Bypass sound on ASA

[668Ci]

I remember when I first put on the s/c the bypass sound used to be really loud. Everytime I depressed the accelerator, I could hear a loud pshhhhh....sound and that was in most gears after 3000 rpm. Well, the sound is not loud at all now, and i was wondering if any of you ASA folks are experiencing the same thing. I tried switching to 710 n bypass valves, but not much difference...Could replacing some of the hose do the trick? I have no leaks by the way as my gauge reads 6.5 psi at WOT.

[vids_blk323Ci]

how old is your kit?

[668Ci]

40k old. However, the sound became quieter after about ~9000k.

[MachRc]

how come you get only 6.5 on a tx-2 kit? From the intercooler it seems like you have the same kit as I do, is it an infinitas kit? .

Anywayz the bypass "Pssssst" sound on my car is about the same if not louder now that I've had it more than 10k. I know 150 bux or so is expensive for a bypass valve but the hyperboost valve I have have been pretty amazing in making that sound(I never heard the bypass valve the kit came with). I get 6.5 at WOT until 5500rpm or so when it starts rising up to 8.5. I've actually maxxed it at 9.5 but I yeah..

[HighBoostin330]

how come you get only 6.5 on a tx-2 kit? From the intercooler it seems like you have the same kit as I do, is it an infinitas kit? .

Anywayz the bypass "Pssssst" sound on my car is about the same if not louder now that I've had it more than 10k. I know 150 bux or so is expensive for a bypass valve but the hyperboost valve I have have been pretty amazing in making that sound(I never heard the bypass valve the kit came with). I get 6.5 at WOT until 5500rpm or so when it starts rising up to 8.5. I've actually maxxed it at 9.5 but I yeah..

Rich has a Technik Supercharger Kit - not an ESS kit. Yes, $150 is expensive for a Hyperboost HX Diverter Valve - however, it has metal interiors whereas the Bosch has a rubber interior.

Rich, my bypass valve continues to be heard clearly - however, I have swapped to the Hyperboost Diverter Valve. I don't think it is an issue since you still hit 6.5psi at redline. What has Samir/Zolti said about this issue?

[668Ci]

I haven't asked them. Maybe they can chime it and help. Also, I don't think the issue is with the valve per se as they are fairly new.

[HighBoostin330]

I haven't asked them. Maybe they can chime it and help. Also, I don't think the issue is with the valve per se as they are fairly new.

That's true. Maybe you have just grown acustom to the sound already. :P I hope you figure this out.

[xmltok]

I had the bosch and i put on the hyperboost, i didnt notice any difference in sound or power..

[HighBoostin330]

I had the bosch and i put on the hyperboost, i didnt notice any difference in sound or power..

The difference in power is more noticeable when you move from the Bosch 710C to the 710N or the Hyperboost HX. If you are moving from the Bosch 710N to the Hyperboost HX, you will not notice much of a difference in power - eventhough the internals of the bypass have changed.

[Mr Paddle.Shift]

Clean out the boost-side lines, ie all pipings after the SC right up to the TB. Clean out the bypass lines as well. Oil vapor tends to condensate and form oily film on the interior of these lines. Clean the bypass valves too.

The other thing is to check the valves, which I doubt are faulty. The Bosch 710N has survived all my track events and is more than enough for our low boost application. But if you must, remove the valve, push the spring and plug the vacuum end. If the spring pushes back, that means the rubber seal is bad, otherwise the valve is good.


I remember when I first put on the s/c the bypass sound used to be really loud. Everytime I depressed the accelerator, I could hear a loud pshhhhh....sound and that was in most gears after 3000 rpm. Well, the sound is not loud at all now, and i was wondering if any of you ASA folks are experiencing the same thing. I tried switching to 710 n bypass valves, but not much difference...Could replacing some of the hose do the trick? I have no leaks by the way as my gauge reads 6.5 psi at WOT.

[668Ci]

Thanks! I'll try that.:pimpin: