slim_boy_fat

Well a mystery solved. After installing my Accuboost & Guru chips et al i was getting some funny reading on my Boost gauge.

I turned the Accuboost down further and further but the boost was not really going down and would occasionally spike up to 18+psi.

I had almost unscrewed the Accoboost totally and was still getting 15psi.

Today got a deCAT and new back box(look fab BTW) and also bypass the CV while i was at it.

Wow, without touching the Accuboost the boost gauge read 5psi, yes 5!!!
3turns of the Accuboost to get it up to 12psi and then i could fine tune to get up to 18.

Wow what a difference, the Accuboost now works!!

Not sure if the problem wsa that my CV is knackered or if everyones is like this BUT

Its a 10min job, you Must by-pass that CV if you want accurate boost control....

All you have to do is use some 6mm fuel pipe to connect wastegate to accuboost(or whatever) and plug the hose to the intake with a bolt and clip
I have just tied up the other pipes.

BTW i think 18psi is too much, wheel spin in 3rd gear at 60mph!!! And that in the dry!!!

Sam Lin

Yes, to use any other form of boost control you need to bypass the CV.

Sam

BoostSciences

A faulty CV inline with a boost controller will cause problems, however a working CV will work fine with a boost controller in series (this does not mean boost control is super accurate, but it will behave normally). Glad to hear you got the gremlins out.

Regards

Aleks951

At the risk of sounding uninformed, what does "CV" stand for? Sorry but I'm still new to this.

slim_boy_fat

Its the "cycling valve" its used by porsche to regulate the boost, any more than 2.0bar (or whatever) and the valve diverts the boost.

Its not used on the Guru chips so there is no point in connecting to it. The boost controler does all the controling you need. Its very easy to bypass.

Aleks951

Ah, thanks for the info. I learn something new every day on Rennlist.

Jake951

I also bypassed my CV for the same reason. I overboosted if it was left in. I know other people have found the same thing. The CV reduces the amount of pressure fed back to the wastegate, which raises the boost level compared to bypassing the CV.

slim_boy_fat

I agree totally, i really think that it should state when you buy these product that you MUST by-pass the CV, especially when it is really a very simple thing to do, and even more especially when you are fitting other chips that dont even use the CV anyway!!!