overboosting

[Bry]

Recently I've noticed my car boosting alot higher than it normaly does,i've got a Blitz sbc id 2 boost controller which has 4 settings and even on the lowest setting I'm still overboosting.I know the cold weather will cause the car to boost higher but I never had this problem last winter and the only things different this year are an spl i/c and last month I had a Cusco flywheel fitted.The main problem I'm having is when the revs get to around 5k the boost starts to rise pretty much in time with the revs,so by the time I'm at 7k the boost is at 1.25bar.Up until 5k the boost will stay at what I've set it at e.g 1bar, then after 5k whoosh up it goes with the revs.Until now the boost has been consistent,what ever boost I have the contoller set on the car will hit that boost and hold it till the red line,so I'm a bit confused that it's started to overboost,the only thing that's changed recently is the Cusco flywheel and the overboosting has only started since that was fitted,but can't think how the flywheel could cause it to overboost.I'd greatly appreciate any suggestions as to what the problem might be,as I haven't got a Scooby
Cheers
Bry

[Graeme Shaw]

Mmm
My car still boosts to 1.1bar even with the avcr set to off!
Like you though it builds gradually and by 6,000rpm im at full boost.

I cant seem to limit it!
I have tried to set as low as it will go, and you can almost see and feel the car try to hold the boost as best as it can up untill abot 5,000rpm.

Graeme

[BenF]

Recently I've noticed my car boosting alot higher than it normaly does,i've got a Blitz sbc id 2 boost controller which has 4 settings and even on the lowest setting I'm still overboosting.I know the cold weather will cause the car to boost higher but I never had this problem last winter and the only things different this year are an spl i/c and last month I had a Cusco flywheel fitted.The main problem I'm having is when the revs get to around 5k the boost starts to rise pretty much in time with the revs,so by the time I'm at 7k the boost is at 1.25bar.Up until 5k the boost will stay at what I've set it at e.g 1bar, then after 5k whoosh up it goes with the revs.Until now the boost has been consistent,what ever boost I have the contoller set on the car will hit that boost and hold it till the red line,so I'm a bit confused that it's started to overboost,the only thing that's changed recently is the Cusco flywheel and the overboosting has only started since that was fitted,but can't think how the flywheel could cause it to overboost.I'd greatly appreciate any suggestions as to what the problem might be,as I haven't got a Scooby
Cheers
Bry

Bry, you tried turning the boost controller completely off and seeing what happens to the boost?

What you're decriving sounds like classic boost creep to me - you usually only get this with Hybrid turbos though.

[The Morris]

Great, im glad its not just me
I get 8 psi until 4000rpm amd then it creeps up to 15psi at 4500rpm. This happened after i changed the bleed valve for a grainger valve and put a new downpipe on. This is with the valve set to minimum.. but it doesnt go over 16 psi so im quite happy.

[Bry]

I've come to the conclusion that it is the cold weather that's one of the main reasons why it starts overboosting as when the weather warms up a few degrees it all seems ok.I don't know the mechanical reasons for why it should happen and as I said in my original post I never had this problem last year. The mods I've aded since last winter are,Departure 2 pro exhaust,SPL i/c,Cusco flywheel maybe somehow these mods combined with the cold weather cause my car to overboost?I have the Blitz sbc id 2 boost controller and as far as I know there's no off button,so I just turned the boost all the way down and what happens is I make waste gate boost pressure up until about 5k then the boost starts to rise again in time with the revs

[KiwiMR2]

Hmmm...still doesn't sound right. I would have expected a decent ebc like yours to be able to control it, overboosting due to cold weather is something I would expect to see from a mbc. Same thing happened with me when I had an ebc but even on the coldest nights my profec be will hold it to what I have set it to. When It's switched OFF I get the lowest possible setting of 7 psi. You sure there isn't something wrong with your ebc?

Cheers
KiwiMR2

[Bry]

Hmmm...still doesn't sound right. I would have expected a decent ebc like yours to be able to control it, overboosting due to cold weather is something I would expect to see from a mbc. Same thing happened with me when I had an ebc but even on the coldest nights my profec be will hold it to what I have set it to. When It's switched OFF I get the lowest possible setting of 7 psi. You sure there isn't something wrong with your ebc?

Cheers
KiwiMR2

It is possible that there's something wrong with the boost controller(it's only 2 years old though) however,I cannot find an off button and I've read the instructions and there doesn't seem to be one,so I suppose I'll have to disconnect the ebc and reconnect the vsv and pipework and then plumb in a boost guage and see if all is well,if it is, then its got to be down to the ebc
cheers for the advice
Bry

[Bry]

But before I do that I think I'll see if I can try my good friend John Rees's Boost solonoid (we've got the same ebc)in my car and see if it solves the problem