I bought (second hand) a set of Sequential HKS BOV with hard pipes for 90 quid.

 

Thats the older version of HKS not the Super Sequential.

 

Anyway...I spend few hours installing them and now my boost doesnt go over 8.5 to 9 PSI.

 

What happen is this.

 

1st attempt:

Install HKS BOV without removing stock recurculation valves. So now I have 4 BOV. Boost goes fine as much as I want.

Problem: BOV does not sound good because of the stock recurculation valves.

 

2nd attempt

I remove the vacuum from rec.valves and i used it for HKS ones. This means that I have cancelled the stock ones...Right?

Problem: Boost does not go over 8.5-9 PSI.

 

Why is this....? Do i have to remove the stock ones completely?

Or am i doing something wrong?

If you had all 4 working at one point, presumably you had vacuum going to all 4. If you're now using the vacuum feed from the stocks to go to the new ones, what has happened the the feed which was previously on the new ones ?

 

If they're now disconnected, you'll have a vacuum leak which will be causing your problem. Having said that, it's probably a bit too obvious ! However, a leak is the most likely scenario.

Originally posted by Hairsy

If you had all 4 working at one point, presumably you had vacuum going to all 4. If you're now using the vacuum feed from the stocks to go to the new ones, what has happened the the feed which was previously on the new ones ?

 

If they're now disconnected, you'll have a vacuum leak which will be causing your problem. Having said that, it's probably a bit too obvious ! However, a leak is the most likely scenario.

 

I have put the vacuum from my first attempt back to its place. So there is no leak from that.

try an ecu diagnostic, there is an error for a boost leak. I had one after fitting hard pipes.

 

Vijay

Whats the maximum boost HKS sequential valves (not Super Sequential) can handle?

 

Mechanic told me that they cannot handle more boost?

What the hell.....Only 9PSI of boost?

Hi NitroPower,

 

Have seen this problem before, reason you are loosing boost pressure with the recirc vacuum line disconnected is without the pipe connected they open slightly (not sure why) and cause a leak back into before the turbo`s, the only way to overcome this is to remove them and then blank off the pipes.

 

However with the recircs removed and running high boost with the HKS bov`s in place a flutter at high speeds (100mph+) when suddenly closing the throttle can occur,I would imagine the stock recirc`s sort of smooth this out because the measured air is not actually lost like the HKS bov`s.Hope that help`s.

 

Jeff TT

I believe the HKS BOV's (which I have too) have no upper rating - since they're better than what any turbo will push out. i.e. 50psi+

 

I'm running 16psi - no probs. I reckon you're are fine, and the problem lies with the standard valves....

 

(padding Jeff's thoughts out here..)

 

See, with the standard recircs in place, i believe the boost might be opening the valves - since you've got no boost being fed down the vacuum line (when on boost obviously) - which would normally equalise the pressure and stop them from opening. Try plugging the vacuum feed instead - bit of tube with a screw in the top.

 

Hmm..... good luck

Originally posted by WillyEd

I believe the HKS BOV's (which I have too) have no upper rating - since they're better than what any turbo will push out. i.e. 50psi+

 

I'm running 16psi - no probs. I reckon you're are fine, and the problem lies with the standard valves....

 

(padding Jeff's thoughts out here..)

 

See, with the standard recircs in place, i believe the boost might be opening the valves - since you've got no boost being fed down the vacuum line (when on boost obviously) - which would normally equalise the pressure and stop them from opening. Try plugging the vacuum feed instead - bit of tube with a screw in the top.

 

Hmm..... good luck

 

So one option is to remove them completely.

 

Another one is to block the vacuum feed of the stock rec.valves? Is that the small metal pipe of the stock rec.valves that the vacuum goes in?

 

Which HKS you have? The Super Sequential or the Sequential ones?

So one option is to remove them completely.

 

....This what I done, not too much grief - but then I did have the rad and condensor out at the time

 

Another one is to block the vacuum feed of the stock rec.valves? Is that the small metal pipe of the stock rec.valves that the vacuum goes in?

 

....Yep.

 

Which HKS you have? The Super Sequential or the Sequential ones?

 

I have the Super sequencial BOV's (2 stage valve). Big n shiney polished aluminium.

 

Cheers

I have jsut purchased second hand hks bov with the hard pipes for my 1991 import. I cannot workout which way around they are supposed to face ! Does anyone have a pic of them installed as this would make it very easy for me ?

 

Thanks a lot.

 

Olly.