boost 'flutter' which is what you have.

Whether you choose to get a type s for peace of mind is your choice.

I have now adjusted the screw and it does open but I still find it will chatter at very low boost.

On say half boost it will mostly blow off with a small amount of chatter just before the valve opens.

When on full boost I cant hear any chatter but couldn't positively say there isnt some pressure going back through the turbo just before the valve opens.

Peter states here http://www.imoc.co.uk/forums/viewtopic.php?t=176063 thats usdm ct20s were steel shafted, maybe thats why they hold up fine. However the previous owner of this bov said he ran this and also no bov on his ct20 and it held up fine but once I get a fear in my head I find it hard to shake.

If it was a steel turbo I wouldn't be worried about chatter in the slightest.

Can you briefly fill me in on what on boost surge is and why it occurs??

[mrturbotom]

It is doing it at full boost? Or just at light loads and low boost?

Low boost and revs not a problem.

Sure you cant adjust it so it vents at full boost? It is adjustable.

Many many on the US forums have adopted to running no bov on the ct26 and ct20 with no problems reported.
All report positive boost response.
I ran no bov for 15k of hard miles on my old car (granted not a ct20), at 1.4bar with no negatives, only positives.
Though it takes a lot to convince people!

It's on boost surge you want to be worried about, not off boost 'flutter' which is what you have.

Whether you choose to get a type s for peace of mind is your choice.

Usdm cars aren't ceramic turbos

[Adam86]

I've run my CT20 without a bov for around 8k including track time. Although it is a hybrid with a steel shaft.

[jimGTS]

Whilst maybe the case usdm have steel shaft ct26, the ct20b wasn't available, so any ct20b they run will be ceramic. I'd imagine more people over there are running the 20b than the 26, and in turn no bov.

Wouldn't take a lot of digging to find the 'no bov' thread over there to see who's running what.

[Odin_S]

I have exactly the same set up as the OP. All you need to do is adjust the bov. I've ran my ct20b like this since '08.

No chatter once adjusted correctly. Only changing the turbo now for more power.
My turbo is healthy on 70k ( granted I do change the oill religiously)