Underbosting :(

[Sefton-EP91]

My car has Been ok and now it's starting to drop boost. The car is running standard ct9 turbo at 0.8 bar but just recently it only making 0.6 bar max. It's got a stock actuator on it. Any ideas?

[Liam_D]

Could possibly have a boost leak dude.

CT9 Standard actuators have a really weak diaphram too so it could also be that. Think you would be loosing more boost than that if that was the problem though.

Edited September 17, 2012 by Liam_D

[Sefton-EP91]

What's the standard boost pressure? 0.8 bar? I'll check the pipes.

[Liam_D]

Yeah believe standard 'hi-boost' is 0.8bar dude.

[Sefton-EP91]

I'll have a check over the pipes. Is there anyway of knowing that the actuator is knakered?

[klyfax]

Low boost, 0.4 bar, high boost, 0.6 bar.

Have you changed anything? What are the mods on it?

[Sefton-EP91]

Just had a look, I didn't even know. The car has a boost controller, it also has a crack in the manifold which is possibly much reason for unboost, would that be possible?

[Starlet-Matt]

Yeh,

Should be the manifold that is causing the problem then really..

[Sefton-EP91]

Low boost, 0.4 bar, high boost, 0.6 bar.

Have you changed anything? What are the mods on it?

Fmic, fuel pressure regulator. Hks ssqv bov, the car has a manual boost controller but I don't know if it Is linked up properly. AC removal, air filter relocation. That's all the engine mods.

[Sefton-EP91]

Ok then looks like my list is gettin bigger for new things to get the car running to top spec

[Sefton-EP91]

Could this be the reason as why it's running abit lumpy? Misfires abit as well?

Edited September 17, 2012 by Sefton-EP91

[Liam_D]

Cracked manifold will cause it to underboost dude so either get that repaired or get a new one purchased.

Doubt it would cause it to run lumpy or misfire unless you have a huge hole in it.

[Sefton-EP91]

Thank you guys for all the help looks like a new mani on order then, any suggestions as to which ones? I like the race tech ones but abit out of my price range tbh.

[StuDoc 72]

Just get whatever is in your budget other than cheap ebay stainless ones unless you can get one thats got a few extra braces on it. Also helps to have a braced de cat takes alot of wieght off the mani.

[funny onion]

My standard actuator was buggered and my standard manifold ha a MASSIVE hole in it. I was only getting about half a bar of boost until I swapped to my external wastegate wepr manifold then it boosted a happy 0.8 (until I whacked it up to a bar). So I'd Say sort a manifold out, then actuator if you're still under boosting. I'm in the process of going vf28 so you could've bought my wepr manifold for cheaps but I think a friend is having it, if not I'll pm you!

[Broony]

i have a wepr tdo04 manifold and i would highly recommend them!! mild steel with stainless welds !! like above fix the manifold and you might aswell do the actuator while your on as it will be about 15 years old anyway so best off doing it while manifolds off, as for lumpyness get the timing checked, spark plus leads etc.

[Sefton-EP91]

Thank you guys for all the help and yeh if your friend doesn't have the manifold then I would highly appreciate it of you would pm me I will change the actuator aswell whilst I have the manifold off. Do you recommend HKS actuator?

[Broony]

they are very good and adjustable

[Sefton-EP91]

Thanks